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James Webb is fully deployed

nasa.gov

201–210 of 522 posts

Re: James Webb is fully deployed

#201

Earlier quoted context omitted.

Yup! If the universe's age were a single year, we're looking back to January 6th. Truly remarkable. :)

what prevents us from seeing back any further?

> what prevents us from seeing back any further?

The other comment mentioning darkness is wrong.

In the very early universe, it was extremely bright and hot. It was only after 100,000 years or so the universe cooled down enough to become transparent.

Re: James Webb is fully deployed

#204
post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

RE>> "I understand the reasons for not putting a camera on or near the JWST"

What are the reasons? I'm sorry ~ I'm ignorant on the topic, but I'd love to learn more. Why/what are the reasons?

Re: James Webb is fully deployed

#205
post #191

Earlier quoted context omitted.

> huge costs in subsequent runs Often that's because they have to rebuild and reset the tooling. Within the run, though, the incremental cost should be minimal. The huge costs may be huge, but not huge compared to the cost of the prototype.

IMO your logic fits with large production runs. In space applications costs can be exaggerated compared to actual production environments because the risks aren’t mitigated by something like the FAA, meaning they are often mitigated by some downstream process. Besides, a lot of the the designs already include critical spares, so there’s more than a single run, even in a one-off design

So build a copy out of the spares! If they're there, they're already paid for.

Re: James Webb is fully deployed

#206
post #187

Earlier quoted context omitted.

> Yes, but the data has diminishing returns as well. I find that hard to believe considering there's literally a universe of things to look at. We find surprising things everywhere we look.

That's not true. The potential for surprises gets smaller and smaller the more data you collect. The Webb will produce surprises at first because it is able to make new kinds of observations that were not possible before, but after a while that new data will be used to improve our models and subsequent observations in the same regime will (almost certainly) be less surprising as a result.

> The potential for surprises gets smaller and smaller the more data you collect.

Mathematically, you are quite correct.

But do you really believe that with one little ole' telescope pointed at the freakin' universe you're going to reach a significant point of diminishing returns?

It's like saying if you invent the first microscope, and discover bacteria, why bother with another one?

Re: James Webb is fully deployed

#207
post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

RE>> "I understand the reasons for not putting a camera on or near the JWST" What are the reasons? I'm sorry ~ I'm ignorant on the topic, but I'd love to learn more. Why/what are the reasons?

[deleted]

Re: James Webb is fully deployed

#208
post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

RE>> "I understand the reasons for not putting a camera on or near the JWST" What are the reasons? I'm sorry ~ I'm ignorant on the topic, but I'd love to learn more. Why/what are the reasons?

Great blog post from NASA themselves explaining it: https://blogs.nasa.gov/webb/2022/01/06/why-doesnt-webb-have-...

the post is really not very long and I would suggest getting it straight from the horse's mouth, but for those not willing to devote a click here are arguably the most relevant bits!

"deployment surveillance cameras would not add significant information of value for engineering teams commanding the spacecraft from the ground."

"Webb’s built-in sense of ‘touch’ (for example, switches and various mechanical, electrical, and temperature sensors) provides much more useful information than mere surveillance cameras can," said Geithner. "We instrumented Webb like we do many other one-of-a-kind spacecraft, to provide all the specific information necessary to inform engineers on Earth about the observatory’s health and status during all activities."

Re: James Webb is fully deployed

#209
post #192

More great news. Congratulations to all who have worked on the project. I understand the reasons for not putting a camera on or near the JWST, but I’m still a little sad that we’ll probably never get to see the thing in situ in all its operational glory. Maybe one day when it finally expires, we can launch a “sample return” mission to tow it back.

Won't it be pretty close to earth in its final position at L2? If so, is there no chance that there will be future missions to do service to it? If so, maybe we can get a photo of if then?

Re: James Webb is fully deployed

#210
post #197

It says it will arrive in 14 days or so at L2. Right now, it is moving 0.3933km/s which according to Google is 1415.88km/h. That is pretty fast. What speed does it need to be at for insertion and steady state? How long will it be breaking? (If at all, or of it is not already doing it).

About 0. It’s climbing a hill and has just enough energy to get to the top. A small burn then will be all it takes to put it in an orbit around L2.

It also needs to get as close as possible to the top of the hill without going over. L2 is not a stable point: you’re either falling back to Earth or drifting away. If it goes over it can never get back as it can only fire in one direction - away from Earth (to protect the instruments from the Sun). So it’s a continuous balancing act where it falls downhill towards Earth a bit, then jumps up without going over the edge, rinse and repeat.
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