Gigantic Air Gun To Blast Cargo Into Orbit

Hugh Pickens writes: "The New Scientist reports that with a hat tip to Jules Verne's From the Earth to the Moon , physicist John Hunter has outlined the design of a gigantic gun that could slash the cost of putting cargo into orbit. At the Space Investment Summit in Boston last week, Hunter described the design for a 1.1-kilometer-long gun that he says could launch 450-kilogram payloads at 6 kilometers per second. A small rocket engine would then boost the projectile into low-Earth orbit. The gun would cost $500 million to build, says Hunter, but individual launch costs would be lower than current methods. 'We think it's at least a factor of 10 cheaper than anything else,' Hunter says. The gun is based on the SHARP (Super High Altitude Research Project) light gas gun Hunter helped to build in the 1990s while at the Lawrence Livermore National Laboratory (LLNL) in California. With a barrel 47 meters long, it used compressed hydrogen gas to fire projectiles weighing a few kilograms at speeds of up to 3 kilometers per second."

Comments

Pumpkins

[trip11]

The real question on all of our minds though: "How far will it launch a pumpkin?"

Re:Pumpkins

[kryptKnight]

For those who don't know, the OP is referring to pumpkin chunking. It's a competition to see whose machine can throw a pumpkin the farthest. There are separate categories for catapults, trebuchets and cannons, and there are annual competitions and championships all over the world.

Re:Pumpkins

[Beardo the Bearded]

Into orbit. RTFH before posting. ;)

Re:Pumpkins

[Anonymous Coward]

what's the difference between a catapult and a trebuchet? if you exerted all the energy required to carry an object to orbit all at once ala a cannon wouldn't you just destroy the object?

Re:Pumpkins

[Anonymous Coward]

A catapult uses a spring of some sort.

A trebuchet uses a falling weight.

The idea of the long barreled cannon is that it can spread out the acceleration of the object over its travel down the length of the barrel, rather than relying on a short rapid acceleration that would be likely to cause damage.

Re:Pumpkins

[Anonymous Coward]

So true, yet so poorly moderated....

Re:Pumpkins

[Anonymous Coward]

Into orbit. RTFH before posting. ;)

Not into orbit. At least, not unless there's a rocket attached to the pumpkin. You may want to RTFS before suggesting someone's question would be answered by RTFH-ing. ;)

Re:Pumpkins

[Sillygates]

Actually:
http://digg.com/odd_stuff/Huge_Cannon_Fires_Pumpkins_at_600_MPH_VIDEO

It hit the top of digg yesterday ;-) .

Re:Pumpkins

[RichardJenkins]

Sounds like they'll have to start a new category for half billion dollar space guns.

Re:Pumpkins

[martin-boundary]

Personally, I just hope they never try to launch a butterfly. One wrong flap and KAPOW... two new hurricanes in Florida!

Re:Pumpkins

[RealGrouchy]

With or without the rocket booster engine?

- RG>

Re:Pumpkins

[MagusSlurpy]

Fuck pumpkins. I'm buying a bunch of capes and then stopping by the animal shelter on my way there!

Re:Pumpkins

[santiagodraco]

Who cares as this is neither. It's a cannon.

Re:Pumpkins

[Hognoxious]

If I remember my SUVAT equations correctly, a = (V**2)/2s. That comes out around 1600 g. I'd advise strong pants.

Re:Pumpkins

[Ukab the Great]

An African or a European pumpkin?

Re:Pumpkins

[Anonymous Coward]

Pff. Only 600MPH? Even with the "prototype" gun, something with the weight of a pumpkin could hit upwards of 6700+ MPH. The full scale project would be several orders of magnitude more powerful, to boot.

Re:Pumpkins

[Dishevel]

Disturbing and Hilarious at the same time.

Re:Pumpkins

[gadget junkie]

A catapult uses a spring of some sort.

A trebuchet uses a falling weight.

The idea of the long barreled cannon is that it can spread out the acceleration of the object over its travel down the length of the barrel, rather than relying on a short rapid acceleration that would be likely to cause damage.

it is a bit more complicated. the trebuchet uses a falling weight, but it also uses a sling- like attachment, which makes it far more efficient. Moreover, it is more precise, since the structure does not have to stop the lever.
For more infirmation, see http://www.trebuchet.com/

G-forces ????

[Anonymous Coward]

Just wondering how they plan to address the problem of controlling the G-forces and prevent damages to the cargo.

The cannon idea was tried before ...... not a test single cargo survived the trip (or made it to orbit).

Re:G-forces ????

[RocketRocketship]

From the article, they acknowledged that this would be unsuitable for cargoes sensitive to high G-forces. They suggested that rocket fuel would be a suitable payload.

Re:G-forces ????

[Tx]

If you RTA (yes I know, not likely), you'll see that they acknowledge this issue, their intent is to use this for robust cargo only (rocket fuel is given as an example, not e.g. satellites or humans). They also state that ablative heatshields would be necessary to survive atmospheric transit, so wouldn't be a fully reusable vehicle either. Sounds like one for the back burner, as it isn't solving the current launch capability issues.

Re:G-forces ????

[2.7182]

Well I think at the Pumpkin Chunkin they use frozen pumpkins.

Re:G-forces ????

[Hojima]

Just a quick bit of physics review: 1)A=V/t 2)d=.5*A*t^2 now substituting, we get d=.5*(V/t)*t^2=.5*V*t. The distance of the cannon is 1.1, the final velocity is 6, thus the time is about .37s. This would imply an acceleration of about 1670G. So the acceleration due to gravity is essentially multiplied thousands of times. Ever watch DBZ? Yea, well even Goku had a tough time with 100x gravity. Don't see how it will work with anything but raw materials. Any structural entity would be reduced to a density stratum.

Re:G-forces ????

[Tumbleweed]

If you RTA (yes I know, not likely), you'll see that they acknowledge this issue, their intent is to use this for robust cargo only (rocket fuel is given as an example, not e.g. satellites or humans)

Send up consumables, for sure. Fuel, water, compressed air, freeze-dried food, etc. Even if just used for that, this is not a bad plan. There's no rule that says you have to use only ONE method to get stuff off-planet.

Re:G-forces ????

[Anonymous Coward]

This would imply an acceleration of about 1670G. So the acceleration due to gravity is essentially multiplied thousands of times.

In fact, I would wager that it is roughly 1670 times the acceleration due to gravity.

...even Goku had a tough time with 100x gravity.

Well, if Goku can't withstand it, what chance to we mere mortals have?

Re:G-forces ????

[riboch]

They probably hope to discover "inertia canceling."

I could not find it in the article, so:
What are the power requirements for such a mechanism?
Where will it be located?
What about ITAR issues?
Why not make it longer for smaller accelerations?

The concerns about the hypersonic regime of fluid flow should not be an issue if they fire from a mountain, there are a hand full of craft that can handle the plasma, although none accelerate like that at such a low altitude.

Aside, what happens to fuel (liquid and solid) under such high g-load? I can find no studies on it.

P.S. I am an Aerospace Engineer.

Re:G-forces ????

[Nyeerrmm]

Actually, the ability to cheaply fill fuel depots in orbit does a significant amount to reduce the problems associated with current launch technology. Consider Apollo. The massive Saturn V rocket was required because in addition to taking the CM, SM, and LM to orbit, it also had to take the fuel to get it from LEO to the moon -- fuel was the most significant fraction of the mass (2:1 or 3:1 if I remember correctly). Instead, if this had been available to move fuel to orbit on the cheap, you could have used a couple of Saturn IB rockets and rendezvoused in LEO with a freshly filled Earth departure stage. I wouldn't be surprised if it would have been able to cut the cost of Apollo in half. This could also allow a new moon mission architecture without the massive Ares V.

Remember, space missions are like exponential Russian nesting dolls. If you remove a layer (in my example, the EDS), you can reduce the initial launch mass drastically. This is why things like ISRU and various electric propulsion schemes are such hot topics, even though they don't help you get off the ground either.

Re:G-forces ????

[Anonymous Coward]

Next time just use v^2 = u^2 + 2 * a * s and you don't need to calculate the launch time first.

Re:G-forces ????

[w0mprat]

It's all about raw materials. Fuel. Water. Food. There are plenty of payload options would be useful even if you couldn't make a probe or satellitte withstand the G forces.

The importance this stuff will be lighten the load on a conventional launch vehicle elsewhere. Saving substantial ammount of money.

Re:G-forces ????

[sjames]

Actually, it solves a LOT of current issues. Maneuvering fuel, food, water, and medicines for example are quite durable under G-force. Those are a large part of what the ISS resupply missions are carrying. The Progress mission hardware isn't reusable either but is likely considerably more expensive than a solid booster with a dumb cargo capsule.

Re:G-forces ????

[Anonymous Coward]

Well.. if they can make a 1.1 km gun, why not make a 4km one and accelerate the cargo much more slowly at first?
That would cost more of course, but if you could "gently" (x 10g's) send something into orbit, you've got a winnar!

Re:G-forces ????

[fast turtle]

I've got one question. How much air are we moving to launch something?

My suspicion is something in the range or Cubic Kilometers per Second instead of CFM and if we're talking that much, what impact on our weather is there going to be with such a large fan running all the time?

What I'd suggest instead is use the tube and combine it with maglev. Allows much better control of the thrust (more accurate) and might remove the solid rocket booster stage for orbit. You also get income from the reactors excess power (when its not charging caps or launching something) and it helps reduce greenhouse gases.

Re:G-forces ????

[Anonymous Coward]

What are the power requirements for such a mechanism?

You can't break the laws of physics, no matter how much power you apply.

Why not make it longer for smaller accelerations?

Because the acceleration for 1.1km is 1670 g and scales like length^(-1) so you'd need it 200x longer to get down to still 8.35 g.

Aside, what happens to fuel (liquid and solid) under such high g-load? I can find no studies on it.

Why do you care, they're going to use "inertia canceling", right?

P.S. I am an Aerospace Engineer.

Make sure you don't work on anything other than fluid flow.

Re:G-forces ????

[kenwd0elq]

No matter what the original impulse power is, there MUST be some sort of propellant - like a rocket motor - that can be activated to modify the trajectory to achieve orbit. Without that, the cargo will impact the Earth.

Re:G-forces ????

[sjames]

It's not even 1 Km^2 total, even if the final pressure in the tube was 3000 atm. Certainly not enough to change the weather.

The beauty of the system is it's very simple which translates to inexpensive (for something of that scale anyway). The engine for orbit is based mostly on the need to take the most direct practical path out of the atmosphere rather than start out on an orbital trajectory.

I'm thinking it'll be a solid fuel engine to withstand the launch stresses and to be inexpensive and reliable.

The idea is to avoid costly precision. Just shoot it up there, track it's orbit and go get it. (yeah, not quite THAT simple...)

Re:G-forces ????

[Nefarious Wheel]

I, for one, welcome our new exponential Russian nesting doll spacecraft overlords.

It had to be said.

Re:G-forces ????

[osu-neko]

My suspicion is something in the range or Cubic Kilometers per Second instead of CFM and if we're talking that much, what impact on our weather is there going to be with such a large fan running all the time?

It would seem to me that it ought to be about equal to how much air we blow around behind the rockets we currently use. In both cases we're pumping huge amounts of energy out and into the atmosphere, at least for the first few minutes after launch. However, if this is a more efficient system (and that's the whole point, ain't it?), it should have less impact on the weather than our current rockets do.

Re:G-forces ????

[demachina]

> Maneuvering fuel, food....

It would be awesome for pancakes.... in fact it could make pancakes out of just about ANYTHING.

Re:G-forces ????

[Anonymous Coward]

Look at it this way: it's each shot is probably on the order of one billionths the amount of hot gasses produced in the US from the use of automobiles. In other words, one grain in a wheat field full of grain. No big deal.

Re:G-forces ????

[DerekLyons]

Actually, it solves a LOT of current issues. Maneuvering fuel, food, water, and medicines for example are quite durable under G-force.

But the containers holding those materials - aren't. So you'll need to considerably increase the structure containing and supporting them, which means your parasitic weight goes up (way up). (Them if you take those containers onboard the station, you make it heavier and increase the amount of reboost fuel required.) The electronics (for guiding and controlling the packages) and their power supplies will be a significant design problem because of the G forces. (Yes, I know they design packages 1/1000th the size to put inside artillery shells. Bigger packages mean bigger problems.) The RCS systems (for guiding and controlling the packages) will be a significant problem because of the G forces. Nothing in this package will be off the shelf or directly derivable from existing experience.
 
This all adds up to quite an expensive package.
 
Not to mention that the low launch costs he promises depend on handwaving away the overhead involved in servicing the debt of a half billion dollar of construction costs.

Re:G-forces ????

[texwtf]

What if the structural entity was immersed in a liquid? That might cancel out the "mashing" effect.

Re:G-forces ????

[edremy]

You'd be surprised what will survive insane accelerations. G-hardening electronics is a solved problem- witness the Army's Copperhead artillery shell. Looking at the speed and barrel length, Copperhead undergoes *much* higher acceleration- 6km/sec over 1100 meters vs. ~1km/sec in about 4 meters. Back when I was in Armor, the DOD was looking at active electronics on tank rounds, and those hit 1.5km/sec in about 3 meters.

You won't ride to orbit on this, but there's lots of stuff that doesn't have to worry about being pulped on launch.

Re:G-forces ????

[Anonymous Coward]

you can save the costly launch for what needs it, yes.
or you can lengthen the barrel and therefore lower the launch acceleration. as the cost of construction is small compared to the cost of rockets, it's still cheaper even if you have to double or tripple the build cost.

Re:G-forces ????

[wvmarle]

Don't see how it will work with anything but raw materials. Any structural entity would be reduced to a density stratum.

Well considering the vast majority of stuff we have to take with us when traveling falls under that (food, water, compressed air, fuel, clothes even) that should be no problem. Getting to LEO is the hard part (energetically), if you can launch the astronauts for a Mars mission to the ISS first, and separately shooting up the fuel and other supplies needed for the next stage using such a cannon, you will save a lot of cost. Assemble your interplanetary craft in orbit, stock up, and off you go. Sounds easier to me than launching from the Earth's surface with all you need in one go.

Re:G-forces ????

[sjames]

It's probably a lot less problem than you think it is so long as air spaces are avoided. Seal the food in vacuum bags and put them in the water. The high Gs only last for about 1/3 of a second and the "shell" is in a barrel that whole time, so it shouldn't be a problem to help support the sides with several hundred atmospheres of pressure.

The rcs would be the most difficult part, but given the amount of benefit, the development would be well worthwhile. Fortunately, it wouldn't have to actually operate under the high Gs, just survive them for 1/3 of a second.

As far as re-boosting, if it's that heavy, I would imagine they'll off-load the fuel, fill it with waste and send it away to re-enter and burn (much as they do with Progress missions), and then perform the re-boost.

Considering that a SINGLE shuttle launch costs half a billion, the cost of building the thing can be made up fairly quickly. Even at the 51 million dollar pricetag for a progress flight, it wouldn't take that many shots to recoup the costs of building.

I'm not saying we can skip the design phase and just start sticking pipes together. There are engineering problems to be worked out, but they are solvable problems without resorting to exotic tech that has never been tried before at any scale (like several of the shuttle systems were). Comparatively speaking, this one is fairly straightforward.

Re:G-forces ????

[dbIII]

What are the power requirements for such a mechanism?

Truckloads to compress all of that gas.

Why not make it longer for smaller accelerations?

The idea of these gas guns is to have them long enough to get things going at close to the wave speed of the gas. They are so simple that a "valve" is a thin sheet of steel with an X scribed on it to make sure it bursts in the right spot to supply the shock wave. You don't get gentle acceleration with such a device.
I'm no aerospace engineer (materials science and engineering turned computer wrangler) but it doesn't take one to play with these multi-stage gas guns. Of course designing the cutting edge ones to go fast on a low budget did involve leading aerospace engineers like Ray Stalker. Many smaller ones were designed pretty well the same way you would design a pressure vessel and a really big air rifle (not by me but I looked at the drawings). I used one to effectively explosive weld mixtures of metal power into solid objects. The physics is not tricky at all in the gas gun since you are dealing with single shock waves at known velocities in a single dimension (ie. up or down). We used an Apple ][ with an interface card to a couple of light sensors to measure the velocity of projectiles in the thing.

Re:G-forces ????

[DerekLyons]

I wrote a detailed reply - but it's simpler to say, you haven't a clue what you are nattering on about.
 
For example - the G's lasting only 1/3 of a second don't make the problem easier, they make it harder because now you're dealing with shock loads rather than straight G forces.
 
The cost of a Shuttle or Progress launch is roughly as relevant as the color of the shirt I'm wearing. What matters is whether or not you can deliver sufficient payloads annually to keep costs down
 
I never said it couldn't be done - I said I think it can't be done economically.

Re:G-forces ????

[jklovanc]

There are two issues with comparing artillery shells with this technology.

Scale.
Many technologies do not scale well. What may work with a 100lb projectile may not work with a 1000lb projectile. Materials react differently when scaled up.

Guidance.
The Copperhead is a ballistic and sometimes glide projectile with minor terminal correction to hit a target. It is basically fired in the direction of the target and when it senses the laser return corrects it's trajectory to hit the target.
The projectile with this technology would need much more thrust and guidance control to be able to change orbit and rendezvous with a spacecraft.

Re:G-forces ????

[zmollusc]

Mmmmmm.....pancakes!

Re:G-forces ????

[Anonymous Coward]

Copperhead undergoes *much* higher acceleration- 6km/sec over 1100 meters vs. ~1km/sec in about 4 meters.

For those who are vaguely curious about the maths, but couldn't be bothered, acceleration is (v^2)/(2*d). So:

Copperhead: (1000m/s)^2 / (8m) = 1.25e5 m/s = 12,500g
Orbital gun: (6000m/s)^2 / (2200m) = 1.6e4 m/s = 1,600g

So the acceleration is about an order of magnitude lower than that of a Copperhead round.

Re:G-forces ????

[karstux]

If all you want to do is have the payload achieve orbit, the thrust and guidance control is actually very simple. All you need is some sort of passive aerodynamic stabilization, to ensure that the craft maintains a constant prograde attitude. Then there would have to be a (solid-fuel) rocket motor, which is triggered by a timer as the craft reaches apoapsis (the highest point after launch, before it starts to drop again). If the thrust and burn duration of the rocket motor are correctly pre-determined (easy to do), you'll end up in a circular orbit.

Re:G-forces ????

[jklovanc]

Sure a gun/rocket can put something into orbit. How does one get the payload from that circular orbit to where it us actually needed? One would need much finer guidance and control to rendezvous with the IIS.

Re:G-forces ????

[MartinSchou]

The idea is to avoid costly precision. Just shoot it up there, track it's orbit and go get it. (yeah, not quite THAT simple...)

Well, just ensure that the container has a decent amount of fuel, engines and built in automatic guidance systems for the last bit.

Once you're in orbit, you can probably settle for small amounts of fuel to change your trajectory, especially if you don't need to have the payload in a specific place for say a year. If we're sending up supplies (food, water, medicine), all we really need to do is keep chucking the stuff up there.

Bonus points if you can make the containers attach to each other for stability.

Re:G-forces ????

[Anonymous Coward]

Forget G-forces, what kind of blastwave does such a cannon create??

Re:G-forces ????

[K. S. Kyosuke]

> Maneuvering fuel, food....

It would be awesome for pancakes.... in fact it could make pancakes out of just about ANYTHING.

Except of pancakes. If they sent the astronauts pancakes, it would make a horrible mess out of them.

Re:G-forces ????

[Ironsides]

You've never heard of Escape Velocity have you. If you get sufficient impulse, no further propellant is required.

Re:G-forces ????

[Ironsides]

How about a space tug? Send the payload into an orbit, even if it is elliptical and unstable, and have another craft meet up with it at some point. The craft never enters the atmosphere and is only used to ferry the payloads from the gun to the IIS or higher. You reduce weight and complexity in your payloads by having everything you'd need to reuse already in orbit.

Re:G-forces ????

[Anonymous Coward]

You're speaking of the HARP program perhaps... and Gerald Bull ('Wiki': mysteriously assassinated) who ran out of funding in Canada. Water, fuel and hard supplies would be unaffected by G-forces, and would prove to be cost effective.. something like this is do-able.

Re:G-forces ????

[bkr1_2k]

"Maneuvering fuel, food, water, and medicines for example are quite durable under G-force."

Have you ever seen what happens to an apple at 60 mph? I can't imagine what it would do at 6 km/s. Well, at least applesauce still tastes good.

Re:G-forces ????

[interploy]

If the tests never made it to orbit, how did they know it was the firing and not the landing that destroyed the cargo?

Re:G-forces ????

[becker]

Hitting escape velocity won't help -- whatever is sent out will be unrecoverable. It will roughly be on Earth's orbit around the Sun, but likely won't coincide.

There is some flexibility by shooting the object past the moon, and getting a little bit of a 'slingshot' effect to modify the resulting orbit. But it would still require steering rockets because even a slight error in the initial path or orbital calculation would make a huge different in the resulting orbit.

This topic would make for a great physics and geometry lesson. Why inertial orbits starting from the surface always intersect the surface (the original topic). Why going from a one-body system to a two-body system might be able to change this, but at the expense of extreme sensitivity. How the complexity of potential orbits vastly increases as you add more bodies.

Even more interesting, is the extreme state sensitivity of the "interesting" configurations. A few seconds of arc difference in the initial course can put you someplace completely different. Simple orbital calculations assume point sources of gravity. That's not a bad approximation if you are far enough away, but a "slingshot" breaks that assumption. You can't even model the objects as uniform spheres -- the earth isn't spherical, and it doesn't have a uniform mass distribution. And for objects such as the Earth that have significant magnetic fields, there will be a deflection on approach and departure.

Bottom line is that anything done in space requires a significant ability to steer, and most operations require the ability to dynamically navigate.

Re:G-forces ????

[sjames]

I can't imagine why a comparison with the two most common current methods of launching wouldn't be relevant in a discussion of costs.

The reason shock forces seem worse is that seemingly minor events can result in surprisingly high G loads for a very short time. A good mechanical watch can deal with a 5000G shock but not nearly that much sustained.

Artillery shells deal with around 15000G. The guided versions include GPS, guidance computer and fin actuators, and explosive charge all of which obviously survive being fired from a gun barrel.

Of course this is all trade-off. A longer barrel could allow a lower acceleration, though no practical design would fall within human launch capability.

Re:G-forces ????

[J05H]

You didn't understand. Escape velocity is for leaving Earth's vicinity. This dude is talking about achieving Low Earth Orbit, LEO or equivalent. No matter how much energy is imparted, to achieve LEO (or MEO, GEO, etc) requires one or more circularization burns. This simply can not be done by applying more initial force to the object. It could be done with Myrabo-type laser propulsion or a small solid rocket.

Re:G-forces ????

[HiThere]

Have you ever heard of air friction? Hitting escape velocity with any significant amount of air above you won't suffice to allow you to escape.

This thing doesn't get things moving quite that fast. I expect that there'll be inefficiencies that he hasn't calculated, etc. So my expectation is that the rocket booster will be needed to achieve ANY kind of orbit. Doesn't make this a bad idea, though. It sounds like the cheapest sky-hook (well, not really) around.

This isn't quite a sky-hook, and wouldn't reduce costs quite as much. Close, though, even if I do expect that there are costs and inefficiencies he's overlooked. (I haven't looked at his projections, and I wouldn't expect to catch the mistakes either. But I'd bet they're there.)

Re:G-forces ????

[thesandtiger]

Are you kidding?

Launching a bunch of consumable stuff into orbit cheaply would allow all kinds of projects to get underway that are currently hideously expensive because they involve very expensive launch.

Wanna go to Mars quickly? Launch a whole lot of fuel cannisters, food, water, whatever into space this way, then launch your crew vehicle traditionally. Water tanks are attached to the crew vehicle in orbit (to provide some radiation shielding), fuel pods are launched ahead for the craft to make a rendez-vous en route... Suddenly things like getting to Mars (or whatever other destination) get a LOT cheaper since you aren't having to launch food, fuel & other consumables conventionally.

If a Gates or Buffet type who want to change the world with their fortunes would get involved - half a billion is virtually pocket change to those sorts - I can think of a lot of worse things to spend the money on.

Re:G-forces ????

[jamstar7]

Thing is, a circularisation burn is trivial once you get going in the right direction at more or less the right speed.

This system would be ok for bulk cargo that doesn't break apart under high gees. Somebody was calculating it'd induce something on the order of 1600 gees, which would pulp and paste a biological payload. That's fine, if you want goo delivered to orbit. But we're going to have to figure out how to get people into orbit cheaper than chemical rockets (spam in a can). An ablative laser launch system might work. Power it with a solar powersat maybe...

Re:G-forces ????

[jamstar7]

I never said it couldn't be done - I said I think it can't be done economically.

OK, the gun itself would run about half a billion, about what a Shuttle flight comes in at. Say the capsuals cost another half billion to develop. Manufacturing costs of the capsuals isn't development cost; we're bound to figure out how to make them cheaper, say, a million per. Amortize the cost of the gun & capsual development over 10,000 launches (hey, you got the hardware here, might as well use it). That brings the development costs down to $100,000 per launch. The more capsuals you send up, the cheaper the development costs get. Those 10,000 launches put 4500 metric tons into orbit relatively cheaply, the equivilent of 180 Shuttle launches @ 90 billion for the lot. Every 60 capsuals equals the payload of 1 Shuttle. Haven't seen the math on power costs yet, but I doubt those capsuals will take more than 5 million per to launch. Figuring at 5 mil/launch, that 4500 tons cost 50 billion. Less than half of what the Shuttle would cost us. That breaks down to about $11.2k/kilo, about $6000/pound. Dirt cheap by today's standard, at 5 million per for launch costs. And somehow I think it'll be less than that if they fully roll this out.

Re:G-forces ????

[Alastor187]

My suspicion is something in the range or Cubic Kilometers per Second instead of CFM and if we're talking that much, what impact on our weather is there going to be with such a large fan running all the time?

Converting Cubic Feet per Minute to Cubic Kilometers per Second. By any chance do your work for NASA?

Re:G-forces ????

[Gilmoure]

Hmmm... Pizza Pancakes...

Re:G-forces ????

[MeatBag PussRocket]

i was thinking that an aluminum or titanium "drum" would probably be sufficient if it were reinforced properly along its vertical axis. 600G or 1600G is really not all that much. compared to what people can withstand, sure, but for a container... not really.

Re:G-forces ????

[Anonymous Coward]

That are accelerations of about
1.64*10^4 m/s^2 for the suborbital launcher,
1.25*10^5 m/s^2 for the artillery shell, and
3.75*10^5 m/s^2 for the tank rounds.

For G's, drop a factor of 10.

Obviously, that's assuming constant acceleration - in reality that assumption will be violated, yielding higher peak acceleration. If the payload can't stand the above numbers, it'll most surely be pulped.

Re:G-forces ????

[Sinical]

I did a little work on MRM, which has an infrared seeker in it, and peak gee-loads were in the 8k-gee range (call it 75,000 m/s^2) as I remember.

Re:G-forces ????

[lessthan]

Sorry, but I don't understand why a circularization burn is needed. You sound like you know what you are talking about. Couldn't the initial boost be tuned, so that the object wouldn't make an complete escape? Wouldn't the object fall back to earth and, if aimed proper, miss? Wouldn't that "missing" create an orbit?

Re:G-forces ????

[jklovanc]

Getting the space tug to meet up with the payload, move it to the space station and then dock with the station would use more fuel than the the payload of the capsule.

The only way a space tug would be viable is if it's fuel was derived from sunlight. We do not have that technology yet. At least not in a production stage.

Re:G-forces ????

[Ihlosi]

Sorry, but I don't understand why a circularization burn is needed.

Because if an object accelerates at one point of its orbit, then the new orbit will still include the point at which the acceleration occurred. At least that's what I remember.

Couldn't the initial boost be tuned, so that the object wouldn't make an complete escape?

Well, you could try to fire it away from Earth so it doesn't come back. But if you accelerate it from the surface of Earth with less velocity than needed to escape forever, then the "orbit" will include the surface of the earth unless you do a circularization burn while you're in space.

I think the simple rule was: If you accelerate at the highest point of the orbit, then the lowest point of the orbit will rise, and if you accelerate at the lowest point of the orbit, then the highest point will rise. Hence, if you accelerate when the object is farthest from Earth, you can lift the lowest point of the orbit (which would be on Earths surface) far enough away from Earth so the object doesn't reenter.

Re:G-forces ????

[karstux]

The really expensive part of space travel, in terms of fuel and energy, is building up the velocity for orbit. I.e., "climbing the gravity well". That part at least is solved with the gun/cannon.

The next most expensive maneuver is changing orbital planes, that is, change the "tilt" of the orbit in respect to earth's axis. It would make sense to build the gun so that the payload ends up in an orbital plane very close to the ISS's. (Or whatever is the intended destination.)

Then, a space tug would only have to adjust height, eccentricity and phase, which are very cheap maneuvers. It might just be economical.

Re:G-forces ????

[riboch]

Yes, this is called a shock tube.

A very simple reference for the mathematics behind the concept can be found in Anderson's "Modern Compressible Flow."

I wonder now about heat and erosion.

I have so may questions, I would love to get my hands on the plans.

Re:G-forces ????

[dbIII]

One simple one I played with was simply a pressure vessel that emptied into a three metre long barrel via a fast acting valve, with a fairly simple assembly at the bottom with a removable target block (big lumps of steel, frequently replaced threaded rod and a lot of vacuum grease). The barrel and block was pumped down to a relatively low pressure with a single vacuum pump. Nitrogen or helium were used to move projectiles (pvc mostly, velocity was all that mattered). That one was limited to velocities less than that of the wave speed of the gas, which was still perfectly adequate for making odd things like iron-pvc composites (the iron powder grains in contact would weld together when the shock wave hit yet very little of the polymer would burn).
T4 was a different beast for much higher velocities which starts with a gas gun driving a projectile and then uses the compressed gas to reach a higher velocity in the next chamber to test scramjet models. I think the first stage had a 87kg copper piston with helium as the working gas, and the valve from that to the second stage was an expendable thin steel plate. The piston got stuck on occassion.
Here's a description: http://www.uq.edu.au/hypersonics/index.html?page=32641&pid=0
It was relocated some time in the early 1990s to a larger building so is a bit longer and capable of faster velocities than when I saw it running. It originally crossed the main corridor of the building I was studying in and shook the building slightly with each shot.

Starting to get afordable

[Anonymous Coward]

At 450 kilos you can launch three people with breathing gear and parachutes. Think of it as the "Econo" version of space tourism.

Re:Starting to get afordable

[mrsquid0]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

Re:Starting to get afordable

[camperdave]

At 450 kilos you can launch three people with breathing gear and parachutes.

Don't forget the big floppy shoes, polka dot cover-alls, and big red rubber noses.

Re:Starting to get afordable

[Jamu]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

I'll make a list...

Re:Starting to get afordable

[Anonymous Coward]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

It's just the opposite of a falling elevator, you just have to jump when it launches instead of before it hits.

Re:Starting to get afordable

[Anonymous Coward]

Doh it's just one if you happen to be launching average Americans. And they can propel themselves by their Unwarranted Self-Importance farts.

Re:Starting to get afordable

[Mishotaki]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

I'll make a list...

screw the breathing gear! make it 4 people, my list is too big!

Re:Starting to get afordable

[Daimanta]

Well pack them up in bubblewrap. Lots and lots of bubblewrap.

Re:Starting to get afordable

[ShakaUVM]

>>Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

Oh, please. I've read From the Earth to the Moon. You just stuff it with cotton and the passengers will be fine, especially with a really really long barrel. Verne wouldn't get this wrong, right? =)

Re:Starting to get afordable

[the_fat_kid]

he's making a list
and checking it twice
he's gonna find out
who's been naughty or nice
Gerald Bull is coming to town...

Re:Starting to get afordable

[youn]

Space Canon Tourism motto: you will http://tech.slashdot.org/story/09/10/11/2130226/Gigantic-Air-Gun-To-Blast-Cargo-Into-Orbit?art_pos=2#come back totally transformed

Re:Starting to get afordable

[youn]

wow, I dont know how I put this link in, I put it by accident... whatever I am on, I want some more :)

Re:Starting to get afordable

[cashman73]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

Perhaps the Mythbusters could test that out using prisoners currently being kept at Gitmo? That would solve two problems right there! ;-)

Re:Starting to get afordable

[khallow]

What if they start as people paste? Then they couldn't get any worse, right? As another poster noted, we can come up with a list and figure out how to unpaste them later.

Re:Starting to get afordable

[osu-neko]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

No no, you encase them in a block of carbonite. They should be quite well preserved. If they survive the freezing process, that is.

Re:Starting to get afordable

[AliasMarlowe]

Only if you want them to arrive on orbit as people paste.

Scotty wouldn't have minded this technique. At least he would not have been spread across Puget Sound by a rocket failure. http://en.wikipedia.org/wiki/James_Doohan

Re:Starting to get afordable

[Eightbitgnosis]

I'm sure we could market space cremations

Re:Starting to get afordable

[jamstar7]

Only if you want them to arrive on orbit as people paste. The G-forces in a cannon launch would be very high.

Perhaps the Mythbusters could test that out using prisoners currently being kept at Gitmo? That would solve two problems right there! ;-)

Naw. Too cruel and unusual. Use Congressional lobbyists and RIAA lawyers.

Re:Starting to get afordable

[mrsquid0]

I would start with sending the people who pull up and stop in the middle of crosswalks, then go with the RIAA lawyers.

Re:Starting to get afordable

[riverat1]

How about we start with the people who suggest we can launch humans this way. After all, they'll probably volunteer for it.

Is that a gigantic air gun ...

[dijjnn]

Is that a gigantic air gun with a 1km barrel in your classified launch facility, or are you just happy to see me?

Saddam already tried just that

[Barryke]

It has been said .. Saddam already tried just that.
http://en.wikipedia.org/wiki/Space_gun

Re:Saddam already tried just that

[Anonymous Coward]

Iraqi space program! LOL!!!

Re:Saddam already tried just that

[tomhudson]

Search for Gerald Bull and read abut his super-gun project.

Re:Saddam already tried just that

[dbIII]

The outcome there really worried a lot of people in the gas gun area at the time since the usual way to get funding was to get governments to pay you to develop things to throw tungsten crowbars at tanks at high speeds. I was just an undergrad at the time but the guy supervising my final year project (using a gas gun to compress metal powders together) had actually talked to Gerald Bull at a conference only a year or two before his murder. The same fate would have faced him in Iraq at some point (Saddam had most of his nuclear scientists killed), just somebody else got to him first.

Re:Saddam already tried just that

[tomhudson]

Too bad we're not smart enough to do make a rail launcher that climbs mount everest or even one of the smaller mountains in north america ... a lot less g forces, a lot less atmosphere to chug through at the top ...

I'll bet the chinese beat us to it.

Re:Saddam already tried just that

[smellsofbikes]

Search for Gerald Bull and read abut his super-gun project.

Or the German V3 built in 1944, that used sequential timed explosions to get greater velocity with lower jerk, and was intended to launch shells 200 km.

NOT a Railgun

[cheesybagel]

This is a light gas gun. It uses a chemical explosion to propel the payload.

Re:NOT a Railgun

[Anonymous Coward]

So since it's not a railgun, I'm assuming we can't call it a mass driver then.

Can I ask what the g-forces on this thing would be? Could we launch people on this without having their insides being squeezed out of various orifices?

Re:NOT a Railgun

[Anonymous Coward]

$500M at 5% investment cost and 5 year build time is $25M/year times 5 years is $125M plus $25M per year. Assume on deployment annual principal amortization of 2% per year or a 50 year life with no net maintenance cost above price variations. $10M.

450KG per projectile and let's be generous that 50% of that is useful net payload.

1st year $150M+$10M and $35M per year thereafter, and assume a 5 year breakeven analysis, $300M. Divided by 225KG net per firing and current cost of $10,000 per KG and a goal of well less assertive than their madness of $2000 per kg, you would need:

$10,000/KG $300M fixed cost (no salaries or rent or repair or profit margin) 30,000 firings.
$2,000/KG $300M fixed cost (no salaries or rent or repair or profit margin) 150,000 firings.

150,000 firings in 5 years is 115 per day on a 5 day work week (maintenance allowance).

Just Anon

Re:NOT a Railgun

[Shadow of Eternity]

With enough duct tape over any likely orifices, I don't see why not. I still don't think they would survive launch though.

Re:NOT a Railgun

[Quantumstate]

With launch speed on 6km/s that is an average speed of 3km/s over a 1.1 km tube giving a time of 1.1/3s. With the change in speed being 6km/s or 6000m/s this gives acceleration of 44200 m/s^2. g is about 10m/s^2 so that makes it about 4420g. Given that most people pass out at about 10g I think this answers your question.

Re:NOT a Railgun

[Quantumstate]

Of course, you just need to remember that your duct tape doesn't need to be able to withstand the full forces, it just needs to be stronger than the parts of you which are not orifices.

Re:NOT a Railgun

[tomhudson]

Assuming initial cost + interest at 5% as you posit, you have a total of $625 million after 5 years.

Carrying costs are therefore $31.5 million annually thereafter.

Even allotting for only 225 kg/shot, that's 2.25 million a shot available.

1 firing a day, 5 day work week, at $10k/kg is more than half a billion of revenue in the first year.

If they did like airplane owners, and ran it 7 days a week, 1 firing a day yields $821 million the first year.

30,000 firings @10,000/kg would be $67.5 BILLION. You dropped a decimal point somewhere.

Re:NOT a Railgun

[jackbird]

I think he forgot somewhere along the way to make the payload more than 1 kg.

Re:NOT a Railgun

[Anonymous Coward]

(I am not the one you were replying to)

$625 million after 5 years

That's for 1 gun. How many shot does the barrel survive? 100? 1000? 10000? That's very generous even for artillery gun.

Even allotting for only 225 kg/shot

Well yes, you need some weight to cover your already hot projectile going through the atmosphere at Mach 9.

1 firing a day, 5 day work week, at $10k/kg

Are you kidding? That's 225 000 dollars per shot. How much you think the propellant (or compressed gas) alone will cost? The expendable heat shield?
The barrel wear?

1 firing a day, 5 day work week, at $10k/kg

Oh, and most importantly: Who the hell would want to pay $10k/kg for a SUBORBITAL launch of an UNBELIEVABLY SMALL cargo container?

Re:NOT a Railgun

[tomhudson]

Gawd, but your math skills suck. No wonder you posted AC.

firing a day, 5 day work week, at $10k/kg

Are you kidding? That's 225 000 dollars per shot

225 kg * $10,000 per kilo = $2,250,000, not $225,000. You're off by an order of magnitude.

Here, lets make it simple:

225 kg x $1 per kg = $225.00
225 kg x $10 per kg = $2,250.00
225 kg x $100 per kg = $22,500.00
225 kg x $1,000 per kg = $225,000.00
225 kg x $1,0000 per kg = $2,250,000.00

Like I said, you dropped a decimal place.

Re:NOT a Railgun

[Anonymous Coward]

Haha, yes, I forgot how to multiply by ten, thanks for spending so much time correcting me.

If you're going to be totally anal about this, you forgot a comma here:

225 kg x $1,0000 per kg = $2,250,000.00

My point still stands, because you can't find launch customers at this price. It will be cheaper to launch kerosene or water on Ares 5 (or any available rocket for that matter) than build a container with a rocket engine and navigation system for each hundred kg of cargo.

Actually, I'm posting as AC because I can't argue with people trying to make a business case out of this without getting a serious karma hit.

Re:NOT a Railgun

[Anonymous Coward]

I think it is similar to the hypersonic 'wind tunnel' Caltech has.
That device divides the 'barrel' into a series of chambers filled with slightly different gas mixtures at different pressures, divided by thin plates which get blasted through. The explosion progresses from one section to the next, and each subsequent section's mix has a faster blast speed and gets the shock front moving faster (I forget the proper term, but you know what I mean).

This would make sense for a gun design, since it spreads out the acceleration forces a bit more than a single blast. It also gets going much faster.

Re:NOT a Railgun

[tomhudson]

Don't be stupid (too late - you showed that when - TWICE - you made simple math errors like not being able to multiply by 10). The container doesn't need either an engine or a nav system, and especially not for "each hundred kg of cargo". Once it's in orbit, a separate ion tugboat can always pick it up. Outside the atmosphere is where ion engines will shine, and this is one practical use for them.

Actually, I'm posting as AC because I can't argue with people trying to make a business case out of this without getting a serious karma hit.

... and not to protect you from ridicule because you can't do basic math?

As others have pointed out, we can already build electronics and hardware that can withstand the launch forces. They don't have to get the costs down to 1/5 the competition - just enough under the competition so that, for enough payloads, it makes sense. Even a 10% differential will be enough of an economic driver. Same as any other commodity (or do you drive out of your way to pay more for "your" brand of gasoline?)

Re:NOT a Railgun

[scotch]

Actually, I'm posting as AC because I can't argue with people trying to make a business case out of this without getting a serious karma hit.

You make cowards everywhere proud.

Re:NOT a Railgun

[bigsteve@dstc]

Strictly speaking, the Livermore gun used a chemical explosion to compress hydrogen to a few thousand atmospheres. The projectile was then propelled by the expansion of the hydrogen in the main barrel.

Re:NOT a Railgun

[osu-neko]

With launch speed on 6km/s that is an average speed of 3km/s over a 1.1 km tube giving a time of 1.1/3s. With the change in speed being 6km/s or 6000m/s this gives acceleration of 44200 m/s^2. g is about 10m/s^2 so that makes it about 4420g. Given that most people pass out at about 10g I think this answers your question.

Naw. What we need to know is... sure, people pass out at 10g, but at what point to their bones break under the weight? At what point are they reduced to a pulp? What what point do they essentually liquify? Or compact to a solid? And how many G's before they finally collapse into a singularity?

Re:NOT a Railgun

[voidphoenix]

A bit under 1700 G, actually. (vf^2 - vi^2) / 2d... I think that's the right equation. Anyway, it gives the same answer as yours, once your calculations are fixed. 6 / (1.1 / 3) = 16.36 km/s^2, not 44.2.

Re:NOT a Railgun

[wvmarle]

Others have calculated the g-forces to be about 1670 g. Not suitable for anything living.

You mention this is an explosion driven cannon (so very much a traditional one). What makes me wonder is with a 1 km barrel, how are they going to keep up the pressure to continue to accelerate the projectile all the way? That needs a really massive expansion of gases, for long time (0.37 seconds: explosions are normally way faster than that), the gases have to travel all the way to the nozzle together with the projectile, etc.

I do have the feeling that a rail gun kind of design would scale much better.

Re:NOT a Railgun

[Anonymous Coward]

Was I talking to you?

Re:NOT a Railgun

[Anonymous Coward]

The fact that you found a math error or two in my posts doesn't make yours any less stupid.
First of all, RTFA. You can't assume this container will go to orbit - it won't, so no ion tugboat (which, AFAIK, is not included in the cost of the gun as presented). Oh, OK, so you place a small rocket on the container, and then a tugboat will, er... And how many tugboats do you have to have on orbit to launch once a day? Do you propose a space station too, to service them? That's one FUCKING EXPENSIVE cheap launch technology.
 

... and not to protect you from ridicule because you can't do basic math?

Well you can't do basic physics, so we're even.

As others have pointed out, we can already build electronics and hardware that can withstand the launch forces.

Oh yes, those artillery shells can maneuver in a near-vacuum, and accelerate under their own power.

They don't have to get the costs down to 1/5 the competition - just enough under the competition so that, for enough payloads, it makes sense. Even a 10% differential will be enough of an economic driver. Same as any other commodity (or do you drive out of your way to pay more for "your" brand of gasoline?)

If you're going to pretend to be an economist, don't tell me about "commodity" when the market is as small as it is.
Where will these payloads come from?

Good thing you probably won't read this, because arguing with you is like talking to a spoiled 8 year old boy. You think because you can do basic multiplication you automatically win?

If it helps, this thing will never get built, so you'll never be proven wrong.

Re:NOT a Railgun

[tomhudson]

Your math errors are huge - an order of magnitude off.

So are the rest of your arguments.

We already have a platform in place. Might as well extend its' life.

The ion tugboat concept is already planned for other missions, so what's your beef with them?

The payloads don't need to maneuver in orbit. They just have to be shot into a stable orbit, so that they can be picked up. Or they can use the trick that was first tested by the Gemini program - split the payload in 2, tether the two parts together, and start 'em spinning. Or even stabilize them by NOT spinning them.

Also, launch vehicle services are already something of a commodity market, with several suppliers competing. This would open it up.

As to whether it gets built or not, if things depend on people with your faulty math skills, nothing would ever get built.

So suck it up that you both don't know how to count, and don't know what you're talking about. No wonder you post AC.

Re:NOT a Railgun

[jlar]

The real question is: How many rolls of duct tape can be moved to ISS per day? Perhaps the air gun will allow us to expand the life time of ISS indefinitely.

Re:NOT a Railgun

[Ironsides]

The way you keep the acceleration going is by having multiple explosions along the way. What you do is line the barrel at intervals with additional combustion chambers. As the projectile passes by, each additional chamber lights off, adding further hot gas/pressure behind the projectile to further accelerate it. You don't achieve a constant acceleration doing this, but it is a lot 'smoother' than having one huge acceleration spike at the beginning.

Rail guns have other issues right now, such as the rails warping. (Imagine having to replace the entire rail after every couple of shots). However, there are some thoughts on using a linear motor to achieve something similar. A linear motor might even be superior under some of the ideas that have been thrown out there. One idea is to create a mile wide circular track that is one long continuous linear motor. You slowly (at your control) accelerate the payload to escape velocity, then switch the payload (similar to train track switching) to a ramp that sends the projectile into orbit. If I remember right, you could even launch humans into orbit this way and have them survive. Wiki calls them Launch Loops, and there are a few different designs out there.

Re:NOT a Railgun

[Anonymous Coward]

We already have a platform in place. Might as well extend its' life.

If you're talking about the ISS, supporting it is not only refueling. Also, that's what Progress does relatively cheap. For solid cargo, you'll still need a normal rocket.

The ion tugboat concept is already planned for other missions, so what's your beef with them?

They're great once you get stuff to a stable orbit.
See below.

The payloads don't need to maneuver in orbit. They just have to be shot into a stable orbit, so that they can be picked up.

I never argued with that. So, how does this gun with a muzzle velocity of 6000 m/s place payloads to orbit with a velocity of 11200 m/s? I hope I'm not off by an order of magnitude again.

Also, launch vehicle services are already something of a commodity market, with several suppliers competing.

They are launching mostly commercial satellites, not hardened epoxy-packed integrated circuits with a single small optical sensor soldered to them.
Then there's the ISS COTS contract from NASA, worth $3.5 billion (and most of the mass is probably NOT raw materials), and that's it.

you both don't know how to count, and don't know what you're talking about

And this coming from who, an aerospace engineer or just a random nobody on the Internet?

Re:NOT a Railgun

[wvmarle]

The way you keep the acceleration going is by having multiple explosions along the way.

I was thinking along those lines but then still the issue of the large empty barrel behind the projectile absorbing a lot of the explosive energy. Ah well just use a bigger explosive then, more power.

However, there are some thoughts on using a linear motor to achieve something similar.

Magnetic may work, as in maglev trains.

Launch loops sound interesting but I think the centripetal forces will still be an issue: at 6 km/sec in a loop 500 m diameter this will still be an issue. I don't remember the formulas so I'll leave it for someone else to give the g-force in such a case.

Re:NOT a Railgun

[tomhudson]

me@slashdot> slashdot -gamemode
SLASHGAME: YOU ARE NAGGED BY AN ANONYMOUS COWARD
SLASHGAME: EXAMINE ANONYMOUS COWARD
SLASHGAME: ANONYMOUS COWARD HAS NO MATH SKILLS
SLASHGAME: INVENTORY
SLASHGAME: YOU HAVE 3 POTIONS AND 4 SCROLLS
SLASHGAME: USE POTION
SLASHGAME: YOU MUST DRINK THE POTION
SLASHGAME: DRINK POTION
SLASHGAME: YOU DRINK THE POTION
SLASHGAME: THE ANONYMOUS COWARD HAS BEEN EATEN BY A GRUE
SLASHDOT: EXIT
me@slashdot>

Re:NOT a Railgun

[HiThere]

A railgun isn't a mass driver unless it's being used to propel the thing it's attached to. What makes a railgun a mass driver is that it's being used as a kind of rocket engine...only without the chemistry.

IOW, even if it *were* a railgun you couldn't call this a mass-driver because that's not how it's being used. OTOH a rocket engine is a kind of mass driver, i.e., it drives you by throwing mass away.

Re:NOT a Railgun

[tomhudson]

You can ignore him now - he was eaten by a grue in this thread.

Instructions for "slashdot --gamemode" here.

Re:NOT a Railgun

[Anonymous Coward]

So, you're going to nag scotch instead of me now?

Re:NOT a Railgun

[Anonymous Coward]

Gee, what a dumass

Re:NOT a Railgun

[Gilmoure]

Slowly, but surely, the air gun could get the EArth moving in a new direction.

Re:NOT a Railgun

[Ironsides]

Lets use a 2km diameter loop, the math is easier.

Acceleration on a loop is V^2/r. So, 6000*6000/1000=6000m/s^2. That's about 612g, in the same area as the space gun proposal.

This will also be used at sporting events

[Anonymous Coward]

To shoot t-shirts into the crowd. Casualties are expected.

Gerald Bull

[Scrameustache]

Gerald Bull was Canadian engineer who died (bullet in the head) trying to build such a cannon.

See http://en.wikipedia.org/wiki/Project_HARP

Re:Gerald Bull

[Anonymous Coward]

Did he shoot his eye out?

Re:Gerald Bull

[Gudeldar]

Bull was killed by Mossad because he was helping Iraq build a "supergun". You make it sound like he was killed because of Project HARP.

Re:Gerald Bull

[oodaloop]

Right you are. Just one of Iraq's special weapons, actually.

http://www.globalsecurity.org/wmd/world/iraq/other.htm

Re:Gerald Bull

[Jonathan]

Supposedly a "supergun". But like the rest of Iraqs' WMDs, it may may have been mythical. It's really not that absurd that Saddam would actually want a facility to launch peaceful satellites. I mean, the guy was a dictator, but he liked money; having a facility to hire out would have given him the cash to build even more palaces for himself.
 

Re:Gerald Bull

[Anonymous Coward]

>Implying that it's perfectly cool for special agents to execute people.

Re:Gerald Bull

[bill_mcgonigle]

I mean, the guy was a dictator, but he liked money; having a facility to hire out would have given him the cash to build even more palaces for himself.

Yes, that's within the realm of possibilities, but he had already attacked Israel before (poorly), so it seems far more likely that's what he was up to.

Re:Gerald Bull

[drerwk]

Remo Williams anyone?

Re:Gerald Bull

[khallow]

Supposedly a "supergun". But like the rest of Iraqs' WMDs, it may may have been mythical. It's really not that absurd that Saddam would actually want a facility to launch peaceful satellites. I mean, the guy was a dictator, but he liked money; having a facility to hire out would have given him the cash to build even more palaces for himself.

Could have happened that way, but it didn't. Saddam Hussein's decades of development of WMDs are pretty well documented. He even used chemical weapons in the 80's on both Iran and his own people. He has a nuclear weapons program that was going on since the 70's. And he dabbled with biological weapons like anthrax. Now, he might have intended to develop a private space program instead of superguns capable of reaching his neighbors like Israel, Iran, and Saudi Arabia. But that doesn't fit his MO.

Re:Gerald Bull

[Lord Kano]

You make it sound like it's OK that Israel murdered him.

LK

Re:Gerald Bull

[Deosyne]

Yes, I'll have one. Thank you.

Re:Gerald Bull

[strack]

if you could point to the evidence of the nuclear and biological weapons programs, thatd be just great. and no. aluminium tubes dont count.

Re:Gerald Bull

[The_mad_linguist]

They're a reason they called Chemical Ali Chemical Ali.

Re:Gerald Bull

[Anand7]

Bull was killed by Mossad because he was helping Iraq build a "supergun". You make it sound like he was killed because of Project HARP.

Gerald Bull designed his "super gun" to put payloads into orbit. He approached the US government with the idea and they rejected it as a launch method but wanted a weapon. Disgusted and disillusioned (he was apparently treated very poorly) his response was to create a truly powerful weapon. Iraq hired him to build one for them. The Mossad killed him in Belgium, a country that exports arms all over the world. It's important to remember that the US military has done this with a number of inventions. The guy who invented the x-ray laser had wanted to use it for medical purposes; excising tumours etc. The US military classified it and now it's a weapon. Another Canadian invented polymorphic encryption for secure banking and corporate communications...US military classified his work and as far as I know he can't even talk about it with his peers.

Re:Gerald Bull

[whitehatlurker]

I find your signature somewhat ironic - they did take the sky from Bull, didn't they?

Re:Gerald Bull

[The Master Control P]

You might have mentioned something minor, like the fact that he was working with Saddam Hussein because Hussein was willing to fund him, at the time he was killed.

But that's way too obvious a reason... it was a conspiracy by the very groups who stood to benefit from reduced launch costs that killed him. Mm-hmm.

Re:Gerald Bull

[DigiShaman]

You can read about Sadam's supergun right here.

http://www.defensetech.org/archives/002751.html.

Would it have worked? Who knows...

Re:Gerald Bull

[Anonymous Coward]

Easy. The CIA dumped all kinds of chemweapons in his back yard when they installed him. Furthermore, most of that shit is absurdly easy to make--just tough to do safely.

You want evidence? It's called the Iran-Iraq war. Look it up for yourself you lazy/stupid cunt. The current war was poorly justified for the purposes of Iraq, but it doesn't change the fact that Iraq DID at one time develop, possess and USE chemical weapons.

Re:Gerald Bull

[Spit]

We're all well aware of Saddam's chemical weapons, the US sold them to him after all. But that's not what the parent was asking, which was about the evidence of nuclear and biological weapons programs.

Re:Gerald Bull

[Anonymous Coward]

As if America or wherever the fuck you live doesn't export guns all over the world.

Re:Gerald Bull

[R2.0]

"Gerald Bull designed his "super gun" to put payloads into orbit. He approached the US government with the idea and they rejected it as a launch method but wanted a weapon. Disgusted and disillusioned (he was apparently treated very poorly) his response was to create a truly powerful weapon. Iraq hired him to build one for them. The Mossad killed him in Belgium, a country that exports arms all over the world."

100% unadulterated bullshit. The US Government sponsored his work in HARP, and it set altitude records for guns. The reason why the program was terminated was that HARP showed that putting a satellite into orbit using ballistic means wasn't feasible using the technology at the time. Aside from the fact that the projectiles couldn't make it to orbit, no one had yet figured out a way to have the electronics survive. And the US military didn't want a "supergun" - experience in WWII showed that they weren't tactically effective and were vulnerable.

So Bull lost his funding, but just would not accept that his idea wouldn't work at the time. So he started designing weapons. No one cared, until the Iraqis commissioned him to build one to point at Israel. At this point, one can argue that he stepped over the line - when one is actively working on a weapon that could ONLY be used to hit Israel (it was fixed in place, remember?) one could argue that he went from supplier to combatant. I don't endorse what the Mossad did per se, but portraying Bull as some kind of innocent scientist working for the good of mankind until he was ruined by the machinations of the US Military is ridiculous.

Re:Gerald Bull

[Hurricane78]

Luckily, here we couldn't care less what the US considers classified or a weapon. If they want, they nuke anything anyway because they think they might have found a "weapon" which really is no bomb but a soccer ball.

Re:Gerald Bull

[Anonymous Coward]

The "Superguns" got all of the publicity but were not much of a worry militarily. They were fixed position, aligned more for what they were declared to do: launch orbital or sub-orbital packages. It would have been a scientific coup for Iraq and a boost for Arab cultural pride.

Bull however, had a history of making mobile, accurate, long range artillery. He also was perfectly willing to participate in clandestine military projects if it would finance his research. He supplied howitzers and shells to South Africa in defiance of international sanctions. Finally, he liked big challenges and there was little doubt that given the right situation, he would provide Iraq with a massively effective weapon.

I think he was killed because he just p*ssed off too many people in high places in the West, and maybe a lot of those people were not comfortable with the thought of Saddam putting packages into orbit let alone having the world's most advanced artillery expert on his side.

Re:Gerald Bull

[khallow]

How about you do your own research? But to get you started, let me point you to this document. It's a British evaluation of Saddam Hussein's WMD program around 2002-2003. While the report appears to be in error about the last few years, it describes the history of Hussein's efforts. For example, for biological weapons:

Iraq started biological warfare research in the mid-1970s. After small-scale research, a purpose-built research and development facility was authorised at al-Salman, also known as Salman Pak. This is surrounded on three sides by the Tigris river and situated some 35km south of Baghdad. Although some progress was made in biological weapons research at this early stage, Iraq decided to concentrate on developing chemical agents and their delivery systems at al-Muthanna. With the outbreak of the Iran-Iraq War, in the early 1980s, the biological weapons programme was revived. The appointment of Dr Rihab Taha in 1985, to head a small biological weapons research team at al-Muthanna,helped to develop the programme. At about the same time plans were made to develop the Salman Pak site into a secure biological warfare research facility. Dr Taha continued to work with her team at al-Muthanna until 1987 when it moved to Salman Pak, which was under the control of the Directorate of General Intelligence. Significant resources were provided for the programme, including the construction of a dedicated production facility (Project 324) at al-Hakam. Agent production began in 1988 and weaponisation testing and later filling of munitions was conducted in association with the staff at Muthanna State Establishment. From mid-1990, other civilian facilities were taken over and some adapted for use in the production and research and development of biological agents.

And of course, the big stick in the WMD deck, a nuclear weapons program:

Iraq's nuclear programme was established under the Iraqi Atomic Energy Commission in the 1950s. Under a nuclear co-operation agreement signed with the Soviet Union in 1959, a nuclear research centre, equipped with a research reactor, was built at Tuwaitha, the main Iraqi nuclear research centre. The research reactor worked up to 1991. The surge in Iraqi oil revenues in the early 1970s supported an expansion of the research programme. This was bolstered in the mid-1970s by the acquisition of two research reactors powered by highly enriched uranium fuel and equipment for fuel fabrication and handling. By the end of 1984 Iraq was self-sufficient in uranium ore. One of the reactors was destroyed in an Israeli air attack in June 1981 shortly before it was to become operational; the other was never completed.

By the mid-1980s the deterioration of Iraq's position in the war with Iran prompted renewed interest in the military use of nuclear technology. Additional resources were put into developing technologies to enrich uranium as fissile material (material that makes up the core of a nuclear weapon) for use in nuclear weapons. Enriched uranium was preferred because it could be more easily produced covertly than the alternative, plutonium. Iraq followed parallel programmes to produce highly enriched uranium (HEU), electromagnetic isotope separation (EMIS) and gas centrifuge enrichment. By 1991 one EMIS enrichment facility was nearing completion and another was under construction. However, Iraq never succeeded in its EMIS technology and the programme had been dropped by 1991. Iraq decided to concentrate on gas centrifuges as the means for producing the necessary fissile material. Centrifuge facilities were also under construction, but the centrifuge design was still being developed. In August 1990 Iraq instigated a crash programme to develop a single nuclear weapon within a year. This programme envisaged the rapid development of a small 50 machine gas centrifuge cascade to produce weapons-grade HEU using fuel from the Soviet research reactor, whi

Re:Gerald Bull

[vg30e]

A lot of people in the defense analysis industry don't put a lot of stock into Gerald Bull being killed because of Iraq's super gun program under Saddam H. The thing about Gerald Bull being killed by the Mossad is that he was also helping with the lesser known Iraqi orbital rocket program. The thing about a super gun project is that it is relatively difficult to conceal a very large cannon being constructed that just so happens to aim at Israel. Israel's air force had already successfully executed a precision bombing attack inside Iraq that destroyed a nuclear facility, so doing another such attack was relatively simple for them in the early 1990's. An ICBM or even an IRBM project would be something that they couldn't easily target (like the vintage Scud missiles) since they are easier to hide than a 1000 meter pipe several feet wide angled up at the sky.

In WWII, Nazi Germany was trying to construct a super gun aimed at England. The Allies didn't know what all the construction was about, but they chose to bomb the large construction site, eventually destroying the cannon before it could be finished.

Re:Gerald Bull

[Anonymous Coward]

And helping improve the SCUDs that Iraq used on neighbors...

Re:Gerald Bull

[jamstar7]

if you could point to the evidence of the nuclear and biological weapons programs, thatd be just great. and no. aluminium tubes dont count.

Funny that. From what I've heard, those aluminum tubes were worthless as components of a uranium seperater but almost blueprint for a next-gen SCUD that would, if you set up within inches of Iraq's western border and had a good easterly wind, could possibly land payloads inside Israel.

Re:Gerald Bull

[Anonymous Coward]

Nope. It was just the faggoty Jews taking matters in their own hands. Again. Why have we destroyed them yet? Ohhhhh right because half of the politicians in the US are either Jews or are paid handsomely by Jews. Great.

Re:Gerald Bull

[Anonymous Coward]

Murdering an unarmed man at the front door of his home, for any justification, is a heinous act. I don't care if it's Hitler walking his dog.

If the Mossad wanted him dead, and they thought he was committing a terrible crime, they could have just Eichmann'd him, but they didn't.

Re:Gerald Bull

[The Master Control P]

I'm not saying that what the killer did was justified. I'm saying that given what we know Bull was working on and for who, to pretend he was killed for trying to build an orbital launch cannon is disingenious.

nothing new here

[jimmywho]

Main problem with Jules Verne's gun is that the people inside could not handle the acceleration caused by them being shot off. Cargo it seems would have a better chance but any sensitive equipment (like 99% of anything used in space) or explosive materials (fuel) wouldn't be able to be shot up in a gun. Once again an old idea with a different name that will only waste money and the minds of others.

Re:nothing new here

[Anonymous Coward]

Sounds like a great way to send up food and water actually. With some work maybe even oxygen.

Re:nothing new here

[Anonymous Coward]

To Darfur :)

Though - seriously, it's a gun that can launch a payload to any spot on earth, and the payload is way smaller than any ICBM, thus harder to detect.

Re:nothing new here

[cheesybagel]

explosive materials (fuel) wouldn't be able to be shot up in a gun

Bullshit. Several weapon systems do just that, including the rocket assisted howitzer shells used in the M109 Paladin.

Re:nothing new here

[Anonymous Coward]

Funny thing, fuel IS one of the objects that they say could be launched with this.

FTFA (that you clearly didn't read): "While humans would clearly be killed and conventional satellites crushed by the gun's huge g-forces, it could lift robust payloads such as rocket fuel."

Re:nothing new here

[symbolset]

If we try hard enough we should be able to think up a form of rocket fuel that survives the transit. Oh, there it is: water ice. Just freeze a slug and toss it up to the satellite with solar power to be remanufactured into oxygen and hydrogen for use as a fuel or breathable air or potable water while in orbit.

The idea works better shooting from Mars, but whatever...

Re:nothing new here

[Night64]

Fuel is not an explosive material. Fuel plus oxidizer plus fuse (e.g., a gun shell) is explosive material. Even then, it will not explode inside the barrel or in transit unless you really want to. Next question, please.

Re:nothing new here

[Anonymous Coward]

How you were modded insightful when you clearly didn't read the article and have absolutely nothing insightful to say says a lot about the current state of the slashdot crowd.

Re:nothing new here

[AJWM]

or explosive materials (fuel)

Fuel isn't explosive. Fuel-oxidizer mixes, or some monopropellants, may be explosive, but are not necessarily shock-sensitive. This would be fine for launching suitably-built canisters of fuel or water, or other insensitive cargoes.

And don't overestimate the sensitivity of some electronics packages -- gun-fired projectiles with electronic fuses are a decades-old technology.

Re:nothing new here

[John Hasler]

> Cargo it seems would have a better chance but any sensitive equipment (like
> 99% of anything used in space) or explosive materials (fuel) wouldn't be able
> to be shot up in a gun.

Nonsense. Guns have been firing projectiles filled with explosives for centuries. The US Army has had shells filled not only with explosives but optics, electronics, and actuators for terminal guidance for dacades. In WWII they had anti-aircraft guns that fired shells with vacuum tube proximity detonators in them. In WWI they used shells with self-winding mechanical timers. Fuel would be easy.

Re:nothing new here

[MichaelSmith]

And don't overestimate the sensitivity of some electronics packages -- gun-fired projectiles with electronic fuses are a decades-old technology.

And the newer ones are laser guided, I believe. So it has en entire guidance system in the projectile.

Re:nothing new here

[Deadstick]

gun-fired projectiles with electronic fuses are a decades-old technology

Matterafact, the proximity-fuzed antiaircraft shells of WW2 had a vacuum tube in them.

rj

Re:nothing new here

[strack]

if only there were some sort of explosive device that could withstand the g forces similar to devices like this. trying to think of one is like taking a shot in the dark. this problem, shell be a tough one to crack. blast it all to hell.

Re:nothing new here

[symbolset]

I don't know why you're arguing with me. You said the exact same thing. And I agree with you. A nice steel can to hold the ice can hold ablative shielding, makes a good candidate for a railgun second stage (explosives only get you so far), and gets to orbit some additional necessary machinable materials.

Re:nothing new here

[Anonymous Coward]

While true, I know one of the guys in that development program, and it was not exactly an easy task. All the components had to be aligned on the axis, coatings improved, etc - not your typical vacuum tube. I know he did extensive development for the Patriot missile program as well.

Re:nothing new here

[HiThere]

Fuel isn't explosive. Not if kept separated. Use separate launches for the oxidizer and the reducer and there's no problem.

Water is heavy, but easily handles acceleration.

My expectation is that even a frozen TV dinner would survive, if somewhat mangled.

And anything sufficiently small would scarcely be affected. Most discrete electronics should be safe...if the shock isn't too strong. It wouldn't be the gravity, but it's higher order components that would be dangerous. dx/d(t^4) and up. An acceleration of 1600 g's wouldn't phase most discrete electronics, but a sudden impact has lots of higher order components. Don't know what an air gun would do. So electronics might need to be specially packaged. (It's doable, but it sure adds to the cost.)

And, of course, air wouldn't be adversely affected.

Not sure what this would do to a warm steak. It might do nothing. It might tenderize it. I'm pretty sure that we experience equivalent accelerations (in our feet, at least) when jumping off a chair and landing on a cement floor. But it doesn't last very long. It's rather hard to imagine what it would be like if it endured for more than a small fraction of a second.

doomed before it starts

[Anonymous Coward]

by their own admission it will damage equipment being launched - so their target market is "cheap ways to transport fuel into space" - not sure how happy I am about rocket fuel being launched out of a gun on my doorstep. So my investors vote is ticking doomed before it starts.

If this was useless, it would already be funded

[ChrisKnight]

$500 million is what BART wants to spend to build a 3.2 mile stretch of elevated rail to connect the Oakland Coliseum to the Oakland Airport, and this boondoggle of a project is already funded. Imagine the progress we would make towards space travel if we spent the same amount of money on technology that will move cargo into space as opposed to moving people too lazy to take the already existing BART Shuttle to the airport?

Re:If this was useless, it would already be funded

[TubeSteak]

Imagine the progress we would make towards space travel if we spent the same amount of money on technology that will move cargo into space as opposed to moving people too lazy to take the already existing BART Shuttle to the airport?

"Cargo" is a very broad term.
You're pretty much limited to solids, liquids, or solids immersed in liquid. Anything with air inside it will crumple in an instant and even solid state electronics probably won't be able to take the insane acceleration.

Re:If this was useless, it would already be funded

[Anonymous Coward]

Don't have a cow, man.

Re:If this was useless, it would already be funded

[Anonymous Coward]

Or walk. Or just don't go to Oakland in the first place.

Re:If this was useless, it would already be funded

[mcrbids]

$500 million is what BART wants to spend to build a 3.2 mile stretch of elevated rail to connect the Oakland Coliseum to the Oakland Airport, and this boondoggle of a project is already funded.

Cool! You mean, when I fly my private plane into Oakland to see a game or concert at the Coliseum, I won't have to wait 10 minutes for the free shuttle to come and get me? That will make my life so much different for the better... worth every penny of that 500 million dollars!

Re:If this was useless, it would already be funded

[sjames]

The biggies for maintaining a human presence in orbit meet the criteria. More conventional flights would be required but they could be fewer and farther between.

Re:If this was useless, it would already be funded

[amohat]

$500 million might be the penalty for not building out BART properly in the first place. Waiting for a metropolis to mature before investing in public transit is a stupid and costly mistake. Which is what the Bay Area is facing right now...the new Bay Bridge is a good example. Why not extend to San Jose and Santa Rosa? What is wasted by sitting in daily, unavoidable traffic jams? What is lost by people unable to take a job across the Bay due to traffic?

Pretty absurd that you would take funding away from public transit projects and give it to a specious space program. At best, sounds like some kind of trickle-down economics. How much space exploration needs to be done for the Bay to get a decent subway system?

California can save $500 million just by reforming its penal code. Or defeating the price-fixing by energy suppliers. Speaking of collusion, even the most cowardly of health care reforms could easily save amount. There's a good place to use your imagination.

Also, pretty silly that you describe people who use public transit as lazy. I thought lazy people stayed at home.

G force.

[jklovanc]

I may be wrong in this calculation but running the numbers I get a weird result.
The gun is 1.1K long with a final velocity of 3km/s.
So the payload would be in the gun for 1.1/(3/2) = 0.73 seconds.
In that 0.73 seconds the payload would accelerate to 3 kms/sec The continuous acceleration would be 3000/9.8/0.73= 417 Gs. That is sure a lot of Gs. Much more than the 3.2 the shuttle produces.

Re:G force.

[John Hasler]

The acceleration is an artillery piece runs to the thousands of Gs. Artillery shells are full of explosives, electronics, and machinery. This gun should be able to handle pretty much all of the consumables and many of the parts and materials needed by the space station.

Re:G force.

[MichaelSmith]

Then there is this idea that you could build a kind of linear accelerator by firing a stream of pellets in the direction of (say) Saturn. Your vehicle can be a toroid which rides the pellet stream, pushing them backwards.

Re:G force.

[Tynin]

I'm wondering about how they would intercept and retrieve the payload once it is in orbit. The amount of kinetic energy it retains from getting to orbit (I'd assume, likely incorrectly, IANARS) would still be pretty massive problem to tackle.

Re:G force.

[registrar]

Correct. The formula you want to remember from high school is v^2 = 2 a s.

Re:G force.

[DerekLyons]

The acceleration is an artillery piece runs to the thousands of Gs. Artillery shells are full of explosives, electronics, and machinery.

Very, very expensive electronics and machinery as it must be made to withstand high shock and high G's.
 
 

This gun should be able to handle pretty much all of the consumables and many of the parts and materials needed by the space station.

So long as you handwave away the expense and difficulty of manufacturing containers that hold those consumables, parts, and materials and protect them from the shock and g loading orders of magnitude greater than they currently experience.

Re:G force.

[godel_56]

In that 0.73 seconds the payload would accelerate to 3 kms/sec The continuous acceleration would be 3000/9.8/0.73= 417 Gs. That is sure a lot of Gs. Much more than the 3.2 the shuttle produces.

Newer howitzers can have a muzzle velocity of almost 900m/s. They achieve that velocity in a barrel length of only 8.52 meters (55 calibres X 155mm). So 3 km/s in 1.1 km doesn't seem like a big ask.

Re:G force.

[Anonymous Coward]

I think you misread the summary. 3 km/s is the muzzle velocity of SHARP, the earlier research project. This proposed one would have a muzzle velocity of 6 km/s, so the final acceleration comes out higher by a factor of (6/3)^2 = 4.

Re:G force.

[Ihlosi]

I'm wondering about how they would intercept and retrieve the payload once it is in orbit. The amount of kinetic energy it retains from getting to orbit (I'd assume, likely incorrectly, IANARS) would still be pretty massive problem to tackle.

That's not an issue. _Anything_ "in orbit" has quite a bit of velocity, else it'd simply fall down. The ISS, for example, is moving at about 7.5 km/s relative to Earth.

In fact, the gun wouldn't put anything in an orbit by itself, since the trajectory of the projectile will intersect Earth. The projectile still needs a rocket motor to actually enter orbit, as the article says.

Re:G force.

[Hurricane78]

The 0.73 seconds are wrong. Because it *accelerates*. It won't be at 3 km/s for nearly all of the gun. It's exponential.

Re:G force.

[Ihlosi]

The 0.73 seconds are wrong. Because it *accelerates*. It won't be at 3 km/s for nearly all of the gun. It's exponential.

Actually, if the acceleration is constant, it's quadratic, not exponential.

s = 0.5 * a * t^2

Re:G force.

[argStyopa]

"This gun should be able to handle pretty much all of the consumables and many of the parts and materials needed by the space station."

Thus, this ALSO becomes the perfect economical method of sending celebrities and other supertourists into orbit as well, killing two birds (in effect, THREE) with one stone.

Re:G force.

[pavon]

No, his calculation is correct. Given constant acceleration:
v = a*t
d = 1/2*a*t^2 (by integrating above)
d = 1/2*v*t (by combining above)
t = d/(v/2) (solving for t)
so plugging in the values for when the payload leaves the muzzle you get the time at which the payload leaves the muzzle, which is exactly what he did.

Re:G force.

[GuanoBoy]

I think the electronics in the Copperhead anti-tank round are built to handle 7000 Gs, according to what I read long ago.

Re:G force.

[jklovanc]

I did get the equation a bit wrong in that the muzzle velocity if 6km/s not 3km/s. so the calculation should have been;
1.1/(6/2) = .36
6000/9.8/.36 =1700Gs.

If acceleration is constant and V0 is 0 then
Average velocity is (V0 +Vt)/2 =Va
Vt = 6km/s
Va = (0+6)/2 = 3
therefore the time in the 1.1km barrel is 1.1/3=.36
Therefore the item accelerates from 0 to 6kms/sec in.36 seconds to convert that into acceleration
6000/.36 = 16667m/sec/sec converting to Gs by dividing by 9.8 = 1700Gs.

A simpler method would be to use Torricelli's equation Vf^2 = V0^2 +2AS
A = Vf^2/(2S) A = 6000^2/(2*1100) =16363 m/sec/sec

Re:G force.

[jklovanc]

Sorry but you missed the point. The electronics are one part. There also has to be liquid fuel thrusters to be able to dock with the space station. It would also need external guidance to be given commands to be able to dock. This is much more complex and fragile than a fin steered terminally guided laser seeking bullet.

this has real potential...for certain things

[eobanb]

I think this could have real potential for getting raw material into orbit. Delicate electronics aboard satellites would obviously not fare too well with such high acceleration, but if we ever wish to build large space colonies in the Earth-moon area, this would be the way to do it. We'd probably need to spend a few billion to launch the machines necessary to process raw material, but apart from that, the rest could be made from raw material. The ISS masses about 400 tonnes. A small space colony that supports, say, 100 residents, would probably need to mass around 50 times that of the ISS, I would think, so that's around 20,000 tonnes, which would require about 50 launches with this gun.

Re:this has real potential...for certain things

[Nefarious Wheel]

Delicate electronics aboard satellites would obviously not fare too well with such high acceleration

How delicate - are we talking about vacuum tubes, with their little feathery grids and filaments? I think the term "delicate" doesn't really apply to electronics any more, or rather doesn't have to. You couldn't use modular circuit boards, of course - you'd snap the connectors off. Or any sort of what we'd consider normal PC electronics, such as pluggable cables or rotating components such as disks or fans. They're built to be easy to build, and to modify.

But custom electronics, single-board stuff and SSD's, that can be made pretty robust. I'd think you could build them for 3-digit accelerations.

Re:this has real potential...for certain things

[crispin_bollocks]

Just pot it all! Can't put my fingers on the facts, but non-operating hard drives are now close to triple-digit G ratings I believe, and SSDs should be pretty robust.

Re:this has real potential...for certain things

[AJWM]

With discrete component electronics you just pot the whole thing in epoxy. I don't know how well that works with integrated circuits -- the point of failure is likely to be the fine wires that connect the chip to the package leads, although those may be light enough that the real concern is vibration rather than steady G force. Even vacuum tubes can be built tough, if they're built small.

But ~400 Gs (per calculations by a poster above) is nothing. The radio proximity fuzes in WW II antiaircraft projectiles didn't use transistors, and had to withstand ~20,000 Gs when fired and ~5,000 Gs of shell spin.

Re:this has real potential...for certain things

[wisdom_brewing]

50 launches? thats 400 tonnes a launch, not 400 kilos... Plus the ISS has a mass of 303,663kg as of june 10th - that would take 674 launches at 450kg a launch with no loss (so say 1,000 to be remotely realistic).

If we could launch once an hour that would take just over a month. not bad at all... the question to ask, what is the cost per launch and how often could you launch?

In any case a space colony to support 100 people could be made much lighter... scaleability and all... probably half what you suggest... but a couple of years doesnt seem unfeasible to get something together... if youre working over a decade and are happy to build a couple of these guys (maybe scale it up if it works well? could get lower G's with a longer tube for slighly more delicate objects...) then you could build something a lot more substantial than anything currently feasibly.

We'd still need classical launches for people, etc, but for building materials, resupply, blah, this would be very useful.

Oblig air gun comment

[Anonymous Coward]

You'll shoot your eye out.

1670 g

[Michael Woodhams]

All you need is a booster rocket (and a cargo) which can stand 1670 g of acceleration (possibly higher, if the gun does not provide uniform acceleration.)

v^2 = u^2 + 2*a*S
u=0, v=6000, S=1100 => a=16,364 m/s^2 = 1670g

Re:1670 g

[John Hasler]

Which, given that artillery shells exceed 2000g and are full of explosives, electronics, and machinery, should be easy.

Re:1670 g

[Anonymous Coward]

What machinery exists inside an artillery shell?

Re:1670 g

[name_already_taken]

What machinery exists inside an artillery shell?

All kinds of gadgets, for example a timing mechanism so that the shell's explosive charge doesn't go off inside the gun.

Re:1670 g

[Duhavid]

Fusing to ignite the main explosive charge, whatever linkages were needed to make the various settings. Early naval shells had some time delay, so that the explosion happened after the shell had had time to penetrate the armour of the other ship. WWII anti air craft shells had some combination of mechanical and electric/electronic control to detect the proximity of an aircraft, and explode near the aircraft, rather than the older time delay fusing ( which itself would have required some mechanical method of setting the delay either just before loading, or after ).
IIRC, some land artillery of the WWII era had an "airburst" option, where it was set off up in the air, causing more damage.

What I always wondered was if the aircraft carrier had not come along, would we have seen some terminal guidance systems for naval and land artillery?

Re:1670 g

[John Hasler]

> What I always wondered was if the aircraft carrier had not come along, would
> we have seen some terminal guidance systems for naval and land artillery?

We did. The US Army had artillery shells with terminal guidance in the 1970s.

Re:1670 g

[Duhavid]

"We did. The US Army had artillery shells with terminal guidance in the 1970s."

I never heard of it. What did it home on? ( or can you say? )

Re:1670 g

[John Hasler]

The one I read about in the seventies had optics in it but there were no specifics about what it homed in on. Later I heard about one that homed on a laser target designator but I don't know if it was the same device. I would expect them to be using GPS now.

What is interesting is that the electronics were not potted. They simply used thick boards supported all the way around the edge and made sure all the parts were installed in contact with the board (i.e., not standing up on their leads). This was the seventies so the parts were DIPs, discrete transistors, quarter watt resistors, etc. Modern surface mount parts should be more robust yet.

I see no major problem shipping most stuff that the station needs via this gun. Some equipment might need to be more robust than usual, but so what? The reason for making such things as light as possible is to save on launch costs. If this thing is 1/10 the cost of conventional rockets you can double the weight of your experiment to make it tough enough to survive the gun and still come out way ahead.

Re:1670 g

[MichaelSmith]

I believe that there are laser and GPS guided artillery shells which have terminal guidance.

Re:1670 g

[MichaelSmith]

$500 million US dollars is about the cost of one Shuttle launch.

Re:1670 g

[John Hasler]

Right, but the operating costs, while lower than those of conventional rockets, will be far from zero.

Re:1670 g

[MichaelSmith]

Yeah also a lot of the cost of operating the shuttle is ongoing. You can't save much money by scratching a launch. And a rocket can launch in any direction, while a gun would have a fixed azimuth.

Re:1670 g

[Thagg]

The most well known of these was the Copperhead It was a cannon-launched guided warhead, with pop-out fins. Apparently it was used in Desert Storm.

Re:1670 g

[Anonymous Coward]

http://www.globalsecurity.org/military/systems/munitions/ergm.htm

Re:1670 g

[strack]

oh no! not a fixed azimuth! thats just terrible! cause, as we all know, the ideal orbit to launch into is changing all the time. and its impossible to use thrusters to change orbit. really. no. honest. also, you know what your talking about.

Re:1670 g

[jafiwam]

Along with this thing, there are rapid fire weapon systems that can program a series of the shells to land at the same time using delayed trajectories and braking.

One gun will seem like 30 guns firing at once for area coverage.

Re:1670 g

[Tekfactory]

We built the ISS in the orbit we did to accommodate the Russians. The shuttle gets less payload per launch to the ISS because it needs more fuel to get there than an orbit closer to the equator. So the orbits you can use NOW are dictated by the rocket you use, and the launch site you choose.

The world's longest boat is 458 meters long, the longest floating bridge is 2 kilometers.

Who's to say you can't have a really big 'sea launch' that can move to launch zones for different orbits.

Though as others have pointed out, you could fire a bunch of payloads into orbit and have a transfer vehicle take them to the staging area, refueling depot or build site.

What I haven't seen talked about as much here is the idea that this thing should be built on a really tall mountain so the projectile doesn't have to go as far or fight so much wind resistance before the rocket motor ignites.

Re:1670 g

[John Hasler]

> ...the ideal orbit to launch into is changing all the time.

There is no one ideal orbit for everything.

> ...and its impossible to use thrusters to change orbit.

The fixed azimuth is a serious limitation. Large plane changes consume large amounts of fuel. For example when a shuttle goes to Hubble it cannot carry enough fuel to also go to the station because of the orbital plane change that would be required. It isn't a matter of getting up there and then zipping around like something on a TV show.

> ...you know what you['re] talking about.

So it would appear.

Re:1670 g

[HiThere]

Hey, it was good enough for "When Worlds Collide" (movie version).

I'd bet that when it comes to where it gets built, pork will trump praticality. If Colorado has a Senator on the right committee, then a mountain lauch will win, otherwise ...well ... the California Sierras are pretty tall, and sereral states have peaks in the Rockies. (Up the side of Pike's Peak?) But most places don't have the right mountains.

Or perhaps we should get a foreign contractor. The Himalayas get pretty high...

Actually, what I really like about a mountain launch is that the angle is steeper, so the velocity is closer to the direction you want it to have. For that purpose a deep pit would work nearly as well...but such pits tend to collapse. And you'd need to somehow ensure that the mountain was sturdy enough to survive the stresses of launch.

Re:1670 g

[HiThere]

That's where an ion rocket would be a good idea. It's slow, but it doesn't use resources quickly. It should be automated, so it wouldn't need a life-support system that would add weight and not much value.

And if you need more thrust than an ion can supply ... well, you might look at the plasma rocket.

There are lots of choices if you don't need something with strong acceleration.

Re:1670 g

[jamstar7]

What I haven't seen talked about as much here is the idea that this thing should be built on a really tall mountain so the projectile doesn't have to go as far or fight so much wind resistance before the rocket motor ignites.

The Altoplano in Peru sounds good to me. Course, I'd prefer a laser launching system over a gun, but that's just me...

Re:Your official guide to the Jigaboo presidency

[lbalbalba]

This a-hole has been posting the same denigrative and racial post multiple times now, think that maybe it's about time we should consider banning this person/account from slashdot by now ?

TFA, my good sir:

[Eil]

While humans would clearly be killed and conventional satellites crushed by the gun's huge g-forces, it could lift robust payloads such as rocket fuel. Finding cheap ways to transport fuel into space will lower the cost of keeping the International Space Station in orbit, and in future it may be needed to supply a crewed mission to Mars.

Agree with you, but .....

[Anonymous Coward]

... can you reply to the right post??

Re:Agree with you, but .....

[lbalbalba]

... can you reply to the right post??

I *was* replying to the 'INSTALLING YOUR N****R' post, just hit the 'parent' button below my initial post to verify. Oh well, nevermind, mod this minus 1 offtopic as well...

Launch loop

[S1ngularity]

I like the launch loop idea (and of course the space elevator). Sounds like getting the gun built would be a decent first step for all the truly wacky space access methods on peoples' radar.

BAD MATH

[dragonjujotu]

Seriously where did you learn to do your math...

baloons?

[fireball84513]

so basically, were just using the classic Wile E. Coyote physics where you can take an object and make it travel anywhere as long as you have a cannon and a LOT of gunpowder

Blast It From Orbit...

[Anonymous Coward]

It's The Only Way To Be Sure...

A helping hand?

[BigBadBus]

Get the guy who built the Iraqi "supergun" to help out...or the people who wanted to build the Nazi V3 cannon!

Re:A helping hand?

[Kartoffel]

Operation Paperclip got the Nazis, and it helped get Americans to the moon.
The Mossad, uhh, "got" the guy who built the Iraqi super gun.

Re:A helping hand?

[Robin47]

He died in an earlier post.

Re:A helping hand?

[MichaelSmith]

O
The Mossad, uhh, "got" the guy who built the Iraqi super gun.

Ah thats good to know. I wonder if they can give me his email address....

Re:A helping hand?

[mjwx]

Ah thats good to know. I wonder if they can give me his email address....

If you want Mossad's attention, just put this jacket on and get on that bus.

Re:A helping hand?

[Anonymous Coward]

those zombie Nazi rocket scientists are hard to keep down

Gravity

[zakeria]

do you not need to be going at 11.2 kilometers per second to escape Earth's gravity? 3 kilometers per seconds does not seem anywhere enough to save on rocket fuel?

Re:Gravity

[Anonymous Coward]

Escape velocity is the speed you need to reach to never fall back to earth. To reach orbit you just need to be traveling fast enough to fall around the planet instead of into it.

Re:Gravity

[John Hasler]

It saves a great deal of fuel by getting the rocket needed to achieve the remaining velocity going 3km/sec and above the atmosphere.

Re:Gravity

[electrostatic]

It would be impossible to go through the atmosphere at orbital speed. Especially at low altitude. When an object in orbit enters the upper atmosphere it's going about Mach 25. Hence the burn.

If it were completely launched into orbit from a low altitude gun, the velocity would have to be much greater than orbital to account for the horrendous air resistance -- simply not possible.

I recall that of the 8-plus minutes the shuttle needs to reach orbit only about 2 minutes are in the atmosphere.

Re:Gravity

[John Hasler]

> If it were completely launched into orbit from a low altitude gun, the
> velocity would have to be much greater than orbital to account for the
> horrendous air resistance -- simply not possible.

Mainly because the muzzle velocity of a gun is limited by the speed of sound in the propellant gas.

1670 g without knowing any formulas

[Anonymous Coward]

One can get to this result without knowing any formulas (like myself) with Wolfram Alpha: http://www.wolframalpha.com/input/?i=6+km%2Fs+in+1.1+km%5D/

Re:Your official guide to the Jigaboo presidency

[Anonymous Coward]

Ah I love the smell of terrified redneck racist in the morning it smells like victory!

Still I pity your need to overcompensate for your inadequacies.

Go up thread and read about artillery shells.

[John Hasler]

n/t

I like my eggs over easy....

[Tangential]

I guess that won't be an option for space dwellers getting their supplies this way. There will probably be a lot of powdered or hard boiled eggs for their breakfasts.

Re:I like my eggs over easy....

[Tekfactory]

2-3 solutions,

Send up the Egg Whites and Yolks separately, even in powdered form, pour each into Japanese food molds shaped like an egg white and a yolk, then tell yourself you're in SPAAAACE and this is close enough.

Send up real Eggs OR Chickens via less destructive transportation, fatten the chickens on grain that does just fine at speed.

Freeze the Eggs? You know flash frozen, no ice crystals, then defrost overnight before breakfast.

If I had the choice of hard boiled eggs on earth or scrambled in space, I know what I'd pick.

Why gas?

[Seth Kriticos]

Wouldn't a rail acceleration ramp (railgun) be better suited for this purpose? At least I can imagine that it would distribute the starting acceleration a lot better. With this thing you'll have difficulties keeping the stuff together you want to catapult up.

Re:Why gas?

[John Hasler]

> Wouldn't a rail acceleration ramp (railgun) be better suited for this
> purpose?

Artillery is well-established technology. No one has built a large railgun yet.

> With this thing you'll have difficulties keeping the stuff together you want
> to catapult up.

Read the discussions about artillery shells elsewhere in tht thread. It isn't that hard.

Re:Why gas?

[Digestromath]

Extreme heat and magnetic forces would make it harder on the payload. Ultra high energy railguns usually need to have thier rails replaced everyfiring. Add in the complexity of, no doubt, hundreds of massive capicitors, it would be like the LHC.

That's booking it

[HangingChad]

fire projectiles weighing a few kilograms at speeds of up to 3 kilometers per second.

That's in the neighborhood of 9,480 feet per second. About twice the speed of a high velocity bullet. A projectile weighing kilograms going twice the speed of a bullet.

Who besides me wants to forget the space thing and launch those projectiles against ground targets?

Re:That's booking it

[MichaelSmith]

Who besides me wants to forget the space thing and launch those projectiles against ground targets?

It goes so fast you would have to do a complete orbit to fire over the horizon. Don't shoot yourself in the back of the head.

Re:That's booking it

[John Hasler]

Naval guns already manage half that velocity with projectiles weighing tons.

Re:That's booking it

[Lord Kano]

Even a hot loaded 30-06 is topping out aroung 3800 fps. This is a good bit more than double.

LK

Re:That's booking it

[calidoscope]

Are you sure about that?

The 16 inch guns on the Iowa class ships had 2700 fps muzzle velocity, about the same as a 30-'06 with a 150 grain bullet. Typical quoted range was on the order of 22 miles, vacuum range would be about 40 miles "according to my preecise calculations".

Re:That's booking it

[DanielRavenNest]

The actual SHARP gun tests were into the side of a hill at Livermore Lab. You had the 50m barrel horizontal, then a 10m long block of concrete with a slightly more than 10cm hole down the middle for the 10cm projectile to fly through. That was to protect the gun from blast damage. The hill had a hole dug in it filled with plastic milk jugs filled with water as "shock absorber". Otherwise your hill would get demolished by repeated firings.

At low speed tests, you could recover parts of the projectile and the milk jugs. At high speeds, pretty much everything vaporized.

The concrete block with the gun behind it was about 50 or 100m from the hill. If fired for best range, ie around 45 degree elevation, the projectile would land in NEVADA from Livermore, CA

Re:I See. Yet Another Cockamamie Scheme...

[porl]

once again, you come here claiming to know things that make us all look stupid, and yet all you can actually say of it is ridiculous predictions with no evidence whatsoever (other than the aforementioned 'you are all stupid and i'm not' type nonsense)... perhaps you have been spending too much time with 'dr' gene ray, the 'worlds wisest human' (self proclaimed of course - www.timecube.com ). your arguments are very similar to his. show us one bit of evidence that this 'lattice' is real, and, more importantly, able to be accessed in any meaningful way. your blog has no evidence to support this whatsoever, so i'd like to know (truly, i would. i am more open minded than you would probably think) where it is you have based your assumptions on. i am sure i am not the only one here who would actually like to know more about this amazing discovery.

Re:We Don't Need Fuel in Orbit

[westlake]

We need a new transportation technology that does away will all that stuff.

You work with what you have.

Re:We Don't Need Fuel in Orbit

[jeffb (2.718)]

Why don't you just say what you really mean: "Waaahhh! Our laws of physics SUCK! I don't believe in them."

Actually, I'm probably confusing you with another poster who spams about his free-energy fantasies. If you're just talking about beanstalks and solar sails, well, maybe, but I think "fuel" and "reaction mass" are going to be the central part of our intra-system arsenal for quite a long time.

Just som simple physics:1700g

[viking80]

0-6km/s in 1.1km give an acceleration of 1700g. Few things will survive this. Especially not people or satellites. Pretty much only uniform solid metal, such as a bullet.

Re:Just som simple physics:1700g

[Plekto]

There's nothing to keep them from making it 11km long and making the forces much less of a problem. That's long, but not unreasonably so (about twice as long as the longest runways). Just have it climb up the side of a really tall mountain at the end.

Re:Just som simple physics:1700g

[viking80]

You are wrong. If you try to bend it upwards at the end, the centripetal forces will be high. 6km/s and a bend-radius of 1km will give an additional 3700g. At 450kg, that means that the load on the barrel sidewall goes from zero to 16MN or 1,700 metric tonnes m.e. Bedrock would not support that kind of local load.

Re:Just som simple physics:1700g

[Plekto]

Obviously the end of the barrel would be straight. The bend would be best done near the beginning so that the last 8-10KM is pointing up the side of the mountain at a slight incline. The problem of course would be to find a suitable location, since the only examples that I know of that might work are usually volcanoes and the like.(ie - not very geologically stable or near fault zones). You also don't want to build this in Alaska or someplace with horrendous weather extremes. A better question might be what is the largest bend that we could put in it without it destroying itself?

OK, apparently I'm NOT confused, spammer.

[jeffb (2.718)]

Whoops, missed your post downthread. Please ignore my second paragraph.

Disaster Area

[MichaelSmith]

Not only is it the loudest gun in existence, it is in fact the loudest noise anywhere at all.

Re:We Don't Need Fuel in Orbit

[Nyeerrmm]

Show me an idea with reasonable designs (materials, layout, feasibility analysis, cost estimates) and I'll be interested.

I agree, our current technology is dangerous, primitive, expensive and cumbersome. It has one advantage though: it works. Unfortunately, I have yet to see an alternative that doesn't rely on some sort of unobtanium. Maybe a space elevator will work some day, but as yet, not even nanotubes are strong enough to handle the mass. If this technology actually pans out, then it makes things a little less dangerous and primitive, and I take that as a win.

Location, Location, Location

[johno.ie]

I'm sure the research team have already considered this aspect of a gun launch. Chimborazo is possibly the best site on the planet for getting stuff into orbit. Not necessarily the best for getting stuff into the same orbit as the ISS, but a plasma powered tug would help with that problem. Another possible site would be Kilimanjaro.

Looking at Chimborazo, there seems to be a stretch of the West side of the mountain that is fairly uniform and about 1km in length. Perhaps that is why they picked 1.1km as a target design length for the launch gun.

Re:I See. Yet Another Cockamamie Scheme...

[algerath]

Hey wait this guy might be on to something, this lattice reminds me of something.
"It's an energy field created by all living things. It surrounds us, penetrates us, and binds the galaxy together."
Yes that sounds similar!
We need to master the lattice and soon we will be able to jump really high, move shit with our minds, and battle each other with laser swords.

space fountain

[Anonymous Coward]

This is a cool concept: http://en.wikipedia.org/wiki/Space_fountain . Lets see this fellow build on of those to get stuf into space!

Re:We Don't Need Fuel in Orbit

[Runaway1956]

I, for one, don't think that rockets are very good. I've been waiting for someone to build a nuclear powered engine, but the bright boys haven't come through yet. Once we have a safe engine, we need to know what to use for reaction mass - do we boil rocks? Iron and other metals could get terribly expensive, real fast.

Oh yeah - I'm waiting for the TV series: NOOKS IN SPACE!

We're using fish??!!!???

[rts008]

Yeah. With carp like this, is it any wonder...

[my emphasis]

I think I see a basic flaw in your understanding of rocket science...;-)

Now get off my lawn, and take your fish with you...it's starting to draw flies!

Doubts

[countertrolling]

I doubt it will work any better than this

First, a clown goes to ISS

[WormholeFiend]

now they're going to start sending human cannon balls too?

Re:I See. Yet Another Cockamamie Scheme...

[Tynin]

The Problem with Motion.

Your The Problem with Motion blog... might not be so bad, if you actually bothered to finish it. Instead all we have is claims with nothing to back it up. Please stop re-posting this blog spam until you finish writing the article in full... so we can at least attempt to understand what you are pushing. As they say, extraordinary claims demand extraordinary proof... or in this case, any proof at all. Maybe even put a disclaimer on the first page announcing you aren't going to finish writing it up at this time, instead of dragging people along, poking fun at some of the greatest minds in science / philosophy, and then ending it all in a rather conspiratorial way. Once the reader has already invested themselves into several pages, it is quite a let down to not even hear what the hell it is you are on about.

All that matters

[Tablizer]

As a tax-payer, I refuse to fund it unless it makes a cool "FffffummmppPPP" sound.

Re:All that matters

[bkr1_2k]

World's largest potato gun. Cool.

Metal Gear?

[Anonymous Coward]

Am I the only one reminded of Metal Gear Solid by this?

Not nearly enough

[jrst]

1. In round numbers:
. ~9.5 km/sec to LEO (given, approximate)
. ~6.0 km/sec from gas gun (FTA)
. ~0.5 km/sec atmospheric drag (FTA)
= ~4.0 km/sec needed from projectile rocket
. 350s ISP for projectile rocket (assumed, optimistic)
= 0.69 propellant fraction
. 450Kg projectile (FTA)
= 310Kg projectile rocket propellant
= 140Kg projectile non-propellant
. ???Kg projectile structure, motor, etc.
= ???Kg net cargo to LEO (in any case, 140Kg)

2. Assuming you want to rondezvous with something in an established orbit (e.g., the ISS), any significant orbital maneuvering is out of the question; in paticular an orbital plane change--whether by the projectile or the target--as it's too expensive.

That limits the number of launch windows. You can't simply launch projectiles into orbit as fast as the gun can fire, otherwise you'll end up with them scattered in various orbits that you have to chase down (again, very expensive).

E.g., there are nominally 2 launch windows/day for Shuttle flights from KSC to the ISS. (Due to various rules, in practice it's limited to 1/day, but we'll ignore that.)

3. Even with optimal launch parameters, orbital rondezvous is still non-trivial, and one reason why even unmanned ISS resuplly vehicles are much more than simply a dumb ballistic container, and have, e.g., OMS and RCS motors, propellant and the weight/complexity/cost penalties that come with them.

Which is why larger, more infrequent and expensive missions will remain the norm for the foreseeable future--with or without a space gun or its ilk.

4. In short, we need an orbital infrastructure that can handle smaller/dumber vehicles. That doesn't exist, and few if any of these proposals account for it. With, e.g., a group of ion/electric tugs it may make more sense. That is, something that can cost-effectively collect those smaller/dumber vehicles and bring them to where they're needed.

Re:Not nearly enough

[Dunbal]

Not only that, but consider this:

      The gun barrel is 1100m long. The velocity of the projectile, as it leaves the barrel, is 6m/s.

      Using the equations of motion:

      s = 1/2(u + v)t

      1100m = 1/2(0 + 6000m/s)t
      1100m = (3000m/s)t
      t = 1100m/3000m/s = 0.367 seconds.

      To find out the acceleration:

      v = u + at
      6000m/s = 0 + a(0.367s)
      6000m/s / 0.367s = a
      16348m/s^2 = a

      g = roughly 10m/s^2 (ok ok 9.8)

      So your projectile has to be engineered to survive 1635 g's for a third of a second while blasted out of this gun. I'm not taking into account any heat - generated by gases or friction along the gun barrel, either. Now apart from rocks, exactly WHAT functional stuff do they plan on hurling into space with this?

      I call BS - or an attempt at getting free grant money...

Re:Not nearly enough

[Anonymous Coward]

If the gun were built right on the equator, not only would it get the maximum benefit from Earth's rotation, but one could fire it as often as one wanted without regard for orbital planes. One just has to tweak the phase of the orbit by moving slightly higher or lower until one meets up with the depot.

Re:Not nearly enough

[bkr1_2k]

As others have mentioned, food, water, raw materials all come to mind. Also, plenty of electronics for ballistics have been designed to survive higher acceleration rates.

Re:Not nearly enough

[Anonymous Coward]

If you can chuck propellant cheaply into orbit, which this thing proposes to do, your points are wrong.

An orbital change is not too expensive anymore.
The complexity of resupply vehicles can be offloaded to a tug.
You don't need ion electric, vasmir or whatever, just plain rocket engines will do.

Still, all this does affects the economics of the idea. I don't know that it makes it unviable, tho.

Re:We Don't Need Fuel in Orbit

[khallow]

Yea, until the science of telekinesis developments to the point where we change the laws of space through will alone, we'll have to depend on primitive zero point energy technologies.

Re:I See. Yet Another Cockamamie Scheme...

[sixwings]

I think you need to take another look.

Short-term Project

[bill_mcgonigle]

Send up consumables, for sure. Fuel, water, compressed air, freeze-dried food, etc. Even if just used for that, this is not a bad plan. There's no rule that says you have to use only ONE method to get stuff off-planet.

One good criticism would be that this is a short-term project. You'll need conventional lift to get the tools up into space to build an orbital mining facility. This air-gun can be used to lift all the materials that those tools will use to build the mining facility and fuel for the crafts that will go get the asteroids and coax them back. But once that's done, we ought not need the air gun nearly as much or at all.

Still, compared to the costs of things like shuttles or ISS, this is pocket change.

Re:Short-term Project

[Tumbleweed]

You'll need conventional lift to get the tools up into space to build an orbital mining facility. This air-gun can be used to lift all the materials that those tools will use to build the mining facility and fuel for the crafts that will go get the asteroids and coax them back. But once that's done, we ought not need the air gun nearly as much or at all.

Depends on what you're planning, really. If your goal is to actually spread the human race out from Earth, this could be used long-term. Just keep sending up loads of water and compressed air, etc., for however long you can afford to do so. Keep the stuff in a stable orbit and just leave it there for however long you need (years, no problem, really). Once you're ready to use it (in LEO, at a Lagrange point, on the Moon, Mars, etc), move it to where you need it, as the most costly part of getting it into orbit has already been done.

That's one of the biggest problems with the U.S. space programs, the lack of long-term thinking and planning (and funding for a long-term strategy).

Re:Short-term Project

[bill_mcgonigle]

Just keep sending up loads of water and compressed air, etc., for however long you can afford to do so

I've heard it argued by folks who sounded like they knew their stuff that it's much cheaper to do it by dragging in asteroids (maybe one with a cubic mile of ice in it) than to shoot it up from earth. I admit, I haven't seen the numbers.

And, yes, it seems unlikely that governments will get this done.

Re:Short-term Project

[Tumbleweed]

I've heard it argued by folks who sounded like they knew their stuff that it's much cheaper to do it by dragging in asteroids (maybe one with a cubic mile of ice in it) than to shoot it up from earth. I admit, I haven't seen the numbers.

Considering we just hit the Moon to try to figure out how much water ice is there, it seems unlikely that we have any good ideas on which asteroids have water ice in them, much less the ability to bring them to where we need them (yet). That's more the type of project I'd expect a few decades _after_ we do what this project is talking about. All in good time, my friend...

Re:Short-term Project

[wvmarle]

For leaving it idle for years, LEO is not good enough. There is still too much drag from the atmosphere there: in a matter of weeks or months (depending on altitude) it will fall back to earth. Those orbits are unstable and satellites need power to stay there.

Also the cannon as suggested would only get the spacecraft to the correct altitude, and rocket engines are still a necessity to get it to orbit.

Re:Short-term Project

[bill_mcgonigle]

Considering we just hit the Moon to try to figure out how much water ice is there, it seems unlikely that we have any good ideas on which asteroids have water ice in them

Some progress on that front:
http://www.usnews.com/science/articles/2009/10/08/ice-confirmed-on-an-asteroid.html

much less the ability to bring them to where we need them (yet)

Yeah, I think smart folks feel it's a pretty straight-forward, if slow, proposition, but we'd have to still design and build the actual devices. Heck, convincing the populace that the rocket scientists wouldn't crash the asteroid into Earth is probably the hardest part.

That's more the type of project I'd expect a few decades _after_ we do what this project is talking about. All in good time, my friend...

Agreed. :) This kind of air gun could be a good way to bridge the gap.

Re:Short-term Project

[Tumbleweed]

For leaving it idle for years, LEO is not good enough. There is still too much drag from the atmosphere there: in a matter of weeks or months (depending on altitude) it will fall back to earth. Those orbits are unstable and satellites need power to stay there.

Also the cannon as suggested would only get the spacecraft to the correct altitude, and rocket engines are still a necessity to get it to orbit.

I agree, which is why I didn't say LEO, but 'a stable orbit'. This method still gets you most of the way there much more cheaply than any other method we've currently got.

Re:Short-term Project

[Anonymous Coward]

You can't just put something up and expect it to maintain orbit without fuel.

Re:Short-term Project

[mlush]

So by making 'space mining' feasible it makes itself obsolete, you say that like its a bad thing..

Re:Short-term Project

[Anonymous Coward]

That's one of the biggest problems with {congress|corporations|The UN|college students|Linux Dev|the reptilian brain|...}, the lack of long-term thinking and planning (and funding for a long-term strategy).

Re:Short-term Project

[bill_mcgonigle]

So by making 'space mining' feasible it makes itself obsolete, you say that like its a bad thing..

Really, if the typical critics had that kind of imagination they wouldn't be critics, so it's probably a non-issue with them. Fighting that lack of imagination would certainly be much harder.

The troubling middle will be researchers competing for funds for their special lift ideas who can see the potential but would rather not see it funded.

Re:Short-term Project

[HiThere]

I think that once you get to LEO an ion rocket could provide enough propulsion to get you higher. It would take awhile, but you were talking about a period of years.

Re:Short-term Project

[mruizcamauer]

Could a protruding tip ahead of the cone provide a way to create a plasma that opens up a tunnel through which the projectile can slip through, reducing drag? Could it split the air in the gun ahead of the projectile such that it did not touch the sides of the cannon but rode on compressed cushion of gas on the sides? If you filled it with a liquid like fuel, what would happen to liquid due to the spin you'd surely want to give to the projectile? would the friction make it not spin, or would it add a lot of pressure at the front and back ends from the liquid that pushes against the walls?

Re:Short-term Project

[Geminii]

If your goal is to actually spread the human race out from Earth,

Not to mention all over the landscape. Ew.

WoW

[argontechnologies]

I just want to know who can make a spit wad that weighs 450Kg??

Re:I See. Yet Another Cockamamie Scheme...

[sixwings]

Well, I disagree that I provide no evidence. I am simply reinterpreting the evidence that everybody has in front of them. Yes, I think it is stupid not to accept causality and the discreteness of nature. Denying causality and discreteness is on a par with the flat earth hypothesis. My claim is not that we are immersed in energy. That is a trivial inference to make. To the infinite embarassment of the physics community, it follows logically from the application of causality to motion. I don't need to show experimental proof for causality or discreteness. It should be a given. My claim is that we will soon be able to tap into the lattice for energy production and propulsion. The experimental proof of that is coming. A little patience, por favor.

By the way, don't go thinking that physics is not filled to the rim with hypotheses and theories for which there is no proof. It's called theoretical physics.

Why the limit on 1.1km

[Anonymous Coward]

Why does the gun have to be limited to 1km? If they don't point it into the air initially, but rather along the ground, and then a smooth bend upwards when payload has reached enough speed, it could be made 10 times as long, reducing the G as much too... And to make both the payload and gun withstand the pressure in the bend they could use maglev tracks or something.

Re:We Don't Need Fuel in Orbit

[Anonymous Coward]

I, for one, don't think that rockets are very good. I've been waiting for someone to build a nuclear powered engine, but the bright boys haven't come through yet. Once we have a safe engine, we need to know what to use for reaction mass - do we boil rocks? Iron and other metals could get terribly expensive, real fast.

Done and...

Oh yeah - I'm waiting for the TV series: NOOKS IN SPACE!

done.

Nuclear rockets have been around for 40-50 years. We just never used them. And any time you have the guy who did the SFX for Star Wars doing documentaries about nukes, you get something pretty damn cool.

Did anyone figure on maintenance?

[baegucb]

A cannon has wear and tear. Such as due to heating, abrasive effects, or stress of launches. There's a reason why they sometimes have to replace the tubes on tanks and howitzers. But they don't cost $500 million each. And since it is the government, they'll probably want to xray the entire thing after every launch looking for cracks.

Re:Your official guide to the Jigaboo presidency

[baegucb]

Explain how you'd ban an AC? By IP address? This is slashdot and we all know how to get around a ban. Moderation makes the posts sink into oblivion.

Re:I See. Yet Another Cockamamie Scheme...

[tibman]

It's a trap!

As Pres.George Bush,Im honored Americans chose me

[Anonymous Coward]

as your president, I'm honored that Americans chose me to be the first to be sent into orbit, but I got this here letter from my Daddy that says I don't got to go -- nya nanny nah gnAA -- zoom, zoom, Zoom, ZOOOM!

P.S. tacos rule.

Re:I See. Yet Another Cockamamie Scheme...

[Nefarious Wheel]

Perhaps he's referring to the truly Astounding Dean Drive!

A wonderous invention that somehow didn't make it from the Golden Age of SF to the far distant future of 2009.

And I've nearly got this perpetual motion thing worked out...

I browse at -1. Moderation is censorship.

[Anonymous Coward]

You wouldn't believe how many insightful posts are getting put at -1 by overzealous mods, that I'm willing to wade through the horseshit just to see an outspoken opinion of experience. It's like Catholics at the top persecuting all over again the mennonites, Amish, hugonaughts, and others just because they can by greater number.

Guess we can see where this is going.

Re:I browse at -1. Moderation is censorship.

[Hognoxious]

It's like Catholics at the top persecuting all over again the mennonites, Amish, hugonaughts

Rubbish. It's not possible that the Catholics persecuted the hugonauts.

Jason's voyage in search of the golden fleece happened long before Christianity.

Re:I browse at -1. Moderation is censorship.

[St.Creed]

Argonauts.. as in "arrrghh you just murdered a piece of classical mythology" :)

And Huguenots.

Re:I browse at -1. Moderation is censorship.

[Hognoxious]

And Huguenots.

I don't see what African pygmies have to do with it.

Re:I See. Yet Another Cockamamie Scheme...

[Nefarious Wheel]

"This cake was made with rotten eggs!"

"I think you need to take another bite."

Orbital factories

[Anonymous Coward]

If moving durable cargo to space becomes truly inexpensive, then transport mainly raw materials that way and build what you need in orbit. Conventional methods would be used only for passengers. If you're talking about building something really big, like a heavily radiation shielded manned transport to mars, it might be a good way to go - better than building it on earth and then launching it.

so I guess...

[Tastecicles]

...it'd be out of the legal range of a non-FAC airgun shooter then?

Bummer.

On saying that, I've yet to find a law which covers large-bore homemade air projectile launchers.

Put one on the ISS

[AliasMarlowe]

It could be used to launch the "organic wastes" at high enough speed that they simply drop, conferring at least two benefits: (i) a boost to compensate for orbital decay, (ii) making people on Earth rather nervous and increasing sales of robust umbrellas. Since it would be used only for eco-friendly recycling, it could not possibly be considered a weapon of any sort.
The cost would be higher, of course, but I'm sure obtaining funding would be even easier. The ground-based version would be a necessary stage in development, used to launch the parts into orbit.

Re:Put one on the ISS

[roguetrick]

You using that euphemism for shit or corpses? Because if it's corpses sign me up.

Re:Put one on the ISS

[K. S. Kyosuke]

Since it would be used only for eco-friendly recycling, it could not possibly be considered a weapon of any sort.

I'm sure this is what medieval siege engineers shouted at the unhappy garrisons of besieged castles they were bombarding with decaying horse corpses: "That's no weapon, we're just recycling!"

Re:Put one on the ISS

[AliasMarlowe]

Since it would be used only for eco-friendly recycling, it could not possibly be considered a weapon of any sort.

I'm sure this is what medieval siege engineers shouted at the unhappy garrisons of besieged castles they were bombarding with decaying horse corpses: "That's no weapon, we're just recycling!"

The besiegers ate horse corpses before they decayed. For bio-warfare ammo, they used decaying human corpses, preferably plagued. They also used shit. ISS could go either way...

Re:Put one on the ISS

[SQLGuru]

The cost would be higher, of course, but I'm sure obtaining funding would be even easier.

I know where they can get a lot of funding.

"Funding provided by NERF(tm)"

Re:I See. Yet Another Cockamamie Scheme...

[TapeCutter]

I don't know about the GP but I only needed one look. Do you realise you have reinvented Luminiferous ether?

Rockets Are Not the Answer

[Anonymous Coward]

Nuclear rockets are just as dangerous as chemical rockets, if not more so. The problem with any kind of rockets has to do with overcoming inertia. If you want to get somewhere really fast, you have to accelerate hard and then decelerate hard. Most cargo and living matter cannot withstand the g-forces. You should take a look at Charlie Ross's excellent essay, The High Frontier, Redux for an overview of the insurmountable problems.

PS. I am posting anonymously because the censorship police on /. is trying hard to keep me from posting.

sixwings

Following Saddam Hussein's Big Cannon?

[Anonymous Coward]

It could be used by terrorists to do something bad to someone at some undetermined time in the future, maybe. We have unequivocal evidence that supports this. It is an existential threat.

The US Government (Israel Branch)

Major Oh Noes!

[Anonymous Coward]

What's to stop the recoil of this darn thing turning the Earth into a giant Catherine Wheel and spinning us all in the wrong direction!?

Maybe on launch day we'll have to have a synchronised 'turn on your spin dryers' moment to act as a global inertial damper.

(This post is an attempt at humour (or humor, if you prefer), do not subject it to any serious scientific or mathematical analysis.)

Longer Gun = Less Gs?

[Anonymous Coward]

Would it work to build the thing ten times longer, end up with a tenth of max G and use it to launch normal satellites? Even if it then costs ten times more to build and to service (without doing any math on it, cause don't know how) after a few launches this thing should still be cheaper then building a giant rocket for each launch.

Would be nice if anyone who knows the numbers could elaborate on this.

Too dangerous

[Anonymous Coward]

...you could put someone's eye out

Re:I See. Yet Another Cockamamie Scheme...

[Anonymous Coward]

lol

just another retard claiming to solve all of physics' "problems" without showing a single calculation. if it can't be used to make a prediction, it's not physics, it's badly-argued philosophy mixed with bile and personal insults.

jog on, son

Kilimanjaro

[findoutmoretoday]

My favorite project: setting up a space gun on the Kilimanjaro. 

Re:Kilimanjaro

[findoutmoretoday]

I checked Chimborazo with 6,268 metres (20,565 ft) is even better.  Now if I could find a 300m/s maglev and a working ramjet

Re:Kilimanjaro

[John Hasler]

Getting above the atmosphere is more important than getting farther away from the center of the Earth.

Re:Kilimanjaro

[findoutmoretoday]

<quote><p>Getting above the atmosphere is more important than getting farther away from the center of the Earth.</p></quote>  Not for a ramjet,  but doing the second I will do the first.  Or is it about the equator: the Denali offers the same altitude as the Chimborazo and is 'American'.  Of course the Chinese hold the mount Everest

Re:Kilimanjaro

[Branko]

Getting above the atmosphere is more important than getting farther away from the center of the Earth.

If that were true, Burt Rutan's SpaceShipOne could easily go to orbit. The higher you are, the lesser atmospheric drag there is, but Earth's gravity well is still very much present (diminishing gradually in accordance to Newton/Einstein long after air drag has fallen essentially to zero).

Re:Kilimanjaro

[lotho brandybuck]

Yes, might also be nice to have a launch site with a little less humidity than... Florida, so anything with liquid H2/O2 doesn't turn into a big icicle before launch. The Atacama desert plains in Chile come to mind. But then, there's not many Florida voters down there.

Hydrogen?

[drinkypoo]

I hope they specified a solar array to generate all that hydrogen; the vast majority of our hydrogen is cracked at great expense from natural gas. It has always boggled my mind that power plants situated on rivers do not convert their excess, night time base load power into hydrogen. There is clearly a global market (hell, it's a welding gas.)

Re:Hydrogen?

[Ihlosi]

It has always boggled my mind that power plants situated on rivers do not convert their excess, night time base load power into hydrogen.

Because this process is hugely ineffective and couldn't produce hydrogen at "market" rates. Also, hydrogen is a major PITA to work with.

A proposal for human access to orbit

[Branko]

Ideal human delivery-to-orbit system:

• A tunnel, probably around 2000 km long, without any air in it, lined with magnetic levitation tracks.
• The human "cargo" is placed in what is essentially a maglev "train" and accelerates at relatively comfortable G to orbital speed (+ whatever extra is necessary to punch through the atmosphere).
• Near its end, the tunnel curves upwards and has a kind of super-fast airlock mechanism to let the "train" transition between vacuum and the atmosphere.

This would be hugely expensive to build, of course, but I have a strong feeling its capital cost would still be less then, say, annual US wasteful spending related to healthcare. Operational costs, one the other hand, would probably be just a tiny fraction of today's chemical rocket based approach.

"Get to low-Earth orbit and you're halfway to anywhere in the Solar system" - Robert Heinlein

Re:A proposal for human access to orbit

[Ihlosi]

This would be hugely expensive to build,

If you're in the business of hugely expensive, why not scrap the whole super-fast airlock and put the exit of the launch tube far enough from Earths surface that the density of the atmosphere isn't a problem anymore?

Otherwise, you still have to deal with heat shield, transition to the atmosphere and whatnot (i.e. the payload will have to be heavier to accomodate for all the shielding), while constructing the launch tube is a problem that can be solved on Earth and doesn't require carrying the solution into space.

Making the launch system more efficient is best done by leaving as much of it as possible on Earth, and only carry to space what's going to be used in space.

Re:A proposal for human access to orbit

[Branko]

If you're in the business of hugely expensive, why not scrap the whole super-fast airlock and put the exit of the launch tube far enough from Earths surface that the density of the atmosphere isn't a problem anymore?

You cannot structurally put the exit of the tunnel high enough to completely avoid the atmosphere. If you could - why not just build a space elevator or even space "tower" or "needle"? For the same reason, you cannot put the tunnel in vertical position because it would be too short for comfortable acceleration, not to mention hugely more difficult to build (compared to what is already an incredibly difficult project).

Of course, the higher you are the lesser problem you have (less friction, lesser "airlock" tolerances). Running the end of the tunnel up the (very high) mountain slope comes to mind.

The reason I made this post is to see if there is anything obvious that could stop this concept from being implemented in principle. So, if anyone has more criticisms - keep them coming!

Re:A proposal for human access to orbit

[Branko]

Making the launch system more efficient is best done by leaving as much of it as possible on Earth, and only carry to space what's going to be used in space.

I fully agree with that. The proposed concept will require some heat shielding (hopefully, reusable on reentry), but essentially all the mass that you eject is usable in orbit (propulsion system is left back on Earth), unlike current systems that have 90-something % of their mass spent on fuel, leaving very little "usable" mass.

Re:A proposal for human access to orbit

[Ihlosi]

You cannot structurally put the exit of the tunnel high enough to completely avoid the atmosphere.

That's mostly a matter of making a pile of rocks that's high enough (wouldn't even require any fancy new materials if you're willing to bring half a million bulldozers). And bypassing all of the atmosphere isn't necessary, but bypassing most of it would be nice.

If you could - why not just build a space elevator or even space "tower" or "needle"?

Because piling stuff 10 km high is obviously harder than piling it 100 km (or more) high.

How new...

[Anonymous Coward]

Wow, I'm utterly amazed at how many so called NEW inventions or ideas come today... this one brought to you straight from the 60's! When they designed and built prototypes of magnetic pulse cannons shooting baskets of metal!

Re:How new...

[Ihlosi]

Wow, I'm utterly amazed at how many so called NEW inventions or ideas come today... this one brought to you straight from the 60's!

Some French guy named Jules called from the 19th century, he wants his idea back.

Re:How new...

[Branko]

Wow, I'm utterly amazed at how many so called NEW inventions or ideas come today... this one brought to you straight from the 60's!

Could you provide me with a reference? I'd like to look it up.

Some French guy named Jules called from the 19th century, he wants his idea back.

I'm fully aware of Jules Verne's "Moon gun", but this concept could never work for humans due excessive acceleration. Maglev approach is the only one that I am aware of (other than rockets) that can provide a kind of "long-distance" acceleration to orbital speed tolerable by humans. Are there any other approaches I am not aware of?

nuclear waste

[Anonymous Coward]

IF this thing works, let's use it to get rid of nuclear waste

Re:I See. Yet Another Cockamamie Scheme...

[bkr1_2k]

You imply that you're working on experimental evidence. How about not spouting off until you have proof rather than hypothesis? Maybe it's just me, but I've heard a lot of hypothesis in the past that turned out to be total crap. "It should be given" that you don't profess results without proof to back up those results.

Theoretical physics has a lot of crap in it too, but at least they try to back up their claims with math and verified evidence. You are doing neither.

$500 Million?

[Anonymous Coward]

$500 Million? Balls. I think they just pulled this number out of their ass. My county just put in a roundabout at an intersection connecting four 2 lane roads. Cost? 1.4 million. A million is chicken scratch now days. Building a gun that shoots shit into outer space? That sounds more like 50 billion. Yes, I just pulled that number out of my ass.

I've met Hunter, and visited the SHARP gun

[DanielRavenNest]

Back when I was doing giant space gun work at Boeing :-). Feel free to ask questions. I'm not about to type in several volumes of technical data, but it's nice to see he's converged on the same muzzle velocity we came up with (5.7km/s).

Our desigh: particle-bed heater with Aluminum-oxide heat storage (it's actually #20 sandpaper grit). It's much easier to store hydrogen at room temperature, then heat it just before it hits the barrel. Using small particles, you get lots of area for heat transfer. The particle bed gets warmed up with heaters of your choice over a period of hours, then you fire the gun and in a second or so transfer a good chunk of that heat to the hydrogen.

Why heat the hydrogen? The speed of sound of a gas depends on the molecular weight and temperature, and hot hydrogen works best. The efficiency of a gun drops dramatically as you reach the speed of sound of the working gas. Think of it this way, speed of sound is how fast pressure waves travel.

If the projectile outruns that speed, there is no way for the gas at the back end to send push to the projectile further up the barrel. It's a bit more complicated than that since you are constantly feeding gas from the back end, and the gas right near the projectile is moving almost as fast, so pressure waves can catch up, but on the whole as you get near Mach 1 of the gas, your ability to push drops way down.

Depending on size of the gun, and where you are launching to, the west slope of Hawaii and the Andes are good locations. The first has *long* even slopes, courtesy of lava flows. The second are shorter, steeper slopes, but somewhat higher altitude (less air to fly through), and closer to the equator.

Re:I've met Hunter, and visited the SHARP gun

[DanielRavenNest]

Part 2:

Our projectile was re-useable liquid fueled. And the mission was to feed a fuel depot for geosynchronus satellites. 3/4 of the mass of comsats in low orbit is fuel to get them to GEO, and stationkeeping for 15 years. The projectile was very simple, pressure fed liquid engine. It used part of the fuel to get itself into orbit, the remainder is transferred to a fuel depot.

The projectile uses GPS nav borrowed from artillery shells to get to the close vicinity of the depot, then the depot has the smarts to find and dock (that way the smarts occurs once, not on every projectile).

Once done, we deorbit and land anywhere, even on concrete. There is a couple of inches of ablative heat shield on the nose, backed up with 10cm of crushable honeycomb. A bit of the heat shield burns off going up, and more coming back. The honeycomb lowers the landing shock to under 1000g's. Since that's the g-force being fired up in the first place, the projectile can already stand that landing.

Our design projectile was about 360kg loaded, if I recall, and about 100kg or less empty, Ill have to dig out the documents to be sure.

We factored in a 4% loss rate on projectiles after you had experience (40% on the first 10, declining as you gain experience).

Costs worked out to $300/kg ongoing if I remember.

Re:I've met Hunter, and visited the SHARP gun

[DanielRavenNest]

Part 3:

You cannot fire such a gun in machine gun style, the barrel will overheat. As it is, we had a replaceable liner that could take high temperature, and the main barrel structure was based on high pressure natural gas lines (went so far as to get quotes from the people who make that stuff).

You can get a bit more efficiency by having a cover over the muzzle, keeping air out, and pumping the barrel down to some fraction of air pressure. You leave a little air in the barrel, which piles up in front of the projectile, and ensures the cover pops open just before the projectile leaves.

Such a gun is *LOUD* I remember figuring out that all living things within 50m of the muzzle get killed, by the combination of shock wave, followed by hot hydrogen that was just behind the projectile burning with the air when it reaches it. I forget what the hearing protection radius was, I think it was on the order of 1 km or so, and the sonic boom as it travels upwards would be audible for quite a ways.

On Hawaii, you would be firing over the top of an active volcano, so other than making ripples in the lava pool from the shock blast, its not too much of an issue. One thing we did not analyze in detail is what happens to all the delicate astronomical observatories on the *other* peak on the island.

Surprisingly, frozen food survives 1000g just fine, as does properly made electronics, fuel, breathing gases, and structural items, so a very large fraction of what you want in space, besides people, can be fired out of a gun.

One cool use for such a gun is launching spools of space elevator cable. A partially built space elevator lowers the speed required to get to orbit via a vehicle. The landing platform at the bottom end moves slower as the elevator cable gets longer. So the gun can indirectly help with the people launching job.

Re:I've met Hunter, and visited the SHARP gun

[DanielRavenNest]

Part 4:

Why a gas gun and not a mag-lev or something like that? Well, foot per foot, a steel pipe is way cheaper than a set of coils, or a humongous power supply. We deliver oil and gas by pipeline for that reason.

Why not use the gun to get full orbital speed? Both the performance of the gun falls off exponentially as you get above Mach 1 of the working gas, and air drag goes as the square of the muzzle velocity.

How much do you lose going thru the atmosphere? Well drag = 0.5 * Cd * rho * A * v^2

Cd = drag coefficient of the projectile, assume 0.15
rho = air density, assume 0.75kg/m^3 at for a muzzle at 4000m elevation
A = projectile area, for 30cm diameter its 0.07m^2
v = 5000m/s lets say

Then drag = ~100kN. With a 360kg projectile thats negative 276m/s. With a 30 degree elevation, distance thru the atmosphere is equivalent to 17km, so about 4 sec of drag loss, at an average of 4500m/s, so around 800-900m/s lost. Net velocity out of the atmosphere will then be 4100m/s. You need to add around 4km/s with the rocket onboard.

With internal barrel pressure of 200 atmospheres (3000 psi, or 20Mpa), projectile acceleration is just under 4000m/s^2 (400g) at first. Firing time in an ideal gun would be 1.25 sec, and barrel length would be a bit over 3km. Higher pressures would get you a shorter barrel.

With a good grade of steel for the barrel, say 60ksi safe working pressure (400Mpa), the wall thickness needs to be internal pressure/barrel strength = 20/400 times the diameter. With 30cm barrel, that comes to 1.5cm wall thickness, or a bit over 1/2 inch. This is quite easy to find commercially.

This is about the smallest gun that would be commercially useful (~100kg net payload). Bigger ones would be more efficient, but more expensive to build.

Something about halfway in scale between the SHARP gun (already done), and this would be a good intermediate step to prove the technology.

The prototype gun would then have the following parameters:

Muzzle velocity - 4 km/s
Projectile mass - 40kg (about 8 standard pumpkins :-)
Projectile/barrel diameter - 15cm
Acceleration - 1000g peak
Barrel length - around 1000m
Working pressure - 23Mpa (3300psi) peak

Old ideas are new again

[default luser]

When I first read this, I was thinking of HARP, the (rather obvious) precursor to the SHARP program. His goal of making HARP a space launch platform was a failure, but the lead engineer (Gerald Bull) was so disgusted with the politics, he went on to created Project Babylon for Iraq. I suppose the moral of the story is: keep the big gun makers employed, or they will go work for someone else :)

Back to the original topic: from the press release, they've doubled the velocity achieved by HARP. If that is true, then it's only a small hop with a booster rocket to LEO. This could really work!

Moon Is A Harsh Mistress

[RazzleDazzle]

Go Manny!

Re:I See. Yet Another Cockamamie Scheme...

[Dragonslicer]

I never knew L. Ron Hubbard posted on Slashdot.

This was my science fair project!!!

[Anonymous Coward]

So how does this compare with launching a rocket from a jet airplane above 40,000 feet. Hasn't Orbital Sciences Corp. ( http://www.orbital.com/SpaceLaunch/Pegasus/ ) already demonstrated this technology.

It's interesting to note that these techniques open new doors for 3rd world nations to launch long range nuclear warheads with minimal investment in rocket boosters. And the rocket is well into its mission before it can even be detected.

Wait a couple of months and you'll find the DIY project in MAKE magazine.

Well regulated Militia

[npcole]

And Americans can each have one under their First Amendment Rights, no? It's what Franklin would have wanted....

Re:Well regulated Militia

[DanielRavenNest]

2nd Amendment dude, and its a bit out of range for home ownership, but perhaps Jules Verne got it right, his gun was financed by the Baltimore Gun Club.

A BFG project promising to "fire your shit into space" with everyone kicking in a subscription might be enough to get a demo gun built.

We need to test some carbon fiber- wrapped frozen pumpkins for g-tolerance :-)

Re:Well regulated Militia

[npcole]

Sorry. I did mean second, of course. But then not being American and being home from a long day, I got my numbers mixed! If only one could correct....

Mind you, maybe the mistake is satire in itself! (Though not deliberate, I'll be the first to admit)

Re:I See. Yet Another Cockamamie Scheme...

[Chris Burke]

I don't know about the GP but I only needed one look. Do you realise you have reinvented Luminiferous ether?

Though at least the Luminiferous Ether guys understood Conservation of Energy...

Re:Major Oh Noes! - Newtons Law

[DanielRavenNest]

For the numbers I posted above, the gun force is 1.4 Mega-newtons (315,000 pounds). So a concrete backstop anchored to bedrock needs to be around 500 square inches in area, if we are generous about shock loads and safety factors. Probably need some of that elastomeric earthquake damper stuff between the foundation and barrel end to prevent cracking.

Re:I See. Yet Another Cockamamie Scheme...

[jamstar7]

I think you need to take another look.

I think you need to build a working model and demonstrate it.


I read that site, and it had some serious flawed assumptions in it. Sure, the Earth is moving on the order of 2-300 miles a second while orbitting the Sun, and the Sun is moving as well in orbit around the galactic center. How did they get in motion? Probably from the Big Bang. Why do they keep in motion? Because in space, there's not enough matter to impact them to significantly decrease their orbital velocities. Vacuum is thin, on the order of one atom of hydrogen per cubic centimeter of interstellar space. Not gonna get a whole lot of delta vee from impacting one. Keep in mind that a uniformly accellerated object shows no inherent motion in its components, they're all accellerated at the same rate. That's why Earth still has an atmosphere.

Re:I See. Yet Another Cockamamie Scheme...

[Chris Burke]

Theoretical physics has a lot of crap in it too, but at least they try to back up their claims with math and verified evidence. You are doing neither.

Worse, his theory explicitly disclaims the mountains of existing experimental evidence. Say what you will about String Theory, it at least attempts to explain the same observed phenomenon that existing theories explain. This loon thinks you can ignore all the experiments demonstrating Conservation of Momentum simply because you don't like it. It's going to be quite a challenge experimentally demonstrating the opposite.

Re:We Don't Need Fuel in Orbit

[jythie]

It was called Orion. Probably would have worked, but it ended up in the wrong end of a funding war against Apollo.

Re:I See. Yet Another Cockamamie Scheme...

[Gilmoure]

This is freakin' amazing! I've seen these letters, punctuation, and spaces arranged in this exact same order before. In fact, I've seen it several times. It's like the letters keep replicating this pattern for some reason.

Too bad these letters aren't arranging themselves in to some interesting or useful pattern. That would be cool!

Re:We Don't Need Fuel in Orbit

[Runaway1956]

A ramjet is not a space engine, sorry. Jets work in atmosphere, and rely on an external oxygen source. More, the reaction mass consisted of external atmosphere. Any working engine in space will resemble a rocket, in that the vehicle must carry it's own reaction mass, and/or find bodies of reaction mass while in space.

It can't go wrong.

[johnkennethhunter]

As a fellow John Hunter, I approve his methods.

Previous technology

[WindShadow]

This table of shell datashows some of the previous technology. I'm not convinced that by the time you build this, with a final stage rocket and guidance system, that it will be quite as cheap as implied. And the final stage needs to be really reliable, other nations would get upset if the payload didn't make it to orbit and big chunks of rocket fuel started coming down on them. And if the final stage doesn't work right, the [DESTRUCT] option might not, either.

My personal favorite is rail car to SCRAMJET ignition speed, airplane tech to get up to 50-70k ft and then one rocket stage to go to LEO. You don't need to lift the oxidizer (using air), you use aerodynamic lift initially, with a high lift to thrust efficiency, and the g-forces could be kept lower than any short duration impulse (gun) launcher.

I think we're closer to having the technology, too.