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The James Webb Space Telescope is (finally), as of now, scheduled to be launched on Saturday December 18, 2021 on an Ariane 5 rocket from French Guiana.

NASA is hosting several pre-launch briefings.

On November 2 NASA hosted a Webb Space Telescope Deployment Briefing:
https://www.youtube.com/watch?v=QIdL7dy7OtI&t=866s

The next two briefings are scheduled (Central time):
Nov. 18, Thursday
10 a.m. – Media briefing on James Webb Space Telescope science goals
1 p.m. – Media briefing on James Webb Space Telescope science instruments


Mark

In the video they described the sun shield deployment as a Rube Goldberg machine. Hopefully it's one that works.

Is anybody in MAS traveling to French Guiana to see the launch?

The sun shield reminds me of a giant clipper ship with its innumerable lines and pulleys. Despite the complexity, I'm optimistic about the mission's success!

setnes wrote: ↑Tue Nov 16, 2021 2:45 pm In the video they described the sun shield deployment as a Rube Goldberg machine. Hopefully it's one that works.

Is anybody in MAS traveling to French Guiana to see the launch?

You are going right?

sandconp wrote: ↑Wed Nov 17, 2021 9:59 am You are going right?

No, but I think it would be super cool.

So now before the deployment is successful or ends in failure I have wondered what my thoughts would be if the telescope deployment fails. Will I condemn the hubris of engineers and managers for creating the "Goldberg" machine or give them a thumbs up for a good try? If successful do I applaud them and sign-on for future risky engineering projects. Is the science of the JWST that superior to spending 10 billion on earth Astronomy or at lease near earth orbit space telescopes? I know rationally the 10 billion may not compare to the monies we spend on other infrastructure projects but if this fails it's going to be tough responding to the usual backlash for wasting public dollars.

https://www.planetary.org/articles/cost-of-the-jwst

clayton wrote: ↑Wed Nov 17, 2021 10:55 am So now before the deployment successful or Failure I have wondered what my thoughts would be if the telescope deployment fails. Will I condemn the hubris of engineers and managers for creating the "Goldberg" machine or give them a thumbs up for a good try? If successful do I applaud them at sign on for future risky engineering projects. Is the science of the JWST that superior to spending 10 billion on earth Astronomy or at lease near earth orbit space telescopes? I know rationally the 10 billion may not compare to the monies we spend on other infrastructure projects but if this fails it's going to be tough responding to the usual backlash at wasting public dollars.

https://www.planetary.org/articles/cost-of-the-jwst

I really never thought of it that way but it definitely puts things into perspective.

I think some of the complications are necessary... or at least worthwhile. Infrared makes sense because we can see farther into the red shifted past, but that's also where many of the complications come into play. The L2 point is ideal because it allows the telescope to have only one infrared shield. If it was in a low earth orbit it would need two shields (one for the sun and one for Earth). Resolving power is a function of wavelength as well as aperture. The aperture needs to be much larger on an infrared scope to have the same resolving power as a smaller visible light scope. This leads to segmented mirrors and a complicated folding design.

Could this have been simpler? Maybe. Could they do a better job explaining to the public why it is so difficult? Probably. Are things this difficult worth doing? Yes.

One NASA manager proclaimed a "One Miracle" rule. A mission should not include more than one miraculous advance or it would have a high probability of failure. It seems to me that the JWST counts on at least two miracles, the segmented mirror and the sunshield. The sunshield needs something like 400 motors and an elaborate system of cables and pulleys. I don't know if the goal of far-infrared images at high resolution could have been achieved any other way.

When the Hubble mirror had the awful spherical aberration, the mission was mostly saved by a heroic repair effort. The early trouble is largely forgotten today. Part of the cost of JWST was to do extremely thorough ground testing so the Hubble disaster isn't repeated. Although there are no plans for servicing JWST, I believe a simple docking ring was included in the design just in case a repair effort was needed. If necessary and possible, I believe we should try a repair, maybe robotic. Maybe the Webb could be brought back to a low orbit where it could be repaired by astronauts.

My share of the taxes for JWST are probably a few hundred dollars. I'd spend it again in a millisecond to support viewing galaxies forming in the early universe. Of course, I'm not your typical taxpayer.

It would be sad to see JWST fail, also tax dollars going to waste (kind of, since there would be a lot of technical research done that will be helpful in the future)...

It would still be better than money spent on other things on the earth...
Caution: this is a digression...
https://www.youtube.com/watch?v=on2yz8S ... =12&t=782s

On November 18 NASA hosted a Media briefing on James Webb Space Telescope science goals:
https://www.youtube.com/watch?v=c5MPaFHCNzs&t=2s

On November 18 NASA hosted a Media briefing on James Webb Space Telescope science instruments:
https://www.youtube.com/watch?v=-M0S1R4wmHc

NOTICE
CNN is airing a 2 hour program tomorrow night Saturday November 20th starting at 8 PM Central Time titled "The Hunt for Planet B"

From the CNN web site:
"The Hunt for Planet B follows scientists as they build and plan for the launch of NASA's Webb Telescope, the most powerful and complex space telescope. Watch the film on CNN on Saturday, November 20, at [edit - 8:00 p.m. Central Time]."

Info on the program:
https://www.cnn.com/2021/11/19/world/pl ... index.html


Mark

The next NASA briefing for the James Webb Space Telescope is now scheduled for this Thursday December 16:

Dec. 16, Thursday (Central Time)
10 a.m. – James Webb Space Telescope pre-launch news conference

Also, on CBS last night (12/12/21) there was a segment on the James Webb Space Telescope starting about 15 minutes 48 seconds into the broadcast.

https://www.cbs.com/shows/60_minutes/

Mark

I watched the 60 minutes program and it was good.