I'm a little embarrassed to say this and I don't know exactly what I pictured in my head, but I had no idea these telescopes were so big[1].
I guess I never saw one pictured next to a human. I've only seen pictures of satellites being worked on so I expected something more human sized? It seems so stupid now, especially since earth telescopes are huge.
It’s really easy to get a wrong intuitive sense of the size of these things! I don’t understand why space agencies don’t always have human figures for reference in their visualizations. Or even a simple scale bar! We just get these silly “the size of a tennis court” type textual comparisons. Few people realize how big the Curiosity and Perseverance rovers are, as another example.
The space shuttle blows my mind every time I see one. It's huge - the size of an airliner - and would glide back at Mach 25. It's a humbling level of accomplishment.
I'm trying to find an article with the exact story, but during the building of some of the early large satellites (something like the MilStar satellites [0][1]) they realized it would be really handy to be to rotate the satellite to work on it from different angles. So the satellite manufacturers repurposed rotary train car dumpers [2] in order to rotate the giant satellites.
I'm surprised that JWST isn't actually all that much bulkier than Hubble, despite the mirror(s) being so much larger. In retrospect I guess that makes sense, since much of Hubble's bulk is the long tube enclosing the mirror, which JWST lacks. Also, the size of things that can be reasonably launched into space is limited by the launch vehicles themselves. (Maybe NASA would have built it bigger if they knew exactly the launch vehicle specs that would be available at the end of 2021, or they might have waited for Starship, but obviously that couldn't have been predicted when work on JWST began.)
The largest geostationary telecom satellites are also quite huge, if you were to stand next to one. In the range of 6500 kg weight and about the size of a school bus.
I marvel at how small they are. Why not add 20, 100, or 1000 more mirrors to JWT? Or launch 10 more of these and go full interferometry? Maybe I've just been playing to much Dyson Sphere Program, but it feels to me that NASA et al are committing the cardinal sin of making the production loop too small.
I think most satellites just unfurl solar panels. This one had to wrap up the big sun shield as well, and the lens pieces were kinda crammed together and then spaced out after deployment too. So the rocket couldn't fit something nearly as large as this as a payload going up.
Really sad that 30 years later we're only slightly larger. This is a major problem for telescopes since there are hard physical limits on resolution vs size.
I think Destin of the Smarter Every Day YT channel had an interview a couple years ago with Dr. John Mather, the senior project scientist of the JWST, where he asked something like "will you be nervous during the launch and deployments", and Dr. Mather replied " I don't get anxious about stuff I can't deal with", and that they've tested everything they thought of to test.
I was super impressed with Dr. Mather, not only that he seemed so wise, but also that this super busy man took the time to do an hour long interview with a random You-Tuber. I think the JWST project is in good hands.
Edit:
I guess Destin is not a 'random' You-tuber, but someone that was well-placed to connect with Dr. Mather. Still, he's not CNN or BBC - he's a guy with a handheld camera that doesn't ask fluff question, but questions intended to help inform himself and his audience. Still think Dr. Mather thinking it was important to spend so much of his schedule with Destin was impressive.
If any of the James Webb team are here, Congratulations! A phenomenal achievement.
So excited to see first images and read about all the discoveries you are going to make. Exciting times!
My daughters (7yo) class have been talking about it, she keeps coming home from school excited to tell me about the latest update on its journey. I love the fact we have these exciting things happening in space science to experience together.
This simple 20 seconds video was far better than hundreds of those link. I mean I couldn't visualize the whole set up and orientation and this video made things crystal clear.
Shortly after launch there were quite a few articles talking about how well the launch went on the Ariane and how that allowed the mission to be extended to 20 years or so.
I'm not sure who it was anymore (possibly Scott Manley on youtube), but apparently ESA had been setting aside the components for the Ariane 5 that tested best to be used for the launch of JWST to lower the risk of failure and that might explain in part why it was able to launch it so precisely - it was not your average Joe's Ariane 5.
If you go to https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html then there are repeated statements about how the rocket did such a good accurate job launching Webb onto its intended trajectory that the telescope hasn't had to use as much of its own rocket fuel as they expected, so the fuel is now expected to last 20 years instead of 10.
Amazing how a few meters of mirror can make out objects billions of light-years distant. Yes it's big - insofar as human-built telescopes have been - yet is so relatively minuscule per what it observes. Having gone from first flight to JWST in such a short time is staggering (Wright Bros 120 years ago - I've been alive nearly half that time); how soon will we achieve orders-of-magnitude bigger telescopes? say, multiple 100x-wider JWSTs operating from multiple LaGrange points? Think big!
I had no idea its final destination was a legrange point thats so cool!
I got confused though, I thought they were saying it was at the one between the sun and the earth (L1). But I guess its at the one behind the earth (L2)? Anyway so cool! Lagrange points always make me think of Liu Cixin :^)
> The L2 point of the Earth-Sun system was the home to the WMAP spacecraft, current home of Planck, and future home of the James Webb Space Telescope. L2 is ideal for astronomy because a spacecraft is close enough to readily communicate with Earth, can keep Sun, Earth and Moon behind the spacecraft for solar power and (with appropriate shielding) provides a clear view of deep space for our telescopes. The L1 and L2 points are unstable on a time scale of approximately 23 days, which requires satellites orbiting these positions to undergo regular course and attitude corrections.
The NPR posting does now provide information as to how the image was taken and I wondered how this image came about. This page describes how the picture of JWST was taken. It was taken by the rocket after it separated.
>>Here it is: humanity’s final look at the James Webb Space Telescope as it heads into deep space to answer our biggest questions. Alone in the vastness of space, Webb will soon begin an approximately two-week process to deploy its antennas, mirrors, and sunshield. This image was captured by the cameras on board the rocket’s upper stage as the telescope separated from it. The Earth hover in the upper right. Credit: Arianespace, ESA, NASA, CSA, CNES
Cubesats fill that role, for when those groups need their own. JWST is from the consortium of half the first world, because they want to measure the same thing. It’s not an either-or.
I am quite relieved that all the deployment worked out and so looking forward to the first images. I hope, planning for a true Hubble successor (a telescope in the visual range) starts soon. Maybe a one-off Starship could be the telescope housing, it would enable an 8m mirror without any folding, just the tip of the Starship would open up once in orbit.
Question; why is the Where is Webb page saying current speed is .1255 miles/second? There's a blurb in the explainer that says that speed is Earth relative.
We are all living vicariously through the good news of the James Webb space telescope successes. Some much needed good news that is based on the innovative push that humanity has. The good side of our human condition.
I have a dumb question. If the telescope is always moving in an orbit around L2 and then also around sun, how does it focus at a single area for long durations ?
Two parts to this answer. The short one is that this amount of orbital motion results in very very small differences in angle given the very long distance of the objects it's focused on and the relatively short exposure times (short with respect to the orbital period of the telescope).
The somewhat longer answer is that the spacecraft establishes an orientation using its Control Moment Gyros (CMGs). The ops team could use the CMGs to maintain pointing if this small amount of image smear ever became significant. But the CMGs would probably induce as much image smear as they removed, since they will induce structural vibrations in the spacecraft, so the utility of this approach would be questionable.
[+] [-] PinkMilkshake|4 years ago|reply
I guess I never saw one pictured next to a human. I've only seen pictures of satellites being worked on so I expected something more human sized? It seems so stupid now, especially since earth telescopes are huge.
[1] https://svs.gsfc.nasa.gov/vis/a010000/a013500/a013522/JWST_v...
[+] [-] Sharlin|4 years ago|reply
[+] [-] sgt101|4 years ago|reply
Keck was the first one bigger - 1989.
The next one Keck 2 was 1997.
https://en.wikipedia.org/wiki/List_of_largest_optical_reflec...
[+] [-] inamberclad|4 years ago|reply
[+] [-] dr_orpheus|4 years ago|reply
[0] https://external-content.duckduckgo.com/iu/?u=http%3A%2F%2Fc...
[1] https://en.wikipedia.org/wiki/Milstar
[2] https://en.wikipedia.org/wiki/Rotary_car_dumper
[+] [-] elihu|4 years ago|reply
[+] [-] walrus01|4 years ago|reply
[+] [-] 83|4 years ago|reply
[1] https://www.astronomie.nl/upload/750x498/images/Telescopen/J...
[+] [-] ademup|4 years ago|reply
[+] [-] theandrewbailey|4 years ago|reply
https://www.nasa.gov/audience/forstudents/k-4/stories/nasa-k...
https://www.sciencefocus.com/space/hubble-space-telescope-ho...
[+] [-] samstave|4 years ago|reply
I mean *WE* /paid/ for them... I would like to access the data provided in real-time.
Where can one get the raw images?
[+] [-] D_Guidi|4 years ago|reply
[+] [-] sp332|4 years ago|reply
[+] [-] amelius|4 years ago|reply
https://www1.udel.edu/udaily/2009/may/cool051509.html
Then it should not be surprising that a telescope is about that size.
[+] [-] lolive|4 years ago|reply
https://svs.gsfc.nasa.gov/10776
[+] [-] archibaldJ|4 years ago|reply
[+] [-] readthenotes1|4 years ago|reply
[+] [-] zionic|4 years ago|reply
[+] [-] sillyquiet|4 years ago|reply
I was super impressed with Dr. Mather, not only that he seemed so wise, but also that this super busy man took the time to do an hour long interview with a random You-Tuber. I think the JWST project is in good hands.
Edit: I guess Destin is not a 'random' You-tuber, but someone that was well-placed to connect with Dr. Mather. Still, he's not CNN or BBC - he's a guy with a handheld camera that doesn't ask fluff question, but questions intended to help inform himself and his audience. Still think Dr. Mather thinking it was important to spend so much of his schedule with Destin was impressive.
[+] [-] samwillis|4 years ago|reply
So excited to see first images and read about all the discoveries you are going to make. Exciting times!
My daughters (7yo) class have been talking about it, she keeps coming home from school excited to tell me about the latest update on its journey. I love the fact we have these exciting things happening in space science to experience together.
[+] [-] itazula|4 years ago|reply
[+] [-] WithinReason|4 years ago|reply
[+] [-] mayankkaizen|4 years ago|reply
[+] [-] bestouff|4 years ago|reply
[+] [-] jamincan|4 years ago|reply
I'm not sure who it was anymore (possibly Scott Manley on youtube), but apparently ESA had been setting aside the components for the Ariane 5 that tested best to be used for the launch of JWST to lower the risk of failure and that might explain in part why it was able to launch it so precisely - it was not your average Joe's Ariane 5.
[+] [-] abhiminator|4 years ago|reply
[+] [-] tunap|4 years ago|reply
[+] [-] mnw21cam|4 years ago|reply
[+] [-] EMM_386|4 years ago|reply
And no back-up, even if the Ariane launch failed. No back-up.
Congrats to everyone across the board for getting this amazing telescope right where it needs to be.
Now all we need is the mirror alignment and we're in for some seriously incredible science.
[+] [-] _joel|4 years ago|reply
That being said, I've waited 25 years so far, a few more months won't hurt
[+] [-] spookthesunset|4 years ago|reply
[+] [-] ctdonath|4 years ago|reply
[+] [-] pkdpic|4 years ago|reply
I got confused though, I thought they were saying it was at the one between the sun and the earth (L1). But I guess its at the one behind the earth (L2)? Anyway so cool! Lagrange points always make me think of Liu Cixin :^)
> The L2 point of the Earth-Sun system was the home to the WMAP spacecraft, current home of Planck, and future home of the James Webb Space Telescope. L2 is ideal for astronomy because a spacecraft is close enough to readily communicate with Earth, can keep Sun, Earth and Moon behind the spacecraft for solar power and (with appropriate shielding) provides a clear view of deep space for our telescopes. The L1 and L2 points are unstable on a time scale of approximately 23 days, which requires satellites orbiting these positions to undergo regular course and attitude corrections.
https://solarsystem.nasa.gov/resources/754/what-is-a-lagrang...
^ cool lagrage point graphic and nasa explanation
[+] [-] craigharley|4 years ago|reply
[+] [-] Aachen|4 years ago|reply
[+] [-] hi41|4 years ago|reply
https://www.flickr.com/photos/nasawebbtelescope/51775886252/...
>>Here it is: humanity’s final look at the James Webb Space Telescope as it heads into deep space to answer our biggest questions. Alone in the vastness of space, Webb will soon begin an approximately two-week process to deploy its antennas, mirrors, and sunshield. This image was captured by the cameras on board the rocket’s upper stage as the telescope separated from it. The Earth hover in the upper right. Credit: Arianespace, ESA, NASA, CSA, CNES
[+] [-] pfdietz|4 years ago|reply
[+] [-] LeonM|4 years ago|reply
I don't think universities should (or could) spend that kind of money on research equipment.
[+] [-] tobylane|4 years ago|reply
[+] [-] Rebelgecko|4 years ago|reply
[+] [-] pwdisswordfish9|4 years ago|reply
https://text.npr.org/1075437484
[+] [-] junon|4 years ago|reply
[+] [-] Dave3of5|4 years ago|reply
[+] [-] hermitcrab|4 years ago|reply
[+] [-] _ph_|4 years ago|reply
[+] [-] spookthesunset|4 years ago|reply
[+] [-] Maxburn|4 years ago|reply
https://jwst.nasa.gov/content/webbLaunch/whereIsWebb.html?s=...
[+] [-] drawkbox|4 years ago|reply
[+] [-] a_code|4 years ago|reply
[+] [-] GlenTheMachine|4 years ago|reply
The somewhat longer answer is that the spacecraft establishes an orientation using its Control Moment Gyros (CMGs). The ops team could use the CMGs to maintain pointing if this small amount of image smear ever became significant. But the CMGs would probably induce as much image smear as they removed, since they will induce structural vibrations in the spacecraft, so the utility of this approach would be questionable.