Okay, let’s suppose that Bill Gates and Warren Buffet decide that they’re going to blow their money in the most pointless way possible: By sending glass spheres the same size and weight as supertankers filled with confetti to the Moon.
The Rules:[ul]
[li]No explosives can be used.[/li][li]No part of the launch mechanism can extend beyond the Earth’s atmosphere.[/li][li]The sphere has to leave the launcher intact, and must shatter on impact with the Moon.[/li][li]The sphere can hit any part of the Moon.[/li][li]The launcher must be reusable.[/li][li]The confetti in the spheres has to be wood pulp paper.[/li][li]Each launcher must be unique in design.[/li][li]The launcher must be a single unit.[/li][/ul]
The only possibilities I’ve come up with which might fit the criteria are a giant trebuchet and an electromagnetic rail launcher. The trebuchet would be made out of nanotubes, the counterweight would be some ferrous metal and there’d be a superconducting magnet mounted below the trebuchet to accelerate the fall of the counterweight and thus boost the launch speed.
The electromagnetic rail launcher holds the sphere on a sled. At the end of the launcher the sled hits a reinforced stop, which slings the sphere into the skies on its way to the Moon.
Now, I’ve not done any number crunching to see if either of these schemes would work, but they’re the only possible ones I can think of. Anybody know of a reason why they might not work? (I realize that no one’s managed to build very much out of nanotubes so far, but Bill’s willing to kick in a couple of billion for the necessary R&D to get it done.) Anybody have ideas for something else that would work and fit the above rules?
I don’t think it would be possible to launch an object like that with sufficient force for it to simply keep on going right out of the atmosphere, that is, without making it burn up as it travels up through the atmosphere, although if your launch mechanism extends to 90%+ of the height of the atmosphere, it seems a little more possible, except that building such a structure would be really really hard.
Then there’s the fact that a glass sphere the size of a WHAT!?! - I wonder if it is even possible to construct such a sphere that wouldn’t break apart under its own weight, even if it were almost solid with no cavity for your confetti.
Mangetout, glass could be made to withstand the temps, I think. As for the weight, well, I don’t know. It would be going from zero to about 25,000 MPH in a couple of seconds…
This is an odd competion - what next, Chocholate coated manhole covers? Still, using a Electromagnetic Rail Launcher, that is very long and extends most of the way out of the atmosphere would probably be your best bet. Make it long enough to allow for a gradual acceleration too.
Damn- I’ve got a list of unconventional launch methods, but they all rely on equipment extending beyondthe atmosphere-
space elevators, rotating tethers, pellet driven space towers and rings;
but you want one that doesn’t extend beyond the atmosphere.
Curses.
Anyway here are a couple of non-explosive methods of launch; Light Gas Guns Pneumatic Catapults
You didn’t rule out rocket exhaust powered by external heating by beamed energy, so here is laser launching;
Well, the railgun method is probably the best- the atmosphere is perhaps 50 km thick- so build a railgun that is thousands of miles long and 50 km high at the end point;
you don’t want to exceed about 3gees of acceleration, so the launch track would need to be as long as the launch path of any rocket-launched manned satellite
(sorry- I’m useless at maths- how long is that?)
anyway, you can extend the launch track right around the world as many times as you want- money is no object, I presume, or do you want to make a profit for some reason?
and you will only get one shot because you cant steer such an unpowered vessel, and the Moon will only be in position once every dozen years or so…
Good luck.
Even if you somehow manage to create a material that can handle the trip through the atmosphere, at the size of a supertanker, it is going to weigh in at tens of thousands of tons - imagine the amount of force you’re going to need to accelerate this to the required velocity in such a short time, if you can only apply this force to the outer surface of the object, then the internal stresses are going to be mindblowing; I don’t think anything short of scrith or General Products hull material is going to be up to the job (and then it isn’t going to break open when it gets to the moon).
Gotta differ here. It depends on the orbital parameters you utilize in launching said vehicle, but from almost any point on earth you can, by careful injection into the proper orbit (obtained by trajectory and velocity at launch) put an object at almost any time into an orbit that will eventually impact the moon (whether in ten hours, three days, or 33 weeks is a part of the paramaters you choose).
Heinlein went into this in some detail in The Moon Is a Harsh Mistress; the actual math to prove it is hairy but calculable.
Careful, don’t get it sandy… If nothing else, we can eat the chocolate. But meanwhile, the ADA says that they’re bad for children’s teeth.
Polycarp, that’s only if you have guidance rockets on your payload. Without any thrusters (most effective ones would rely on explosives), you’ve got one shot at it, and the Moon had better be in the right place when you get there. You could still re-use it more often if you chose the right position for the Moon-capsule collision, but you’ll not have much leeway.
My idea: Don’t try to launch a supertanker-sized glass sphere from Earth, as that’s impossible (the size of the sphere makes it prohibitive). Instead, use your railgun or coil gun or mother-of-all-trebuchets or what have you to launch equipment to a convenient near-Earth comet or rocky chondrite asteroid. Use solar power to melt down the rocky material to glass, and shape it into a sphere in orbit. Either make the central cavity very small, and put in a bare handful of confetti, or grow trees hydroponically and pulp them on-site (you’ll probably need a comet for the appropriate raw materials). When your projectile is ready, use whatever water (or other volatiles: Dry ice, methane, ammonia, etc) you have left in a solar-powered steam rocket to nudge the ball’s orbit. Collision with the Moon will easily be energetic enough to destroy the whole thing (the glass ball, not the Moon).
Ain’t no Orion bias here. I just thought it’d be interesting to see if something so absurd could be done.
Chronos, I think that the guidance rockets are only needed if you’re trying to get the projectile to a specific place on the target body. If you’re just trying to hit the target somewhere, you’ve got a much larger window to work with. After all, the Moon’s about the size of Africa, so even if you’re just using Kentucky windage for your targetting, you’ve still got a pretty good chance of hitting it.
The sphere specs don’t preclude internal bracing – some sort of honeycombing could provide the strength required. Breaking it shouldn’t be a problem – just have it swing around the Earth a couple times getting a gravity-driven speed boost. Get it going fast enough before impact, and it’ll break.
Nope; I’m still going with impossible - I don’t think there is any kind of bracing that could stand up to the task - either the thing is going to be too light and flimsy, or so heavy that it requires a great deal more energy applied to a very small part of it (i.e. the outside), which is going to create unimaginable stresses (the force will transfer itself through the material as a shock wave) and destroy it
OK. We put the damn sphere in a cushioning device for launch, allright? We float it in an even bigger supertanker-sized egg full of that super-light foam, or a tempurpedic bed or something.
It’s not impossible, it’s just improbably difficult. And stupid.
Originally posted by Mangetout Nope; I’m still going with impossible -
not if you use an acceleration track wrapped several times round the equator - you could accelerate at 1.5 gees and still get into a transfer orbit;
and perhaps I was a little pessimistic- after all the Moon does have gravity of its own,
with a bit of luck and skill, you could miss it and end up hitting the far side.
Perhaps there would be a launch window every year or so.
A rail gun up the side of Pike Peak will do quite nicely, except for the supertanker part. That sort of payload size brings monster complications with it.