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Magnetic Ring Could Launch Satellites, Weapons
MattSparkes writes, "A new study funded by the US Air Force has suggested a cheaper method of sending satellites (possibly missile weapons) into orbit. A 2-km-wide ring of superconducting magnets would contain and propel a payload, accelerating it over a period of hours, before suddenly flinging the satellite into space at 23 times the speed of sound. The satellites would be engineered to withstand the g-forces encountered (2,000 g), and be cased in an aerodynamic shell. A two-year study has been commisioned and will begin within a few weeks at LaunchPoint Technologies in Goleta, California." New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet."
Am I the only one seeing the parallel?
I'm a fiscal conservative, it's a pity we don't have a political party anymore
Space burials (presumably of cremated remains). At $200 each (plus cremation) I am sure they could sell a few thousand of these per year. Now if they could only figure out a way to allow living people to withstand 2000g of acceleration, space tourism might actually be affordable.
I Am My Own Worst Enemy
that gauss density could be fatal and/or affect instruments.
I know there's a relationship between bird migration and magnetic fields, too, as a lot of them blindly smack into the brick walls at a local MRI center.
A feeling of having made the same mistake before: Deja Foobar
Well I guess it was only a matter of time before someone came up with something like this. After all, if you can move trains with a series of electromagnets fired in a set order, why not use the same concept to fling things into space.
We could fling refrigerators at North Korea! How's that missile testing going, Kim, did we mention we can launch frigidaire's into orbit? I'd prefer launching cows in homage to Monty Python and the Holy Grail, but at 2000g, that would probably equate to throwing hamburger.
"Don't you know you're going to shock the monkey?"- Peter Gabriel
Judging from the artists conception, Evil Knievel plans to use it to complete the elusive canyon jump.
Autonomous Retard -- Is your camp safe? UnsafeCamp.com
Yes!
As for it being a target, fuck that. Full steam ahead.
If we're not driving payloads into space at Mach 23 within 10 years, the terrorists have already won. Or something.
this sounds like a circular particle accelerator.
how come no one thought of this before?
In the 70s a book called "The High Frontier" laid out this technology. The guy who wrote it had a lot of the patents on things like the technology for the european bullet trains and what-not.
"New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet.""
I knew lawn darts were dangerous...but god-damn.
Bill Clinton: Pimp we can believe in. - The Shirt!!!
Coming soon to a Six Flags Amusement park near you!
The claim is that the ring could put payloads into orbit for $745 per kilogram.
What's the bet that, like most estimates of this kind, it ignores the cost of building the ring to start with...
One of the "most important targets on the planet", eh? That means DHS will give it, what, $1? Everything will work out perfectly!
The space ring will get $1 of anti-terror funding, and a small town in the Appalachians will get most of the rest, giving them the money to build and even BETTER space ring! Next year the same thing can happen. Thusly, the competitive process of capitalism lives on, even in these trying times.
On topic, though, this space ring sounds like a cool concept, I hope the media doesn't start raving about how the extraordinary magnetic fields will cause brain cancer.
Anyone else think the comments just weren't rendering right before they turned off ABP and saw ads?
If this ring is going to be "one of the most important targets on the planet", maybe they should build it as a series of concentric rings instead of a single ring. Perhaps havethe rings use alternating colors.
Unknown host pong.
Personally, I am not that sure I'd want anything with nuclear fuel (such as some satellites have these days) being accelerated to mach 23 on or near land, let alone trusting the casing to withstand 2000g. Is this a solution looking for a problem? I also wonder how much energy it would use to do such a thing compared to the energy expended launching the payload using a conventional solid/liquid fuel rocket.
today is spelling optional day.
I wasn't aware of laser-guided artillery.
I know of laser-guided rockets and missiles and such. But I was under the impression that anything lauched from a cannon depended upon the artillery team to have done the calculations prior to firing it.
How far away from the launch site would windows* be broken by the sonic boom?
* "windows", in this case, being the glass kind. Windows(tm) doesn't need a sonic boom to crash.
Which is exactly why we should build a space elevator instead. Wait.
????
"
It is cowardly, and a betrayal of whatever it means to be a Jew, to act as a white man
-James Baldwin
No yuo.
-"New Scientist points out that if such a launch ring were built, it would instantly become one of the most important targets on the planet."
Yeah, it's true, and that f***ing sucks. That statement right there sums up everything that is wrong with humanity.
Suggestion for the first test: Enter it in next year's Punkin Chunkin' contest!
>> "What would the robut do? Frame someone!"
I read that as 'To Moon a Harsh Mistress' at first.
... Or at least blow their asses up if they do not capitulate imediately!
I only look human.
My mother is a halfling and my dad is an ogre, so that makes me an Ogreling
This is a decades old concept.
Direct launch using the electric rail gun
In APL The 1983 JANNAF Propulsion Meeting
A better implementation than the artist's conception that I've previously heard of, was to build the rail gun into a tall mountain.
The primary reason was to help get above the bulk of the atmosphere, but it also has the added benefit of being extremely secure.
"one of the most important targets on the planet."
Even though it will be covered in a giant mound of ferrous scrap.
My faith is expressed through Nihilism. Do you understand?
in The High Frontier, as well as in Heinlein's TMIAHM, the flinger is set up on the moon. In TMIAHM, the flinger is used for returning grain to earth (until the lunatics turn it into a WMD) but in Gerard O'Neill's book the flinger sits on the moon and lauches moon rocks into lunar orbit where they get scooped up by a refining plant, as well as putting a lot of dust in lunar orbit where it means lots of in-warranty windshield replacements for all the various and sundry near-moon spacecrafts.
Wow! Sounds cheaper than the current rocket-fuelled method! Oh wait...
I think a scram cannon (think Gerald Bull's supergun) would be even cheaper to use - and I suspect the acceleration would be lower, too, depending on design.
Who cares if it launches at 2000g's.. Is it windows compatiable?
...then we can play catch.
for 2 hours,
19620 m/s^2 * 7200 seconds = 141264000 m/sec
Somehow I don't think that this is right.
I want to delete my account but Slashdot doesn't allow it.
http://en.wikipedia.org/wiki/M712_Copperhead
Now you're aware...
The world is made by those who show up for the job.
First the FUD:
New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet.
What a moronic comment.
You have a STATIC launcher.
It can toss things into ballistic trajectories.
One at a time.
With a warm-up of TENS OF HOURS.
I don't know if New Scientist realized this, but we have launch technologies that are
a) less vulnerable
b) more accurate
c) mobile
and
d) a little quicker to fire than that.
On another note, and not that this will mollify the crowd that fears a weapon in every technology, but in regards to the difficulty of punching something through the atmosphere at Mach 23, I seem to recall SDI experiments where a high-power laser was used to heat a 'track' through the atmosphere (in that case, to fire a particle beam weapon down the track with less atmospheric attenuation ). Couldn't a similar idea significantly reduce the air resistance for this sort of a projectile?
-Styopa
Are you guys paying attention? I see a new ride in the next few years ahead!
hmmmm.. perhaps if we build it on the surface they will come...
It's going in a circle. The 2 hours is to accelerate its speed to mach 23 (think in terms of a whip-around-the-head sling). The 2000g's comes from going mach 23 in a 2 km circle.
The world is made by those who show up for the job.
NO NO NO... I imagine the 2000g's is coming from moving at nearly constant speed but in a CIRCLE!
I agree, somwhere someone misquoted something.
2000g is the expected angular acceleration.
My
Apparently this launch ring has already been used to sling newscientist.com's webserver into space.
I believe the 2000g of force to which they are referring is of the centripetal kind (i.e. exerted onto the object by the magnets toward the center of the ring).
There will, of course, also be force due to acceleration, but it will presumably be lesser than the centripetal force.
Your lapse is forgivable, but only because the proliferation of terms like "Gauss gun", "rail gun", and "mass driver" in SF has overwhelmed their usage as technical terminology. But the point is, THIS IS NOT A RAIL GUN.
A rail gun is a parallel, non-touching pair of conductive rails, joined at the back-end by a partial circuit capable of generating an extremely high current flow (amps) of electicity in a very, very short time. A conductive projectile is injected into the gap between the rails (so that it touches both rails at once), which completes the circuit. As current flows from one rail to the other, through the projectile, it generates a powerful magnetic field. The Lorentz force causes the projectile to be pushed toward the far end of the rails--the magnitude of the force depends on the current flow.
Rail guns can achieve extremely high velocities, far higher than conventional explosive-charge guns. The velocity of a firearm projectile is limited by the velocity of the expanding explosive gasses that propel it out of the barrel; the gas velocity is in turn limited by the speed of sound in the gas medium, which has a physical upper limit for any type of explosive. Rail guns don't suffer from this limitation.
I have seen references to a 'Gauss gun' which consists of a series of solenoids stationed along a tube barrel, timed to trigger so that a ferrous metal projectile will be pulled faster and faster down the barrel by each of the solenoids in turn. I don't know how valid this terminology is, though.
"My pacemaker!"
"Flyin' in just a sweet place,
Never been known to fail..."
"When the sled had been accelerated to its top speed of 10 kilometres per second, laser and pyrotechnic devices would be used to separate the cone from the sled. Then, the cone would skid into a side tunnel, losing some speed due to friction with the tunnel's walls. The tunnel would direct the cone to a ramp angled at 30 to the horizon, where the cone would launch towards space at about 8 kilometres per second, or more than 23 times the speed of sound. ... Anything launched in this way would have to be able to survive enormous accelerations - more than 2000 times the acceleration due to gravity (2000g)."
They claim that the payload would be accelerated slowly around the ring. The huge acceleration occurs when the payload's trajectory is changed to angle it up 30 degrees towards the sky. Why wouldn't they angle the ring itself at 30 degrees, releasing the payload at the point where the tangent points up at 30 degrees? They wouldn't need a ramp at all, just a piece that moves out of the way before the payload swings around the loop again.
It's not being acccelerated at 2000g; that would be the centripetal force at mach 23. (A bigger ring would result in a lower force.)
You forgot direction. The acceleration is almost completely towards the center of the circle (centripetal).
The satellites would be engineered to withstand the g-forces encountered (2,000 g)
2000g corresponds to dropping the satellite onto concrete from how high?
Your equation holds if the acceleration were the constant, net, unidirectional acceleration on an object. It doesn't apply here.
There are 0x40000000 types of people: those who understand 32-bit IEEE 754 floating point, and those who don't.
If they build one big enough, they could even launch garbage... out of orbit. That's one way to reduce landfill size. (Notice I didn't say it was a good way).
You mean, like Vandenberg, and Cape Kennedy, and...
Anywhere the capability exists to put a payload into orbit is a target.
That "most important target" bit was a simple piece of scaremongering.
668: Neighbour of the Beast
Once upon a time, the Air Force came up with an idea to have satellites carrying tungsten rods that could be launched to strike ground targets (see: http://www.weeklystandard.com/Content/Public/Artic les/000/000/005/700oklkt.asp).
Now they are talking about using a "aerodynamic shell", with an engine to adjust trajectory, to send satellites into space. Did anyone else notice that the nose of the shell is tungsten?
Sounds like a cover story to me.
If "disco" means "I learn" in Latin, does "discothèque" mean "I learn technology"?
Didn't the Transformers use something similar to this?!?
Memories become legend, Legend fades to myth, and even myth is forgotten by the time that age comes again.-Robert Jordan
This is nothing new. There was one of these rail-guns on Kauai, HI a number of years ago...must be over 10 years now. The problem was the noise of the projectile breaking through mach levels. The sound was incredible and the shock wave ended up killing acres of vegetation on the island near the site. They're going to have to find some way to float this thing out at sea....possibly submerge the complex in case of a storm.
Using the same sort of drill that made the Chunnel, Yucca Mountain, etc., how about drilling a hole into a mountain instead, and launching from that? Seem like the high Gs of this design are due to the circular path; use a long straight shot to produce acceleration only in the forward direction instead, and you end up launching from 10,000+ feet rather than nearer sea level.
For a velocity of 8,000 m/s: acceleration along a (say) 4,000 meter path: v = at d = 1/2a t * t -> 8000 = a * t -> 4000 = 1/2 * (8000/t) * t * t = 1/2 * 8000 * t = 4000 * t -> t = 1, a = 8,000 m/s^2 = 800 G, a fair bit less.
Ooh, a sarcasm detector. Oh, that's a real useful invention.
You forget that it's circular. It's accelerating by changing direction as well as increasing speed.
"[Regarding the 'cloud,'] ownership was what made America different than Russia." -- Woz
cost effective. I can see 40 years or so into the future when we've all got these railgun missles that somebody will make a decision that parallels NASA's choice to go back to rockets for vehicle launch. Rockets are cheaper than a reusable vehicle? Rocket's are cheaper than our railgun centrifuge?
...all they did was increase your energy level. Will the wonders of magnetics never cease???
120 characters for a sig? That's bloody useless.
It's already developed, has a pretty good record of success, and is cheap (comparatively).
Additionally, it doesn't subject its payload to 2000Gs, doesn't send anything ripping through the thick parts of the atmosphere at mach 23, and doesn't create an easy target for sabotage.
Launching from an asteroid or maybe a very small moon this could make sense, but intuitively this doesn't seem like a good fit for launches from earth.
That novel did not describe a ring. The electromagnetic launchers in that book were both "simple" linear accelerators. :)
In the launch-ring article, I noticed the air-resistance problem being mentioned, during the initial acceleration phase.
I might suggest this idea as pointing out a solution to that problem.
a giant ring being used as a space weapon... i'm suprised no one has mentioned Halo yet
No one has talked about the G forces that would hit that thing when they encounter that 30 degree ramp. Don't ya think that at 17,000mph, when it's deflected upwards that it's gonna plaster all its guts to the inside wall? I know they didn't forget this little detail but I wish they had more info on how they intend to handle that.
If I didn't have absolutely NOTHING to do, I wouldn't be here.
The article and basic approach remind me of Gerald Bull's work and his disturbing tale of doom as documented on the Doomed Engineers site:
Gerald Bull had a vision and an obsession, a vision that led to estrangement from his native Canada, prison in America, and ultimately assassination by Israel. His vision was of an entirely new way to get into space: small rockets boosted by giant guns. To achieve it he worked for some of the worst regimes on earth: South Africa, China, and ultimately Iraq. His work affected the course of two modern wars and revived the ancient field of artillery.
A gauss gun is essentially an open-ended linear motor-instead of using magentic fields to push on magnetic fields produced by an armature that causes it to spin, the magnetic fields in the coil push on the payload in a linear fashion so it exits the end of the gun.
http://en.wikipedia.org/wiki/Gauss_gun
A rail gun has a conductor, such as a copper bar, placed accross two rails rails with opposing charges. When the bar completes the circuit between the rails, the current flowing through the bar causes a force (Lorentz force, I think) that causes it to accellerate down the rails.
http://en.wikipedia.org/wiki/Rail_gun
Rail guns actually exist capable of firing a projectile through several inches of armor (in labs, at any rate). The closest I've seen to a real gauss gun, other than video games and scifi, is when I saw a lab tech bring an electric clippers too close to an MRI (missed someone's head by _that_ much).
science is a religion
I might have some dead bodies I'd like to shoot into space.
I'll pay $200 each, no sweat.
Hell, I'll pay $2000 as long as nobody opens the coffins before launch!
Uh, I think the 2000g is not from direct linear acceleration, but from centripetal acceleration. I.e. at the start of the acceleration process, the G forces are substantially less. But as you come up to speed, you have centripetal acceleration resulting from traveling Mach 23 around a 2Km ring. Its been a long, long time since freshman physics, so I don't recall the exact calculations involved, but I seem to recall they were simple. Maybe someone else can post the math.
But the upshot of this is that 2000g is the peak acceleration, and is not sustained for the entire acceleration period.
I would like to see some references to comparing linear accelerators with the ring concept. I suspect that a combined approach, would be quite useful. E.g. imagine a 2Km ring used to accelerate to some mid-range mach number (e.g. mach 5 or some such), where the centripetal acceleration is low -- human sustainable maybe, followed by a longer linear acceleration (maybe another 5 Km or somesuch) to crank the unit up to orbital velocity. This may help mitigate the power considerations with a strictly linear approach, while avoiding the worst of the G forces imposed by a ring.
An interesting engineering problem would be to design a system that assumes some basic properties: maximum ring size of say 2km (or pick some other arbitrary range. I'm sure 5km rings are doable out in the desert), maximum G force imposed determined by human tolerance -- what are the forces endured by shuttle astronauts?, maximum power output determined by a typical nuclear reactor (assume sustained output, though one could imagine charging a bunch of capacitors to generate a higher burst... not sure that we have capacitor technology to handle that kind of load though), launch angle of ~30 degrees. (Though I think with a long linear ramp, we could exceed that angle and get to a much higher degree -- e.g. add 30 degress to an incline created by a slope, maybe get to 45 or 50 degrees.)
Another interesting idea would be to hybridize somewhat. Add ramjets or rockets to the craft to kick in a few seconds after launch. Now you don't need a full mach 23 at launch, but if you can loft to mach 10 or so, and hit 20-30km, you can get the rest of the way to orbit with a lot less fuel. Of course, that means your launcher has to cope with additional weight, increasing power requirements on the ground. I'm not sure how the trade-off works. Sounds like fun math, though.
I wonder how the projectiles will hold up to the stress and heat of that kind of speed at a low-altitude (read: higher air density, more friction). Due to air friction, not only would the payload have to have excellent heat resistance (and we already know we have a tough time making that stuff stick to our current rockets), but also would need to go faster than a conventional launch device due to both the speed losses and the lack of additional thrust after takeoff. If they can do it, it'll be awesome.
If not, perhaps a hybrid approach could be adopted... use the ring launcher to get a high initial speed, then use much smaller conventional rockets on the ass-end of it to supply the continuous thrust necessary to achieve orbit?
There is no mod option "-1: Disagree" for a reason. "Overrated" is not an acceptable substitute. Post something instead.
Expanding on the hybridization idea, if you can get above the bottom few 10kms of atmosphere, your rockets (ramjets might not be effective at that altitude) can impart a lot more effective acceleration because they don't have to fight against atmospheric effects. (There is the n^2 fall-off in gravity's influence as well, but I suspect that's trivial at those kinds of differences compared to atmospheric drag.)
Too bad the Mossad assasinated Gerard Bull back before Gulf War 1. If he had finished his super gun, Saddam could have put quarter ton satellites in orbit for a tiny fraction of the cost of the ring, fifteen years ago. Of course, if they failed to make orbit, they would have fallen back on Tel Aviv. Most important target in the world sounds about right.
Yes, Google does turn up many pages. But that is not my question.n itions/m712.htm
n itions/m107.htm
This is the Copperhead:
http://www.globalsecurity.org/military/systems/mu
This is a regular cannon round:
http://www.globalsecurity.org/military/systems/mu
Note the differences between the two. From those two pages, it does not appear that the Copperhead is anything like a regular shell. The only similarity they have is that they are both launched from the same cannon.
The question is: Is the Copperhead more like a laser guided rocket than an artillery shell? Does it experience the same initial SLAM that the conventional round does? Regular rockets do not. They accelerate over a longer distance than an artillery shell does. That SLAM is what would damage the electronics in the shell.
What about using this thing to shoot water/food/structural materials into space? That is where the savings really come into play. If there is to be a moon base, all the water has to be shipped up there. People need lots of water, so cutting the cost per kilogram to 1% of current levels is a very big deal.
This post climbed Mt. Washington.
Except that the proposed design accelerates the payload around in a circle -- using magnets arranged inside a torus -- not a long straight runway. I doubt a linear runway would be practical; it would just be too long. The advantage of a torus is you can keep using the same magnets to accelerate the payload, over and over, until you've reached sufficient speed to let it fly.
Unless the circle was ridiculously large (probably the size of a continent or better), you're not going to be able to get up to escape velocity before you'd (as a human being) would be crushed by the effects of the centripetal acceleration.
I'm not going to do the math right now, but I'm pretty confident that of the 6,000 Gs they're quoting, most of them are in the radial direction and not in the tangential, so that even if you brought the payload up to speed slowly, you'd still be crushed. It would be just like being in a centrifuge.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
I wonder why not make this vacuum and 10 miles in diameter. The article is wrong in the gravity claim. It's not gravity if the capsule runs at a constant speed. It's the circular travel at high speed that generates a force to keep it circle (the centripetal force that counters the momentum's centrifugal force). The larger the diameter, the smaller the force (linear relationship?). Cost could be an issue here.
I wonder what's the challenge of using lazer to supply energy for a space craft. I know that burn is not one of them becuase you can have wings that expand far from the craft to receive the lazer light.
The reason that most meteors don't hit the ground is because they are so small. The one that do hit the ground and are found right away often have FROST on them since they were so cold in space. As for exploding into a million pieces, meteors aren't designed for reentry.
Any compentent aeroshell engineer could design a case that would protect the payload (such as a capsule covered with the stuff they use for ablatively cooling rocket nozzles). The big concern usually with burning through airframes isn't that we don't have materials that can withstand the heat and friction; it is that those materials typically aren't very light-weight or are too expensive.
Besides, once the track is set up, it should be easy to try out new aeroshell designs! One of the stumbling blocks right now is trying to accellerate a test article to high enough speeds. Very often, they stick a test article on a sounding rocket that sends back data during re-entry.
And yes, IAARS.
science is a religion
I think a lot of folks here are confused about the "2000 gs" part of this device. This acceleration is from the centripetal acceleration needed to keep the payload moving in a circular path.
Here's the math:
The acceleration A needed to keep something moving at speed V in a circle of radius R is V^2/R.
A = (8 000 m/s)^2 / (1000 m) = (64 000 m/s/s) = 6 400 gs.
TFA says "More than 2000 gs" - my guess is that this is a mixture of sloppy journalism, and maybe confusion over the minimum acceleration needed to get to escape velocity (about 5.5 km/s). If they did get their wires crossed and report the 8 km/s figure but the g force of getting to escape velocity, the needed A is:
A = (5 500 m/s)^2 / (1000 m) = about (30 000 m/s/s) = 3 000 gs, so they're still wrong.
Incidentally, I love the ring idea, but it could only ever launch pretty specialized cargo due to the g forces needed. What I'd love to see would be a linear accelerator which got a rocket up to about 3-4 km/s, then the rocket would take over. EM launching systems with reasonable length can be built for low speeds, and rockets have high efficiency only when they're already moving fast (otherwise, most kinetic energy goes into making the exhaust, and not the payload, go fast), so a switchover plan seems pretty natural (except that it demands all the infrastructure of a small EM launcher as well as all the problems of a chemical fuel rocket - although some of these problems are less of an issue if you can accelerate the rocket to faster than the fuel's exhaust velocity before it reaches the muzzle of the EM launcher - then your shiny equipmetn doesn't get burned.)
My 2. Enjoy!
Expected time to finish is 1 hour and 60 minutes.
To dig a hole miles deep and toss it there? The core is radioactive anyway.
Didnt' we do this already with Jodie Foster and some crazy rich guy who lived on an airplane. I think the documentary was called "Contact"
--------========+++Dont Feed The Lab Techs+++========--------
And a giant metal stick embedded in a mountain would make the coolest lightning rod EVER. Hey dude, wait a minute, power problem SOLVED. ;)
Seriously, embedding things in/on very tall mountains creates some pretty serious logistics problems during the build phase, which might push this already prohibitively expensive project right into the "imaginary" category with a lot of other things that would be ideal if we could pay for them.
TFA mentions they're going to accelerate it in a circle, to about 10 km/s, and then divert the launch projectile onto a ramp which will deflect it upward at a 30 degree angle, at about 8 km/s. There's a huge amount of energy dumped into the ramp there... why not build the accelerator at a 30 degree inclination to the horizontal, and then all you have to do is let it go at the appropriate time, and you won't be losing 20% of your speed due to the friction of the ramp.
Less is more.
I'm guessing they are thinking of the centripetal acceleration required to keep the payload going around in a circle. At a top speed of 10 km/s and if the ring has a radius of 1 km, the acceleration required to keep the payload curving around and around is 10^4 m/s or about 1000 gravities.
Say they want to launch a real satellite. A modern GPS satellite has a mass of about 800 kg. Add in the fairing and sled and whatnot, and the payload mass would be at least thrice that, say 3000 kg or so. At top speed the outside wall of the ring has to supply a force of 30 MN or roughly 3400 tons to keep the payload going around in a circle. That would have to be a very, very sturdy ring. I can see why they imagine only launching microsats with a mass of 10 kg or less.
It's also hard to see how they can imagine launching "bulk" cargos like food and water to orbit -- you'd definitely want to launch that type of cargo in large quantities, since someone in orbit has got to go to the significant expense, time and trouble to rendezvous with it. Even a restriction of 1000 kg per launch might be expensively small. Focussing on the low Earth-based cost per launch misses an important point: unlike a manned Shuttle (which delivers 16,000 kg per launch to orbit), or even a traditional ELV with expensive computer guidance, you've either got to factor in some (expensive) costs for something in orbit to "catch" all these small payloads being flung up, or you've got to build some small, reliable, very durable (i.e. expensive) orbital guidance and maneuvering hardware into each of those 1000 kg payloads.
The Millennial Project: Colonizing the Galaxy in Eight Easy Steps. He talked about its use in sending humans and cargo into space cheaply and efficiently. As for dealing with the sonic boom generated by the launches he suggested burying it in a mountain in a remote region or constructing it at sea.
Warning: I'm a computer scientist not a physicist.
Escape Velocity: v ~= sqrt(2*g*r) or 11,200m/s for the Earth according to Wikipedia.
v=a*t therefore a=11,200/7200 for a two hour acceleration period. That's a fraction of g not 2000 g!
This makes some assumptions: 1) that the projectile leave perpendicular to the Earth's surface and 2) neglecting air resistance. Neither assumption is acceptable, but we shouldn't be off by THREE ORDERS OF MAGNITUDE.
Now some electronics can withstand high-g, e.g. laser-guided artillery rounds. But I doubt any telecommunication or spy satellite could with their deployable solar arrays. Who knows? My only point was the linked article is silly and the editors are apparently less than college-educated.
Am I crazy, or did they get the math wrong in the article?
The acceleration equation for circular motion is: a = v^2 / r
We are given:
Velocity: 10 kilometers/s
Width of ring = 2 kilometers, so radius = 1 kilometer
So:
v = 10,000 m/s
r = 1,000 m
a = (10,000 m/s * 10,000 m/s) / (1,000 meters) = 100,000 m/s^2
The acceleration due to gravity is about 10 m/s^2
This gives: (100,000 m/s^2) / (10 m/s^2) = 10,000 g
So it seems that their 2,000 g is way off. Even if we use 2 km for the radius it is still 5,000 g.
Reading code is like reading the dictionary - you have to read half of it before you can go back and understand it.
I can't see this ever having the relevance any greater than LC-39 at KSC as a military target as the launch takes (FTA) 'several hours' and creates substantial heat.
By the time you've got your 'weapon' off the ground, the enemy (presumably a nuclear equipped nation) has already spied you running the thing up via IR spy satellites or even ground observers. The enemy can then send a conventional ICBM or even FOBS over before the launcher sends it's payload.
Surely a system like this can't rival the target relevance of ICBM launch facilities and supercarriers etc?
Ripping an new rectum in the fabric of spacetime.
Seems to me like that would be bad(tm).
Mainframe/UNIX Bit Twiddler and long time Windows/Linux Hobbyist.
The Theorem Theorem: If If, Then Then.
Everything takes longer and costs more.
Chas - The one, the only.
THANK GOD!!!
Its a lot simpler to work out the velocity, 23x340 (Mach 23, 23 Times the speed of sound) is 7820ms-1 (Nearly 8Kms-1) the scarier thing is how much energy is required for a launch at this speed for a 1Kg projectile (E = 1/2MV^2 anyone?) E = 1/2*1*7820^2 E = 61,152,400J Thats the total energy out to get mach 23, Then onto power: P = E/t (energy over time), lets say 2hours and 6 hours. (7200s And 21600s) t = 7200, P = 8493.4W t = 21600, P = 2970W Now thats not too bad, 8.5Kw or 3Kw, Your choice, These things are big but the electricity demand will be larger, a LOT larger due to heat resistance in the electronics and such other things.
If it's good enough to use for rail gun amo and satellite-launched gravity-well weapons, it may be a good fit for other high-temp, high-friction envirionments. My guess is that it isn't used for spacecraft already because of its mass; in this case, the mass doesn't matter as much since the fuel and launch mechanism isn't being launched with along with the payload.
science is a religion
Real rail guns have names like "Big Bertha", "Julie" or "the Paris Gun".
Physics geeks need to make up a new name for their amped-up jacob's ladders and stop stealing googlespace and wikishare from World War veterans.
Why can't it be a spark gun? A jake gun? A Tesla gun? Oh, that last one's taken.
You RTFA?!?
I want to delete my account but Slashdot doesn't allow it.
In other news: "Swatch is set to make billions after releasing a fully plastic watch."
Yes, as I specifically mentioned when I said: "The only similarity they have is that they are both launched from the same cannon."
So, we've established that both are launched from the same cannon.
And then I clarified my question for you:
"Does it experience the same initial SLAM that the conventional round does?"
Yes, we've already covered the cannon part. The cannon part has been covered. We have both covered the cannon part.
Now, "ballistic". As in ICBM (Inter-Continental Ballistic Missile). So "ballistic" can apply to standard rounds and rocket propelled devices. Is the Copperhead more of a "standard round" with the associated SLAM or is it more of the rocket/missile variety that accelerates over a longer distance?
This matters because, in the FA, the payload (electronics) will disengage at 2,000g's. Their example was that such is already accomplished at 10x the g's.
Run away! Run away!
"Ein Volk, ein Reich, ein Führer." -Adolf Hitler
"We are one Nation, we are one People." -The One 'leader'
The long-term expensive part about space is not sending equipment up. It is the costs of fuel, water, air, and food i.e. consumables. Fuel and Water can all withstand the high Gs. If this works, the first thing that would make sense is to send all of these up. At that point, you can make the ring pay for a large part of its costs. From there, sats. can be developed that can withstand those forces.
The down fall is that the privatization world will probably be a bit upset about this.
I prefer the "u" in honour as it seems to be missing these days.
Have you consider centripetal accelerations?
"Objects moving in a straight line with constant speed have constant velocity and require no force to do so, since they experience no acceleration (see Inertia). However, an object moving in a circle at constant speed has a changing direction of motion."
Source: http://en.wikipedia.org/wiki/Centripetal_force
Let's put this at the south pole and use it to slow down the rotation of the Earth! Or speed it up. Whatever flops your mop, really.
Interesting. This is something many have already proposed to escape the moon's gravity well in s.f. The twist of using a circle and accelerate it over time is very clever indeed.
(8-DCS)
ahem... so have engineers designed new ways to maximize the magnetic flux without overloading the superconductors then? (believe me these will have to be superconducting magnets) The larger the object the larger the force to accellerate it, Major current problems involve the production of magnetic field resistant superconductors, with Nobium-Tin being pretty much the best ones, high temperature superconductors are bitches when it comes to current density, Nobium-tin is better by orders of magnitudes, but even more would be needed. beyond that, most magnetic launchers have one huge problem, friction. Even in low pressure areas the friction is still very high, the force of drag increases proportional to the cube of the velocity? and if this projectile should touch the rails... say goodbye to the magnetic launcher... it would immediately fuse the two contacts (as a magnetically levitating device must contain a ferro/para-magnetic metal with which to levitate against the mag rails) and the METAL would fuse the rails causing arcing and ruining the device! in addition the acceleartions would be !VERY! high, centrifuges are measured in hundreds/thousands of g's, this one operates at 20000g? anything liquid would separate, anything like glass(which is a liquid) would start creeping all over the place. running in a circle means that there will need to be another rail controlling the missile/satellite/launchee device in radial movement... it would be much better to operate this machine up the side of a mountain in a tube of helium, or a vacuum sealed one, with a top that opens whenever needed! peace out. and btw IAA REIT/EEIT (rocket/electrical engineer in training) ciao
Geez... There are all sorts of things that you might want to fling into space where you don't really care that much about being gentle. For example, use it to fling food and water up to the space station.
If the space shuttle isn't a target this won't be one either. Either because people won't waste their time or because it will have enough security. Whatever the reason is for why space shuttles and rocket launches aren't targets.
Federal Express, when it absolutely, positively has to be there at 23 times the speed of sound *
* Disclaimer: 23 X speed of sound service available between limited destinations. May be subject to 2000g so please wrap delicate items approprately.
Support Right To Repair Legislation.
It's a sad state the world is in, when a potentially beautiful thing like this is primarily sought after for it's military applications
Yeah, I tell you, the whole place started going downhill with that "fire" business, and it's been going to hell in a handbasket ever since "steel."
When has a new technology ever not been put to some immediate military use? The only motivators more powerful than wanting to kill each other, in terms of stimulating technological development, are probably laziness and a desire for physical comfort. In any case, more resources have been poured behind more research because of military applications than as a result of pure curiosity.
That's not to say that their use is a good thing -- I'm not engaging in the broken window fallacy here -- just pointing out that a whole lot of stuff today only exists because the resources were allocated to its development because someone thought it would come in handy during the next war.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
This ring could fling mass up to a skyhook to recharge its orbit. Imagine a LEO skyhook that catches dozens of dead weight shots from this gun and uses that momentum to promote its orbit to a highly eccentric one. Then the satellite can exchange this orbit potential with a target at its low altitude point through a tether or skyhook style method. The target could be a large satellite in LEO or even a suborbital payload. Once the potential is transfered the target can have its orbit promoted to GEO or other significant altitude.
This method saves a lot of reaction mass in a heavy lifter because you can aim for a high alitutde but a suborbital trajectory. IE it's easier to shoot straight up than curve towards an orbital path at sufficient speed. For instance the X prize is all about sub-orbital. LEO is much harder and GEO is even harder still.
So I guess now a cow really can jump over the moon. Looks like it's time to cash in on that promise your sarcastic friend made to you in grade school.
Well, all you need to do to fix that is to use a small black hole as your centripetal force. As all matter experiences gravitation equally, the body's structure wouldn't experience centrifugal stress.
Great, so instead of being turned to jelly by centrifugal forces, I'll be turned into spaghetti by tidal forces?
Oh, say does that Star-Spangled Banner entwine / The myrtle of Venus with Bacchus's vine?
A ring/linear hybrid doesn't help the situation much. For a linear track with constant acceleration the first half of the velocity comes in the first quarter of the track. Going to mach 5 in a ring and then from 5 to 25 in a linear track only reduces the linear track length by 4%. You might as well build the whole thing straight.
For your 5 km diameter track, if you put human endurance at 10 g, you get a maximum speed of about 500 m/s. That's 1/16 orbital speed, less than mach 2. If you quadruple the size to 20 km you double the maximum speed to 1 km/s, an eighth of what you need. Want to guess how large it needs to be to achieve orbital speed with only 10 g of centripetal acceleration?
"Magnetic Ring"
What will Goatse think of next?
Wouldn't it be a lot easier to just float things into space. There would be no friction, no heat, and less energy to consume. Floating is the answer.
So, we should figure out anti-gravity.
The above is not worth reading.
First thing that comes to mind when I imagine something travelling at Mach23 in a circle is that it'd make one hell of a racket! A large contributing factor is that it could also form standing shockwaves inside the ring - which could be interesting, no? Just in terms of the sound-wave energy density it should be pretty unique. I'm kinda curious as to what that'd do to any critters unfortunate to be living inside the radius of the thing... (If there are any compressible fluids people around, what happens when two shockwaves intersect? It's been too long since university courses on the subject...)
The back of the envelope: Lets say it's 6km in circumference, at Mach23 (or roughly 8,000 m/s at around sea level) it'd go round the track in about 3/4th of a second. Since we've got a diameter of 2km, which takes sound around 5.7s to traverse (at sea level), so we'd certainly see some interesting interference effects if they left the middle of the ring empty as seems likely. Obviously I'm also assuming that the projectile isn't in some sort of evacuated tube or anything (We weren't talking about using the internet to launch sattelites were we?)
-srw
In TMIAHM Hainlein does suggest building something like this on the earth - it's only been 40 years and now someone else has the idea!
Genius is one percent inspiration and 99 percent perspiration, which is why engineers sometimes smell really bad.
Can't anyone see that this is nothing but Pentagon pork-barrel spending? It is worthless, impractical, and will/would be colossally expensive to implement.
Like we have nothing more pressing on the docket.
I think this idea makes sense, and could really do things for space exploration. It may not be able to fling humans up there (or could we simply submerge them first?), but if you put enought small compact briks into space, you'll have a castle.
;)
In other words, small pices of a space station could be flung up, then the crew arrive by slower checmical rockets. It's a really neat idea... If I was the Lego company, I'd invest
I was under the impression that noise was the largest obstacle to this type of launch device - and the article doesn't even mention it. It would make for some very annoying pressure waves over large tracts of the earth.
...because "hacker" sounds way sexier than "code drone."
I won't be impressed until they come up with a giant ring of superconducting magnets that can send things to other galaxies.
Ah, but "why build one when you can have two at twice the price?"
This project is pure bullshit to suck billions out of federal coffers.
The speed has nothing to do with it. Gravities are a unit of acceleration.
Au contraire. When we have something travelling in a ring, it's speed is directly related to its acceleration, it's just that the acceleration is along a vector pointing to the center of the ring. So we're looking at the centrifugal/centripetal forces. If this thing is travelling at 10000 m/s along a 2000m ring (their numbers), you end up with a centrifugal force of about 5000g's
Fc=(mv^2)/r, Fg=m*9.8m/s^2, so we have Fc/Fg = (mv^2)/(r)/(9.8m/s^2) ~ 5000g. They say 2000g, so the numbers don't quite add up somewhere, but in the ballpark.
So to get to the top speed necessary on the track in question, the object will be subject to massive sustained g forces
Angular acceleration of the magnitude needed would also cause enormous 'tidal' stresses in any solid object whirling around like that, especially the projectile itself. Since it is the largest object that is whirling (it contains the payload, so it must be bigger), it will experience the highest stress.
No micro-fractures or stressed metal allowed. The cost of maintaining such a high stress carrier - or manufacturing many throw aways - will eat up a lot of savings, especially considering this thing really only has one valuable payload.
Thor's hammer. Read Foot Fall by Niven/Pournelle for a description. This ring is a surface launcher for hammers. 10 kilo (about 22 pounds) payloads? 3000 launches a year? Yeah, we'll use it *wink wink* explore the moon *nudge nudge*.
Pavlov wouldn't be so famous if he'd used a can opener instead of a bell.
Remember that it's on a *curving* path - that means it is continually accelerating, even if its linear velocity is constant. This takes quite a bit more math to calculate, but the multiple-thousands-of-gees is in the correct magnitude.
Pavlov wouldn't be so famous if he'd used a can opener instead of a bell.
The moon's crust is about 20% oxygen, on average. The hard part is splitting it from the rest of the lunar regolith. 4 billion years plus getting hammered by hard radiation leave only the molecules that are really determined not to come apart.
But figure out how to split the O2 easily, and all we'll have to ship up there is H2. And eventually, of course, we could ship it in from further out in the solar system...
Pavlov wouldn't be so famous if he'd used a can opener instead of a bell.
Okay, 2000 gees, jeez....
Might want to dispense with the rail gun and use a gun gun. Explosives and a barrel.
There was a modestly successful early science fiction author who wrote a book about it. His name escapes me.
A 2-km-wide ring of superconducting magnets would contain and propel a payload, accelerating it over a period of hours,
So it's wasting all that energy making it go around in circles (it's changing direction, thus accelerating) while it ever-so-slowly ("a period of hours"!? ye gods and little fishes!) to escape velocity. I got news for you -- a low acceeration rocket like the Shuttle makes orbital velocity in 8 minutes at a modest 3 Gs.
Orbital velocity is about 7km/sec. Say 10km/sec to allow for drag losses escaping the atmosphere and gaining altitude. Accelerate at 1000 G and you can reach that speed in 1 second, in a distance of 5 km.
They're talking about a ring 2 km wide; take that as the diameter and they're talking a 6.28 km circumference. With fewer magnets and less total energy they could do it with a linear accelerator.
What idiot wasted taxpayer dollars thinking this up?
-- Alastair
Couldn't they use magnetic levitation to keep it at a distance?
What I wonder about is whether a maglev would be able to support the weight of the payload. If the centrifugal force is 2000 Gs, then the equivalent weight of a 500 Kg satellite being launched would be 1000000 Kgs. I would think they would need awful big magnets to provide enough repulsion to prevent the load from hitting the structure supporting the magnets. And if the magnets were powerful enough, they would need the material holding them in place to be strong enough to not allow the magnets to be ripped or pulled out of place. Imagine if a payload with an apparent weight of 1 Megatonne came into contact with the cement supporting the magnetic track while moving at 8 Km per second. It might be like a small atomic bomb. Now what if they were trying to launch a section for the space station at say, 10,000 Kgs earth normal weight, but now it weighs 20 Megatonnes? I think structural engineering and building a magnetic system powerful enough to prevent things like this will be very hard to overcome. I know that the closer together the magnets get, the more powerful the repulsion, but I still would doubt if we had magnets that powerful. One touch at those speeds with that weight... Also, what would the effect be on a people or materials from magnetic fields powerful enough to overcome those forces?
-- I ignore anonymous replies to my comments and postings.
What I like about the idea of releasing the projectile at a high altitude is that the atmosphere there is much thinner. Also, if it's done on the equator, we get the advatage of getting to use the earth's rotation to speed up the projectile. This isn't to say that smaller launchers like the proposed one would be useless. For launching construction beams, water, food, etc., this would be great. But I think we could do even better and it might not be that much more expensive.
What if I measure time in milliseconds, does my drop off of a 9.8 millimeter building now produce the same 2g's?
The amount of force felt on impact with the ground has more to do with your decelleration: the elasitcity of the collision. It would have to do with the length of your legs, and how long the interval of time taken to absorb the impact.
...because "hacker" sounds way sexier than "code drone."
Hmmm... but, assuming a 5km ring, what is the maximum speed for 10g? Again, I'm sorry, but I don't recall the exact force equations involved (and I haven't got a freshman physics text handy)
If they made one of these rings out of flexible material, they could deploy it submerged at sea, even secretly from a submarine. Electromagnetics and maybe even the projectile's mass could keep the ring circular and stable, in addition to locking solenoids. Then they could redeploy it anywhere at will, without exposing a land target to incoming attacks. Situationally deploying such a device on land would require clearing the ejection route, not to mention securing the entire area against intruders.
Since powering these rings could use energy so much cleaner and more efficiently than rockets, we should be investing in them as our next generation space launchers. Maybe there's even a way to shoot really fast things into space which pull slower human capsules behind, tethered elastically.
--
make install -not war
So if our radial force is 7.2 MN, and our track is (using round numbers) 6 km in circumference, and the payload is moving at a velocity of 6 km/s, so that it traverses once around the track in one second, the energy expended just to keep going in a circle is around 43 MJ, hence a power dissipation of > 43 MW.
Note that at 6 km/s, our payload energy is only at 36% of the launch energy, and assuming 43 MW of linear acceleration, we would require several minutes to achieve launch velocity.
In short, for accelerations lasting many hours, an enormous amount of power will be expended in preserving circular motion, and the efficiency will be lousy. Even if acceleration times are shortened, the amount of power needing to be dissipated will still be enormous.
Imagine that this Twinkie, err... lawn dart represents an orbital vehicle designed to be launched from the proposed magnetic ring. It would be a lawn dart thirty-five feet long, weighing approximately six hundred pounds.
That could be ugly.
-William Shatner can be neither created nor destroyed.
Jack O'Neill suggested this tech? I'd assume it would be Samantha Carter or Rodney McKay.
Please, for the good of Humanity, vote Obama.
If you're using a magnetic ring to launch things into space, the first thing you should launch is a magnetic ring to use for launching things back at earth.
What sound do people on rollercoasters make? Hint: it's not Xbox 360.
I had a look at the picture, thats no ring, its an open ended loop.
I thought the ring whould indeed be a ring, placed so many feet in the air, the ship launchs, aims to the center of the ring, and get a boost from the surrounding pulsating magnetic fields, helping it in orbit.
But alas, they dont want to use that yet.
Acceleration is a vector, dumbshit.
... down to the millisecond.
"and over here you see the exit apetu-" *KLANNNNG!*
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
So a human-rated ring would be around 700km? So why not people?
Look at the money we've spent on manned spaceflight in the last 30 years and tell me we couldn't build a large enough device for human travel. Plus, unlike the pay-as-you-go, lets-keep-engineering-more-complexity, as soon as you built it, it would immediately start paying for itself. Launches every day or so? Known technology? Simple component pieces? The economics of scale? It's a no-brainer, folks.
"but I still would doubt if we had magnets that powerful. "
Sitting in front of me are two magnets.
1x1x1" at 1T and 3x2x2" at 2.5T
I can not press those two magnets together with anything in my shop, including a 25 ton screw-vice. Since these are not nearly as powerful as available in non-superconducting configurations, I'm rather confident that the superconducting versions will have no trouble with the repulsive force. What I would worry about is the atomic iron in your blood being "borrowed" by the magnet if you are too close (IIRC that happens at ~10T)
-nB
whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
Like the whole spinny-rings thing in "Contact"??
Oh wait, that was terrorism. My bad.
But wait, they were saved by the *build two* approach!
Definitely been done in anime before... I forget what series it was but there was a great example of basically this same concept, but the whole assembly was in space. I think it was in Planetes... or something similar..
Maybe you could launch lots of say 0.5kg payloads. Of course then you have a bigger problem with air friction :/
England Australia is more of a straight line that USA Australia
It helps to think of it as a really big, really expensive Hot Wheels track.
Nuclear. It not magical but has a bad habit of spreading.
Anything near them have the habit of becoming radioactive as well. Lower than the source but still radioactive.
We cannot clean up Nuclear to well.
Basicly each time we build a Nuclear power plant we have more Nuclear matterial to get rid of than what we stated with. Ok not as radioactive. But more. Does not mean if it fall to earth that is it any good for people or animals exposed.
Pumping CO2 into ground does not work either. There is more power than what we need in the Tides and Currents and Wind and Solar and geothemal than what we need. Just we are not prepeard to do the expence to get it. Nuclear and Coal and the like are just cheep now.
Since this would be a great device for launching payloads to... well... anywhere on the planet, then I would guess that the most likely group that would want to target this would be us (assuming it was built in another country). The good ole USA would not tolerate an rail-gun that might fall into the hands of the turrurists!
On another note, can you imagine the sound of a sonic boom made by a Mach 23 projectile? Blooooody Hell!
Anyway it seems to me like the real challenge would be to prevent the projectile from tearing itself to pieces in flight. You'd want it to be inherently stable. For instance if the center of pressure from the drag is behind the center of gravity the drag will tend to keep it going in a straight line. Unfortunately much of the drag will be concentrated at the very tip where the shock is generated and will cause the projectile to tend towards tumbling out of control.
-- QED
They're already talking about "a sled carrying the projectile", so it is not magnetically levitated. I'd even wager that the sled's track would be on the outer wall of the circle. That's still a mass of friction.
Do we have any fluid dynamic experts in the house that could say which is better...
1) accelerate the satellite in a vacuum, to have it slam into atmosphere at mach 23 exiting the launch tube....
or 2) accelerate in atmosphere (perhaps pressurized), accelerating the air with it, and using the resulting air stream to ease the projectile's entry into (comparatively) stationary atmosphere
Disadvantages of the second are the fluid properties of air moving that fast. (turbulence, resistance) So are the advantages.
OK... I'll give you that. :-) But what about the materials that have to hold that weight in place. The magnet would have a force of potentially many megatonnes applied to it, on and off, each time the launch vehicle passed over it as it moved around the circle. Wouldn't you think that the bonding agent or the structural material holding the magnets would be prone to failure with those kinds of repetitive stress? (Kind of like the Darwin award guy who would jump at his high rise office windows to show how strong the glass was... but then one time the fasteners holding the window into the building failed and both he and the window fell to their demise.)
Interesting note on the iron in blood... I was thinking that strong magnetic fields might have a health effect... but not something that direct. Would that also mean no human cargo if it meant having to get close to the magnetic field?
-- I ignore anonymous replies to my comments and postings.
I'm only guessing, but why would you need to send up a complete chunk like this? Why not ship it in bundles of components that weigh between 500 and 1,000 Kgs. Its not like the launch platform isn't re-usable, so maybe slingshot bundles of components up, and then fire up a rocket with a command crew to control the assembly once in orbit.
Hell, if they ever manage to create autonomous robots, or even nanomachines, just fire the raw materials into space and get them shaped, stamped and welded in orbit.
I'm sure those hostile nations will welcome their new refrigerator flinging overlords.
(I'm so sorry...)
5 Redundant ones IIRC.
Still 10% went off basically at the minimum distance and 10% never went off.
John McAfee 'It was like that time I hired that Bangkok prostitute; to do my taxes, while I fucked my accountant'
The shock wave from running 23 times the speed of sound, at ground level, is going to be an interesting problem to overcome as well. Considering that the pressure differential across the shock wave at Mach 23 is HUGE. I don't really feel like solving the equation, but for example, the pressure differential across the shock at mach 2 at sea level for a 20 degree body (40 degree wedge) is somewhere around 3 atm. So, a 3 times atmospheric pressure wave is going to hit whatever is near that thing, and that's just at mach 2. Also, the temperature behind that shock is 400K (that's 127 celsius).Shocks (and temps) get much stronger the higher the mach. (I'm just reading off the table in my textbook) The normal shock pressure and temp differentials for Mach 23 are around 618x and 104x, respectively. That's times whatever pressure and temp they start at. Those are not small numbers.
;).
They've got a LOT to overcome...(also, IAARS as well
Couldn't you load more than one payload into your launch ring? Actually, couldn't you have your first payload be a sacrificial shot that makes the launch shock less for the immediately following launches.
More like some poor bastard getting pulled in and accelerating until what ever's ferrous get's pulled off.
-William Shatner can be neither created nor destroyed.
The down fall is that the privatization world will probably be a bit upset about this.
The current crop of privateers, yes. If a space-oriented VC could envisage a suitable marketing plan, this would be the ideal private space infrastructure project. Most of the existing cheaper-faster-better startups focus merely on making a cheaper tube 'o fuel. Our current crop of missile makers are still basically building their product by hand. When a launch vehicle and payload go BOOM, a good portion of the contractor's and customer's capital goes with it. It's like watching the auto industry before Ford.
If a Paul Allen or consortium were to bankroll something like this, they wouldn't be betting the farm on each test launch.
Luke, help me take this mask off
So what would happen if you put this same type of system on the moon? Would this allow us to launch explorations into deeper space easier? Less load for fuel etc and more room probes?
Oh, so how much mass gets dumped out the back side of ANYTHING that moves in space? Satelites are limited by the amount of propellant mass they can bring with them. Space stations need to boost them selves to maintain orbit. Oh, and they wanted to kick something over to mars right? That means proprotionally equal junk shooting out the shuttles ass. How much mass does the shuttle bring up just to putter around in space with?
... aerodynamics isn't my field. Still, that energy is dangerous...dump it back down with some basic guidance and you can hit anywhere on the planet with minimal notice. Or how about as an anti-satelite weapon? You don't need much mass or anything more than a basic fragmentation grenade to take out just about anything we currently throw up in orbit. If you can aim your toy then you can throw things on ballistic trajectories too...your "super gun" tossing refrigerators at iraq from the midwest USA.
So how about if I told you the next mission to the moon/mars/uranus didn't have to lug fuel into space with the ship or run shuttle trips full of 'dead mass' to supply it? Hrm, that sounds pretty darn useful all of a sudden, eh? I'm pretty sure a solid block of fuel (or inert mass for ion drives, nuclear rockets, etc.) with some aerodynamic abaltive coating could survive a couple thousand G's of accelleration.
You can launch hundereds of slugs into nearly identicals orbit tagged with basic transponders, pick em up, strip off the ablative coating and you've got your multi-tonne reaction mass for pennies on the dollar. Yes, it'd be a pain in the ass to collect hundereds of slugs in similar but different orbits but still far far cheaper than paying to lug it up via our wonderful but antiquated shuttles. Heck, you could even park slugs in high orbit for emergencies, spare reaction mass, or whatever you'd like.
Ok, and the weapon use like everyone needs to talk about. Throw a tonne of mass into space and you keep a significan percentage of the energy you spent getting it there. Dun ask me what %
Space burials (presumably of cremated remains).
Somewhere in space, there is a planet full of bugs, with giant balls of cremated humans hitting it, and a bunch of bug news programs showing grainy footage of our magnetic ring used to launch our rain of terror upon their world.
transporter_ii
Doctors destroy health, lawyers destroy justice, universities destroy knowledge, religion destroys spirituality
Am I the only one that immediately thought that this sounded like a 'Supergate'? Pesky Ori.
You've never done any work for the federal government before, have you?
Have you been touched by his noodly appendage?
No, they wont attack it. The plane that they've 'borrowed' (for jihad) will unexplicably be pulled towards the magnet. Duh, I wonder why...
Dude. You're wrong. The payload won't sit in the middle of the ring and won't fall through a wormhole. We're not there yet, SETI is still on it.
40 years ago Boeing engineers experimented with HIBEX missiles that achieved 400g 3km/s.
M109 crew answer: Sir, that's the middle of a big freakin' hole.
Back on topic, though... it's been the case, for awhile, that if the U.S. knew where an enemy was, it could turn it into a fine mist (or a small puddle of slag), either with small arms, conventional artillery, smart bombs, nukes, whatever.
A mass driver in Utah that can drop a five-ton block of tungsten anywhere in the world, even if it is perfectly accurate, doesn't do much to change that equation. It makes it cheaper, true, and it means more infrastructure in the US and less overseas. Which means less U.S. servicemembers in a position to get killed. (Which, being one, I'm all for.) But without good intel, the most advanced weapon in the world isn't going to do you any good.
Have you been touched by his noodly appendage?
The real problems have been the limits on the weight of stuff you can haul up to orbit and then out of the gravity well, especially since conventional rockets use fuel which makes up a big part of that weight, so they're mostly hauling themselves rather than their payloads. A ground-based high-g launcher may not be as cool as a skyhook elevator, but you can heave huge quantities of useful stuff up into orbit (and also fuel for any rockets that are heading farther away, whether to the moon or Mars or whereever.) Instead of needing to make lots of grocery trips up to the Space Station, you can heave the stuff up from the ground and let them wrangle it, and send them parts to start making bigger space stations, rockets for asteroid-mining, or whatever.
Some kinds of equipment can't take the stress of high-g launches - precision telescope mirrors or whatever. So send them up on the slow expensive rockets, or send up the raw materials and let the space station crew assemble them or cast them into shape.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
"New Scientist points out that if such a launch ring were built, it would instantly become "one of the most important targets on the planet.""
If the ring is built, it will most likely be built by the United States. The same United States that right now, via a combination of nuclear weapons at underground launch sites around the world, mounted on jets in the form of cruise missiles, and moving around the oceans on submarines, has the power to quickly raze just about any area on the planet - enough nukes to wipe out human life entirely, if the desire arose. The same United States that already has launch sites for rockets and space shuttles that it has been using for the last five decades to put things in orbit. Given all that our nation already possesses that can do what the magnetic ring could, exactly why is the extra convenience it offers likely to make it an "important target?" Especially since it would be far easier to rebuild than something like the space shuttle and related facilities?
Oh right, it's because New Scientist is a crappy publication aimed at the monosyllabic masses, and the Slashdot editors should be ashamed of themselves for linking to it.
A sonic boom is just the air compression wave created by any object which moves at Mach 1 or greater. It is generated continuously by any such object. The reason why a pilot hears it only on passing through Mach 1 is because at faster speeds the wave is behind his vehicle.
Also note that the point at which the wave is generated moves along with the object, and hence it moves at the speed of the object. In contrast, the wake itself always moves away from the point of generation at exactly Mach 1.
...which has a great section on the problem of g-forces, or in a few words: what happens when you drop a wrench in a submarine?
Anyone who whines about being modded down should be.
A question i was wondering about. Firstly would this result in eveerything that it launches all ending up orbiting near each other, it would be useful for building a space station i guess but what about beyond that.
The theoretical energy/speed loss due to the ramp is 0%.
The idiot that knows the difference between linear acceleration and centrifigal "force."
Where's the Ark?
Trolls make great pets. Adopt one today!
What acceleration technique can we use that provides 1000g acceleration roughly consistently over a 5km distance in one second? I can't think of anything.
The advantage of the circular device is that the accelerators can be switched on and off in time (faster and faster). However, they still only provide a few g. How many Tesla would we need to generate 1000g (possibly from 5km away!).
Justin.
You're only jealous cos the little penguins are talking to me.
Heck no! Take that back! Them's fightin' words!
The world is made by those who show up for the job.
Mu metal can shield the field. In fact the instruments for which these are steering magnets make liberal use of Mu metal (gee I wonder why).
As to the multi ton stress, yup, I'm betting that next to a superconducting magnet (and associated cooling system) big and robust enough, this will be the major design challenge. Now, we know that there are materials out there that can handle the load (think super sky scrapers), but repeated load cycling would make an issue of it. I'm thinking something like high purity glass or synthetic saphire rods longitudinally embedded in concrete of approprite strength should do the trick of secondary load bearing and dissapation. As to the primary load, some sort of glassed steel may do the trick.
-nB
whois gawk date unzip strip find touch finger mount join nice man top fsck grep eject more yes exit umount sleep dump
remember on that movie the abyss where they go super deep and they use a breathable liquid to get oxygen at super super deep depths, without being killed
would it make sense to pack a person into a capsule with this breathable liquid filling the whole chamber, then even if they were getting insane G-force they wouldnt be getting slammed/crushed around because the liquid would have near the same density as the persons body.
would this help make a difference?
If the magnets are only providing a few g, how at high speeds do they provide enough force to turn the payload enough to keep it from running into the circular accelerator walls?
At escape velocity, about half a second after the payload is heading south in that accelerator (at about 7km/sec), it will be heading north at 7km/sec (ie, the same speed but with the opposite velocity vector). Compute the acceleration necessary to do this, given that the payload can make no physical contact with the accelerator walls. How much force do the magnets need to apply?
Show your work.
-- Alastair
Or, to put it another way,
What acceleration technique can we use that provides 1000g acceleration roughly consistently over a 5km distance in one second?
The same technique that provides 2000g (from TFA) of centripetal acceleration consistently over a 6.28 km distance (pi * 2km, from TFA) in just under a second (6.28/7, taking escape velocity as 7km/sec, although TFA uses 10km/sec).
Actually, the former would be a lot easier, which is my point.
(The payload is not tied to a string or riding on rails, the only thing that can provide that centripetal force is the magnets. TFA keeps referring to a "sled" without further specification. If you can think of something other than magnetic fields that would support said sled at 2000g and Mach 23 without destroying itself and the ring, I'd love to hear about it.)
-- Alastair
Cockroaches can survive the 2000 g shock and come up crawlin!
If my calculation is right, a human-rated liner maglev launch system would be about 2000 km long. And I bet this would cost less then Iraq war while bringing much more benefit to the humanity.
Let's see...
d = V^2 / (2 * a)
d - distance
V - velocity
a - acceleration
By replacing V=11000 m/s^2 (approx. Earth's escape velocity) and a=29.43 m/s^2 (3g, reasonably comfortable for humans), you get:
d = 2055725.45 m = 2055 km (or 1 276.9178 miles)
Of course, if we factor-in air resistance, the needed length would increase, but I reckon not by too much...
run rings around Uranus?
Previously: "Linux... Toward the Sunrise..." Now: "Linux... Toward the-- No, now, part of Every Sunrise"
The accelerative magnets are only providing a few g, there clearly are other - much stronger - ones preventing an impact. Crucially, these ones don't need to change the force they are delivering quickly. If a linac approach was used then the very strong magnets would need to turn on and off very quickly and at precise times.
Justin.
You're only jealous cos the little penguins are talking to me.