Wednesday, December 23, 2009

Mars Sample Return to Cost

Note: broken link to Jones' presentation fixed. 

Mars sample return missions have been proposed in one form or another for thirty or so years (see http://futureplanets.blogspot.com/2009/02/great-website-saturn-ring-observer-and.html although Portree's blog is no longer on the web, but the list of studies gives the message).  The Mars science community has settled on a three mission series with a nominal cost of >$6B that, if successful, would provide an excellent science return.  (But note the difficulty and risks of sample return missions: http://futureplanets.blogspot.com/2009/03/why-mars-sample-return-is-so-hard.html).  The proposal to the Decadal Survey begins with the Max-C rover that would cache samples in 2018, a Mars orbiter and Earth return vehicle in 2022, and a Mars lander/ascent and fetch rover in 2024 (http://futureplanets.blogspot.com/2009/12/new-mars-sample-return-plan.html and http://futureplanets.blogspot.com/2009/12/new-mars-sample-return-mission-part-two.html).  This series of missions would require  half of NASA's planetary exploration budget for a decade, assuming no cost overruns and no budget cuts.  The science would be extraordinary, but the series of missions could become NASA's planetary program for a decade.  (Although, the flight of the orbiter-return vehicle and the ascent vehicle could follow Max-C by years if not decades, spreading out the cost and the risk that the subsequent missions might not fly.)

I'm on an informal discussion group that discusses future planetary missions.  One of the members, Phil H. argued that the Mars sample return should be designed to cost, and he agreed to have his argument posted here.  I'll let you evaluate his arguments and reach your own conclusions.  This is an issue that has been debated by the planetary community for decades.

I always welcome thoughtful commentaries; please send me any that you might have.

You can find the presentations that Phil refers to at:





Phil's essay follows:

    I think that for Mars Sample Return to actually fly, NASA needs to design a mission "to cost."  This would be similar to the approach that the Solar Probe team was forced to follow.  When it became apparent that the Classic Solar Probe mission, including Jupiter flyby, was too expensive to get approved ($1.1 Billion), they went to Plan B.  This Plan B is called Solar Probe Plus and it was designed to come in under a cost ceiling of $750 Million.  Solar Probe Plus is now the design of choice and will be launched in 2015-2017.    
    This was similar to the Pluto Express case.  When JPL could not bring in a proposal for under $1 Billion, it was put out to bid for $650 million, as I recall.  The APL proposal won.  As a result, the New Horizons probe is  now on its way to Pluto.  
   Recently, there have been several proposals for low-cost, low-risk MSR missions.  I have attached a couple of these reports.  What these missions have in common is a realization that the first MSR needs to be as simple as possible in order to be approved and to succeed. 
   I refer you to the end of the BASALT mission proposal (by J.Jones?), in which it is stated that "To make sample return viable, we must devise a low-risk, AFFORDABLE mission."  I agree and believe that is the only way that an MSR mission will ever get approved. 
   I refer you to McKay's proposal which like Jones' concept, is simple.  McKay also adds the further risk-reduction effort of sterilization of the returned samples.    With sterilization, NASA can avoid the expense of a Receiving Lab designed to reduce the risk of an Andromeda Strain situation.  However, as McKay points out, even with sterilization, biologically significant data can still be derived from the returned samples. 
  Another insightful comment from p.10 of McKay's MSR proposal  -  "Don't try to solve the 'life on Mars' question in a single mission.    The VIKING MISTAKE."  This is advice that NASA should heed.
   By contrast, recent MEPAG reports continue to advocate "Battlestar Galactica" schemes for MSR.  Perhaps, someday these "dream" MSR missions will be flown.  However, in my opinion, the first one or two Sample Return missions need to simplify, simplify.  As seen with the MSL Rover, complexity grows as a spacecraft progresses from Phase A to Phase B.  It is better to start off with a simple design for MSR, since it is a given that, for it to fly successfully, it will need to be "tweaked" by the engineers.  This will add some complexity and cost.  However, if one starts with "Battlestar Galactica," then one has no margin for growth in cost, complexity or risk.  
    Mars Sample Return will require several new technologies.  Each of these adds to the complexity and cost of the mission.  In my opinion, it would be better to limit the number of "miracles" necessary to fly the first MSR.  There are several "miracles" that must be developed in order for MSR to fly, e.g., Mars Ascent Vehicle (MAV), Earth Return Vehicle (ERV), Mars Orbit Rendezvous and Docking (or ISRU for a direct ascent vehicle).  If we can fly a simple "groundbreaking" MSR mission, such as described by Jones and McKay, then we can not avoid the costs of developing those steps.  However, if we can avoid, in the First MSR mission, extra costs such as a biologically secure receiving lab, or fetch rovers, or complicated sampling procedures, then perhaps we can afford MSR. 
    If NASA does approve a cost-capped MSR, then I believe that the next step should be to put it out for bid, as is done with Discovery and New frontiers missions, and as was done for the Pluto Express mission, as described above.  There are other capable entities out there, such as APL, NASA Goddard and Lockheed-Martin, that can bid for these missions.  With JPL's monopoly at an end, perhaps we will see the forces of the marketplace bring the costs of Mars missions down.   This would go along with my intial comments that the MSR should be built to "cost."  This might sound radical, but that is exactly the way that business is conducted in the Discovery and New Frontiers missions.
    One more note on how simplifying MSR might impact the MAX-C Mars Rover.  There is talk now of the need to sterilize some or all of the MAX-C Rover in order not to contaminate any cached Mars samples.  This would occur if MAX-C becomes part of an MSR mission.  If, however, those Martian samples are themselves sterilized, then this would reduce the cost, and decrease the risk, of the MAX-C Rover.  
   I want to see MSR occur, and I want that to happen soon.  I believe that with a simple mission design, that might come to pass.

3 comments:

Bruce Moomaw said...

The problem, as always, is whether a Groundbreaker SR would include enough searching for astrobiological evidence to be worthwhile (at least in the eyes of Congress). Jones' proposed mission doesn't have official biological goals at all. McKay's mission (perhaps landed in a sedimentary-rock area?) would have limited ones, but -- even if one assumes that heat sterilization of the returned sample is avoided -- the odds of returning biological evidence would be sharply diminished by the inability of the mission to visit any outcrops of sedimentary rock and to sample individual features on them that look promising as possible preservers of biological evidence.

I'm far from being totally unswayable on this topic, but it seems to me that Phil (and McKay and Jones) have presented something very far from a convincing case -- largely because Jones himself freely admits that he has specialized nonbiological interests in Mars samples, and McKay (judging from his proposed list of sample-return goals) seems to be leaning toward the same position. I differ from Phil in that I'm willing to wait considerably longer for a much better sample, and I suspect Congress will feel the same way -- are they really going to approve a mission that will still cost $5 to 6 billion for geological goals? (Judging from the audience wrangle at the recent Decadal Survey Mars Panel meeting that followed Bruce Jakosky's presentation on the desirability of flying MSR quickly -- and he was only saying that we ought not to fly any more missions after MSL to scout around for optimal landing sites if MSL comes up empty-handed in its search for organics, which is a much softer position than Jones' and McKay's -- the Mars science community is still as divided in its feelings as I am.)

One side note: Phil is wrong in saying that sterilization of the samples during the return to Earth would make it unnecessary to (partially) sterilize the MAX-C rover, since the purpose of partial MAX-C sterilization is to minimize the amount of terrestrial organic contaminants (dead or alive) that get into the returned Mars samples. There may still be a good argument for gamma-ray sterilization of the sample during the return home -- maybe just to minimize possible public panic during the initial government debate over whether to fly an MSR mission at all.

pechisbeque said...

Hi, apparently the link is broken again.

Thanks for all your blog entries, they are extremely interesting.

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