David.Smith@cmu-cs-ius.arpa (03/31/84)
That story about the Russians and Americans on the moon sounds a little far-fetched. I would assume that they would have done the targeting well enough to land the shells pretty close to the target. But if they fired a shell off at orbital velocity, any elevation in the firing angle would cause the orbit to intersect the ground. The shell would come back at the same velocity vector at which it had left, so it would have to come out of the ground.
Ian%SRI-NIC@sri-unix.UUCP (04/01/84)
From: Ian Macky <Ian@SRI-NIC> I seem to remember that the projectiles the Americans and Russians were firing at each other were high-velocity rifle rounds, not some sort of heavy artillery, which is why they were fired parallel to the ground, and so were able to make it all the way around and sneak up from behind.
jlg@lanl-a.UUCP (04/07/84)
Even if the shells were fired parallel to the ground (this able to orbit), they still wouldn't come back to launch point (not for a long while anyway). The reason is that the moon turns under the orbiting projectile. If you have ever watched the ground track projections of LEO vehicles, you will have noticed that the orbit seem to precess around the planet. The only way to avoid this is to have an orbital period that is an integral multiple (or divisor) of the planets rotation period. A surface orbit of the moon does not meet this requirement. (Well, maybe they were on the lunar equator firing exactly east or west!)