As NASA Celebrates Successful Deployment of James Webb Telescope Mirror - What Happens Next? (nasa.gov) 67
"Mirror, mirror...is deployed," NASA tweeted Saturday, confirming that the James Webb telescope "has taken on its final form. For the next ~6 months, the space telescope will cool down, calibrate its instruments, and prepare to #UnfoldTheUniverse."
With a diameter of 21.3 feet, the telescope's mirror is the largest mirror ever launched into space — a joint effort with the European Space Agency and Canadian Space Agency. "Good news keep coming," the ESA tweeted yesterday. " Mike Menzel, NASA Webb Mission Systems Engineer said yesterday in press brief that Webb might have 'quite a bit of fuel margin... Roughly speaking, it's around 20 years of propellant', adding that's still to be determined."
Long-time Slashdot reader cusco writes that "For years naysayers have confidently declared that the numerous automated operations necessary to fully deploy the James Webb Space Telescope were going to guarantee its failure. Today they've been proven wrong."
From NASA.gov: "Today, NASA achieved another engineering milestone decades in the making. While the journey is not complete, I join the Webb team in breathing a little easier and imagining the future breakthroughs bound to inspire the world," said NASA Administrator Bill Nelson. "The James Webb Space Telescope is an unprecedented mission that is on the precipice of seeing the light from the first galaxies and discovering the mysteries of our universe. Each feat already achieved and future accomplishment is a testament to the thousands of innovators who poured their life's passion into this mission...."
The world's largest and most complex space science telescope will now begin moving its 18 primary mirror segments to align the telescope optics. The ground team will command 126 actuators on the backsides of the segments to flex each mirror — an alignment that will take months to complete. Then the team will calibrate the science instruments prior to delivering Webb's first images this summer.
"I am so proud of the team — spanning continents and decades — that delivered this first-of-its kind achievement," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate in NASA Headquarters in Washington. "Webb's successful deployment exemplifies the best of what NASA has to offer: the willingness to attempt bold and challenging things in the name of discoveries still unknown."
Soon, Webb will also undergo a third mid-course correction burn — one of three planned to place the telescope precisely in orbit around the second Lagrange point, commonly known as L2, nearly 1 million miles from Earth. This is Webb's final orbital position, where its sunshield will protect it from light from the Sun, Earth, and Moon that could interfere with observations of infrared light. Webb is designed to peer back over 13.5 billion years to capture infrared light from celestial objects, with much higher resolution than ever before, and to study our own solar system as well as distant worlds.
"The successful completion of all of the Webb Space Telescope's deployments is historic," said Gregory L. Robinson, Webb program director at NASA Headquarters. "This is the first time a NASA-led mission has ever attempted to complete a complex sequence to unfold an observatory in space — a remarkable feat for our team, NASA, and the world."
Saturday the Canadian Space Agency tweeted "Wow.... Congratulations to everyone involved. We can't wait to see what the telescope has in store for the international astronomy community!"
With a diameter of 21.3 feet, the telescope's mirror is the largest mirror ever launched into space — a joint effort with the European Space Agency and Canadian Space Agency. "Good news keep coming," the ESA tweeted yesterday. " Mike Menzel, NASA Webb Mission Systems Engineer said yesterday in press brief that Webb might have 'quite a bit of fuel margin... Roughly speaking, it's around 20 years of propellant', adding that's still to be determined."
Long-time Slashdot reader cusco writes that "For years naysayers have confidently declared that the numerous automated operations necessary to fully deploy the James Webb Space Telescope were going to guarantee its failure. Today they've been proven wrong."
From NASA.gov: "Today, NASA achieved another engineering milestone decades in the making. While the journey is not complete, I join the Webb team in breathing a little easier and imagining the future breakthroughs bound to inspire the world," said NASA Administrator Bill Nelson. "The James Webb Space Telescope is an unprecedented mission that is on the precipice of seeing the light from the first galaxies and discovering the mysteries of our universe. Each feat already achieved and future accomplishment is a testament to the thousands of innovators who poured their life's passion into this mission...."
The world's largest and most complex space science telescope will now begin moving its 18 primary mirror segments to align the telescope optics. The ground team will command 126 actuators on the backsides of the segments to flex each mirror — an alignment that will take months to complete. Then the team will calibrate the science instruments prior to delivering Webb's first images this summer.
"I am so proud of the team — spanning continents and decades — that delivered this first-of-its kind achievement," said Thomas Zurbuchen, associate administrator for the Science Mission Directorate in NASA Headquarters in Washington. "Webb's successful deployment exemplifies the best of what NASA has to offer: the willingness to attempt bold and challenging things in the name of discoveries still unknown."
Soon, Webb will also undergo a third mid-course correction burn — one of three planned to place the telescope precisely in orbit around the second Lagrange point, commonly known as L2, nearly 1 million miles from Earth. This is Webb's final orbital position, where its sunshield will protect it from light from the Sun, Earth, and Moon that could interfere with observations of infrared light. Webb is designed to peer back over 13.5 billion years to capture infrared light from celestial objects, with much higher resolution than ever before, and to study our own solar system as well as distant worlds.
"The successful completion of all of the Webb Space Telescope's deployments is historic," said Gregory L. Robinson, Webb program director at NASA Headquarters. "This is the first time a NASA-led mission has ever attempted to complete a complex sequence to unfold an observatory in space — a remarkable feat for our team, NASA, and the world."
Saturday the Canadian Space Agency tweeted "Wow.... Congratulations to everyone involved. We can't wait to see what the telescope has in store for the international astronomy community!"
This telescope will be awesome (Score:4, Insightful)
But I don't particularly remember these "naysayers". Why not just revel in this great accomplishment and not bother setting up the strawmen?
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Because I'm going to hold my breath until first light.
Just joking, but the naysayers did have a legitimate concern about the complexity of the system. I sure hope JWST is going to work well for many years--but I'm also optimistic that we will have space robots that can fix it if that's required within less than 20 years.
So does anyone know about their plans for the first image?
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Yeah, but there's a world of difference between legitimate concern regarding complexity and "this will never work".
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I believe it was only intended to be functional for 5 years, but they are now saying its probably closer to 10 years.
If it where up to me, I'd have strapped a little ion rocket on the back so when failures happen, or its time for a refuel, they can just drive it back to the ISS and send up a crew to service it , refuel it, and send it back for another 10 years.
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There is a refueling port on it (an idea which was initially rejected but apparently NASA reconsidered), and automated robotic actions are no longer bleeding edge tech. There is even an autonomous strap-on power pack that can hook itself to an aging satellite in GEO and take over station keeping when the craft's fuel is getting low. If in a decade it needs servicing it will be entirely possible to to do so.
JWST not in GEO (Score:2)
There is even an autonomous strap-on power pack that can hook itself to an aging satellite in GEO
The problem is that the JWST is much, much further away than GEO which is only about 42,000 km. It orbits the L2 Lagrange point on the far side of the Earth to the Sun which, if memory serves, is about 1.5 million km away. It's entirely possible that they may develop some automated system to refuel it if there is a still clear demand for the science it is producing by then but this will be much, much harder than refueling a satellite in GEO and far from a guaranteed certainty.
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Of course, but tech does not hold still. By the time it's needed the technology will have advanced far beyond what is currently available and possibly beyond what is imagined. (Assuming it's not needed really, really soon, of course.)
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I was a bit confused about the L2 description. I'm guessing it means the point where the gravitational influence of the earth and the sun are approximately equal on the line that extends through the sun and earth? I looked at the definition, and it appears that L2 is beyond the earth, while L1 is the one between earth and sun on that line. (L4 and L5 sort of make sense, but L3 is confusing me...)
And no one said anything about the plans for first light. I'm sure they are thinking about it carefully...
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I suspect that they're waiting on a first light target for something really, really interesting that LIGO or one of the other experiments find to maximize the impact. At least that's what I would do, especially since they're coming up with all sorts of interesting targets that Hubble and the earthbound observatories can't resolve.
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Just the ACK.
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It will be really cool if everything works. When Hubble failed, it was heartbreaking.
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Just concurrence.
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Listening to one of the long winded talks on youtube from the science team they are aiming to take and publish a few "wow" factor pictures as one of their first tasks to get the show on the road. This makes sense as there are plenty of skeptical folk about who want to know where their money went. They have not said what the pictures will be but I am hopeful that we will indeed feel a wow about what they show us. Hubble was just a repurposed spy satellite optically and it did some amazing science so I think
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Just the ACK and me, too.
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Yeah, I don't either. I do remember a lot of people being rather nervous about it, hoping nothing will go wrong, myself included. And that certainly was a point of risk of the mission. But hey, no risks, no rewards. The NASA team's hard work and attention to detail appears to be paying off. This is fantastic news all around, so congrats to them.
I'll admit I'm not going to breathe completely easy until we see the thing in operation, and the data looks good. Memories of Hubble, I guess. Ugh, "months" t
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I do remember the NASA-haters claiming that it was going to be a multi-billion dollar disaster because of its complexity, mostly because they pissed me off so badly.
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Comment removed (Score:3)
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Permalink [twitter.com]
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Yes, congratulations to the ESA and Arianespace for the flawless launch.
Now we wait six moths to a year (Score:2)
Re:Now we wait six moths to a year (Score:5, Informative)
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That, and they also put actuators on the back of each mirror that lets them change the shape of each mirror as needed.
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to see if any glaring mistakes pop up in the construction. I seem to recall Hubble having blurry vision for a few years until they sent up corrective lens.
So check this out: Mirror alignment [youtube.com].
From the JWST status page:
Individual Mirror Segment Movements
Nominal Event Time: UPDATE: Launch + 17 days (Jan 11)
Status: Future.
The primary mirror wings are now fully deployed and latched into place, but the individual mirror segments remain in their launch configuration. This operation is a multi-day multi-step activity to activate and move each of the 18 primary mirror segments (which are adjustable) out of their launch configuration. The primary mirror segments and secondary mirror are moved by six actuators that are attached to the back of each mirror piece. The primary mirror segments also have an additional actuator at its center that adjusts its curvature. The telescope's tertiary mirror remains stationary.
After all individual mirror segment deployments are completed, the detailed optical mirror alignment process begins which is about a 3 month process. In parallel, as temperatures cool enough, instrument teams will turn on their instruments and begin each instrument's commissioning process.
It's designed the exactly NOT be like Hubble.
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Except this part of the above quoted segment, which says that you didn't read what you replied to.
The primary mirror segments also have an additional actuator at its center that adjusts its curvature.
The Hubble issue would only be an issue if it was the secondary mirror that had an issue, and since they tested it in a vacuum chamber, I am pretty sure they would be able to tell if that was an issue.
Moths! (Score:2)
Moths in space!!
One Last Burn (Score:5, Informative)
The reverse-origami operation required to unpack the JWST from its launch fairing straightjacket has succeeded, a significant and impressive achievement thanks to a lot of design, redesign, modelling, testing, testing and more testing. The folks involved must be congratulated, remembering that some of the team who worked on the JWST have passed away before they got to see this occur.
There is still one more critical step coming up though, the final rocket motor burn (MCC-2) which should put the JWST into its halo orbit around the L2 point. That should occur around the 19th or 20th of this month.
Halo orbit around L2 (Score:2)
One thing I don’t quite grok - how does an orbit work around a point of unstable equilibrium? Is it just that the L2 “point” is somewhat more of a diffuse area than a point, meaning the falloff as you move some distance away is still fairly minor?
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One thing I don’t quite grok - how does an orbit work around a point of unstable equilibrium? Is it just that the L2 “point” is somewhat more of a diffuse area than a point, meaning the falloff as you move some distance away is still fairly minor?
Here's an animation [nasa.gov] which should provide answers to your questions.
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I guess I didn’t sufficiently explain my question.
That’s a nice picture, but it doesn’t explain *how* an orbit actually works around a point of unstable equilibrium.
By definition, unstable equilibrium means any item not precisely on point will fall further away over time. So how is it possible for an orbit to exist around such a point? Certainly one could fly a circular pattern any place (constantly burning fuel), but the term orbit implies making use of gravitational attraction.
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I don't understand the math, but the theoretically stable L2 also assumes the JWST has zero mass and the Moon doesn't exist, but because JWST has mass and the Moon does exist, L2 is a close approximation of stable.
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That's the thing - L1, L2, and L3 are unstable points of equilibrium. L4 and L5 are stable - which actually makes them less suitable for spacecraft since cosmic garbage tends to collect there.
https://solarsystem.nasa.gov/r... [nasa.gov]
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Think of it this way.
If you have ever driven a manual transmission car, you have had to start out on a hill. You can even do this with an automatic with a decent hill. JWST is near the top of the hill, which if you sat on it perfectly, your car wouldn't move. It is near the top, but instead of trying to sit at the top, it periodically gives a little burst of acceleration to push it up the hill, but not quite to the top. These boosts happen in JWST's case when they have to dump the reaction wheels' speed
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Re:Halo orbit around L2 (Score:5, Interesting)
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Okay, that makes some sense - thanks!
I guess mentally I’m trying to hold onto the idea of a large central object creating a gravity well. But there can be types of orbits which have a somewhat different mechanism but accomplish the same thing.
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If you imagine gravity as the "rubber sheet" model, there are three big moving lumps on the rubber sheet, the Sun, the Earth and the Moon pulling it down. As they move they create the Lagrange points, gravitationally lower than the rest of the Solar System's rubber sheet but higher than the deep gravity wells of the three bodies.
There are of course many other large bodies in the Solar System but those three are the important ones in Earth's vicinity.
The JWST will "orbit" one of those lower rubber-sheet loca
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L2 describes a position and orbit where in an ideal system there would be zero acceleration relative to the Earth's rotating reference frame. If you go away from it, you'll face acceleration pushing you further away as any unstable equilibrium but as long as thruster can keep you near it, the acceleration will be very tiny meaning minimal fuel usage. The halo orbit comes from a detail that L2 is not stationary since the Sun-Earth system is influenced by other grav
What's next? A good night's sleep ... (Score:1)
... for the team that made this happen. They've earned it.
How do they align and focus the mirrors? (Score:2)
Here is a question about "what happens next?". I have been wondering about this but unable to find an answer. Here's hoping that someone on Slashdot will have some knowledge:
The JWST has 18 mirror segments. Each has six motors at the corners plus one central actuator to change the curvature of each segment. Presumably, each segment must be fine tuned to camber and shape to have perfect focus and alignment, each of the 18 segments perfectly zeroed in on a common point and perfectly registrated to each ot
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I suspect it's similar to tuning a multi-barrel carburetor, adjust the mixture on one side until the motor is running better, then adjust the other, then go back to the first, repeat until any adjustment makes it worse.
This is Webb's home page, https://jwst.nasa.gov/index.ht... [nasa.gov]
The 'Where Is Webb' link will show you where in the deployment process it is.
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IANA NASA Scientist, but you could see which parts of the image move when you move the mirror. Move one at a time and you're able to tell each reflection apart.
Joint effort? (Score:2)
"With a diameter of 21.3 feet, the telescope's mirror is the largest mirror ever launched into space — a joint effort with the European Space Agency and Canadian Space Agency. "
Huh? I know the US has become a dirty word, but JWST is primarily a NASA effort (e.g, as in US. James Webb was the NASA administrator from 1961 to 1968.
Unless they meant only the primary mirror? I don't know who is responsible for that.
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Wasn't the launch vehicle from the ESA? Its ride was an Ariane 5 that took off from French Guiana.
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ESA provided the launch integration facilities as well as the launch itself on the Ariane V. The launcher plus the upper stage put the JWST into an almost perfect trajectory. This means the JWST's onboard fuel supply was conserved and it's believed that has added another ten fricking years to the expected operational lifespan of the telescope.
Canada provided one of the four main imaging instruments on the JWST plus part of the main bus guidance system. ESA has provided another instrument plus optical compon
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The ESA supplied one complete instrument (NIRspec), a major component of a second instrument (MIRI optical bench assembly), the launch and ongoing operational support.
The CSA supplied one complete instrument (FGS-NIRISS) and ongoing operational support.
So out of the four instruments aboard, more than half of them are supplied by partners.
So its fine to say its a joint effort with both the ESA and CSA, as they both have major contributions.
Or did you miss the "with" in "a joint effort *with* the..." and thou
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More likely it's just the typical illiterate Journalist unable to communicate the difference between a mirror and an entire spacecraft mission.
What's next? (Score:1)
Reboot Rover and NERVA.
Semi serious question (Score:2)
How do you think NASA would respond if in one of the pictures some type of alien craft was clearly visible. And yes, I realize the optics aren't designed for "close up" pictures, but go with the question.
This is why [imgur.com] I ask the question. Or maybe something such as a Rama craft. We know they hired some theologians [slashdot.org] to discuss this point, but what if they don't realize the craft is in the picture and someone releases it before they find out?
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This is why [imgur.com] I ask the question. Or maybe something such as a Rama craft. We know they hired some theologians [slashdot.org] to discuss this point, but what if they don't realize the craft is in the picture and someone releases it before they find out?
James Webb is unironically the first telescope we've ever built as a species which might be able to spot alien civilizations. This is because everything else is light, radio, xray, etc - not very well-suited for detecting signs of non-technological or post-radio-technological life (nevermind that we couldn't pick up the signals we produce from the distance of the nearest star anyway.) James Webb looks in infrared, which is a band you can't really see from terrestrial telescopes as the atmosphere blocks it
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Correction: any Earth-sized planet in another stellar system will most certainly NOT subtend "several pixels"; instead, any such planets will be point sources. In brief, diameter of Earth is around 10^7 m, while the nearest star is of order 10^(16) m away from us. The angular size of the Earth at such a distance would thus be 10^(-9) radians, which corresponds to 0.0002 arcseconds.
In comparison, the diffraction limit of JWST at a wavelength of 2 microns is roughly (2 x 10^(-6) m)/ (6.5 m) = 3 x 10^(-7) r
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The telescope's field of view is pretty narrow, so it can only capture images of things it's intentionally pointed at. It will not randomly pick up a passing alien spacecraft. If the aliens have built something that approximates a Dyson sphere around a nearby star, JWST could see it as a very large diffuse IR source different from anything that occurs naturally.
Much more likely, there'll be a detection of potential biosignatures like oxygen and methane in the atmosphere of an exoplanet.