Hacker News Reader

Comment by Out_of_Characte | Hacker News Reader

Its easy to say "Just build two of them" or to say the telescope shouldn't have so many single points of failure.

To that I say that a single copy is the only reasonable option. JWT is essentially a prototype and a product in one. The first to employ such a complex radiation shield, The first to have berrylium mirrors (AFAIK), The first to orbit L2.

A copy would inherit any unknown problems with the first telescope, which is especially bad if you've read how many times the JWT has run overbudget and ran into issues. You're better off launching the prototype product to learn what will go wrong and go from there.

The lack of doubles in space shows how exiting the field is because I'd rather have novel prototypes than another hubble.

View on HN

> The lack of doubles in space shows how exiting the field is because I'd rather have novel prototypes than another hubble.

There are some doubles though. Voyager 1 & 2, Spirit and Opportunity…

Didn't the CIA have a very similar telescope to Hubble that they donated?

It was the NRO in 2012. I don’t know if the CIA operates satellites itself.

Were they made togheter?

I think the spy hubbles are better examples.

Can you imagine the added complexity for the Hubble design for it to work as space observatory or earth observatory.

I wonder if the he Hubble was myopic because of this.

Yes Spirit and Oppy were made together and it's the same rover design. Also relevant for this discussion due to circumstances one of them outlasted the other 8 years. Imagine if we only had sent Spirit.

Without a complete and honest accounting of the risk profile, which is something NASA and its contractors have historically not been great at, it's hard to say whether test/backup hardware would have been warranted.

IMO "build two, launch one and see what happens" was absolutely not the right approach here. But the goal of the program is to get a functional JWST instrument into position, and if there's any relatively (wrt. the entire program) cheap way they could have substantially de-risked that outcome—by tooling up for a possible second production run, flying a "dumb" article to test the deployment procedure in situ, or whatever else—it should have been seriously considered.

Frankly, this sort of judgment is something I don't trust NASA to get right in practice, through no major fault of their own. Congress runs NASA like they run the rest of the country: setting them up to fail, blaming them when they inevitably do, withholding realistic funding for congressionally mandated programs while simultaneously helping their military-industrial cronies wring out every last dollar. The only way to get anything at this scale done is to lowball up front and beg for more money later.

Good point. But doing two concurrenct desing would allow as backups for failures not in the telescope itself. For things like lauch, assembly, handling, etc.

If everything goes as planned, having two observatories sure would be appreciated by the scientific community.

Also, I assume, most the costs are associated with the project and setup of fabrication.

Reply on news.ycombinator.com