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Comment by jerrya | Hacker News Reader

Building a new something that was designed, built, tested and launched quite a while ago is difficult because a lot of knowledge of the processes have been lost, along with tooling, supplies, etc.

However, I do wonder why they build 1 Kepler space telescope and not 2, or 3, and then store the already built ones until they are wanted.

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Given what the previous instrument taught us, the science questions change, so the instruments you need also change. For instance, it surprised everyone when it turned out that most stars are more variable than the Sun is, and this extra variability has complicated the Kepler data analysis.

Additionally, you can incorporate lessons learned (from an engineering perspective, not science) into the next instrument. Some things work well and are preserved, and others don't.

Here's a link to some tech awards relevant to future exoplanet instruments: http://exep.jpl.nasa.gov/technology/

As sigstoat said, Kepler is a fairly recent spacecraft. And yeah, it's interesting that they don't treat spacecraft like this as small-batch production runs. The incremental cost of producing 5 Kepler replicas and keeping equipment and processes documented at the time of initial production seems very small compared to doing the same project all over again a decade later. Even if they have to do some major changes, I imagine having a ready to go spacecraft helps.

On the flipside, I guess the arguments for componentization apply. If off-the-shelf components are improving all the time, integrating them into a full spacecraft should be getting cheaper and easier over time.

What I really wonder about is, given how troublesome and relatively lightweight gyros are, why didn't they have more spares?

kepler wasn't built that long ago, as these things go. and ball aerospace which designed and built it is already designing and building an almost identical spacecraft for the b612 foundation. so of all the spacecraft you might want to duplicate, kepler would be a really easy one at the moment.

Interesting, I'd never heard of B612. So they're sufficiently well-funded to commission a $500M Kepler-class probe?

last i'd heard they were still trying to get more silicon valley bigwigs funding it. ball was treating them as a sufficiently "real" customer that it was talking to subcontractors about the mission, but i hadn't heard about any big checks for hardware being cut.

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