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djdsf t1_iu2q0ea wrote

Reply to comment by alle0441 in NASA spacecraft records epic ‘marsquakes’ as it prepares to die by marketrent

While that's true, wouldn't the argument that keeping something alive for longer is also cheaper than building a whole new one and sending it to space again?

I'm understand new tech as well, but come on, there has to be a world somewhere where keeping this thing alive for an extra year for maybe $3M more is cheaper than sending another one that will run 3 years for $70M right?

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Count_JohnnyJ t1_iu2qzi0 wrote

"Cheaper" doesn't matter when you have X budget, and if you don't spend it, you'll have a smaller budget the next year because you obviously didn't need that much.

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Ex_Machina77 t1_iu3txs8 wrote

That only applies to rolling budgets like the US Army utilizes. But essentially that's a myth propagated by terrible supply personnel, who failed to do their jobs properly.

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CartmansEvilTwin t1_iu39520 wrote

That's not really how this works.

These things have a specified lifetime of e.g. 2 years. That means, each component is built and designed to last 2 years with a probability of 99,9%. That in turn means, that there's a high likelihood for the device to survive much longer then two years. Adding additional safety margins for a designed lifetime of 4 years will make the whole thing much more expensive and maybe even less capable, simply because it's going to be heavier.

And additionally, NASA engineers often enough hack devices to work much longer. The Kepler telescope for example had one too many reaction wheels fail and was thought to be dead, but some clever engineer find a way to use the remaining ones to still do some science.

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