Mars Sample Return Options

[PDP8E]

very funny doug!

My hack at the problem...its just a broad outline...please turn flame throwers to idle
There is probably nothing new here, other than independent parallel invention

To do the Mars SAR mission and to bypass the mach 5 problem (not enough atmosphere for heavy landers to decelerate safely)
then it must be a divide and conquer solution.

the spaceships required are

* earth-to-mars vehicle that carries a single return-to-earth vehicle with return fuel
* earth-to-mars vehicle(s) that carry one or more of the 2 required landers

Assemble the fleet in mars orbit (use a circularizing method, aerobrake or engine) fly in formation

The two landers:

* One with the MAV 1stage and launch platform (2000lb of propellant) -- use a tested EDL & a sky crane
* the other: a beefy rover with the MAV 2ndstage (1000lb of propellant), also the sample return container/nosecone -- use a tested EDL & a sky crane

The MAV 1stage lands first.

a few days later the Rover/MAV 2nd-stage lands-- very near the first (2 km?) -- precision landing required

The rover loads a contingency sample into the return container
The rover & second stage set out and find The MAV 1st stage. The MAV stages are mated (both stowed horizontally)
Rover still has access to the sample container (which has the contingency sample locked and loaded)

The rover (sans 2nd stage) goes on a science mission to find the best samples (2-6 week mission, 2-20km )

The Rover comes back and loads the samples

MAV is erected vertically - checkout - launch

Rendevouz with Earth return vehicle - sample container stowed

Leave orbit and head back to earth

Rover continues science studies until it dies

I don't think there is any new or breakthrough science needed here
Just alot of complicated machinery that needs to be robust and elegant.

ok...flame throwers set to stun....


Cheers

[Guest_Zvezdichko_*]

I think that the biggest problem won't be the anything concerning the landing phase, but the MAV itself. We all know how complex launching a single rocket is with all problems, delays and so on. A MAV (or a mars rocket) has to be fully autonomous and, of course it has to work flawlessly. That's why I suppose that it will be solid-fueled because it's the simplest design and there aren't many options for failure.

I think that the two-launch scenario (an orbiter plus lander) is the best. The orbiter, while waiting for the MAV to arrive may be busy collecting atmospheric samples using aerogell (already tested on Stardust and Genesis). The MAV may be delivered on the surface using a skycrane technique, specially redesigned for this purpose. I can't think of a better idea. Though I know how difficult fully automated docking may be.

[vjkane]

I suspect that when the failure modes are analyzed that the lander/rover/launchers combination contains the overwhelming portion of the MSR risk. I think that having two sets of lander/rover/launcher should be baseline. If both deliver samples, great. However, if you send one and it fails, then the entire $5-8B is gone.

[hendric]

Why don't we just land a tank on Mars? It can rove around, picking up interesting samples and loading them into rocket-assisted shells. Once it is ready to launch, it can use a compressed air gun (remember the post-Columbia tests? ) to fire the shells upwards, one at a time. Fill the tank with CO2, heat it up nice and hot, and BLAMMO! Rifling on the barrel handles the guidance task for the first "stage". That's got to be good enough for a dozen or two km of altitude on Mars. Ignoring drag, 300m/s gives you 12km; 500m/s gives you 34km, enough to reduce the atmospheric pressure by 95%. Then, WOOOSH, your rocket boosts you to orbit!

Problem solved!

I CAN HAZ 8BIZZILLION DALLARS NOW?
K TNX

(Sorry, in a goofy mood)

[John Whitehead]

Has anyone met a propulsion engineer who finds mossbauer spectra interesting?

The rocket guru didn't cower
When confronted with data Mossbauer
She studied for weeks
Spirit's olivine peaks
But who else grooves on MAVs for an hour?

They'd pay for a tiny launch tower
And order propellants for power
But they sought a cheap rocket
Plucked from someone's hip pocket
Their grasp of the MAV didn't wow 'er

Seriously folks, it is too easy for all of us to take the other person's work for granted. But I thought that scientists and mission planners have a strong direct influence on budet decisions that could lead to funding technology for launching off of Mars, while rocket engineers have little or no direct influence on the budget planning process for science. Ideally rocket engineers would have an indirect influence, by creating a 100-kg MAV to leave room on MSR for more science. Yes there are technically valid solutions that permit a heavy MAV, but they all cost more.

Another recent news article:
www.guardian.co.uk/science/2008/jul/14/mars.spaceexploration

Re the latest comment from hendric, the MAV has to be relatively fragile in order to obtain the high ratio of propellant to inert mass, so it would not help to shoot it out of a cannon just to reduce the MAV velocity requirement by 10 percent or so.

John W.

[JRehling]

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[JRehling]

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[dvandorn]

Just exactly how much sample do you expect to return to Earth with a MAV that weighs, grand total with sample container and fuel, 100 kg?

No more than a gram, I would imagine -- and that would be pushing it.

Can I ask exactly what you think we can do with a gram or less of Martian surface materials? And why we would spend a billion dollars (or multiples thereof) for such a miniscule amount?

Just... curious.

-the other Doug

[djellison]

Just exactly how much sample do you expect to return to Earth with a MAV that weighs, grand total with sample container and fuel, 100 kg?

Typical figures quoted are about 1kg

[SpaceListener]

The MSR mission is very pricely. Why so much difference?

As an example, the most expensive mission to Mars would be for MSL by between 1-2 thousand millions dollars (I don't say billons -> millions millions). And the MSR would be between 3 to 5 times more expensive than MSL with just adding a few hundred of kilograms of weight to the spacecraft in order to return a 1 kg of sample. Well, I too agree that by sending as many in-situ spacecrafts to Mars would yield a better cost-benefit to science. Just a thought

[PDP8E]

Does SAR stand for something besides Synthetic Aperature Radar, or is this a typo for MSR?

Hey JR,

SAR is the OLD school 'sample and return' acronym.

It doesn't have a place name attached to it so it can be used for anywhere (moon,mars, asteroid, the antarctic ....)
as opposed to MSR ...

thanks for pointing out the anachronism

My Bad!

Cheers

[Mariner9]

The cost of the mission is sure to be a political trouble magnet, no doubt about it. And I'm among those who have doubts about the likelyhood of this all coming to pass.

But, in defense of the benefit of the mission, consider this.

We are rapidly getting into a point of diminishing returns on the Mars unmanned missions. Mars Global Surveyor was a huge step forward in our understanding of the planet, but can anyone reasonably think that we could find another 300 million dollar orbiter to make another quantum leap forward? The next generation of orbiters, MRO, cost more than double that figure at around 700 million.

Same thing with Phoenix. For about 500 million we get a nice little chemistry lab at the north pole. We should learn a lot of good fundamental information, if for no other reason that we have only had a small handful of landers on Mars before this. But fly a second mission of that class, and the ammount you advance your knowledge is somewhat smaller. Do you learn 4 times as much flying 4 more of them? Not likely. I really doubt we will see many more landers like Phoenix.

MSL is a great mission, but in order to advance beyond the MERs, we had to jump in cost from 800 million to 1.9 Billion. Now, to improve on MSL, what next? Do we move up into the 2-3-4 billion dollar range?

So, while there is still a lot we can learn with the in-situ unmanned missions, it starts to cost more and more to advance less and less.

Eventually Mars Sample Return, as expensive as it is, starts to look cost effective in the 'bang for your buck' department.

[nprev]

Hmm. Food for thought, Mariner.

The only real heartburn from a data return standpoint I have is that MSR would bring us a sample from one, count it, one, very small area of Mars. The planet's geological diversity is really becoming apparent (esp. from MRO & MEX), so much so that I wonder what the real value of a sample from a landing-friendly area of Earth would be as far as drawing conclusions about global, or even regional processes.

Maybe I'm underestimating our present understanding of context here, and perhaps not appreciating objectives. Certainly this argument could be applied to anything short of a full geological survey of Mars. That being said, MSR does need to define very specific sampling objectives, IMHO. Do we want phyllosilicates, sediments, evaporites, or what, and what specifically are we trying to find out?

Sorry for the devil's advocate position here, but when we're talking about spending this kind of money critical questions will be asked; better be some really good answers.

[dvandorn]

Exactly. If our $10 billion would buy us 100kg of samples, gathered by and trundled back to the MAV(s) by capable MSL-type rovers, picked up from a variety of landforms and geologic expressions, then I'd be all for it.

But if our $10 billion buys us a kilogram or less of soil and a few rock chips from within a grab-sampler-arm's reach of the MAV, then I don't care if God Himself is going to analyze the samples, the chances of finding anything truly instructive about Mars would, I think, be far less than if we spent the same money on three or four more MSL-capable rovers.

I strongly believe in bringing samples back from Mars. But I don't think a kg (or less) for $10 billion is worth the money. Not even worth $6 billion. IMHO.

-the other Doug

[Mariner9]

Most of the documents I have seen indicate that the baseline mission calls for collecting samples via rover for at least 6 months. Unclear to me if there is a large stationary lander with MAV mounted on it, with a rover returning with samples in tow, or if the lander is one large rover with MAV mounted on it.

In any event, it means that while you won't have samples from all over Mars, you at least get samples taken from a number of locations possibly ranging up to 10-20 kilometers away from the landing site.

Compare this to the MSR studies done in the 1980s. At that time there was a belief that Viking orbiters told them all they needed to know to get a site selected. And some studies even ommited any idea of a rover, and just had the lander grab rocks with a long robotic arm.

So really, 3 or 4 MSRs would be nice, but even just the one mission in 2020 would still be a tremendous advance in knowledge, and unlike the 1980s, we wouldn't be taking a shot in the dark on a location.

Maybe it really is time to bite the bullet and go for it. I keep thinking about Alan Stern's comment to the effect of "it's better to get 80 percent of something, than 100 percent of nothing".

In other words, no matter how long we wait, we're not likely to get the perfect set of MSR missions all over the planet, so why not at least get one?