Amazing design.
Was worried for a moment when they picked up heat issues during deployment but could resolve it a million miles away.
Well done to NASA/ESA/CSA/Northrop Grummam and all others who worked on it.
James Webb is fully deployed
511–520 of 522 posts
Re: James Webb is fully deployed
#512Earlier quoted context omitted.
Wow. I’m an astronomer and somehow I never learned this! Thank you for the link! Of course a solar powered satellite can’t be parked in the shade. Can’t believe I never thought about that.
My first thought is, "Why didn't they eschew solar power entirely and 'simply' park it in the shade?" Surely they considered that, and the wins would have been massive -- no sunshields needed. So I'm sure the downsides must have been massive as well. Not enough plutonium fuel, or perhaps it just wouldn't provide enough power over the life of the mission. And of course the radioactive fuel would generate its own heat…
The dark side of the Earth is very bright in IR. Getting far away from the Earth and moon makes them dimmer. Also, going for L2 makes sure the Earth, moon, and Sun are all always in the same direction, so the sun shield will block all significant IR sources.
Re: James Webb is fully deployed
#513Amazing feat of engineering. NASA can be proud of achieving something that no other space agency could do. It took courage to keep shovelling money and effort into this project and some amazing science to get it deployed into space.
I agree with the sentiment, but I think some people might take issue with the suggestion that this was entirely NASA's achievement.
ESA and CSA seem to be in every headline so I wanted to emphasize that only one org would've poured so much money into a project. NASA gets way too much flak and little credit these days.
I'm European btw.
Re: James Webb is fully deployed
#514Earlier quoted context omitted.
Couldn't they just use an image intensifier tube for night vision? I think they should just stick with the excuse of it being costly and unnecessary.
We're talking about "see the faintest light from stars millions of lightyears away"-dark (for that reason you also can't shine a light on it), with our sun in the background. To see something on that side, you'd basically need the vision capabilities the telescope itself has and that's obviously not going to happen.
> to see something on that side, you'd basically need the vision capabilities the telescope itself
I'm not sure if that's correct - there's a lot of photons hitting the telescope (the night sky), and night vision systems can work off of a relatively small number of photons
Re: James Webb is fully deployed
#515Since 90% of the cost is probably in R+D of the telescope, one could build and deploy another for another 10%. Why isn't this done? Why is every space telescope completely unique?
It seems that NASA and the Soviet Union used to build duplicates. https://flyingbarron.medium.com/the-james-webb-space-telesco...
They technically did build duplicates of some (not exactly which missions, possibly all) rovers because of the communication delay i.e. you practice the dance moves on earth then send them to mars since you can't really do anything once it gets going.
Re: James Webb is fully deployed
#516Earlier quoted context omitted.
Even when doing things by hand, making a duplicate alongside the original is not much more time. That happens to me every time I do something by hand.
This is true for things like motor mounts and pipe flanges, but not for things like optical surfaces and lathe ways. Even in cases where it is true, if you didn't make the duplicate alongside the original, you have to do the setup again to make a duplicate.
Yes, make it alongside the original. I've been saying that all along.
Re: James Webb is fully deployed
#517Couldn't we make a photo of the deployed James Webb telescope from the Hubble space telescope?
Re: James Webb is fully deployed
#518The picture is a visualisation, but does the telescope have a camera pointing at itself?
Maybe we could use the Hubble space telescope to make a photo from the James Webb telescope ;-)
Re: James Webb is fully deployed
#519Earlier quoted context omitted.
This is true for things like motor mounts and pipe flanges, but not for things like optical surfaces and lathe ways. Even in cases where it is true, if you didn't make the duplicate alongside the original, you have to do the setup again to make a duplicate.
Yes, make it alongside the original. I've been saying that all along.
Doesn't help with telescope mirrors, as you likely know from experience.
Re: James Webb is fully deployed
#520Earlier quoted context omitted.
This is true for things like motor mounts and pipe flanges, but not for things like optical surfaces and lathe ways. Even in cases where it is true, if you didn't make the duplicate alongside the original, you have to do the setup again to make a duplicate.
Yes, make it alongside the original. I've been saying that all along.
I think your mindset is stuck in thinking about this as an airplane production environment because that was your experience. And your points make sense in that type of environment. But research aerospace in which JWST operates is a very different scale, operating much more at the margins where the tech is less well understood and takes much longer to develop. Investing billions for redundancy on an unproven system is a big risk (besides the fact that it would likely be designed differently - and better - if started today).
The sunk cost fallacy already drives a lot of these projects...imagine how much worse it would be (and how many other, competing projects wouldn't get funded) if the costs were higher.