

How have NASA's Mars robots lasted 24 times longer than expected (so far)? - jackfoxy
http://gcn.com/articles/2010/06/30/mars-rovers-owe-longevity-to-proven-technologies-nasa-leader-says.aspx?s=gcndaily_010710

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mkramlich
The most interesting takeaway for me was something that had almost the
opposite implications from the story's topic. It was the engineer saying that
what these robots have done over the last 6 years could instead have been done
by humans there in 1 week.

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dmfdmf
I don't want to rain on their parade but with a design life of 90 days and the
rovers still operating after 6 years (2160 days) this is an engineering
failure. Why? These robots were way over built for their mission which means
they probably cost much more than they should have. Its one thing to get lucky
and extend a mission a few months past the design life but 24 times the design
life means they could have been built for much less. I hope the design team
goes back and learns from this and incorporates the lessons learned in future
missions.

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CapitalistCartr
I think you're misunderstanding the design parameters. Most of the cost of a
mission to Mars is getting there. The actual rover is cheap by comparison, so
it pays to pack as much into each mission as the weight limit will allow.

The big risk is mission failure, so the design goal is 100% certainty. The
result is that the odds of it lasting for several/many times the design life
is pretty good. Imagine if your car were designed to be as certain as
technology would allow that it would run, trouble free, for 100.000 km. The
odds that it wold last many times longer are pretty good.

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camiller
The rovers also had to be designed to withstand the rigors of interplanetary
transit and landing on Mars. The driving around bits are less prone to
damaging the rovers.

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wglb
I forget which software team that I was on where I came across the phrase
"Failures in schedules are failures in management."

So I wonder if this could be applied here. Or to put it another way, we know
how to build things better than we know how to estimate their useful lifetime.

