no MARDI images from Phoenix Options

[mcaplinger]

http://www.msss.com/msl/mardi/news/12Nov07/index.html

[nprev]

Wasn't so much the probability of occurrence as the nature of the conflict. Potential interference with IMU inputs during EDL (where, obviously, they're needed the most) is scary indeed, and I'm sure that the Phoenix team is not at all anxious to repeat the MPL disaster (which, admittedly, arose from completely different root causes; the point is the same).

Losing the imagery is far better than accepting even a very small risk of losing the vehicle, so gotta vote WAY on the side of caution here; think they did the right thing. We're all well aware of how problematic landing on Mars has been historically; don't think that we need to take unnecessary chances. To quantify a little bit anyhow, here's where I'd put this on a probability vs. consequences plot, and it ain't makin' it.

EDIT: Just to clarify, I am in no way trying to denigrate MARDI or its science return. Context data is invaluable, and it's really a damn shame that we won't get it from an instrument of this quality. However, given the fact that the spacecraft is in flight and no work-around appears evident, mission assurance needs have to take precedence.

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[ugordan]

Losing the imagery is far better than accepting even a very small risk of losing the vehicle

Except that in this business there's always at least a "very small risk of losing the vehicle". Most of the time it's much greater than 1 in a 1000, realistically speaking. Personally, I think this decision was influenced by too great of a paranoia. There's trying to lower the realistic risk beyond that what's feasible and then there's trying to lower the mathematically calculated risk. This decision seems to me to be more of the second one in nature, not that much is gained while quite a bit of nice science is lost.

[nprev]

Except that in this business there's always at least a "very small risk of losing the vehicle".

Oh, yeah, man, no doubt; should've clarified that comment a bit. What I meant was that it seems unwise to accept a known risk in addition to the unknowns and the uncontrollables. If MARDI was essential for EDL, then by all means this would be an acceptable risk; since it's not, then mitigating it is appropriate.

Not that I'm not severely bummed... ...was really looking forward to those images, and I feel bad for the MARDI investigators. Sometimes systems engineering is anything but kind...