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@sonhouse
Excellent question. The NASA website shows four temp readings and is only updated once per day. The explanation is that the temps change so slowly. Right now, on the side facing Earth/Sun, the shields are at 131F, and the equipment panel is at a very nice operating temp of 52F.
On the cold side, the mirror average temp is -298F and has consistently lowered day by day. A much more consistent reading of -329F is where the instrument radiator is located.
Currently 707,300 out with 191,400 to go! It is cruising along at just over 799mph, still slowing but all seems to be in perfect order.
@Liljo
They really had to fine tune the trajectory to get natural gravity forces to slow it down so it can enter L2 and 'orbit' around empty space. I imagine there will be other course corrections in the next few months especially when it gets close.
@sonhouse
Why no photos or videos of the actual Webb scope in real time? Why didn't they plant several GoPro-style cameras on this Webb scope to monitor it's condition, it's progress and it's surroundings?
@bunnyknight
It would not have taken much to put some kind of camera onboard but I guess they were hyper worried about weight, launch abilities and all that, getting it to an exact spot in space in a few months, but you would have thought someone could have put on some simple camera with connection to the data link, those cameras are almost weightless now, I have one on a cheapo drone I just bought and it is amazingly light.
But NOOO all they could do was think about a stinking TELESCOPE🙂
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@bunnyknight
Well...they are actually monitoring its condition down to minute details. There is no telling how much scientific data they are collecting that isn't released to the public. They are able to tell exactly how fast it is going to 1/10000 of a second, the exact temp of at least four different parts of the scope, distance to within 1/10 mile, etc.
I'm pretty sure they are very well aware of its surroundings...they call it SPACE. Like Son said earlier, it's pretty empty! All they could really send us is pictures of the 'scope. And there are tons of those already!
@Liljo
The only real reason to have external cameras would be to monitor the clicking of mirrors and the other unwinding stuff but I guess they consider the assembly to be reliable enough not to need them for maintenance purposes.
And there are certainly hundreds of photos of Webb and we all know what it looks like now so we wait and see what it produces.
I wonder when they will pull first light, maybe some test before the mirrors all deport in place and cooling down to low Kelvin numbers, they might try some test before it is totally ready. That would be interesting, to see the dif between mirrors not aligned perfectly to later when a second image can compare to the first to see the improvements.
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@sonhouse
I just read where the mirrors have to reach -370F. I was previously thinking they had to be -400F.
Either way....man....that is COLD.
Currently 730,000 miles away--169,000 to go. Mirror at -306F. All is well.
Slowing even more as gravitational pull from the Sun and Earth do their part. Now traveling 753.84mph.
@bunnyknight saidThere's photos from pro and amateur telescopers on earth. Here's a few on the twittersphere if you're legit interested.
@sonhouse
Why no photos or videos of the actual Webb scope in real time? Why didn't they plant several GoPro-style cameras on this Webb scope to monitor it's condition, it's progress and it's surroundings?
https://twitter.com/_NGC3982/status/1478496657234878464
This thing is so cool. I want one.
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@wildgrass saidYou are correct at when it reaches the target. Once there, they plan to use certain thrusters to get the scope positioned. Every now and then there will need to be adjustments, but for the most part gravity will then lock it in place. It's position will remain constant, orbiting the sun at a rate that always uses the Earth to block the sun.
Does anyone know what the final cruising speed will be? I don't know if I'm doing the math right, but its still slowing down (now 730 mph). At that speed I think it reaches the target in ~ 9 days.
Can you imagine the mathematics, the engineering, all the calculations involved? Mind boggling!
It is simply going on momentum right now. The gravitational pull of both Earth and Sun are doing the job of slowing the scope, but in the end they will have to use on-board thrusts to do the final placement. It is scheduled to be fully placed on January 23. As a side note to this, the more accurately they have calculated the rate of deceleration, the less fuel they have to use for final placement--and that will have a direct bearing on how long the scope will remain in L2. They are hoping for between 5.5 and 10 years!
@wildgrass saidWow, great photo! I can even see two little alien saboteurs tampering with the mirror assembly.
There's photos from pro and amateur telescopers on earth. Here's a few on the twittersphere if you're legit interested.
https://twitter.com/_NGC3982/status/1478496657234878464
This thing is so cool. I want one.
@Liljo
When it reaches the target at L2, won't it be in Earth's shadow, sort of like a perpetual solar eclipse? Seems to me that Earth should block almost the entire solar disc at that distance.
@Liljo
It's neat when you get free deceleration like that. So maybe they only have to burn to lose 600 mph or something like that.
They have fuel to keep the scope in position for over ten years.
Since it is in Earth orbit, just not close to Earth, it can only see straight out the ecliptic, like always pointing away from the sun, so the come across the same target every few months, it can swing sideways as well as up and down so they can cover the whole sky pretty much. As soon as a target gets into view, you can watch it for months on end. It is all about collecting as many photons as possible and you do that by either having the sensor on target for a long time or a bigger scope which pumps a lot more photons than a small one. Webb gets long long times on target as well as a huge 21 foot, near 7 METER scope.
And then there are the spectrum analyzers, very accurate in sussing out what molecules are encountered watching target stars.