Mars Sample Return Options

[Rakhir]

Next phase reached in definition of Mars Sample Return mission

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

[dvandorn]

Well, here's another thought -- instead of relying solely on Mars Orbit Rendezvous (MOR) to collect up all of your separately-launched samples, why not add to this with an element of Mars Surface Rendezvous (MSR)?

It seems to me that the most challenging part of this architecture, both to land on Mars and to get back up off of it again, is the ascent vehicle.

If you want to sample six types of terrain, would it make sense to land six ascent vehicles and then go hunt their easter eggs in Mars orbit, using up tremendous amounts of propellants in rendezvous maneuvers? Or would it make *more* sense to land only two ascent vehicles, each of which is loaded with samples from three different rovers? (I'm thinking that it *must* be easier and cheaper to design, build and fly two MAVs which can each place 30 kilos of samples into orbit than it is to fly six such vehicles which can each loft 5 kilos of samples.) Yeah, you'd "bunch up" each set of three rover sites into something like 100-km circles around each MAV (assuming your rovers can drive as far as 50 km to deliver their samples), but that seems a small price to pay. Besides, there must be many locations on Mars where you can access several different and interesting geological units within a 100-km circle.

Granted, you'd be betting that your rovers would be able to navigate to your ascent vehicles. But again, success could be a graded event -- if only one of your ascent vehicles worked, or if only one or two rovers were able to deposit samples in each, you'd still be looking at a pretty successful mission.

And you'd only need enough fuel in your Earth return/orbiter vehicle to make two rendezvous maneuvers, not six. That could be a truly substantial mass savings.

Yes, we're talking about spending something similar to what Apollo cost just to get 50 or 60 kilos of Mars back to Earth -- at least four major Ares V-type launches, probably more, and a *lot* of spacecraft all operating at once cost a lot of money. But it's a fraction of what putting men on Mars will cost, and a lot of people would argue it's scientifically justifiable.

-the other Doug

[JRehling]

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