James Webb Space Telescope begins historic mission

[dstig1]

Fully deployed! That has to be a huge relief to the team. So many things could go wrong but it looks like nothing did. I look forward to it making it to final orbit and then first photos next summer.

Where Is Webb? NASA/Webb

During Webb's launch, deployment and commissioning, 'WhereIsWebb' tracked Webb's 'flight' to L2 orbit, its state and progress during its deployment and commissioning process, and finally the release of its first images. This process is now complete. During this process, the page constantly...

www.jwst.nasa.gov

 

[ArlyA]

Huge relief to me as well!

 

[oldballs]

Fully deployed! That has to be a huge relief to the team. So many things could go wrong but it looks like nothing did. I look forward to it making it to final orbit and then first photos next summer.

Where Is Webb? NASA/Webb

During Webb's launch, deployment and commissioning, 'WhereIsWebb' tracked Webb's 'flight' to L2 orbit, its state and progress during its deployment and commissioning process, and finally the release of its first images. This process is now complete. During this process, the page constantly...

www.jwst.nasa.gov

Thanks for the link. Let's hope it continues to work as planned.

Cheers,
Mike

 

[ovrszd]

My wife and I discussed the unfolding at length. No pun intended.

The thickness, or thinness, of the heat shields is described in terms I don't understand. Only when they start comparing measurements to human hair thickness does it get my attention. The tension phase seemed like it could have the highest failure rate. If the shields failed, the project would be dramatically limited.

Good news.

Now we gotta set by patiently for a couple weeks while it crawls it's way out to L2 Orbit.

 

[ruffdog]

Those thin heat shields are also made in a way that won't rip far if debris hits them. It's a hostile environment out there with lots of bits and pieces floating around.

 

[ovrszd]

Those thin heat shields are also made in a way that won't rip far if debris hits them. It's a hostile environment out there with lots of bits and pieces floating around.

I was very intrigued by that design!!!! Look how many "thought" and "scenario" hours went into that design.

 

[ruffdog]

I was very intrigued by that design!!!! Look how many "thought" and "scenario" hours went into that design.

Agree....when they were talking about all the cables, pulleys, latches, solenoids, etc, it is amazing it has unfolded in that environment.

 

[ovrszd]

Agree....when they were talking about all the cables, pulleys, latches, solenoids, etc, it is amazing it has unfolded in that environment.

Yep. And this reinforces my position. The technology developed and used on projects like this bleeds down to the normal consumer at some point. Would never claim that justifies the dollar amount. Just saying the payback is broad.

In one of their videos it claimed each of the mirror panels contains a golf ball size piece of gold. Used gold for it's flexibility which gives them the ability to "curve" each section to fine tune the focus. Amazing.

 

[dstig1]

My wife and I discussed the unfolding at length. No pun intended.

The thickness, or thinness, of the heat shields is described in terms I don't understand. Only when they start comparing measurements to human hair thickness does it get my attention. The tension phase seemed like it could have the highest failure rate. If the shields failed, the project would be dramatically limited.

Good news.

Now we gotta set by patiently for a couple weeks while it crawls it's way out to L2 Orbit.

They said the layers were made in 2 thicknesses - 0.050 and 0.025mm. 0.05mm is .001" or if you prefer 1 mil or 1 thou (thousandth of an inch) in machinist/engineering terms. The thinner one is half that at 0.0005" or "5 tenths" (ten thousandths). Your closest example would be plastic bags. I just measured a plastic grocery bag with my calipers and it came in about 5 tenths, so the same as the thinner layers of the heat shield. Garbage bags will often list their thickness on the package and they are often 1-3 mils. The heavy duty construction bags can get up to about 6 mils, but that's about as thick as I have ever seen one.

So grab a couple different bags to compare and you should have a good feel for what these thicknesses mean.


I'm more curious about the velocity profile of the telescope as it keeps slowing down. Considering there is no drag from atmosphere, are they having to constantly fire the engines to keep slowing it down? Otherwise I would expect it to maintain speed as a body in motion stays in motion and all that. Seems like that would take a lot of fuel to slow it down so much. They don't really talk about that at all other than a couple course correction burns in the timeline.

 

[ovrszd]

They said the layers were made in 2 thicknesses - 0.050 and 0.025mm. 0.05mm is .001" or if you prefer 1 mil or 1 thou (thousandth of an inch) in machinist/engineering terms. The thinner one is half that at 0.0005" or "5 tenths" (ten thousandths). Your closest example would be plastic bags. I just measured a plastic grocery bag with my calipers and it came in about 5 tenths, so the same as the thinner layers of the heat shield. Garbage bags will often list their thickness on the package and they are often 1-3 mils. The heavy duty construction bags can get up to about 6 mils, but that's about as thick as I have ever seen one.

So grab a couple different bags to compare and you should have a good feel for what these thicknesses mean.


I'm more curious about the velocity profile of the telescope as it keeps slowing down. Considering there is no drag from atmosphere, are they having to constantly fire the engines to keep slowing it down? Otherwise I would expect it to maintain speed as a body in motion stays in motion and all that. Seems like that would take a lot of fuel to slow it down so much. They don't really talk about that at all other than a couple course correction burns in the timeline.

Layman talk here. I assume there is some drag, even in space? I assume that's why it's speed as slowed at a pretty steady pace after day 3? I also assume when it reaches L2 Orbit location it will take very little propulsion to put it in orbit?

My concern about energy required to go into orbit was just the opposite of yours. I had it going .7 miles per second and requiring a LOT of energy to slow it into orbit. But it's solving that problem daily.