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Comment by minitoar | Hacker News Reader

It’s the telescope of Theseus, though.

Because some component bays designed to be swapped out were swapped out? Far as I know they haven’t replaced the 2.4m main mirror or the housing, you know, the “ship”

Yes, that is the joke I was making. Thank you for explaining it.

I think their point was your joke doesn't make much sense when only a small subsection of the entire telescope was ever replaced.

In my opinion that's part of what makes it funny, and is also a core issue in the Ship of Theseus problem -- who's to say how much it can be changed and is still "the same thing"? Maybe the thing that was replaced was very small but was very important to the identity.

That’s not what the Ship of Theseus is. The thought experiment is: if you replace 100% of the original object then is it the same object. Not like, if you change the batteries in the remote is it the same remote.

Sort of. The broken optics famously got fixed in the first HST shuttle mission, and there have been other replacements over time. A lot of it is the same, though.

And of course, the HST is in LEO, which means it is reachable with current rocket tech, which the James Webb, being situated at L2 won't be. But that's not to say you could not have a large platform at L2 (or another Lagrange point) that could be serviced by robots, or even manned craft, if it was designed that way.

I guess my point was: without that servicing it would’ve been a pretty short life span (literally 0?). The swarm approach helps with this.

But Hubble wasn't a one-off design. It shared a lot of design elements with other space telescopes that are more earth-focused :) So it had a lot more benefits of scale than JWST.

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