Members of MPSET: Charles Wetzel, Gentry Lee, and Charles Kohlhase
Introduction by Jeff Moore: Members of MPSET introduced, Charles Wetzel, Gentry Lee, and Charles Kohlhase. Jeff asks them to provide the group with their insight into the technological hurdles facing MSR, and their implications for budgets/schedules. Followed by discussion.
: Concerns expressed by some members of panel that JPL was "hijacking" sample return by building rovers. . .
Also, there is a lack of appreciation, for the large technical concerns and technology development issues that have to be confronted and overcome before we can do sample return of any sort.
Impression from what Laurie has said, that MPSET work is indicating that regardless of what kind of sample return, you couldnt get to Mars and back w/ a sample without overcoming some fairly sizeable hurdles, and thats going to have a substantial impact on the budgeting and scheduling.
One minute summary of the MPSET: Mars Program Systems Engineering Team, chartered as part of the development of the new Mars Exploration program and its function is to tie together all the interim project elements from an engineering sense and to therefore represent the program systems engineering.
One of the first tasks to try to sort through all the different ways to do a Mars Sample Return mission:
determine which modes were viable
define technology plan that should go with modes, what should be developed, demonstrated, etc. . . for reasonable probability for success
: this is articulated and summarized in the Hubbard et al. paper sent out to everyone.
sample scientist, worked with Mars meteorites, keen on getting pieces of Mars back to work on in the laboratory
Disappointed with the pace of the program
What is the current notion, preferred scenario and time line for sample return? Details of mission, lunar style grab and go? Mega-rover?
basic mission not a grab sample, would involve a rover
Some degree of argument over how much traverse capability rover would have
Certainly at least a scientific sample that is both vertically and horizontally scattered
Some subsurface drilling, at a minimum trenching
Some roving capability
Sample brought to a MAV, Mars Ascent Vehicle, that would blast off from surface
Baseline for the program: take place in 2011 (launch) and sample return in 2013, currently looking at different ramifications of the Mars Exploration Rover cost overruns, because the Mars program is "a zero sum game" it influences the rest of the program.
Unknown speaker (Allan Treiman??):
There has been concern in the community Im from about the notion of so called "hijacking" the Mars sample return program, we see the actual date of return receding into the future.
How will missions currently planned address the technical problems associated w/sample return?
will tick through a few "miracles" the requirements to do a sample return, that an experienced engineer would suggest a valid demonstration, before you commit the money.
Need MAV that flies off surface of Mars.
Also, you either need to do a direct return or if you do not have enough mass to return back to earth, you must have a Mars Orbital Rendezvous.
Two major miracles you need to demonstrate beforehand (prudent engineering).
Attempt in building the program has been to blend scientific achievement and technology demonstration in the precursor missions along the way.
Has heard that we are hijacking the sample return in order to do rovers, but does not believe that is true.
If it was sufficient to do sample return mission where all you had to do was simply send a fetch rover away from a rover vehicle, in a 100 meter region, or send something with a deployable arm and do the same thing, then that would be a Mars sample return mission that could be done with fewer technologies demonstrated prior.
At least with the people we have spoken to, that is not the sample return mission that people want to fly.
Regardless of sample return mission you still need to: get there, land, gather sample, blast off surface, and bring sample back to earth w/o contamination. You have to do these things whether you do a grab sample or a scientifically chosen sample.
Unknown speaker (Allan Treiman??):
comfortable w/that and accepts that there is a need for some kind of roving capability. What in the current mission is going to address the questions of a launch from Mars surface and an orbital rendezvous?
The plan in the program is to use the French orbiter thats going to be launched in 2007 together with the technology that we are flying on board and demonstrate in Mars orbit that orbital rendezvous can be achieved.
Entire program associated with the Mars Ascent Vehicle must be sufficiently demonstrated (on Earth and other places) that it will be able to accomplish the mission.
Unknown speaker (Allan Treiman ??):
The orbital retrieval is going to be tried at Mars?
That is the current plan, yes.
How would you do that? Would you rendezvous a preexisting space craft that is already in orbit or take a piece that youve changed its orbital parameters and try to reacquire it?
there are several different ways, but basically it is thrown out and see if you can locate where it is and retrieve it.
basically two pieces youd fly on the same mission?
right but you would fly the same space craft that your going to use with the rendezvous with all the same sensors and same processing algorithms that would be demonstrated later.
There are engineers that believe challenge is sufficiently great, that it should not be considered and we should be going to another entire entry system, which is another generation and would have to be developed on its own and launched on its own directly from the surface of Mars.
Whatever decision you make on sample return you have to show that you can do it.
there are other engineers that believe that it is not so difficult, that it could be done with demonstrations on Earth.
If youre going to do direct return, you blast off the surface of Mars with the sample in a container, and that comes back to earth.
In order to do this: land on the surface of Mars with everything necessary to fly back to Earth, it has to be mounted on the top of the vehicle that leaves the surface of Mars (everything has to be packed).
This means you need new entry systems, new parachutes, because the entire mass is greater than the mass of the current Mars entry and landing systems are capable of supporting.
Therefore the earliest Mars return sample would be a Mars orbital rendezvous.
What are the precursor activities to a Mars Ascent Vehicle?
The current belief is that you can test everything on the Earth.
Almost no test that you can run from the surface of Mars, that you might not just as well just put a sample on top of it.
Some believe it would be prudent to have two separate landing vehicles with two Mars Ascent Vehicles.
Some discussed putting MAV on top of a rover and carrying it with everywhere , so you didnt need to bring the sample back.
Weve seen the drawings, looks like a 1950s Military mobile rocket launcher.
Imagine a launch vehicle inside an airshell, land on the surface of Mars, erect it, drive for about 100 miles around (over bumps)-I THINK NOT.
Charles Wetzel ?:
That is an architecture that has been previously proposed that we have not found favor in. Leads to large scale rover deployment. The MPSET has expressed that these are bigger than what is needed. Leading down a path that is not the most prudent sample return.
Large rovers are becoming less attractive?
Charles Wetzel ?
MPSET has been working w/ the most talented systems engineers that exist in the country. We are going to develop an annual report.
?: One of the issues mentioned by Charlie is the acquisition of sample at the landing site. Some view this as a contingency if the rover comes off and doesnt come back.
Interest within the academic drilling community, from Italians, and Canadians, terrestrial analogs within the geopetrolium areas-concept of having a rover going far enough from the lander to collect, to assure you have sample diversity.
Mass of the sample we return is small.
Number of potential different types of samples, that a rover could get in a horizontal diversity, the X, Y diversity. The drilling capabilities are intriguing. Not just from a grab sample on the side of the rover , but something that is horizontally selective, horizontally diverse, when we start drilling down and be able to do a combination of down hole science and science for the sample as they are being extracted from the drill.
and this drill would be carried on the rover?
?: No, this would would be carried the lander. It has been looked at to put the drill on the rover as well, that leads down the path of making the rover more complicated that it needs to be and also different complications when your dealing with an area w/ limited resources (in time and energy while your on the surface of Mars). Fundamentally roving and drilling are incompatible activities .
Does this imply that the "Winnebago" scale rovers may be larger than what will be actually built to fly?
My personal belief it that large rovers, the size talked about a year ago are not anywhere on the horizon
?: They are not suitable, not the kind of rover you want to use for sample return.
So, we probably wont be building rovers larger than the ones well be using in 03?
Some people have said they may be twice that size, but not six to eight times that size.
?: again with the focus on sample return, that class of rover is all you need for sample return.
can we assume the 07 rover (now the 09 rover) will be more or less a prototype of the rover taken on the sample return mission?
Glad you asked that question, because the 07, 09, so called smart lander mission is both a science mission on its own and a prototype to demonstrate a number of technologies with Mars sample return.
One is the advance entry decent and landing that has guidance and hazard avoidance and a very small foot print.
Since I sat on the 07 Science Definition Team, I want to make it clear that there are two missions defined that are acceptable for science, either which have good precursor capabilities.
The mobile explored, which leaves a dead lander and "goes over the hill" to three different locations separated by each other by 3 kilometers.
There is another one which is a platform. The platform holds the normal meteorology, seismometer, etc., and a drill that can go down to 10 meters.
The two missions currently embraced by the SDT for 2007 show this same fractionization, between horizontal diversity and vertical diversity. I have heard eloquent arguments from both sides as to which is better.
is a draft of your SDT available?
It will not be passed out until approved, but you can ask the SDT head, Ray Arvidson Should be approved next week.
Any other questions for the MPSET?
From the sample return community, what is described in the 07, 09 mission sounds a lot better (than the "Winnebago") we need to have a precursor to sample return?
Im glad to hear that, weve tried hard in the MPSET activity and in the SDT a new kind of thinking, Mars program thinking. Not to optimize each project, but how they relate to each other both from a science and engineering point of view.
Unknown speaker: One last question, is the MiniMAV concept from a couple years ago, still the standing concept for Mars ????
?: effectively the answer is yes, there is a level of conservatism regarding the mass? for the MAV low, to mid 100 kilo range.
The more recent work has uncovered optimistic assumptions, another reason for keeping the rover small. Still a relatively small MAV, maybe 200, 250 kilo, not any bigger than it needs to be.
When will your MPSET report become available?
?: Targeting late Jan early Feb.
Thank you and goodbye to MPSET members. Jeff asks for feedback.
Sounds a lot closer to what the sample science community has been talking about. Would like to hear what Steve has to say about MEPAGs thoughts. The notion of a lander with a scooper and drill is one of the acceptable sample return alternatives. Talk of a small rover focused on sample return is also something were comfortable with. The problem we had seen was with the Winnebago rover, which contributed nothing to the goal of sample return. Quite comforting to hear the MPSET is not considering this. They are considering the goal of sample return as something that drives them, rather than something that is tacked on.
always Scotts intention about Winnebagos. They were proposed last year because they thought they would have to carry a MAV on the back. Now, we can go back to a more realistic rover, the 07-09 rovers will probably be the prototype rover that will be sent out, collect rocks, and return to MAV.
I did hear second hand from Matt Golembeck, that there were other things discussed from the MEPAG meetings that are other precursors to sample return discussed. One which has to do with the Mars Program landing site selection activities. . . down the road in the view of landing site selection for sample return.
It will evolve into the process we went through for the Mars Pathfinder and the aborted 01 lander, and we are now in the middle of for the 03 lander. Clearly, when MRO comes on line, largely engineered toward certifying landing sites. What we are principally doing to pick landing sites is going to have to change in several ways, not only from its emphasis from sample return but how do we manage data acquisition and data analysis?
Raging debate within MEPAG and outside of MEPAG about how to prepare for sample return. Most of sample people say we have done all we can to go out and pick a site, just a matter of making the decision.
Battle between the hard rockers and the astrobiologists?
The astrobiology community has wanted to pick the perfect rock. The more hardrock, geochemical community would be satisfied with a sample return from anywhere, for the first one.
You hear from others that the hardrock people dont need a sample return, they already have samples sitting in Houston.
I know they say that, early on NASA didnt want anyone to know about the Martian meteorites, because of the diminished chance of sample return. We can do good work on any sample that comes back.
Jeff Moore: Can imagine sites that are astobiologically interesting that also represent some of the strata covered in the Highlands. One thing we need to resolve as a community.
Good-byes and Jeff will try to aquire a copy of the SDT report and distribute to members. Jeff will be on travel and working in the field during the next two weeks. Another telecom on the 7th Nov.