Mars Sample Return Options

[StargazeInWonder]

I would add that docking in Mars orbit is something new. That would make Mars EDL and Mars orbit docking new.

Agreed, almost nothing here seems truly new, but some aspects, like ERO, are operations that have been accomplished before, but have new parameters in this case. Rather than say that there are four completely original actions required here, it's more like six or seven that have been done before but have some new element or factor here. Is ERO from Mars orbit really harder than from an asteroid? Seems like no – just a little.

And given that two sample returns to Earth have had technical issues, it highlights that none of this is without significant risk.

It really seems like it's all quite doable – just a lot of new and newish risks in a sequence that has to be pretty infallible or those Perseverance samples end up somewhere we'd never get them back.

[bobik]

You'd think there would be more recent papers by now, but I haven't found them.

I have the impression that information on the MAV design has died down since industrial contracts have been issued.

[Explorer1]

Teleconference on Monday, 1 PM EST about the new plan for MSR

[John Whitehead]

About 15 minutes into the news conference, NASA Associate Administrator for Science Nicky Fox mentioned that one way to reduce MSR cost would be a smaller MAV. About time.

On the other hand, in subsequent Q&A she said no time for technology breakthroughs, must rely on high-heritage technologies.

They plan to solicit new mission ideas from industry and NASA centers (as has been done multiple times over multiple past decades).

About a half hour after the start of the news conference, the Washington Post reporter pointed out the seeming contradiction between "whole new approach" and "heritage technology."

(submitted here about halfway through the news conference)

[StargazeInWonder]

About a half hour after the start of the news conference, the Washington Post reporter pointed out the seeming contradiction between "whole new approach" and "heritage technology."

It would seem clear from the context that "whole new" means applicable technologies new to this specific mission plan and "heritage" means applicable technologies established previously in the history of spaceflight. So there's no contradiction, but it remains open if the intersection between the two sets might be the empty set.

The Washington Post writeup (behind a firewall for non-subscribers) doesn't mention this question, but quotes Bill Nelson as saying that:

1) A previously-projected cost increase from ~$4B to ~$10B is unacceptable.
2) A previously-projected delay to a 2040 return is unacceptable.

Further quotations from Nicky Fox, Scott Hubbard, and Bethany Ehlmann play out the dialectic that a cheaper outside-the-box solution that doesn't increase risk is desirable; desiring that doesn't mean that such a solution exists; but they are seeking such a solution now.

[bobik]

Science Mission Directorate Community Town Hall: NASA Response to Mars Sample Return Independent Review Board Report and NASA's response in written form.

[Explorer1]

Looks like the current plan is for Perseverance to return to Jezero ~2028 and stay there with the samples while waiting for the MAV's landing.

[mcaplinger]

Looks like the current plan is for Perseverance to return to Jezero ~2028 and stay there with the samples while waiting for the MAV's landing.

That's what https://science.nasa.gov/wp-content/uploads...ated-signed.pdf says, yes. This document also establishes a performance floor of 18 samples, so they just can't return the Three Forks depot. Though they said this in a very wishy-washy fashion.

It's far from clear given the greater context, though, what the heck's going to happen. The industry solicitation ( https://nspires.nasaprs.com/external/viewre...SMSR_Amend9.pdf ) is a weird move and only makes sense to me if somebody thinks that SpaceX can just rip up the current architecture entirely and do something based on Starship (which in the near term seems extremely unlikely to me.)

"A proposal may, but is not required to, propose to study a mission design that
incorporates elements of NASA’s MSR Program or NASA’s Artemis Program as
Government Furnished Equipment (GFE)" -- I presume saying anything about Artemis is an opening for SpaceX to propose something based on Starship HLS hardware, otherwise it's just a total non-sequitur.

Oh, and they decided that the SRL had to have an RTG on it for better MAV thermal control, claiming that the cost was about the same and ignoring the fact that there is a severe Pu238 shortage, etc.

[volcanopele]

I will say one good thing about this and that they finally solved my biggest complaint: why have another rover/helicopter to deliver samples to the MAV when you have a perfectly good rover that can get you most of the way there. Yes, that depends on Percy surviving until then, but it would eliminate some of the duplication of effort. That being said, why not just have the MAV land at Midway and let the rover complete its mission of collecting samples between where it is now and there?

[mcaplinger]

why not just have the MAV land at Midway and let the rover complete its mission of collecting samples between where it is now and there?

"It was concluded by the MIRT technical/architecture team that Midway is inaccessible as a landing site".

The helicopter was a not-unreasonable bit of redundancy that didn't seem like it was a big cost/mass driver. Losing the helicopter because they insisted on adding an RTG doesn't seem like progress to me. But it's pretty obvious that this whole mission is toast now anyway.

[StargazeInWonder]

The original sin here really goes back (at least) to when Perseverance was in the planning stages and the caching was added. That decision raised my eyebrows, not as an obvious mistake but as a weird malleability in the planning process, putting tactics before strategy. From at least that point forward, there's been this weird blend between two or more possible future plans, and the consequences of that are what we're seeing now.

[mcaplinger]

The original sin here really goes back (at least) to when Perseverance was in the planning stages and the caching was added. That decision raised my eyebrows, not as an obvious mistake but as a weird malleability in the planning process...

Remember that M2020 started out as MAX-C, for which the whole point was caching, it wasn't "added."

But caching goes much farther back, there was a serious proposal to add caching to MSL. See https://www.researchgate.net/publication/22...aching_missions from 2010 for example.

Caching on M2020 always seemed to me like a fairly transparent ploy to get a foot in the door by collecting samples, which would then motivate their return via (in part) the sunk-cost fallacy. (Someone less cynical would just view it as a sensible partitioning of an incremental approach.)

[Explorer1]

An important aspect, however, is that the caching method allows finding the most scientifically interesting samples to be gathered, rather than whatever is in range of a fixed lander's scoop or robotic arm. China's sample return will just rely on chance to gather whatever happens to be at the landing site. If an interesting rock is a just few cm out of reach, it has to stay there. There's always a tradeoff.

In hindsight, perhaps a much lighter 'Pathfinder' MAV, which just gathered whatever soil/rock was in reach (and perhaps atmosphere samples), would have been a good test of the most critical failure point. But, of course, predicting budgets so far ahead of time is impossible.

[StargazeInWonder]

This very thread presents an interesting sample of the discussion going back to 2006; it suddenly jumps at one point from 2009 to 2015 in the space of only two posts. I guess the pivotal decision was putting (1) the caching and (2) the return into concrete enough of a plan where the knowledge of whether or not the sampling rover would be usable for the retrieval was unknown. That was not part of anyone's original plan and seems like a sort of operational blackmail a la the sunk cost fallacy.

Reading between the lines of the Washington Post article (or any other coverage) there are people rightly pointing out that risk is inevitable and now someone at the top saying that the things one might trade off to mitigate risk are intolerable. So something has to give. Whether it's a risky but lucky success, years of thumb-twiddling, or Perseverance's samples lost in space remains to be seen.