Alex,

Several of my co-workers were involved with the Mars Sample Return (MSR)
Earth Entry Vehicle (EEV) design study prior to the project being terminated.
What I observed was a very different approach to spacecraft design. Normally
we design for mission success. However with EEV the design was to optimize
benign failure. For example Design #A could have a higher probability of
bringing an intact sample to the Earth's surface than Design #B. However
Design #B would be preferable if it's prime failure mode resulted in the
sample being cooked by reentry heat but remaining contained in it's capsule
after impact. Another strange aspect about EEV was designing for
litigation. It's assumed that EEV will be subject to numerous EPA studies
and law suits. Therefore it is a "better" design to use obsolete and more
expensive Thermal Protection System (TPS) materials with established flight
history than modern cheaper TPS materials with less flight history.
Another "cute" aspect of EEV are these probability studies where an effort
is made to determine the probability of failure. I've seen similar
studies performed for nuclear reactor designs. These probability studies
involve summing up the probability of failure for each sub-system and then
computing an overall probability of failure. What I find amusing about
this process is say they come up with a reliablity of 1:1,000,000,000 for
EEV failure. What's the probability of finding a viable Mars bug on the
Martian surface that could actually live in the Earth's humid oxygen rich
atmosphere? Probably less than 1:1,000,000,000. So an EEV approach of
transporting a huge cannon to Mars and then shooting a bare rock back to
Earth as an artificial SNC meteorite probably has an insignificantly higher
risk of back contamination. As you know, SNC meteorites frequently rain
down on the Earth. It's no big thing.

Among others, we can thank G. Levin and Barry D. for this stupidity.
Ultimately this will cost the US taxpayer hundreds of millions of dollars.

Gary