Next phase reached in definition of Mars Sample Return mission

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

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

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.”

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/

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...

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.

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.


Click to view attachment



Go to

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


for more photos.

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.

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

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

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.

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

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

Sounds like one of the old Soviet manned Mars mission proposals, IIRC.

Such a mission has a lot to be said for it. For one thing, it's easier to send a lot of lab equipment to, say, Phobos than to the surface of Mars, and it's likely cheaper (in terms of energy) to get the mass of the equipment you want to use to study Mars rocks to Phobos than it is to bring the rocks all the way back to Earth.

So, you set up a manned microgravity habitat on/in Phobos, outfit it with the best analysis tools you can easily get out there, and send down small sample return probes that bring you up a few kg of carefully selected rocks and soils every few months. Your PIs live on Phobos and send the detailed data back to colleagues on Earth.

What would be the minimum lab requirements for a Phobos geological analysis base? You'd want to have fine-scale composition and isotope analysis, as well as the best rock dating equipment you can afford to transport. You'd also want equipment for examining micro-fossils (just in case) and for examining ices and such for possible biological activity or remnants.

What suite of instruments would best serve your purposes in such a set-up? What are their power requirements? And how much of it can be feasibly transported via rocket from Earth to Phobos? Those are the questions I'd be asking right now...

-the other Doug

One fairly big problem that I see with the idea though is that the stuff that you loft up from the Martian surface would also have to land on Phobos and do so incredibly precisely and without damaging your lab. That's pretty hard if you ask me - It seems to me that it would be a lot easier to send stuff all the way back to Earth. The Delta-V difference between "Mars-Surface to landed on Phobos" and "Mars-Surface to Earth C3=0 orbit" is only 1.5km/sec.

It seems to me that the most efficient way to use a manned outpost on Phobos would be to search for bits and pieces of Martian rock on Phobos itself. Nearly every large impact on Mars must have caused some debris to end up on Phobos. You could do the preliminary selection and analysis on Phobos and send the most interesting bits back to Earth for detailed study. In this way it should be possible to get at least a rough outline of Martian historical geology and also "ground truth" data to interpret orbital imagery.

Another fairly simple and cheap, though very limited form of sample return would be to expose a Stardust-type collector during aerobraking and returning it using a small Earth-return stage.

SCIM has been proposed in the last two Scout competitions and would follow that mission profile.

Would it be cheaper to bring the rocks or the PIs back to Earth? The PIs are coming back, right?

Well, it depends... the PIs have to get their results published before they can come home, after all...

-the other Doug

Publish or perish?

Literally!

-the other Doug

Mars Mission May Be Moved Up
By Frank Morring, Jr.
Aerospace Daily & Defense Report
July 6, 2007

Didn't know where to put this...

"Let's get this done ... make some history," Stern concluded.

This is how I like to hear them talking!

Was this by any chance the 'Mars Twilight Flyby' that NASA was planning in 1966?

As I remember the documents I looked through the plan was to fly past Mars, drop off six probes (1 orbiters, 3 hard landers & 2 soft landers), one of which would rocket into orbit a capsule containing a Mars rock/atmosphere sample and film from a high resolution camera for pickup by the manned flyby craft.

On the way back the astronauts would analyze the surface samples and beam the results back to Earth.

gndonald:

"Was this by any chance the 'Mars Twilight Flyby' that NASA was planning in 1966? "

No. It's about Phobos, and has evolved into my abstract for the Phobos conference.

Phil

[...]

I get your point, JR. In all fairness, though, there does seem to be some precedent for the strategy. Ranger/LO/Surveyor were all precursors to Apollo, so since Mars is the espoused future goal for US manned exploration it's getting the lion's share of UMSF attention.

Not necessarily saying it's the right way to go, but merely speculating on the apparent reason for the focus.

I think you missed the "far into the future" part. Mars sample return is going to be harder than the current missions, and it's likely to take a lot of time. And it can fail like any other mission, for technical or monetary reasons. We can get into the situation when specialists are waiting for additional financing, and there are no working rovers on Mars. The sample return mission is just too big for the pipeline now.
A think we need an "entry" strategy - how to implement ambitious missions efficiently, so that we don't end up with another over-expensive and unsustainable Apollo-like program.

[...]

Mars is also special because it the easiest extraterrestrial planet to research. Try getting samples from Mercury or Venus. Now that would be hard!

The Moon and asteroids are easier, but some questions can only be answered by researching planets. Mars is a natural stepping stone for planetary research. We may learn enough about Mars at some point, but the technology developed for Mars will be reused for other celestial bodies.

A massive one-off project would be less useful for further exploration than smaller specialized missions. MER-like robots can be driving on Europa one day.

Nonsense.
Liver cancer will continue after one cure has been found. The cure may be expensive, lengthy etc
We know how to set broken bones yet research continues and better "cures" are the outcome

Has ocean research finished.

Not until there is a human presence on Mars, will the missions end. Strike that, there may be Martian weathersats.

A question here: If you have a ~30-40 kg small satellite and you want to launch it from mars surface into mars leo, how much energy do you need for it? And how big would be the rocket? Is there any more detailed study on this online?

Thanks

not sure, but I think you'd first want to launch it in lmo

You can find some of my back of the envelope calculations on that question in an early post in this thread ( here )
The delta-v that you need is 4.1km/sec to from the martian surface to LMO. Assuming you're using an engine with performance similar to an ammonium perchlorate solid motor (ie an Isp of around 280), then you will need at least 135kg of fuel. You will need an actual launch shell to put it all in which would add another 10-20kg + another 30-60kg of fuel to cope with that extra initial mass.
Note I've made no allowances for atmospheric mass here and that will be significant even though the martian atmosphere is not very dense.
Excluding drag you are talking about an initial mass of at least 215kg to get 40kg to LMO.

And finally you need a (martian) ground assembly to hold it all before launch and I've no idea how to estimate how massive that might be.

I would assume that the return stage would be integrally mounted to the descent stage in the proper configuration--pointy end up, propellant loaded-- before Earth departure; physically configuring it for launch on Mars in any significant way seems really risky from a technical standpoint. Still, lots of mechanical complexity needed to put the payload aboard, unless it's a simple scoop...

[...]

I'm probably going to get my head handed to me for saying this, but can't a case be made for a Mars sample return with a direct Mars to Earth trajectory, bypassing a rendezvous in Mars orbit with an Earth return stage?

The obvious counter to this idea is that the size/weight of the Earth return rocket on Mars would be MUCH larger than that needed to reach low Mars orbit. OK, agreed. But there are a lot of advantages to direct to Earth launchings from Mars. One: A Mars orbiter to receive the sample canister wouldn't be needed. That eliminates an entire launch from earth and an entire spacecraft. Two: No need for a rendezvous in Mars orbit. This is an extremely complex operation to do unmanned, and I think it is the pacing technology for when a sample return could be done. It also raises the cost of the mission enormously.

The alternative is to launch a single massive spacecraft to Mars, have it collect and store samples by whatever means is preferred, wait until the next alignment of earth and Mars, then launch the sample return spacecraft directly to earth (no orbiting Mars first). This would require the use of a much larger launch vehicle from Earth than a standard sample return scenario, but that cost would be offset by requiring no Mars orbiter launch, and the much greater simplicity of the Mars to earth portion of the mission (which should also reduce costs greatly and, more importantly, give a greater chance of success).

I've made my case, let the carnage begin.

Well - yes - carnage indeed. Instead of a 5kg litle satellite to launch from the surface - you have to land, and then launch again - a much larger launch vehicle, to launch not only the small sample cache but also a complete, fueled, spacecraft and entry capsule - able to not only enter the Earth's atmosphere at the other end - but navigate with TCM's between Mars and Earth. A full up proper spacecraft - perhaps 100kg (complete guess). Landing and then launching your return capsule is not easier.

You're making the requirements of the MAV an order of magnitude larger - and thus the landing requirements an order of mag larger (when we don't know how to land >750kg on the surface) and thus the first launch vehicle from Earth being an order of magnitude larger....which doesn't really exist

I think from a biohaz perspective (even if it's just paranoia) - taking a small cache from orbit, putting it into another large entry capsule that is then sealed makes a lot of sense. If you have the entry capsule on the surface, you've exposed it to the Martian environment as well.

I can perhaps see the case for single launch - a viking like split between lander and orbiter, and then then a re-rendezvous on orbit for the return to Earth - but taking EVERYTHING you need to get from Mars back to Earth ( a complete spacecraft) all the way to the surface and back makes the entire problem much more difficult than it needs to be. Also- orbit rendezvous and return offers the option for multiple samples collected and launched from multiple sites to be returned via a single orbiter.

Thanks, Doug. I knew I was going to be defeated on this, but reading the details answered a lot of questions I had.

It's not 'defeated' - I mean, there's merit to making as few manouvers in the system as possible. If you could make a spacecraft with the necessary Delta V and entry ability to do the Mars to Earth flight - but <10kg - perhaps it could be done - but I'd want my return vehicle to be very big, very reliable, and packed full of redundent systems.

Doug

Of course the points Doug mentions are valid and pretty serious drawbacks for the Direct-to-Earth approach.
However, there is (at least) one point in favor for it: ISRU, aka the Zubrin Fuel Processor.
By far the greatest part of the mass of the return vehicle must be fuel, so if you can somehow land with empty tanks and then do a refill the whole plan makes more sense. You probably can't do DTE without ISRU. But even in a split mission approach ISRU could perhaps be an interesting option.

There is also another issue with the split mission architecture. Is it really possible to automatically rendezvous with a completely passive cannister? Something that doesn't have a radio, position control, an energy source, etc... How do you know its orbit with enough accuracy? But if it can't be a passive cannister, how much hardware must be added before you can find it in orbit? What does that do to that 5 Kg mass number?
Actually, I don't believe in such small numbers, it will probably be more like 100 Kg. At least.

I think a sample cache cannister would have a small battery and a beacon radio.. It'd be interesting to know how much intelligence was required on the 'dumb' part of the recent DARPA orbit rendezvous demos when doing the automated undocking and redocking.

Here's a thought. You could make your sample cache a derivative of a cube sat.

Doug

A cube-sat? Hmmm, I believe at Delft University (Holland) they actually are developing something like that called a nano-sat. As I recall it was 30 cm. (12 inch) on each side, or something. (And it carried a radio) I will see if I can find some more information on it.

Cubesats are a well established and popular platform ( you'll even find extensive info about them here )

It's 10 x 10 x 10 cm and no more than 1kg

You can extend the platform into a double or triple cubesat ( 10 x 10 x 20 and 10 x 10 x 30 , 2 and 3kg respectively) for added performance.

Doug

So I guess the 'cannister' could look something like the Delfi-C3 nano-sat

This one doesn't have active attitude control, but that's basically all it's missing for being a perfect MSR cannister. Work is also being done to develop autonomous rendezvous, where nanosats would catch up with big satellites for maintenance or repair. This cube-sat development could really be extremely useful for MSR architectures!

So, I'm willing to lower my bid to 10 Kg!
2 Kg of samples.
5 Kg for the standard cubesat bus
3 Kg for attitude control, thrusters and a docking mechanism.

This may be WAY off base, but has anyone considered a purely ballistic MSR mission profile?

What I'm thinking of here is a single-stage (or two at the most, if the upper stage has robust thrusters & agile nav capability) DTE reentry vehicle from the surface of Mars...minimal course correction requirements, tight launch window, maybe even solid-fueled at least for the initial boost phase. Advantages: Relatively simple G&C. Disadvantages: (1) very tight launch window, (2) probably high velocity wrt Earth for entry phase. Don't know without a formal risk analysis how these very coarse factors would play out, nor whatever other dragons there may be.

(BTW, thinking of grams, not kilograms, in terms of sample return quantities: even a very little bit of Mars would go a long. long way in terms of answering fundamental/nagging questions such as the presence or absence of superoxides, carbon abundance/source, iridium ratios, etc., etc., ...)