Mars Sample Return Options

[Rakhir]

Next phase reached in definition of Mars Sample Return mission

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

[RNeuhaus]

A very good article :Returning To Sample Mars, At the recent Viking thirtieth anniversary celebration, Noel Hinners championed what could be the next great challenge for planetary science: a Mars Sample Return mission. Hinners pointed out that, like Viking, Mars Sample Return will prove to be extremely difficult but immeasurably rewarding.

In resume: This mission must be of international cooperation.

Rodolfo

[ljk4-1]

Sample return has been highlighted as a key priority for future planetary missions in discussion meetings held at the first European Planetary Science Congress in Berlin.

http://www.europlanet-eu.org/index.php?opt...6&Itemid=32

Prof. Bernard Foing, Project Scientist for the SMART-1 mission, said, “Europe has now looked at the Moon, Mars and Venus and we have put our finger on Titan. These are great achievements. But for the future, it is not enough to briefly ‘kiss’ the surface of other solar system objects. We must bring them back to Earth for analysis.”

[climber]

Isn't it a coïncidence! Mark Adler is talking about his own experience on the subject on TPS blog today and tomorrow here : http://www.planetary.org/blog/article/00000701/

[spdf]

Funding a Mars sample return mission is not a good idea. This is a very expensive and complex mission. However since the ways to test space technologies on Earth are limited the possibilities are quite high that a Mars sample return cannot be achieved on the first try. Thats the way it is. But I don t think because of the high cost the public and many "space enthusiast" will have tolerance for a failure on the first try. The political climate is simply not right for high risk missions. So imagine the bashing after ... .

[climber]

Funding a Mars sample return mission is not a good idea. This is a very expensive and complex mission. However since the ways to test space technologies on Earth are limited the possibilities are quite high that a Mars sample return cannot be achieved on the first try. Thats the way it is. But I don t think because of the high cost the public and many "space enthusiast" will have tolerance for a failure on the first try. The political climate is simply not right for high risk missions. So imagine the bashing after ... .

If you read what Mark Adler says, he doesn't foresee a MSR before well, 20-30 more years. World will be different then...

[RNeuhaus]

First watch how the russians will be doing by returning the Mars' moon samples with the Phobuss-Grunt spacecraft. Phobus-Grunt is scheduled for launch in 2009. This is indeed cheaper than landing on Mars.

In order to go on on the MRS project be feasible that the man feel highly confident for the success of the project. I think, up to know, we are still close and need about 5-10 years more in order to improve the technology and also to collect money and support from many nations. Up to now, not only russians are doing it but also along with ESA and China.

More details, visit on Phobus-Grunt a Reality? topic

Rodolfo

[Guest_Zvezdichko_*]

First watch how the russians will be doing by returning the Mars' moon samples with the Phobuss-Grunt spacecraft. Phobus-Grunt is scheduled for launch in 2009. This is indeed cheaper than landing on Mars.

In order to go on on the MRS project be feasible that the man feel highly confident for the success of the project. I think, up to know, we are still close and need about 5-10 years more in order to improve the technology and also to collect money and support from many nations. Up to now, not only russians are doing it but also along with ESA and China.

More details, visit on Phobus-Grunt a Reality? topic

Rodolfo

I'm actually quite pessimistic about the Russian Phobos-grunt sampling attempt. Of course, a lot of things have changed since the previous failures, but ... the mission is very ambitious for the current financial state of Roscosmos. Russia hasn't returned samples for more than 30 years ( the Moon ), and the last partially successful mission to Mars was 20 years ago. A Phobos sampling mission requires still untested technologies - Phobos lander, Phobos ascend vehicle. The return capsule will be quite different than these used in the 70s.
And yet, this attempt is worth trying.

[PhilHorzempa]

Recent written comments by Alan Stern indicate that he wants to initiate MSR, Mars
Sample Return, in the near future, perhaps in FY2008.

Also, the National Academy of Sciences now recommends a new approach to MSR.
Instead of one Grand mission, it should be spread out over several years. It suggests
that all future Mars rovers be equipped with a sample caching system. After several
missions, NASA/ESA would decide whcih site held the best samples, and a retrieval system
would be sent. Once the samples were launched into Martian orbit, they could linger there
until an orbital rendezvous vehicle was sent. This would spread the risk and cost over
several years, instead of gambling everything in one Battlestar Galactica mission.

The recent Orbital Express mission has been a pathfinder for an unmanned rendezvous
and docking craft that would be an important part of MSR. However, it's mission is ending
before NASA has a chance to fully utilize it. See the article on this link -

http://www.space.com/missionlaunches/07063...al_express.html




Another Phil


Here is a view from Orbital Express. Imagine that someday, someday this will
be the view from Martian orbit as the Mars Ascent Vehicle closes in for docking with
the Earth Return Vehicle. The background view will be slightly different. We will see
the Martian deserts below, but only empty river channels and rift valleys.






Go to

http://www.darpa.mil/orbitalexpress/mission_updates.html


for more photos.

[hendric]

On the surface that sounds like a good idea, only sending the "retrieval system" to the interesting caches, but I think that would end up being just as complicated as the BSG style missions. The retrieval system would end up requiring rover-like mobility, since it has to reach the cache in the previous mission. It could probably forgo most instruments, but it would still be a large, precision landed rover. It makes more sense to develop a sample return canister/rocket to be taken on each Mars mission, with the rendevous occuring in space instead of on the ground. The space retrieval bus could even collect multiple canisters before returning home.

[Guest_Analyst_*]

It makes more sense to develop a sample return canister/rocket to be taken on each Mars mission, with the rendevous occuring in space instead of on the ground. The space retrieval bus could even collect multiple canisters before returning home.

The return capsule/rocket and "launch pad" is very massive. There is no chance to have every rover carry one. We are talking about several hundreds of kilogramms minimum.

The missions can be spread as described above: (1) landers/rovers to select samples, (2) extra lander to carry sample into orbit and (3) orbiter to escape Mars and return to earth. I strongly doubt this will be more efficient than one single MSR mission. Its hard to integrate, several launches, even more things can fail etc. In the end you need all the same elements. I doubt this will be more cost effective. MSR is a classic flagship mission like Viking or Cassini. I don't see a clever way to change this.

Analyst

[dvandorn]

It all comes down to what you really want out of an MSR mission. Remember, Mars is a fairly big planet as far as rocky planets go. It has a significant gravity well which requires a lot more energy to escape than, say, Luna requires. It also has an atmosphere that gets annoyingly in the way as you try and leave, requiring more energy to achieve orbit from the surface than an airless body would.

So, sending a sample off the surface and back into Mars orbit is not an insignificant operation; it takes more fuel than you'd think. If you include the fuel needed to inject the sample into a trans-Earth trajectory, as well as the heat shielding needed to get it back to Earth intact, you're landing an awful lot of mass on Mars that is dedicated to the return-to-Earth systems. (I'm trying to get y'all used to the idea that an MSR return-to-earth stage on a lander is going to need to be a *lot* bigger, beefier and energetic than, say, the upper stage used by the Russian Luna sample return landers. It's not the "model rocket on a Viking" setup some artists have imagined, it's more like landing a Thor or a Delta on Mars and having it ready to launch with no ground support equipment beyond that you bring with you.)

It would take an Ares V to get such a lander onto Mars with the ability to return more than a few grams of soil and rocks. Such a lander would be so heavy with just the fuel and other things needed to get your sample back to Earth that you'd have no mass left for roving to look for and pick up good samples, much less for a comprehensive survey sensor package.

So, even though it requires three separate launches and spacecraft busses, the concept of splitting the mission into three major pieces -- the survey spacecraft, the surface launch spacecraft and the return-to-Earth spacecraft -- lets you distribute the weight required into pieces that don't all have to be landed and don't all have to support Earth return. Remember, the same booster can get kilograms into Mars orbit that can only get grams onto the surface.

So -- if you want a single scoop of Martian soil, a sample that weighs no more than two or three kilograms, then a single spacercaft architecture is usable. If you want to return tens of kilograms of samples, and not just whatever a scoop can pick up from off the side of the lander deck, you're actually better off with the three-spacecraft architecture. Until and unless we make some propulsion system breakthroughs, it's just not energy-economical to do it with the single spacecraft concept -- not to get enough of a sample back to make the mission worthwhile, anyway.

-the other Doug

[helvick]

I don't think it can be done easily but I don't think the mass penalty is quite that bad. My back of the envelope scratchings based on some Delta-V and typical Isp's from here.

Martian Surface to LMO ~ 4.1 km/sec
Mars LMO to Earth C3 orbit ~ 2.9 km/sec
Total ~7km/sec Delta-V.

To get a 1 kg sample of mars dirt to Earth C3 orbit.
Assume we have motors with an Isp of about 280 (like ammonium perchlorate solids)
Two stages:
(1) LMO Stage - Motor, shell and supports for the mars launch first stage weigh ~ 5kg
First stage then needs ~ 37kg of fuel to get 11kg to LMO ( its own 5kg dry weight plus 6kg for the initial mass of the Earth Transfer Stage)
(2) Earth Transfer stage weighing 2kg dry (container+2nd stage motor+1kg payload+beacon)
Requires 4kg of fuel to produce +-3.1 km/sec Delta-V
Total initial mass = 48kg.

Alternatively.
Single Stage to LMO
Mars Surface to a Mars orbit stable over a couple of years. Say we need 4.4km/sec Delta-V (LMO + some margin) and the dry weight including payload we are working with is ~ 6kg.
Total initial mass = 29kg.

There's lots of holes in these of course (launch stage drag, no earth capture component ... ) but I reckon you can get 0.5-1kg of sample back for <100kg of landed mass. That's not possible today of course but it isn't warp drive level science fiction either.

That said we are limited today to landing something less than a ton or so onto the Martian surface even with the biggest launch vehicles so without something comparable to the Ares V no-one is ever going to return more than a kilo or two.

[antipode]

Drifting a bit OT here, but its obvious to all that MSR will be:

1) VERY expensive
2) Technically risky
3) Possibly providing limited 'bang for the buck' even if it succeeds

Might sample return better be conducted as part of a MANNED precursor mission - one that simply orbits Mars Apollo 8 style (plus visits to Phobos etc). Small surface probes/rovers could then be dispatched from orbit, controlled in near real time etc etc. I know such missions have been proposed, and I'm aware of the objections to them, but MSR is one of those missions that, like controlled fusion, is so hard and so expensive that its always 20-30 years in the future.

P

[Phil Stooke]

Antipode, funny you should mention that, as I am now writing up a description of a mission which includes some elements of what you describe. More on this later.

Phil