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James Webb Space Telescope emerges successfully from final thermal vacuum test

phys.org

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Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#11

Post by enceladus_ice »

d33 wrote: post #8
NikolaeVarius wrote: post #7

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

Could you elaborate on the complexity, comparing it to other complex science projects that succeeded? I'm a layman, curious if this is actually riskier than what humanity has done so far.

I think a big amount of the complexity comes from the folded up sunshield. I remember it had torn during a test deployment last year.

Here is a quick animation showing the whole deployment process: https://www.youtube.com/watch?v=vpVz3UrSsE4

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#12

Post by maxxxxx »

gjm11 wrote: post #5
mkoryak wrote: post #3

How many megapixels is this one?

The main imager is the Near Infrared Camera. It has ten 2048x2048 sensors. They're configured in two kinda-independent groups with separate optics. Each group uses one of those sensors for longer wavelengths (so you get two lots of 2048x2048), and four of them for shorter wavelengths (so you get two lots of 4096x4096). The two modules can (and I guess usually will) be pointed at adjacent regions of the sky; I expect…

Considering how much camera sensors have improved in the last few years I wonder how outdated these sensors are (or not)

Edit: makes me also wonder if with all the delays they upgrade any equipment in the meantime.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#13

Post by bumby »

d33 wrote: post #8
NikolaeVarius wrote: post #7

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

Could you elaborate on the complexity, comparing it to other complex science projects that succeeded? I'm a layman, curious if this is actually riskier than what humanity has done so far.

For one, I think it has an astronomically (ha) high number of single-points-of-failure. A quick Google search reported 344.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#14

Post by afpx »

nn3 wrote: post #9

At this price point it better be good. It has to make up for all the other astrophysics missions it killed with its (near) endless budget overruns.

That's a bit cynical. There are many examples of NASA missions that had far exceeded the original expectations.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#15

Post by FrojoS »

d33 wrote: post #8
NikolaeVarius wrote: post #7

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

Could you elaborate on the complexity, comparing it to other complex science projects that succeeded? I'm a layman, curious if this is actually riskier than what humanity has done so far.

This video explains it very well. https://www.youtube.com/watch?v=k8yRDrl76d0

Half way through the video, I understood why it's so expensive and risky.

On the other hand, Apollo 11 had many 'firsts' that couldn't be tested before the actual mission and it worked out 'first shot'. Of course there were some problems and Apollo 13 showed that the odd's where not too good.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#16

Post by okket »

maxxxxx wrote: post #12
gjm11 wrote: post #5

Earlier quoted context omitted.

The main imager is the Near Infrared Camera. It has ten 2048x2048 sensors. They're configured in two kinda-independent groups with separate optics. Each group uses one of those sensors for longer wavelengths (so you get two lots of 2048x2048), and four of them for shorter wavelengths (so you get two lots of 4096x4096). The two modules can (and I guess usually will) be pointed at adjacent regions of the sky; I expect…

Considering how much camera sensors have improved in the last few years I wonder how outdated these sensors are (or not) Edit: makes me also wonder if with all the delays they upgrade any equipment in the meantime.

Hard to tell, since you can't use off-the-shelf sensors. They have to withstand the harsh environment in space, for a very long time, without any maintenance.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#17

Post by [deleted] »

d33 wrote: post #8
NikolaeVarius wrote: post #7

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

Could you elaborate on the complexity, comparing it to other complex science projects that succeeded? I'm a layman, curious if this is actually riskier than what humanity has done so far.

[deleted]

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#18

Post by afpx »

afpx wrote: post #14
nn3 wrote: post #9

At this price point it better be good. It has to make up for all the other astrophysics missions it killed with its (near) endless budget overruns.

That's a bit cynical. There are many examples of NASA missions that had far exceeded the original expectations.

Plus, check out some of the engineering on this $10B masterpiece.

https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/201800...

In my opinion, much better for Human advancement than the typical $10B infrastructure project

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#19

Post by knd775 »

NikolaeVarius wrote: post #7

Man, I really want this telescope to succeed its mission, but I just can't get over how complex its deployment procedure is. I am extremely pessimistic about it actually managing to deploy as planned.

And this isn't like hubble, where we could (and did) send up a space shuttle to fix an issue after launch. Really scary.

Re: James Webb Space Telescope emerges successfully from final thermal vacuum test

#20

Post by Datenstrom »

maxxxxx wrote: post #12
gjm11 wrote: post #5

Earlier quoted context omitted.

The main imager is the Near Infrared Camera. It has ten 2048x2048 sensors. They're configured in two kinda-independent groups with separate optics. Each group uses one of those sensors for longer wavelengths (so you get two lots of 2048x2048), and four of them for shorter wavelengths (so you get two lots of 4096x4096). The two modules can (and I guess usually will) be pointed at adjacent regions of the sky; I expect…

Considering how much camera sensors have improved in the last few years I wonder how outdated these sensors are (or not) Edit: makes me also wonder if with all the delays they upgrade any equipment in the meantime.

I was working on an in space assembly project at NASA recently although it was in a research department so we were not concerned about using space rated equipment. We were exploring both traditional methods and reinforcement learning. The cameras we were using were 2048x2048 and I asked around about what we could expect to have available if it went to space and I think the best off the shelf space rated camera was about 720p so anything more would need to be custom.
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