Mars Sample Return Options

[Rakhir]

Next phase reached in definition of Mars Sample Return mission

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

[Explorer1]

The entire motivation of the MSR program is the study of samples on Earth, anyway. Instruments in Earth orbit are only a slight improvement from those we bring to the surface of Mars.
Part of the issue is that the entry capsule has no parachute, so there's more chance of a breach when impacting at terminal velocity. But the parachute was removed due to mass requirements, as I recall, so adding it back would be counterproductive.
And the only way to decisively remove PP requirements would be to prove a negative, which is essentially impossible (and this forum has rule 1.3 anyway).

[StargazeInWonder]

The entire motivation of the MSR program is the study of samples on Earth, anyway. Instruments in Earth orbit are only a slight improvement from those we bring to the surface of Mars.

My notion was that the protection could occur in Earth orbit, then the protected samples could be brought to the ground. Eg, put the dirty capsule into a casing, the outside of which never touches any martian stuff. Then land.

As mcaplinger notes, this has more than one problem of its own, one of which is risk.

Cassini led to protests because Cassini had plutonium onboard. It's hard to put a price tag or perform rational analysis of risk factors in the public consciousness. But when the cost of the program is $11 billion and a risk factor in the public consciousness is part of that cost, possible cost savings involve manipulating the consciousness of risk, which is not the same thing as risk itself. Zubrin seems to wish the whole thing away. With Cassini, NASA weathered the protests. Note that one of the vocal Cassini protesters was Michio Kaku, who is one of the most prominent publicizers of science and technology.

http://www.cnn.com/TECH/9710/04/cassini/

Planetary protection doesn't have any definite equations governing the risks that it is trying to address. It seems to be a PR exercise with engineering components.

[mcaplinger]

Planetary protection doesn't have any definite equations governing the risks that it is trying to address. It seems to be a PR exercise with engineering components.

Semi-serious proposals have been made for Earth-orbiting labs to quarantine and examine returned samples. https://www.hou.usra.edu/meetings/deepspace2018/pdf/3189.pdf is a recent example that references the early-80s Antaeus Report https://ntrs.nasa.gov/citations/19820012351

This concept sort of showed up in the (unwatchable IMHO) movie LIFE ( https://en.wikipedia.org/wiki/Life_(2017_film) )

Of course, these would all be staggeringly expensive.

I suspect Zubrin is right and planetary protection from Mars is probably not needed. But it's one of those low-probability/high-consequence things that few people would be willing to risk if it was up to them. And Michael Crichton just did too darn good a job when he wrote https://en.wikipedia.org/wiki/The_Andromeda_Strain

[StargazeInWonder]

Very helpful links, thanks! And Crichton is the inevitable reference.

Japan proposes the return of some Phobos samples (probably) before MSR. This seems to raise and dispel similar risks since the research expects martian material to exist without the same strong filters as such martian meteorites as make it to Earth. Where there is no equation is in where on the continuum we need to worry and where we don't.

Martian meteorites (already here)
Martian material in Phobos samples
Martian material in the Perseverance tubes (no protection)
Martian material in the Perseverance tubes (some protection)
Martian material in the Perseverance tubes (the most imaginable protection – still breachable by some level of mishap)

Nuclear reactor safety has included such considerations as what would happen if an airplane accident happened to breach the containment. That sounds like an unreasonable level of concern, and yet it has been exceeded on at least two occasions.

[mcaplinger]

Japan proposes the return of some Phobos samples (probably) before MSR. This seems to raise and dispel similar risks...

I would have said that Phobos sample return was clearly "Category V unrestricted" and thus nothing special had to be done, but apparently there is some question about that, at least according to https://nap.nationalacademies.org/catalog/2...e-martian-moons -- though they ultimately agreed with the unrestricted categorization.