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View Full Version : NASA admits pulling a 'Scotty' with Mars Rovers



skrap1r0n
2005-Jan-31, 07:26 PM
NASA admits pulling a 'Scotty' with Mars Rovers (http://www.smthop.com/articles1details.asp?NewsNum=374)

I thought this was pretty humerous.

tlbs101
2005-Feb-01, 12:29 AM
All humor aside, I'd be interested to know the actual calculated system failure rate (or Mean Time Before Failure [MTBF]), the criticality number, and the methodology (MIL-HDBK-217, NASA-975, or ???).

I'm sure that whatever the calculated failure rate is, they multiplied it by 2 as the article states, and reported that number. For systems of this nature, there is nothing wrong with "fudging" the numbers in the conservative direction.

Nethius
2005-Feb-01, 04:10 PM
i had a feeling they were pulling a Scotty shortly after the 3rd month or so... wasn't 90 the original estimated time?

I was actually hoping they were doing that with the Huygens probe as well, but i guess what they said is what we got.

ToSeek
2005-Feb-01, 04:48 PM
i had a feeling they were pulling a Scotty shortly after the 3rd month or so... wasn't 90 the original estimated time?

I was actually hoping they were doing that with the Huygens probe as well, but i guess what they said is what we got.

There weren't a whole lot of options with Huygens, considering that Cassini went over the horizon after only a couple of hours. Even if Huygens were to last ten times longer than expected, that still wouldn't be enough to stick it out until Cassini's next flyby.

Romanus
2005-Feb-01, 06:38 PM
"She canna take much more o' this!"

Somebody had to say it. There. ;)

Seriously though, I think this is standard procedure--to "overdesign" a spacecraft so that it can easily go above and beyond its primary mission. For instance, the Voyagers' instruments were never designed to work beyond the orbit of Saturn; Voyager 2 was practically reprogrammed to make it work like a charm at Uranus and Neptune. Mars Global Surveyor's nominal mission was only for one Martian year, and here it is on its going on four-plus years. Say what you want about Ames, JPL and friends, but they know how to build things to last.