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Webb deployment timeline adjusted to focus on initial spacecraft operations
https://www.spacedaily.com/reports/Webb … s_999.html
Specifically, the team is analyzing how the power subsystem is operating now that several of the major deployments have been completed. Simultaneously, the deployments team is working to make sure motors that are key to the tensioning process are at the optimal temperatures prior to beginning that operation.
Using an approach to keep mission operations focused on as few activities as necessary at a time, mission managers have chosen to wait to resume sunshield deployment steps after better understanding the details of how Webb is functioning in its new environment.
"Nothing we can learn from simulations on the ground is as good as analyzing the observatory when it's up and running," said Bill Ochs, Webb project manager, based at NASA's Goddard Space Flight Center. "Now is the time to take the opportunity to learn everything we can about its baseline operations. Then we will take the next steps."
Webb's deployment was designed so that the team could pause deployments if necessary. In this case, Ochs said, they are relying on that flexibility in order to properly address how the massive and complex observatory is responding to the environment of space.
"We've spent 20 years on the ground with Webb, designing, developing, and testing," said Mike Menzel, of NASA's Goddard Space Flight Center, Webb's lead systems engineer.
"We've had a week to see how the observatory actually behaves in space. It's not uncommon to learn certain characteristics of your spacecraft once you're in flight. That's what we're doing right now. So far, the major deployments we've executed have gone about as smoothly as we could have hoped for. But we want to take our time and understand everything we can about the observatory before moving forward."
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So depending on the orientation parts could be to hot or cold to function..should have found this in testing
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For SpaceNut re #102
My interpretation of the report in #101 is that the temperature requirements were well known, and they were adhered to in testing.
The spacecraft is no longer in the temperature controlled test facility.
As I interpret the report, the engineers are waiting for the needed temperatures to show up before activating the mechanisms.
There is nothing that was not learned in testing, as I read the report.
(th)
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Here is an update on progress in unpacking the James Webb:
https://www.yahoo.com/news/nasas-space- … 25841.html
MARCIA DUNN
Mon, January 3, 2022, 2:29 PM
CAPE CANAVERAL, Fla. (AP) — NASA’s huge, new space telescope is doing well more than a week after liftoff, following a pair of problems overcome by ground controllers, officials said Monday.The tennis court-size sunshield on the James Webb Space Telescope is now fully open and in the process of being tightened. The operation should be complete by Wednesday.
The $10 billion telescope — the largest and most powerful astronomical observatory ever launched — rocketed away Christmas Day from French Guiana. Its sunshield and primary mirror had to be folded to fit into the European Ariane rocket.
The sunshield is vital for keeping Webb's infrared-sensing instruments at subzero temperatures, as they scan the universe for the first stars and galaxies, and examine the atmospheres of alien worlds for possible signs of life.
Getting the sunshield extended last Friday "was really a huge achievement for us," said project manager Bill Ochs. All 107 release pins opened properly.
But there have been a few obstacles.
Flight controllers in Maryland had to reset Webb’s solar panel to draw more power. The observatory — considered the successor to the aging Hubble Space Telescope — was never in any danger, with a constant power flow, said Amy Lo, a lead engineer for the telescope's prime contractor, Northrop Grumman.
They also repointed the telescope to limit sunlight on six overheating motors. The motors cooled enough to begin securing the sunshield, a three-day process that can be halted if the problem crops up again, officials said.
“Everything is hunky-dory and doing well now,” Lo said.
Ochs expects the tightening of the sunshield to be drama-free.
“The best thing for operations is boring, and that’s what we anticipate over the next three days, is to be boring," he said.
The best news I saw was that all 107 of the pins that ** had ** deploy properly did so.
(th)
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NASA Begins To Tension Webb Telescope Sunshield
https://aviationweek.com/defense-space/ … -sunshield
Today we start tensioning the most Sun-facing layer of #NASAWebb's 5-layer, tennis court-sized sunshield.
https://twitter.com/NASAWebb/status/1478045927621410823
Webb Team Moving Forward With Sunshield Tensioning
https://blogs.nasa.gov/webb/2022/01/03/ … ensioning/
Why does the sunshield have 5 layers instead of just a single thick one? Each successive layer of the sunshield is cooler than the one below. The heat radiates out from between the layers, and the vacuum between the layers is a very good insulator.
https://twitter.com/ESA_Webb/status/1477634939776643072
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James Webb telescope begins crucial sun shield tensioning
https://www.spacedaily.com/reports/Jame … g_999.html
The James Webb Space Telescope began one of the most complicated parts of its deployment Monday as NASA sent commands to fully extend the first layer of the observatory's critical five-layer sunshield.
The $10 billion space telescope -- the largest and most powerful in history -- still is in the first half of its 29-day deployment schedule as it flies through space to a position over one million miles from Earth.
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For Mars_B4_Moon re #106
At the price of putting my ID in place of yours, thanks for providing these updates on the progress of the James Webb telescope deployment.
From my perspective, successful deployment of the heat shield is by FAR the most important engineering experiment for which the Webb will be remembered. Long after the astronomical discoveries are consigned to history books (or the digital equivalent) the mastery of holding 50 Kelvin temperatures will persist as one of the most important technical achievements of this period.
In another topic, GW Johnson is working on propulsion methods for the Large Ship of RobertDyck. In one of the scenarios I have seen recently, GW Johnson has proposed sending a stash of LH2 along with a vessel to Mars, to provide for both orbit matching at Mars, AND return to Earth, AND orbit matching at Earth.
The deep cold technology being pioneered by James Webb would allow such a concept to actually work.
It should be borne in mind (all NewMars members already know this) that the technology in test here has NEVER been tried before, in human history. There is a strong likelihood it will work, but it may NOT work. The design is based upon the best guesses by the scientists who designed the shield, and by the engineers who brought it into being.
Thanks again for keeping the forum up to date on this very important technology experiment.
(th)
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They almost have a telescope done? Not yet but all is going well and Mirror Segments, instrument tests and Alignment will take a few more weeks
Timeline here :
https://planet4589.org/space/misc/webb/time.html
News-
'JWST’s secondary mirror has extended into position and is being latched into place, according to NASA TV’s coverage of the deployment.'
https://twitter.com/jeff_foust/status/1 … 8960238594
JWST sunshield fully deployed
https://spacenews.com/jwst-sunshield-fully-deployed/
“We’ve still got a lot of work to do, but getting the sunshield out and deployed is really, really big,” Bill Ochs, JWST project manager at NASA’s Goddard Space Flight Center, told project officials in the mission operations center after telemetry confirmed the final layer was in place. “It constantly reinforces what I tell everybody that the JWST team is the best in NASA.”
Deploying the sunshield, a structure roughly the size as a tennis court that had to unfold in a precise manner, was one of the biggest challenges for setting up the telescope. It involved many mechanisms that were single-point failures and was the subject of extensive simulations and contingency planning before launch.
Last edited by Mars_B4_Moon (2022-01-05 12:09:50)
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PDF file
'High Performance Cryogenic Radiators for James Webb Space Telescope'
https://ttu-ir.tdl.org/bitstream/handle … 141.v2.pdf
12 pages on cryogenic radiators for JWST
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James Webb Space Telescope’s Specialized Heat Radiator Deployed Successfully
https://twitter.com/NASAWebb/status/1479113597338873858
Our “trap door” is now open: the ADIR (Aft Deployable Instrument Radiator) has swung out from the back of the telescope to radiate heat from our science instruments into space.
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NASA to host coverage for Webb Telescope's final unfolding
https://www.spacedaily.com/reports/NASA … g_999.html
NASA will provide live coverage and host a media briefing Saturday, Jan. 8, for the conclusion of the James Webb Space Telescope's major spacecraft deployments. Beginning no earlier than 9 a.m. EST, NASA will air live coverage of the final hours of Webb's major deployments. After the live broadcast concludes, at approximately 1:30 p.m., NASA will hold a media briefing. Both the broadcast and media briefing will air live on NASA TV, the NASA app, and the agency's website.
As the final step in the observatory's major deployments, the Webb team plans to unfold the second of two primary mirror wings. When this step is complete, Webb will have finished its unprecedented process of unfolding in space to prepare for science operations.
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Final wing is now deployed!
https://twitter.com/nasahqphoto/status/ … 4014518272
Short celebration, but we’ve still got work to do.
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Let's all hope that the optics are working properly--unlike Hubble on the first go-around!!
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For Oldfart1939 re #113
Thanks for the reminder of the next phase of testing ...
One difference between Hubble and this telescope is that all of the panels re independently configurable under computer control.
My understanding is that it will take several months for the individual panels to be adjusted so they are all aligned with the target star.
(th)
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I was surprised and pleased all the deployment widgets worked properly. I read somewhere that it will take weeks to a few months to align all the mirrors and get a sharp image. It said they do not plan to publish any images until that focusing effort is done.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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The adjustments they are making are analogous to the collimation process that owners of Newtonian/Dobsonian telescopes contend with constantly. All telescopes require periodic collimation, except for high grade refractors. Each of the mirrors will require careful alignment to bring them to a single focal plane and focal point. The Keck telescopes in Hawaii are a similar problem, as they are composed of many smaller mirrors requiring alignment to function. The Large Binocular Telescope on Mt. Graham in Arizona is just 2 mirrors, but it's still the same set of problems on a drastically smaller scale.
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This will be done multiple times as the reflections are refined for more distant objects with even less brightness are targetted to be observed.
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James Webb Space Telescope should have fuel for about 20 years of science
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Finally in its location and getting ready to go to work.
The James Webb Space Telescope Is in Position—And Now We Wait
On Jan. 24, just shy of one month after its Christmas Day launch, the $10 billion observatory arrived at a spot in space known as L2—where the gravity of the sun and the Earth effectively cancel each other out, allowing the spacecraft to circle an invisible point as if it were orbiting a solid body like a planet. There the telescope will station-keep for up to the next 20 years, peering deeper into space than any observatory ever has before.
The Webb telescope operates in the infrared spectrum, detecting exceedingly faint heat signatures from stars and galaxies that formed up to 13.7 billion years ago—or just 100 million years after the Big Bang. In order to pick up such vanishingly tiny electromagnetic signals, the telescope’s 18-segment mirror has to be kept exceedingly cold—as low as -234º C (-390º F).
Entering the L2 orbit was a delicate exercise. The spacecraft had to fire its main engine for exactly 297 seconds—just shy of five minutes—slowing its speed by a mere 5.8 km/h (3.6 mph), and easing it into an orbit that will see it complete one circuit around the L2 point every six months or so. Those orbits will not be entirely stable, however, with some drift inevitably creeping into them as a result of the position of the spacecraft relative to the Earth and the sun. For that reason, Webb will periodically have to fire its on-board thrusters to make minor course corrections—and that fact was a cause of concern.
The telescope was launched with a full tank of maneuvering fuel, enough for it to operate for at least 10 years—not bad, but not nearly as long as the 32 years and counting that the Hubble Space Telescope has been in service in a stable low-Earth orbit, where it needs no such fuel. Engineers equipped the Webb with grappling handles and a refill port, allowing for the possibility of an uncrewed spacecraft to fly out and top off the tank with more fuel as needed
So to keep the station keeping going we will need to have a rescue mission to refuel the telescope already in the works since it takes so long to design stuff.
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here is the better topic
This topic is one of two that contains the word Webb ... It is no longer appropriate, since Webb is on station, but I decided not to create a new topic....
https://www.youtube.com/watch?v=fPdKUObyhw4
There appears to be a web site dedicated to tracking Webb ... the YouTube able appears to show live data, but it may just be a snapshot.
If someone has time, please look for the web site and post a link here. The site appears to report on temperature on the cold side, which is the reading that is most relevant to success of the mission. The cold side needs to drop to (about) 50 Kelvin.
(th)
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I am surprised and pleased that the complex deployments went off without a hitch. Congrats to NASA and its Webb team.
Let us hope the mirror focusing efforts go as well.
GW
GW Johnson
McGregor, Texas
"There is nothing as expensive as a dead crew, especially one dead from a bad management decision"
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We may have a bet riding on answering this question Does outer space end – or go on forever?
We should be able to get answers for what is close by but who knows the question
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All 18 segments of the primary mirror on the James Webb Space Telescope seem to be working properly 1 1/2 months into the mission, officials said Friday. The telescope's first target was a bright star 258 light-years away in the constellation Ursa Major.
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Canada’s Fine Guidance Sensor on NASAWebb
has successfully completed its first use as part of the mirror alignment phase – locking on to a guide star and sending data to the telescope’s positional system 16 times a second!
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