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.