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A Space Cannon That Might Actually Work
Unequivocal writes "Chalk another one up to Jules Verne. Physicist John Hunter is proposing a space cannon with a new design idea: it's mostly submerged. 'Many engineers have toyed with the [space cannon] concept, but nobody has came up with an actual project that may work. Hunter's idea is simple: Build a cannon near the equator, submerged in the ocean, hooked to a floating rig ... A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.' Though it won't work on people, with launch costs that low, who cares?"
It'll always be more expensive to send people up, at least in the near term, but we will need to send up a lot of other things that could be done in unmanned launches using this or another innovative technology. Ideas such as this could work; it's merely an engineering problem at this point.
I wonder how ice cream would get after those accelerations
The last guy with a plan to build a super-cannon (a Canadian named Bull) did some work for Saddam Hussein. The Israelis didn't like that much, so they murdered him.
I've calculated my velocity with such exquisite precision that I have no idea where I am.
I want to order pizza and ice cream on earth, delivered by cannon.
it works on people, so long as they're already dead. Why does this matter? Because now I can get the Star Trek space-burial I always wanted!
stuff |
This subject line says it all when it comes to efficiently placing things in low earth orbit.
Here is an interesting "tech talk" at Google where John Hunter explains the workings of the cannon:
http://www.youtube.com/watch?v=1IXYsDdPvbo
If you try to launch an object from the surface of the Earth using a "cannon" the projectile won't be doing anything other than decelerating throughout its flight and this means bringing the projectile to very high velocities where atmospheric heating and stresses become major problems. Then again, launch its self may be a problem as the Hydrogen propelling the projectile is detonating at an extremely high temperature and pressure. Small nitpick as well from TFA:
A big reason space food is what it is instead of the Earthling food we're all accustomed to has to do with keeping the station reasonably clean and experiments doubly so. Crumbs and fluid loose in the station can cause problems.
Sigs are too short to say anything truly profound so read the above post instead.
Dammit. Those music-stealers ruin everything.
Correct me if I'm wrong, but 13,000mph isn't fast enough for any kind of stable orbit.
I don't suppose the $250/lb launch costs include the build cost amortized over the lifetime of the system? Or the maintenance costs for that matter. The cost per pound on rockets includes those factors, and far too many people only work up the cost of electricity or whatever when working out the "launch cost" of one of these schemes.
In the end, once you've figured up the total cost of the system it's often more than just using rockets, even though rockets are so terribly inefficient.
I read the internet for the articles.
http://en.wikipedia.org/wiki/Project_Babylon
Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!
PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...
One that hath name thou can not otter
Though it won't work on people...
I'm sure it would launch people just fine.
Wow, that article is horrid. They don't even mention Hunter's startup company: Quicklaunch. On that page you'll find his Google Tech Talk on the subject which answers many of the questions that people are asking here.
How we know is more important than what we know.
I suppose it is a good a plan as any to get the RIAA to fund rail gun development.
I suspect if this works flawlessly, IF, that space flight in general will be a lot cheaper (even for humans). The big reason for the space shuttle is that it can carry massive amounts cargo with the benefit of people as well. With a cannon that can blast cargo up to orbit, NASA can utilize something like the X prize winners.
Commercial space flight here I come!
Make it long enough and it CAN launch people. (You'll need good streamlining to avoid nasty deceleration when it leaves the muzzle, though.)
The ocean is DEEP. Something that's roughly neutrally buoyant (i.e. a gun barrel supported by floats distributed along its length) needs to spend negligible structural strength supporting itself. (It only needs to be strong on any part that protrudes from the water - which might be a lot to avoid sinking it when it recoils.) You might want to put "helper combustion chambers" along it periodically to boost and smooth the acceleration if you want to launch live stuff though.
Also you can make it larger diameter and put sabots on the projectile while it's in the barrel to reduce the internal pressure variations or fire very dense loads. (Doesn't really help the materials strength issues, though, because the curvature lessens as diameter rises.)
Recoil? By being submerged it's an inside-out hydraulic shock absorber. B-)
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way
Keep watching the Tech Talk, he 'rails' on rail guns.
Basically, world record for rail gun right now is 5.5 km/s, after 200 million being spent on it. World record for Hydrogen gas gun is 11.2 at a fraction of the cost. Energy storage costs and other factors kill using electric for so large of a project.
He spends quite a bit of time discussing it when he goes over the history of rocket/guns, about 25mins in I think.
Also, he was paid by the navy to make gauss guns and rail guns, he just doesn't seem them as the right tool for this.
-Malakai
A Dragon Lives in my Garage
You have next door neighbor whose mutt is shitting projectiles at 13,000 mph?
Finally, the problem of cheap space access resolved!
One that hath name thou can not otter
In my experience, pizza holds up less well to acceleration than people do.
Yes gents, Saddam Hussein could have given us cheap access to space ensuring new area of prosperity for mankind, and era of space colonization...and we killed him!
OR Saddam hired a quack who was assassinated before he was revealed to be a complete phoney.
Had there been something resembling a successful test, I'd say we may have screwed up, but the only mentioned test was a failure. Also I don't hold Saddam's judgment in very high regard, it doesn't sound like there was much peer review on this project, and the US tends to take useful technology and scientific talent from it's enemies rather than destroy it.
Therefore I doubt this was anything that would have been useful, but I suppose we'll probably never be able to verify or deny your conspiracy theory.
It's just that people won't be people if they try.
Sing it with me now!
People are people
So how can it be
That you and I accelerate
So awfully?
The enemies of Democracy are
The reason space is expensive has more to do with the complexity of the rocket engines and the companies that build them than the propellant. If you want cheap access to space, focus on that. Capital-intensive projects that put heavy wear on their components (like guns) won't make things cheaper. The goal should be to *reduce* the number of parts that need maintenance.
The real key demand for this technology is launching propellants to an orbital depot. The political climate has changed (temporarily I would say) so it's ok to talk about propellant depots again. ULA are doing some interesting research. That's actual hardware being risk reduced there. Once you have propellant on-orbit you can plan deep space missions using Soyuz class vehicles - going beyond LEO doesn't need Saturn class launchers. That's the cost comparison that we have to look at.. not "is it cheaper than Soyuz?" but "is it cheaper than Apollo?"
How we know is more important than what we know.
Sorry, but I don't see the benefit of floating the cannon in the ocean. You have a very long structure that must be kept really close to perfectly straight that is subject to currents, waves, coriolis effects, etc. Worse, you are stuck with the projectile emerging into the densest part of the earth's atmosphere.
It would make a lot more sense to build a fixed structure on an appropriate, high mountain near the equator. Places like Peru or Ecuador come to mind as well as Mauna Kea on Hawaii. I'm sure there are more places that would be "developable" and logistically acceptable.
Cheers,
Dave
They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty.
Ben
The man doesn't seem like a quack to me: http://en.wikipedia.org/wiki/Project_HARP
Also, the only mentioned test wasn't exactly a failure what I see; it just revealed some problems, which is understandable with such project.
(and y'know, I was aiming more at Funny...)
One that hath name thou can not otter
PS. If a supergun has a basic design similar to German V-3, it might be almost bearable to humans...
No. If you work out the G forces required at launch to ballistically get into orbit, solid objects such as electronics will not survive. Live subject would not have a chance.
Tesla was a genius. Edison however was a overrated hack who liked to torture puppies.
I think anybody on Slashdot who refers to Saddam as the martyred hero of space travel is not being serious.
If Saddam had taken half the resources he put into exotic weapons and invested in his conventional forces, he'd be alive today — and probably the most powerful man in the Middle East. But training and equipping armed forces is hard work. A lot of dictators just can't be bothered. Instead they model themselves on the villains in James Bond movies: lots of parties, gloating, glitter, and top secret projects, but none of the dreary stuff that has to do with actual governing.
First of all, you can't get into stable orbit ballistically; you have to use a rocket motor at apogee of ballistic trajectory, at the least.
Also, we do have clear examples of electronics (from the 60's...) surviving launch to half of orbital velocity from a modified big naval cannon (Project HARP). And that's more or less a "normal" cannon, very short, very high acceleration. Look up V-3; such design can maintain almost constant acceleration, close to average one, and be hypothetically several kilometers long.
So why don't we go totally overboard, and assume a barrel length of 30km; and close to half of orbital velocity (so it will be easier, since there's ^2 in this part of equation ;p) - 3.5 km/s. From simple calculations that gives 20 g. Definitely bearable, as far being launched from a cannon into space goes. With 5 km/s you have 42 g.
Yes, widely unpractical and even...stupid. But I didn't actually suggest using it for humans, just said that it might be almost bearable.
One that hath name thou can not otter
If this launcher is anchored at the surface, how will they compensate for the motion of the waves at the surface? Does that eventually become a non-issue due to the weight of the launcher?
How would they 'catch' the cargo once it was launched into orbit?
How rigid would such a structure need to be, and are there currents in the ocean that would cause bending stress issues between surface and the deepest parts of the structure?
You are misinformed (and here you didn't even need to perform any basic calculations...)
http://en.wikipedia.org/wiki/G-force#Human_tolerance_of_g-force // I would venture a guess they were breathing and their brain was supplied with blood // without loss of consciousness or apparent long-term harm. The record for peak experimental horizontal g-force tolerance is held by acceleration pioneer John Stapp, in a series of rocket sled deceleration experiments in which he survived forces up to 46.2 times the force of gravity for less than a second. Stapp suffered lifelong damage to his vision from this test //"this test" likely means eyeballs-out
Early experiments showed that untrained humans were able to tolerate 17 g eyeballs-in (compared to 12 g eyeballs-out) for several minutes
(emphasis mine)
In my hypothetical scenario with 20 g that acceleration would last only 17 seconds, quite bearable. In the overboard example with 42 g, it would last 12 seconds (eyeballs-in!), which still might be survivable (and with eyeballs-in, which stresses eyes less, perhaps even without long-term damage)
One that hath name thou can not otter
That's like someone building something next door to you that's so loud that it's literally painful and saying, "Fuck you. Seriously. Why should you get dibs on the whole town."
Space game using normal deck of cards: http://BattleCards.org
Dear sir,
If we twisted the cable around the earth, and the cable was connected to the moon on the other end, we could tow the moon back here.
Whichever country it landed on would then be the largest country in the world. (Although it would also be squished.)
We could use this technique to explore space cheaply.
I will authorize funding for space exploration only if this method is used.
Regards,
Your Elected Representative
PS - As a side benefit, we can invade the moon.
-- IANAL, this isn't legal advice, and definitely isn't legal advice for you. Also, Squee!
The original Popular Science article is a much better read and includes additional detail, including the fact that the projectile will experience 5,000G forces. Definitely not for human passengers.
'The tyrant will always find pretext for his tyranny.' - Aesop's Fables
What does that remind me of.......
In all seriousness, Saddam only thought he had all of this doomsday projects in the works. The reality, which is supported by evidence apparently (from what I hear), is that most people working for Saddam were terrified of him and his sons and flat out lied or blew smoke up his ass about how far along they were with his ultimate weapons.
The only thing more tragically retarded and pathetic is the fact that a president and some intelligence agencies fell for the same bullshit. Or did they? :)
Great, this could put a whole new light on lost baggage: "Dear Mr. Jones. Your baggage was fired Tuesday. It should have arrived at the ISS before you did. Unfortunately, the capture system failed. The capsule has entered an unstable, atmosphere grazing orbit and will burn upon re-entry in about two weeks. We're sorry, but this loss is covered in the waiver you signed. Sincerely, A. Pratt"
------ The only greater hazard to your liberty than n politicians is n+1 politicians.
The same principle works in multistage gas guns used in things like hypersonic shock tunnels and dynamic compaction of metal powder into solids. It works, but I get the impression that for military things explosives or rockets get the job done with less hassle.
My undergrad thesis supervisor back then worked in the field and actually met this guy at a conference a year or two before he was assassinated.
Seriously.
Why should whales get dibs on the whole ocean.
People like you are the reason Kirk had to go back in time to the 1980s. Sheesh.
Exotic weapons? Saddam Hussein? Uh, citation please.
Mind, you, I said the same to Colin Powell...
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.
Depends on what you mean by exotic. If you mean nuclear, there's not much evidence. Well, there's evidence that Saddam put money into developing them, just no evidence that the money bought anything more complex than a centrifuge. There are, however, numerous documented examples of Iraq using chemical weapons, including some tests on their own population. Specifically, they are known to have had sarin, tabun and VX, and may have had others. He also put a lot of money into developing biological weapons.
As the grandparent points out, if this money had been invested in equipping and training a conventional force instead, he'd probably still be alive and in a strong position. Chemical and biological weapons have almost no tactical utility and very little strategic value. A well-trained and well-equipped conventional army has both.
I am TheRaven on Soylent News
I never cease to be amazed of some of the silly things that are published on Slashot.
A system like this will cut launch costs from $5,000 per pound to only $250 per pound. It won't launch people into space because of the excessive acceleration, but those guys at the ISS can use it to order pizza and real ice cream.
The ISS obital inclination is 56 degrees. Any 'ice cream delivery' made from a 0 degree inclination transfer orbit would have a relative velocity of about 7500 mph. The ice cream would effectively become an ASAT weapon.
an ill wind that blows no good
Well yes. We still have the receipts for some of those. But he didn't have them at the time. As to conventional forces... I don't think it would have made much difference. The USA had air support. Every time the Iraqis tried to put something in the air or looked like they might, the US blew it to pieces. And anyway, the Iraqi army was never defeated. They just took their uniforms off and the US is still fighting them.
Aide-toi, le Ciel t'aidera - Jeanne D'Arc.