Mars Sample Return Options

[StargazeInWonder]

Yeah, I'd say that the newer article basically contains one literal bit of new information, which is that the plans are, in their view, on pace.

n is small, but so far China's track record of accomplishing their stated objectives in space exploration seems solid.

From the standpoint of their effort having scientific value, I wonder if they will return any sedimentary rocks and/or if they will complicate their MSR plans by making the effort to do so, or maximize simplicity, at the cost to science, by just grabbing any samples and returning them.

So far, every martian meteorite in possession is igneous. China has suggested that Chryse Planitia might be the site where they would attempt to sample, given the abstract of this paper:

https://agupubs.onlinelibrary.wiley.com/doi...29/2023JE007937

Mars Pathfinder suggests that a landing site in / near Chryse might be able to access some sedimentary samples.

[John Whitehead]

In the budget agreement released Sunday, lawmakers clarified that the ultimatum in the Senate’s proposal was no longer on the table.

Good news, recalling that the Senate in 2023 threatened to cancel MSR if the mission could not be squeezed into the optimistic budget and schedule.

Immediate future work will focus on the system to deliver the samples to orbit. It could mean that NASA would launch the samples into orbit and then collect them some (maybe many years) later. I don't believe that's what is meant.

Hopefully the meaning was focusing on rocket technology progress for launching off Mars. The MSR Chief Engineer (new at NASA HQ as of 2023Oct, see post #493) has a testing background, so it will be interesting to see if the official NASA response to the report from the second MSR Independent Review Board (IRB-2) refers to MAV testing, seemingly overlooked in the IRB-2 report (see attachment to post #493).

Regarding the Planetary Society interview with the MSR IRB-2 Chair (Post #494 to #497), I concur with the disappointment that the interview lacked details.

The last few years have shown that the MAV design became heavy enough to need a huge lander, even without a fetch rover riding along. Keeping things big would be the best outcome for science, to bring back the most samples. Compared to past Mars landers, a heavier one might shed less of its entry velocity aerodynamically. Possibly an inflatable decelerator would help to slow it down, or more of the slowing would use rocket propulsion. Another approach would be to make the MAV smaller by reducing its non-propellant mass (lighter rocket hardware and-or fewer samples). In any case, some kind of new engineering seems necessary for the lander, the MAV, or both.

On 2024Mar5, a Mars science committee (MEPAG) stated to the Planetary Science Advisory Committee (PAC) that Mars scientists are looking forward to NASA's response to IRB-2, one slide from that meeting attached below (MEPAGtoPACslide2024Mar5.pdf). After the long wait since October, we will hopefully see a workable path forward for MSR.

Attached File(s)

 MEPAGtoPACslide2024Mar5.pdf ( 155.62K ) Number of downloads: 45

 

[StargazeInWonder]

This feels like someone has turned on the oven to pre-heat it for baking a cake, then decided to form a committee to find a store that sells essential cake ingredients, and agreed to send out a survey to the diners to find out if they want cake, and has ordered a cookbook. The mis-sequence of preparation and planning is almost comically askew. Of course, there's no re-starting the process now. The good news is that the sampling by Perseverance is an asset that has already been accomplished. There are ways to end up with a successful sample return. But there's no way forward that isn't going to end up attracting negative attention to how inefficient the path has been.

[John Whitehead]

Thanks for the analogy. Yes, the people who set the oven to "preheat" were planning a recipe that turned out to take longer to mix, and they made incorrect assumptions about availability of ingredients. Translating back to MSR, one assumption is that engineering is always a procedural activity, even though there is often a need for iterative creative design-build-test to find what will work.

In addition to MAV capability being beyond the state of the art for small rockets, the Capture, Containment, and Return System (CCRS) in Mars orbit was more than a year behind schedule as of late 2023, according to a report from the NASA Inspector General (IG) on 2024Feb28. https://oig.nasa.gov/docs/IG-24-008.pdf

Page 25 of the IG report explains the importance of not being too heavy to fly, in regards to the CCRS. Strangely there is no mention of the MAV being heavier than expected. Searching the PDF turns up "CCRS" in 84 places, while "MAV" appears only 14 times, referred to as "a rocket" with no further details.

I agree that the sampling by Perseverance is an asset that will make it worth the effort to push MSR forward.

[mcaplinger]

In addition to MAV capability being beyond the state of the art for small rockets...

This has been a common theme of yours over the past many many pages of this thread, but the OIG report doesn't highlight anything about MAV development being a concern (other than a $45M budget increase from a MAV motor contractor, page 22). The mass margin discussion on page 25 is about the ERO and its launch and has nothing to do with the MAV.

You may well be right about potential eventual problems with MAV development, but the program has run into plenty of trouble without that worry!

[mcaplinger]

There are a lot of details about the MAV design as of 2022 in https://ntrs.nasa.gov/api/citations/2022000...EEE_R1.pptx.pdf

After this, it seems like they wanted to go to a larger design with more mass margin.

Note the sounding-rocket-based flight test on slide 15.

[vjkane]

The journal Science published an article about the progress of the Perseverance sampling mission. It also stated that the project management is engaged in a key debate: should the rover sample only the crater and then return to the crater floor or also sample the ancient terrains beyond the crater?

For those who don't remember, the top two choices of the scientific community for sending Perseverance to were Jezero crater and the ancient terrain nearby. For a long time, the expectation that if healthy, the rover would leave the crater and sample both areas. (How lucky are we that they are next to each other?)

Landing the craft to return the samples is simpler on the crater floor - lower elevation (denser atmosphere) and large flat areas.

The debate was hinted at by the abstracts presented at the recent LPSC conference, where several argue for sampling beyond the crater.

Science article: https://www.science.org/content/article/nas...ines-signs-life

Relevant LPSC abstracts:

https://www.hou.usra.edu/meetings/lpsc2024/pdf/1336.pdf

https://www.hou.usra.edu/meetings/lpsc2024/pdf/2079.pdf

https://www.hou.usra.edu/meetings/lpsc2024/pdf/2377.pdf

Note: I personally (for all that doesn't matter) want to see Perseverance go well beyond the crater.

[john_s]

It seems possible, given the health of the rover and how quickly it can move when it needs to, that they could perhaps go well beyond the crater rim, and still come back to Three Forks well before the sample return lander arrives there.

John

[vjkane]

It seems possible, given the health of the rover and how quickly it can move when it needs to, that they could perhaps go well beyond the crater rim, and still come back to Three Forks well before the sample return lander arrives there.

John

Not sure where Three Forks is. This is the map from the abstract in my post above. You can see the current rover position, which I think has taken ~25 km to get there. The highest priority location to go to for this and the other abstracts is Monument Valley. As you can see, it is a long distance, and even more if the rover has to return to the crater floor.

I'm wondering if even the Northwest and Southwest Rim locations would be considered within reach of the rover has to return to the crater floor.

Attached thumbnail(s)

 

[mcaplinger]

Not sure where Three Forks is.

With all the maps people have made, you'd think this would be an easier question to answer, but this is where I think it is from the JPL map (which has crappy labeling options BTW). (The little green blob above where I added the "depot" label.)

It's not clear if the rover has to make it back there for MSR, but the farther away we get, the more risk-adverse I suspect people will become.

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[fredk]

With all the maps people have made, you'd think this would be an easier question to answer, but this is where I think it is from the JPL map (which has crappy labeling options BTW). (The little green blob above where I added the "depot" label.)

That's where Phil says it is, so that's good enough for me:
http://www.unmannedspaceflight.com/index.p...mp;#entry252923

[John Whitehead]

There are a lot of details about the MAV design as of 2022...larger design with more mass margin...sounding-rocket-based flight test on slide 15.

That March 2022 IEEE Aerocon presentation was previously seen in Post #424 (the "Presentation" link in the post text, not the link in the quote from 2021). Slide 15 says that Stage 2 of the MAV would be tested at a high altitude over Earth, "to replicate Martian surface environments." But Stage 2 needs to function at high altitude over Mars, without Mars surface atmospheric density. Also in Post #424, the full paper corresponding to the 2022 presentation says it would be desirable to flight test the whole MAV.

Re "a lot of details," should we worry that 3D CAD has made it too easy for design concepts to look like finished engineering?
Agree that larger and more mass margin could be helpful, but how big can the Mars lander be, to deliver the MAV?

[mcaplinger]

That March 2022 IEEE Aerocon presentation was previously seen in Post #424 (the "Presentation" link in the post text, not the link in the quote from 2021). Slide 15 says that Stage 2 of the MAV would be tested at a high altitude over Earth, "to replicate Martian surface environments." But Stage 2 needs to function at high altitude over Mars...

Sorry, the link I found was a PDF and the original link was a PPT so I missed that it was already discussed. There also seems to be some confusion on the NTRS web site, as I often can't find MAV work with a search on NTRS, only via other search engines. You'd think there would be more recent papers by now, but I haven't found them. Maybe I'm just not using NTRS correctly.

Slide 15 is confusing IMHO by showing the whole vehicle "Notional Qualification Test Article" and then showing what seems to be just the interstage and Stage 2 in the lower right, but it's hard to say for sure. Since the avionics and RCS are in the interstage, perhaps they are using the sounding rocket's upper stage as a mass surrogate for the test. I'd like to believe that Marshall has a justification for proposing this. Previous work has mentioned balloon tests but I'm not going to bother to track those down.

It's unclear to me what the real cost drivers with MSR are, but I maintain that if it's the MAV, they are not yelling that from the rooftops that I can see. It's a bit sad to go through this very long thread and see my optimism wax and wane about whether MSR will ever happen, but I am definitely in a trough at the moment. All we can do is wait from the MIRT report.

[StargazeInWonder]

At the risk of being overly reductive (but with the intention of being pretty reductive!) I think that on an abstract level the gist of the matter is:

• When NASA attempts a new flight architecture, unproven, the probability of it working is pretty good, but understandably not perfect. Let's call the probability of success of a new untested flight architecture Ps (surely not the same for all kinds of effort). Maybe that's 85%?
.
• MSR requires a few new flight architectures all to succeed. Some of those, if they fail, would permit a second try, but some would not, and would destroy, disperse, or otherwise lose the samples if they failed. Let's say there are 4 of those.

• The probability of a catastrophic failure for MSR, then, is something like 1-Ps^4, which is disturbingly high for an investment so vast.

In a sense, this is nobody's fault, just a really ambitious project. They made up for this level of risk with Apollo by having lots of iterative development with many launches and space tests before the real thing. So to have a mission architecture with lots of untested success-critical steps tested all at once is simply unprecedented.

If they just went ahead and tried it, it might work (60%? 40%?), but the risk of a colossal unrecoverable failure is really worrisome.

Of course, none of this is news. It seems like the source of the angst is that at times along the way, the tension has simply been ignored by the program.

[mcaplinger]

MSR requires a few new flight architectures all to succeed... Let's say there are 4 of those.

Which ones are you thinking of? Mars EDL and Earth EDL are well-proven at these scales, and the ERO seems pretty straightforward, leaving the MAV as the major new element.

I'm not as pessimistic about the MAV as John is, but it's certainly new and doesn't get as much attention as it deserves.

Surprisingly to me, the program seems to have run aground on issues less fundamental than these.