[X] My Assistant

[Rakhir]

Next phase reached in definition of Mars Sample Return mission

http://www.esa.int/esaCP/SEMJAGNFGLE_index_0.html

[monitorlizard]

I concede now that I was way off with the ASAT idea. It just seems a pity that the Air Force has so many missiles of different sizes and ranges but none seem to be usable as the basis for an MAV.

As long as I'm throwing crazy ideas to the crowd... What if instead of thinking in terms of a 1 kg or larger Mars sample , we go much smaller, say ten grams. Someone has already pointed out here that you could extract a huge amount of science from such a sample size. So you get maybe a small pebble and a little soil. Now the MAV can be smaller, though I admit you still need the same guidance systems, attitude control, radio beacon, etc. (maybe some systems could be made slightly smaller in proportion to the smaller capsule needed for the sample).

Using a balloon to raise an MAV to an altitude of several thousand feet would be a way to make the MAV even smaller, acting as a sort of first stage for the rocket. I don't know how the trade-offs would compare, but if everything were of minimal size, it might be doable. I know it probably seems unnecessarily complex and not worth the effort, yet the U.S. Defence Department studied this very same concept before Sputnik as a way to achieve Earth orbit before the Soviets.
Maybe the fact that they never did it should tell me something.

[djellison]

Using a balloon to raise an MAV to an altitude of several thousand feet would be a way to make the MAV even smaller,

And also a way to make the MAV far more complex that it ever need be. Balloon's are not great on Mars. The atmosphere is so thin that you would have to have an ENORMOUS balloon to get something like this aloft - and you still have the far from trivial issue of launching from a balloon, particularly w.r.t. orientation for launching. A comparatively simple solid fueled two stage MAV with a cube-to-nano sat sized payload with a radio beacon of some sort - keep it as simple as possible. If you send a mid-scale rover in advance to get samples - then an MSL-scale lander could house both the MAV, and a contingency sample gathering micro-rover. The hard part is the on-orbit rendezvous - and how to convince people that you've got the samples very very tightly locked up.

Doug