James Webb Space Telescope

It's fascinating, isn't it? I couldn't imagine having to cater for all the things that could go wrong and creating fixes and safeguards to pre-empt these issues. Is this what sending your children off to university feels like?
 
The accuracy of the launch and flight path means that the satellite has more fuel in reserve than originally expected, so 10 years is a real possibility.

Edit: just realised this pretty much duplicates Venusian Broon's post.
 
I was curious given that the Hubble has been up for 30 (twice its estimated lifespan) so did a little digging about Webb. Apparently, because it’s so far out, it will have to burn fuel occasionally for ‘station keeping’. I’m assuming Hubble being closer didn’t have this problem (at least not to the same extent). Also, Webb’s distance from Earth will, it seems, make it impossible to carry out maintenance or repair.

So, with all that, I finally understand how crucial this precision launch has been:)
 
15.02 GMT The second panel of the Wevv is being unfolded live on NASA tv.
 
Foxbat said:
I was curious given that the Hubble has been up for 30 (twice its estimated lifespan) so did a little digging about Webb. Apparently, because it’s so far out, it will have to burn fuel occasionally for ‘station keeping’. I’m assuming Hubble being closer didn’t have this problem (at least not to the same extent). Also, Webb’s distance from Earth will, it seems, make it impossible to carry out maintenance or repair.

So, with all that, I finally understand how crucial this precision launch has been:)
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It's at the L2 Lagrange point so that can use the Earth to help shield it from the sun, but this point is unstable so it will be constantly being nudged out of its optimum position (on a timescale of 23 days apparently). Hence the need for fuel to nudge it back into the correct position.

Yes it's a bit too far out for maintenance trips, but as @Parson points out if it lasts more than 10 years, who know what sort of ship/tech we might have!
 
Venusian Broon said:
Yes it's a bit too far out for maintenance trips, but as @Parson points out if it lasts more than 10 years, who know what sort of ship/tech we might have!
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My guess is a robotic maintenance satellite. Robotics is up-and-coming technology - well up to the job by 2032 and will be an order of magnitude cheaper than sending astronauts out there.
 
Venusian Broon said:
It's at the L2 Lagrange point so that can use the Earth to help shield it from the sun, but this point is unstable so it will be constantly being nudged out of its optimum position (on a timescale of 23 days apparently). Hence the need for fuel to nudge it back into the correct position.

Yes it's a bit too far out for maintenance trips, but as @Parson points out if it lasts more than 10 years, who know what sort of ship/tech we might have!
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I’ve read somewhere that it might be possible to produce an artificial lagrange point by using two spacecraft. I wonder, therefore, if it might be possible some time in the future to send out another satellite to act like a kind of cosmic counterweight and increase Webb’s stability that way?
 
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Foxbat said:
I’ve read somewhere that it might be possible to produce an artificial lagrange point by using two spacecraft. I wonder, therefore, if it might be possible some time in the future to send out another satellite to act like a kind of cosmic counterweight and increase Webb’s stability that way?
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Interesting, would love to see the idea. Off the top of my head, the centre of mass of the two satellite system would still behave like a single mass, and being much, much lighter than the Earth and Sun would still wander off, but no doubt I'm missing something!
 
Justin Swanton said:
It's a bit like the Hadron Collider: it cost $4,4 billion to build and studies the behaviour of subatomic particles. Very much a case of theoretical knowledge with little or no practical application. As far as I know (feel free to correct me) our understanding of the building blocks of matter has long since outstripped our ability to make any technological use of that understanding. It's now purely knowledge for knowledge's sake. Does that justify spending billions of dollars? It seems odd to me.
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In most cases basic research is done to further our knowledge and understanding. However, without it we would not have the science, technology, medicine etc that we have today.

It’s already a struggle for many fields that basic research does not have the funding it needs nor attracts enough researchers. Mainly due to the question you ask: what’s the use of it. But if all research was specialized it would leave gaps in our understanding that down the line will hinder further steps. Plus the fact that specialized research often means proprietary results while basic research tends to be shared for the betterment of all. However, we’re approaching the dreaded political part of this discussion so I’ll leave it there
 
I thought this was a good article for us astronomical ignoramuses:)
www.bbc.co.uk

James Webb telescope completes epic deployment sequence

With the unpacking of its big mirror, the $10bn telescope is on track to begin its historic mission.
www.bbc.co.uk

This, I thought, was an exciting quote from the leader of the mirror development team
"Webb is so powerful, almost anywhere we look we're going to be breaking new ground in a huge way,"
 
Foxbat said:
I thought this was a good article for us astronomical ignoramuses:)
www.bbc.co.uk

James Webb telescope completes epic deployment sequence

With the unpacking of its big mirror, the $10bn telescope is on track to begin its historic mission.
www.bbc.co.uk

This, I thought, was an exciting quote from the leader of the mirror development team
"Webb is so powerful, almost anywhere we look we're going to be breaking new ground in a huge way,"
Click to expand...

I was just coming to post that link - great piece. And so impressive it's all working so far, as so many things could have gone wrong. Really looking forward to deeper insights on exoplanets once it's in position and fully running. :)
 
Brian G Turner said:
I was just coming to post that link - great piece. And so impressive it's all working so far, as so many things could have gone wrong. Really looking forward to deeper insights on exoplanets once it's in position and fully running. :)
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I'm looking forward to that too. Don't take any cold water I've splashed around as a lack of enthusiasm for the project. The universe is a fascinating place.
 
Brian G Turner said:
I was just coming to post that link - great piece. And so impressive it's all working so far, as so many things could have gone wrong. Really looking forward to deeper insights on exoplanets once it's in position and fully running. :)
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I think what helped me the most in this article was understanding the importance of the sun shield. I thought the analogy of trying to see the flames from a match against a backdrop of a burning haystack explained the problem perfectly:)

Re the Concorde analogy made in a recent post….I hate flying but love Concorde. I’m lucky enough to have one sited in a museum a mere five or so miles from my home. I never thought I‘d get to go inside one of these awesome jets on my wages:)

Highly recommended for anybody who loves engineering(y)
 
The focussing of each individual mirror comes next. That involves six (I think) motors attached to the rear of each mirror to pull it into shape. Each motor has to be heated before it can be used. Then the mirror as a whole is focussed.

It's incredible that, so far, each individual component of the many hundreds involved has worked faultlessly.
 
Okay, here's something I don't understand.

The Webb telescope will be able to pick up signals from the earliest time in the formation of the universe. Those signals have been traveling towards us for billions of years. That means we're billions of light-years away from the source of the signals. How, if we aren't traveling at the speed of light, has there been enough time for us to get so far away? :confused:

Or to put it another way, if those signals are traveling at the speed of light, how come they didn't pass us years ago? How come they're only just catching up with us now?
 
Brian G Turner said:
There's a video on YouTube showing it unfolding:

Looks quite simple, but there are around 400 pulleys involved in that, and goodness knows what the effect of just one of those breaking would have had.
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My guess is that there is a certain amount of redundancy built in - if a few pulleys malfunction the others can take over their job in order to ensure the tasks get done,. and vice versa. The whole project isn't a bust just because one pulley motor doesn't work.
 
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