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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.
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!
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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.
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
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.
10 mins into the Google Tech Talk he gives a slide with the amortization cost per lb. About 20 mins in, he breaks the project up into phases and costs needed to complete each phase.
http://www.youtube.com/watch?v=1IXYsDdPvbo
It's worth watching the video for more info on G-Force hardening, Hydrogen re-capture, per-lb cost and project milestone/costs.
-Malakai
A Dragon Lives in my Garage
Min orbital velocity = 7.6 km/s
Earth Escape Velocity = 11.2 km/s
Funny coincidence, world record for hydrogen gun == 11.2 km/s
These guys plan to have the gun propel the projectile to 6.0 km/s, and then the projectiles themselves are rocket motors that will add an additional 3.0 km/s. That gives them enough acceleration to reach orbital velocity and take into account friction/gravity losses.
The reason they plan to limit the gun to 6.0 km/s is because that requires the hydrogen gas to only reach 1700 kelvin, which after taking into account heat exchange with the barrel, it ends up being a few hundred kelvin below the melting point of steel ( the barrel ).
-Malakai
A Dragon Lives in my Garage
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
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.
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
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
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
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? :)
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.
Sorry, but I don't see the benefit of floating the cannon in the ocean.
1. You can aim it. This is a big fucking deal
2. Weight is not a factor. You can build your cannon as heavy and as strong as you please.
3. You don't have to worry about safety because any failures will happen underwater and away from land. This is also a big fucking deal