20.03.2021
JWST moving towards October launch
WASHINGTON — NASA’s James Webb Space Telescope is making continued progress for a launch in October as engineers close out a series of technical issues with the spacecraft but deal with one new problem.
In a March 16 presentation during a meeting of NASA’s Astrophysics Advisory Committee, Eric Smith, JWST program scientist, said engineers had either completed work on, or were in the process of wrapping up, several technical issues the program had been tracking in recent months, none of which posed a risk to the mission’s schedule.
Those issues included concerns about residual air pressure in the spacecraft’s sunshield that could stress it when the Ariane 5 rocket that will launch JWST jettisons its payload fairing. Smith said that issue has been closed after adding a couple patches to the sunshield to ensure it could handle double the required pressure differential. Another issue, fasteners on the spacecraft that may not have been installed with sufficient torque, has also been resolved by retorquing those fasteners.
The project has 48 days of schedule margin remaining, which Smith said was in line with projections at this phase of development. “We’re burning it down at the pace expected,” he said of that schedule margin.
JWST is currently going through a final series of deployment tests, including of its primary mirror. The spacecraft will then be prepared for shipment later this summer to Kourou, French Guiana, for final launch preparations.
Smith said the program is dealing with one new technical issue. Two communications transponders suffered separate problems during testing in January. Engineers have tracked down the problems with the two units and started repairs this week. “Those boxes will be back in time for us to make our planned shipping date,” he said.
That issue, he acknowledged, will use some of the remaining schedule margin. “The plan right now is that we’ll get them back in time so that we don’t have to use all of it,” he said. “That’s the main thing that we’re watching regarding the margin.”
One other issue is the name of the spacecraft itself. The telescope is named after James Webb, the NASA administrator for much of the 1960s known for his leadership of the agency during the race to the moon. Earlier in his career, Webb worked at the State Department and reportedly oversaw policies there to purge the department of LGBT employees. Some object to the name for that reason and have called on NASA to rename the telescope.
Smith said both NASA’s chief historian, Brian Odom, and other historians outside the agency have been studying Webb’s activities at the State Department. “They haven’t completed their research in the archives yet, but when they do, that’s when the agency would come out with a position on that,” he said.
Roman delays
While JWST is sticking to its October launch date, the next flagship astrophysics mission, the Nancy Grace Roman Space Telescope, is likely to be delayed because of a slowdown in activity during the pandemic.
“We do have COVID impacts,” said Julie McEnery, senior project scientist for the mission, previously known as the Wide Field Infrared Survey Telescope, or WFIRST. In a presentation at the same meeting March 16, she said the program has been running at “70% efficiency” since the start of the pandemic a year ago, and would likely remain there for several more months as the pandemic slowly ebbs.
“The delay is on the order of months, not years,” she said, adding that the pandemic was the only issue the telescope was facing. “Fundamentally, Roman is on track. Except for the COVID-related impacts, everything is coming together and is where it needs to be.”
Speaking to the committee March 15, Paul Hertz, director of NASA’s astrophysics division, said Roman’s launch date would likely move from late 2025 to the middle of 2026 because of the pandemic. “It will need additional funding to pay for that schedule slip,” he said, but didn’t give an estimate of that increased cost since the agency is still reviewing estimates of the delay and related costs.
Quelle: SN
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Update: 10.04.2021
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NASA’s Webb Telescope Packs Its Sunshield for a Million Mile Trip
Engineers working on NASA’s James Webb Space Telescope have successfully folded and packed its sunshield for its upcoming million-mile (roughly 1.5 million kilometer) journey, which begins later this year.
The sunshield — a five-layer, diamond-shaped structure the size of a tennis court — was specially engineered to fold up around the two sides of the telescope and fit within the confines of its launch vehicle, the Ariane 5 rocket. Now that folding has been completed at Northrop Grumman in Redondo Beach, California, the sunshield will remain in this compact form through launch and the first few days the observatory will spend in space.
Designed to protect the telescope’s optics from any heat sources that could interfere with its sight, the sunshield is one of Webb’s most critical and complex components. Because Webb is an infrared telescope, its mirrors and sensors need to be kept at extremely cold temperatures to detect faint heat signals from distant objects in the universe.
In space, one side of the sunshield will always reflect light and background heat from the Sun, Earth and Moon. Thermal models show that the maximum temperature of the outermost layer is 383 Kelvin, or about 230 degrees Fahrenheit. Meanwhile, the other side of the sunshield will always face deep space, with the coldest layer having a modeled minimum temperature of 36 Kelvin, or about minus 394 degrees Fahrenheit.
Fully deployed, the telescope’s sunshield measures almost 70 feet by 47 feet (21 meters by 14 meters). When stowed inside the rocket for launch, the folded sunshield will be packaged in a very confined area in between other structures of the observatory to accommodate the limited space inside the 18-foot (5.4-meter) diameter rocket fairing.
“There is nothing really analogous to what we are trying to achieve with the folding up of a tennis court-sized sunshield, but it is similar to packing a parachute,” said Jeff Cheezum, a lead sunshield design engineer at Northrop Grumman. “Just like a skydiver needs their parachute packed correctly in order to open perfectly and to successfully get back to Earth, Webb needs its sunshield to be perfectly stowed to ensure that it also opens up perfectly and maintains its shape, in order to successfully keep the telescope at its required operating temperature.”
The month-long process of folding the sunshield began with laying the five layers as flat as possible. In its deployed state, the sunshield resembles a multilayered silver ship, so its inherently curved surfaces added a degree of complexity to this step. Afterwards, the layers were lifted vertically and propped onto special support equipment so that they could be properly restrained for folding. A team of technicians then carefully folded each layer in a zigzag pattern to create accordion-like stacks of membranes on either side of the telescope.
The first layer of the sunshield is two-thousandths of an inch (0.005 centimeters) thick, while the other four layers are only one-thousandth of an inch thick. For the team, a built-in challenge was the delicacy of folding such thin layers. The folding process also had to account for components such as the sunshield’s 90 different tensioning cables, which must be stowed in a specific manner to ensure the sunshield deploys smoothly.
With the successful completion of sunshield folding, the engineering team has prepared the sunshield for its complex deployment in space. The sunshield will unfold at the end of the telescope’s first week in space after launch, stretching out to its full size and then separating and tensioning each of its five layers. Testing for this unfolding and tensioning procedure was completed for the final time on Earth in December 2020.
“Think of it backwards; we want the deployed sunshield to achieve a specific shape so we get the performance we need. The whole folding process was designed with that in mind. We have to fold cleanly and carefully the same way each time, to ensure the unfolding occurs exactly the way we want it,” said James Cooper, lead sunshield engineer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
For instance, one of the most intricate aspects of the folding process involved aligning the membrane stacks. Each of the sunshield’s layers has hundreds of intentional holes, which are deliberately arranged to avoid light and heat from passing to the optical elements of the telescope when the sunshield is fully deployed. These holes must be lined up during folding so that Webb technicians can insert “pins” through the holes in each membrane stack. The 107 “pins,” or membrane release devices, will help restrain the layers for launch, but release to unfold the sunshield once the telescope is in space.
“It’s a very methodical process that we use to make sure everything is aligned correctly,” said Marc Roth, mechanical engineering lead at Northrop Grumman. “Our team has been through multiple training cycles, and we’ve implemented many lessons learned from the previous times we’ve done this process, all culminating in this last sunshield fold.”
Over the next three months, engineers and technicians will finish stowing and securing the packed sunshield. This process will involve installing the membrane release devices, rigging and securing all of the sunshield cables, and stowing covers for the sunshield membranes. It will also include stowing the two “arms” of the sunshield — the Mid-Boom Assemblies — which will horizontally extend the sunshield outwards during deployment, as well as stowing the two pallet structures that hold the sunshield in place.
The observatory will additionally undergo a final mirror deployment before it is shipped to its launch site in French Guiana, South America.
The Webb engineering team continues to follow personal safety procedures in accordance with current Centers for Disease Control and Prevention and Occupational Safety and Health Administration guidance related to COVID-19, including mask-wearing and social distancing.
The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
Quelle: NASA
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Update: 7.05.2021
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Media Invited to Virtual Briefing as NASA’s Webb Prepares for Launch
Media will have the opportunity to see the iconic golden mirror of NASA’s James Webb Space Telescope open for the last time on Earth during a virtual briefing Tuesday, May 11, at 1 p.m. EDT (10 a.m. PDT). Officials from NASA and Northrop Grumman will discuss the significance of the mirror’s deployment and next steps for the mission as it prepares for launch, which is targeted for Oct. 31. The event will air live via the following link:
https://northropgrumman.qumucloud.com/view/JWST#/
The world’s largest and most powerful space telescope, Webb opened its iconic primary mirror wings in May as part of the telescope’s final testing regimen at Northrop Grumman in Redondo Beach, California. The conclusion of this test represents an important milestone as Webb marches toward launch.
Briefing participants include:
- Greg Robinson, James Webb Space Telescope program director, NASA Headquarters
- Bill Ochs, James Webb Space Telescope project manager, NASA’s Goddard Space Flight Center
- Scott Willoughby, vice president and program manager, Northrop Grumman
- Begoña Vila, instrument systems engineer, Goddard
- Eric Smith, James Webb Space Telescope program scientist, NASA Headquarters
- Klaus Pontoppidan, project scientist, Space Telescope Science Institute
This event is open to U.S. and international media. Media who would like to ask questions via Zoom during the event must provide their name and affiliation by 1 p.m. EDT (4 p.m. PDT) Monday, May 10, to Laura Betz at laura.e.betz@nasa.gov to receive the Zoom link. Those following the briefing on social media may ask questions using #NASAWebb.
Once it launches and is operational, Webb will be the world's premier space science observatory, helping solve mysteries in our solar system, looking to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners ESA (European Space Agency) and the Canadian Space Agency.
Quelle: NASA
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Update: 13.05.2021
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Webb’s Golden Mirror Wings Open One Last Time on Earth
For the last time while it is on Earth, the world’s largest and most powerful space science telescope opened its iconic primary mirror. This event marked a key milestone in preparing the observatory for launch later this year.
As part of the NASA’s James Webb Space Telescope’s final tests, the 6.5 meter (21 feet 4 inch) mirror was commanded to fully expand and lock itself into place, just like it would in space. The conclusion of this test represents the team’s final checkpoint in a long series of tests designed to ensure Webb’s 18 hexagonal mirrors are prepared for a long journey in space, and a life of profound discovery. After this, all of Webb’s many movable parts will have confirmed in testing that they can perform their intended operations after being exposed to the expected launch environment.
“The primary mirror is a technological marvel. The lightweight mirrors, coatings, actuators and mechanisms, electronics and thermal blankets when fully deployed form a single precise mirror that is truly remarkable,” said Lee Feinberg, optical telescope element manager for Webb at NASA's Goddard Space Flight Center in Greenbelt, Maryland. “This is not just the final deployment test sequence that the team has pulled off to prepare Webb for a life in space, but it means when we finish, that the primary mirror will be locked in place for launch. It’s humbling to think about the hundreds of dedicated people across the entire country who worked so hard to design and build the primary mirror, and now to know launch is so close.”
Making the testing conditions close to what Webb will experience in space helps to ensure the observatory is fully prepared for its science mission one million miles away from Earth.
Commands to unlatch and deploy the side panels of the mirror were relayed from Webb’s testing control room at Northrop Grumman, in Redondo Beach, California. The software instructions sent, and the mechanisms that operated are the same as those used in space. Special gravity offsetting equipment was attached to Webb to simulate the zero-gravity environment in which its complex mechanisms will operate. All of the final thermal blanketing and innovative shielding designed to protect its mirrors and instruments from interference were in place during testing.
To observe objects in the distant cosmos, and to do science that’s never been done before, Webb’s mirror needs to be so large that it cannot fit inside any rocket available in its fully extended form. Like a piece of origami artwork, Webb contains many movable parts that have been specifically designed to fold themselves to a compact formation that is considerably smaller than when the observatory is fully deployed. This allows it to just barely fit inside a 16-foot (5-meter) rocket fairing, with little room to spare.
To deploy, operate and bring its golden mirrors into focus requires 132 individual actuators and motors in addition to complex backend software to support it. A proper deployment in space is critically important to the process of fine-tuning Webb’s individual mirrors into one functional and massive reflector. Once the wings are fully extended and in place, extremely precise actuators on the backside of the mirrors position and bend or flex each mirror into a specific prescription. Testing of each actuator and their expected movements was completed in a final functional testearlier this year.
“Pioneering space observatories like Webb only come to fruition when dedicated individuals work together to surmount the challenge of building something that has never been done before. I am especially proud of our teams that built Webb’s mirrors, and the complex back-end electronics and software that will empower it to see deep into space with extreme precision. It has been very interesting, and extremely rewarding to see it all come together. The completion of this last test on its mirrors is especially exciting because of how close we are to launch later this year,” said Ritva Keski-Kuha, deputy optical telescope element manager for Webb at Goddard.
Following this test engineers will immediately move on to tackle Webb’s final few tests, which include extending and then restowing two radiator assemblies that help the observatory cool down, and one full extension and restowing of its deployable tower.
The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
Quelle: NASA
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Update: 14.05.2021
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Ariane 5 issue could delay JWST
WASHINGTON — Ongoing work to address a problem seen on two previous Ariane 5 launches has kept that launch vehicle grounded for months and could delay the high-profile launch of NASA’s James Webb Space Telescope later this year.
The Ariane 5, one of the world’s most reliable launch vehicles, last launched in August 2020, placing two communications satellites and Northrop Grumman’s Mission Extension Vehicle 2 into geostationary transfer orbit. The long hiatus in launches led to speculation there was an issue with the rocket.
In a statement to SpaceNews, Arianespace acknowledged that “post-flight analyses conducted on two recent Ariane 5 launches have indicated the occurrence of a less than fully nominal separation of the fairing, however with no adverse impact on the Ariane 5 flights in question.”
The company did not elaborate on the problem, but industry sources familiar with the issue said that, on both the August 2020 launch and the previous Ariane launch in February 2020, the separation of the faring induced vibrations into the payload stack well above acceptable limits. Neither incident damaged any of the payloads, but raised concerns about the effect on future missions, including JWST.
“We have decided to conduct a set of additional checks with RUAG and ArianeGroup to ensure the best level of quality and reliability; the progress of these investigations remains positive,” Arianespace said. Ruag, which manufactures the Ariane 5 payload fairings, did not respond to a request for comment about the status of that work.
Arianespace declined to give a schedule for upcoming Ariane 5 launches, saying the only date it was publicizing was for its next mission, a Soyuz vehicle carrying another set of OneWeb satellites scheduled for launch May 27. However, NASA officials said there are two Ariane 5 launches scheduled before the JWST launch, which the agency had been publicizing an Oct. 31 date for.
The first of those two Ariane 5 missions is scheduled to carry the Eutelsat Quantum and Star One D2 satellites for operators Eutelsat and Embratel Star One, respectively. In its latest earnings statement May 11, Eutelsat said the launch of Eutelsat Quantum has slipped from the late second quarter of this year to the third quarter, but did not offer a more specific launch date.
At a May 11 media event about JWST, Greg Robinson, program director for the telescope at NASA Headquarters, confirmed there were two Ariane 5 launches ahead of JWST. “They’re going through the process of getting the rocket ready for the upcoming launch, the first of three,” he said. “Once they launch, we’ll be able to launch in about four months after that.”
That would suggest JWST will miss its Oct. 31 launch date, although perhaps only by weeks. An Ariane 5 launch of Eutelsat Quantum and Star One D2 at the beginning of the third quarter, or early July, would allow for a launch of JWST in early November, four months later.
Unlike planetary missions, JWST does not have to launch in a narrow window. “We have launch windows almost virtually every day,” Bill Ochs, JWST project manager at NASA’s Goddard Space Flight Center, said at the event. “We have multiple, multiple opportunities for launch.”
At an April 27 Space Transportation Association webinar, Steve Jurczyk, at the time NASA acting administrator, also suggested a delay in the JWST launch. “There are two Ariane 5 launches before the JWST launch,” he said. “They’ve slipped to the right a little bit.” He said NASA was closely following both preparations of JWST as well as the status of the Ariane 5 manifest.
The current situation is ironic because, for much of JWST’s development, the Ariane 5 had been considered the least risky aspect of the $8.8 billion space telescope. The vehicle typically launched several times a year, and last suffered a total launch failure in 2002. JWST itself, meanwhile, suffered extensive technical problems that delayed its launch by years and added billions to its cost.
At the May 11 media event, though, project officials said final preparations of the spacecraft are going well, and that it should be ready for shipment to French Guiana by late August, a schedule that would support an Oct. 31 launch.
The margin in that schedule has been gradually diminishing, as expected. “When we ship, the schedule margin will be pretty close to zero, but still on plan,” Robinson said, noting there are no “liens” on the schedule for the remaining work before shipment. “Right now we’re in a really good place.”
“We’re getting pretty close to the goal line,” he added. “We just need to punch it over.”
Quelle: SPACENEWS
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Update: 4.06.2021
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JWST launch slips to November
WASHINGTON — American and European officials acknowledged June 1 that the launch of the James Webb Space Telescope will likely slip from the end of October to at least mid-November because of delays linked to the Ariane 5.
At a European Space Agency briefing about the space telescope, representatives of the agency and Arianespace said they were finalizing reviews to correct a payload fairing problem found on two Ariane 5 launches last year that had grounded the rocket since August. Arianespace described the issue last month as “a less than fully nominal separation of the fairing” on those two launches.
“The origin of the problem has been found. Corrective actions have been taken,” Daniel de Chambure, acting head of Ariane 5 adaptations and future missions at ESA, said. “The qualification review has started, so we should be able to confirm all that within a few days or weeks.”
He did not elaborate on the problem or those corrective actions, beyond stating that the problem took place during separation of the payload fairing. Industry sources said in May that, on the two launches, the separation system imparted vibrations on the payload above acceptable limits, but did not damage the payloads.
The issue is not linked to a modification to the payload fairing required for JWST. Arianespace has been testing new vents on the fairing designed to reduce the pressure differential once the fairing is separated and thus reduce the loads on the spacecraft. “The issue of the modification of the venting system and the fairing anomaly are different,” de Chambure said.
The Ariane 5 is scheduled to make its next launch, the first since the August 2020 launch that had the payload fairing anomaly, in the second half of July, said Beatriz Romero, JWST project manager at Arianespace. That launch will be the first of two commercial Ariane 5 launches before the JWST launch.
At a May 11 media event, Greg Robinson, program director for JWST at NASA Headquarters, said that the JWST launch would take place about four months after the first of the two commercial Ariane 5 launches ahead of it. That would push the launch, currently scheduled for no earlier than Oct. 31, to at least the middle of November.
At the ESA briefing, Thomas Zurbuchen, NASA associate administrator for science, offered a similar schedule. Asked if a mid-November launch was likely, based on 10-week launch processing schedule that begins with JWST’s shipment from California to the launch site in French Guiana in late August, he said that timeframe is “approximately correct.”
“We want to be sure that we launch exactly when we’re ready, not a day earlier,” he said. “That is, when the spacecraft is ready and when the rocket and the fairing and everything is ready.”
Romero said several factors will go into setting a formal launch date, including the readiness of the rocket, the payload and the spaceport. “We are currently consolidating all of that information for the definition of the launch date,” she said. Arianespace has reserved a “launch period” for JWST that begins Oct. 31 and runs through early December.
An independent review commissioned by NASA of JWST in 2018, when technical problems with the telescope triggered another round of delays and cost increases, had recommended that NASA increase the oversight of the Ariane 5 to the same level as the agency does for missions launching on U.S. vehicles. While NASA did enhance its oversight, it fell short of the level recommended by that independent review.
Zurbuchen said that NASA has not had any problems getting information from its European partners on the status of the Ariane 5. “We’ve had all the information that we need. We’ve had in-depth technical discussions with all parties aligned with one goal, and that is to create mission success,” he said.
The briefing was primarily intended to preview the upcoming launch of JWST and the science that the observatory will perform once in space, emphasizing the roles that NASA’s partners, ESA and the Canadian Space Agency, play on the mission. Günther Hasinger, ESA director of science, estimated that Europe’s contributions to JWST, in the form of instruments and the Ariane 5 launch, to be about 700 million euros ($850 million), roughly the same as an ESA “M-class” science mission.
Gilles Leclerc, director general for space exploration at the Canadian Space Agency, said Canada’s contribution of an instrument and fine guidance sensors cost the agency about $200 million Canadian ($165 million) over 20 years. “This is an investment in discoveries of the universe,” he said.
NASA now estimates it will spend $8.8 billion on JWST through the spacecraft’s launch.
Quelle: SN
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Update: 3.07.2021
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Webb passes key launch clearance review
The international James Webb Space Telescope has passed the final mission analysis review for its launch on an Ariane 5 rocket from Europe’s Spaceport in French Guiana.
This major milestone, carried out with Arianespace, the Webb launch service provider, confirms that Ariane 5, the Webb spacecraft and the flight plan are set for launch. It also specifically provides the final confirmation that all aspects of the launch vehicle and spacecraft are fully compatible.
During launch, the spacecraft experiences a range of mechanical forces, vibrations, temperature changes, and electromagnetic radiation. All technical evaluations performed by Arianespace on the mission’s key aspects, including the launch trajectory and payload separation, have shown positive results.
“We are thrilled to have passed this important step towards the launch of Webb and to have received the green light from Arianespace and NASA,” says Peter Rumler, ESA Webb project manager.
Webb will be the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, ESA is providing the observatory’s launch service using the Ariane 5 launch vehicle. Working with partners, ESA was responsible for the development and qualification of Ariane 5 adaptations for the Webb mission and for the procurement of the launch service.
Ariane 5 will deliver the telescope directly into a precision transfer orbit towards its destination, the second Lagrange point (L2). After separation from the launcher, Webb will continue its four-week long journey to L2 alone. L2 is four times farther away than the Moon, 1.5 million km from Earth in the direction away from the Sun.
Mission analysis experts at ESA helped to compute the launch window, a complex issue because it involves ensuring that Webb can be inserted into its target orbit and at the same time the Ariane 5 upper stage will safely escape from Earth.
The telescope will observe the Universe in the near-infrared and mid-infrared – at wavelengths longer than visible light. To do so, it carries a suite of state-of-the-art cameras, spectrographs and coronagraphs.
ESA plays a crucial role in the Webb mission. Aside from procuring the Ariane 5 launcher and launch services, ESA is contributing the NIRSpec instrument and a 50% share of the MIRI instrument, as well as personnel to support mission operations.
Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA). Webb's partners are working towards the launch readiness date of 31 October 2021. The precise launch date following 31 October depends on the spaceport’s launch schedule and will be finalised closer to the launch readiness date.
Quelle: ESA
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Update: 8.07.2021
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JWST passes launch review
WASHINGTON — The James Webb Space Telescope is one step closer to launch after a review of its Ariane launch vehicle, while NASA continues a separate review of the name of the spacecraft itself.
The European Space Agency announced July 1 that it, along with Arianespace, had successfully completed the final mission analysis review for the launch of JWST on an Ariane 5. “All technical evaluations performed by Arianespace on the mission’s key aspects, including the launch trajectory and payload separation, have shown positive results,” ESA said in a statement.
The Ariane 5 that will launch JWST has few changes from the version used for other missions, such as launches of commercial communications satellites. Maurice Te Plate, ESA JWST systems engineer, said at a June 28 session of the annual meeting of the European Astronomical Society that there will be some modifications to the payload fairing, including acoustic protection to lower loads on the satellite during launch and a separation system for the fairing with a low shock load.
The modifications for JWST are largely limited to the fairing. “The rest of the rocket is not so much different from other Arianes,” he said.
Problems with the payload fairing separation system on two Ariane 5 launches last year have effectively grounded the rocket since its last launch in August 2020. Arianespace announced July 1, after a Soyuz launch of OneWeb satellites, that the next Ariane 5 launch is scheduled for July 27.
That upcoming launch, of two commercial satellites, is the first of two Ariane 5 missions before the launch of JWST. While both NASA and ESA are maintaining a formal “launch readiness date” of Oct. 31 for JWST, the schedule of upcoming launches suggests JWST will launch no earlier than the second half of November.
Speaking at a June 30 “meeting of experts” held in place of a formal meeting of NASA’s Astrophysics Advisory Committee, Eric Smith, program scientist for JWST at NASA, declined to give a specific launch date for JWST. “Historically, they have taken about 60 days between launches,” he said. “But we need to wait until the launch provider says this is the current schedule.”
Reviewing JWST’s name
Work on the spacecraft itself is going well, Smith said, as workers prepare to ship it to French Guiana for launch processing. “Things look very good for completing all the work by August to have it ready for shipment,” he said.
One open item has nothing to do with the spacecraft itself, but rather its name. NASA renamed what was originally known as the Next Generation Space Telescope in 2002 after James Webb, who was NASA administrator from 1961 and 1968 and is credited for guiding the agency through the development of the Apollo program while also supporting science missions.
That choice has come under scrutiny in recent years given allegations that Webb, while at NASA and, earlier, the State Department, supported discrimination against LGBTQ people. That includes one case, cited in a recent online petition that has garnered more than 1,200 signatures, of the arrest, interrogation and firing of a NASA employee for being homosexual in 1963, when Webb was administrator.
NASA historians are conducting a review of historical records about Webb and his role in such events, but neither Smith nor Paul Hertz, director of NASA’s astrophysics division, offered many details about the progress of that review at the meeting of experts.
“I wish I could give you a timeline,” Smith said when asked when the review would be completed. Limited access to some historical archives because of closures linked to the pandemic has reportedly slowed that assessment. “I wish I could give you more, but I’ve shared all that I can really share at this point.”
Hertz said at the meeting June 29 that a decision whether to rename JWST would be made “at the highest levels of the agency” given the mission’s high profile. “When we make that decision, we must be transparent with the community and the public about our rationale.”
He added that there was no specific timeline for that decision but suggested it might take some time given the changeover in agency leadership. “There are a lot of people who are new to this discussion, so it might be soon, but it might be not quite as soon.”
Quelle: SN
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Update: 16.07.2021
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James Webb Space Telescope Testing Progress Continues
Engineers have made considerable progress in checking off NASA’s James Webb Space Telescope’s final series of tests. Three big milestones have recently been completed, bringing the world’s most complex and powerful space science telescope ever built much closer to being fully prepared for its million-mile journey to orbit. These three testing milestones are outlined below:
Deployable Tower Assembly Testing: Completed
This telescoping tower helps Webb maintain its necessary super cool operating temperatures by separating its mirrors and instruments from the comparatively warmer Sun-facing side and spacecraft bus. When fully deployed, the tower reaches ten feet in length, which also gives the observatory’s sunshield just enough room to unfold its complex mechanisms. Recently this tower was fully extended for the very last time in testing, just as it would once in space. Testing teams then lowered the tower and locked it into place to prepare for launch later this year. The next time this tower will deploy will be when Webb is in space.
AOS (Aft Optics Subsystem) Cover: Removed
Webb’s “lens cap” has been removed! A technician can be seen carefully removing what’s known as Webb’s aft optics subsystem cover. This important piece of protective equipment has kept the observatory’s instruments clean, contaminant-free, and safe from stray light while it was assembled and fully prepared for flight. Now that launch is so close, the cover has been removed to allow engineers freedom to continue packing up the rest of the observatory into its flight-like formation.
Unitized Pallet Structure: Stowed for Launch
Webb’s tennis court-sized sunshield folds up perfectly to rest on what is known as a unitized pallet structure. These long support structures are part of the observatory’s complex folding mechanism that allows it to just barely fit inside an Ariane 5 rocket for launch. Now that Webb’s lens cap has been removed, engineers were free to finish the process of folding the pallets upward into their final configuration for launch. In the accompanying picture, Webb’s pallet structures can be seen partially lifted, but they have since been fully raised and locked in place for launch later this year.
The testing was conducted in a clean room at Northrop Grumman in Redondo Beach, California.
The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
Header caption: Here, Ball Aerospace technician Larkin Carey can be seen carefully removing Webb’s "lens cap" from the Aft Optics Subsystem which has kept the observatory’s sensitive instruments clean, contaminant-free, and protected from stray light throughout the integration and test process. Image credit: NASA/Chris Gunn
Quelle: NASA
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Update: 26.08.2021
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NASA’s James Webb Space Telescope Has Completed Testing
After successful completion of its final tests, NASA’s James Webb Space Telescope is being prepped for shipment to its launch site.
Engineering teams have completed Webb’s long-spanning comprehensive testing regimen at Northrop Grumman’s facilities. Webb’s many tests and checkpoints were designed to ensure that the world’s most complex space science observatory will operate as designed once in space.
Now that observatory testing has concluded, shipment operations have begun. This includes all the necessary steps to prepare Webb for a safe journey through the Panama Canal to its launch location in Kourou, French Guiana, on the northeastern coast of South America. Since no more large-scale testing is required, Webb’s clean room technicians have shifted their focus from demonstrating it can survive the harsh conditions of launch and work in orbit, to making sure it will safely arrive at the launch pad. Webb’s contamination control technicians, transport engineers, and logistics task forces are all expertly prepared to handle the unique task of getting Webb to the launch site. Shipping preparations will be completed in September.
Webb Will Soon Be on its Way
“NASA's James Webb Space Telescope has reached a major turning point on its path toward launch with the completion of final observatory integration and testing,” said Gregory L. Robinson, Webb's program director at NASA Headquarters in Washington. “We have a tremendously dedicated workforce who brought us to the finish line, and we are very excited to see that Webb is ready for launch and will soon be on that science journey.”
While shipment operations are underway, teams located in Webb’s Mission Operations Center (MOC) at the Space Telescope Science Institute (STScI) in Baltimore will continue to check and recheck the complex communications network it will use in space. Recently this network fully demonstrated that it is capable of seamlessly sending commands to the spacecraft. Live launch rehearsals are underway within the MOC with the explicit purpose of preparing for launch day and beyond. There is much to be done before launch, but with integration and testing formally concluded, NASA’s next giant leap into the cosmic unknown will soon be underway.
Once Webb arrives in French Guiana, launch processing teams will configure the observatory for flight. This involves post-shipment checkouts to ensure the observatory hasn’t been damaged during transport, carefully loading the spacecraft’s propellant tanks with hydrazine fuel and nitrogen tetroxide oxidizer it will need to power its rocket thrusters to maintain its orbit, and detaching ‘remove before flight’ red-tag items like protective covers that keep important components safe during assembly, testing, and transport. Then engineering teams will mate the observatory to its launch vehicle, an Ariane 5 rocket provided by ESA (European Space Agency), before it rolls out to the launch pad. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
The James Webb Space Telescope is an amazing feat of human ingenuity, made more impressive by the obstacles Webb personnel overcame to deliver this amazing space science observatory. Earthquakes, a devastating hurricane, snowstorms, blizzards, wildfires, and a global pandemic are only some of what the people behind Webb endured to ensure success. Webb’s story is one of perseverance – a mission with contributions from thousands of scientists, engineers, and other professionals from more than 14 countries and 29 states, in nine different time zones.
“To me, launching Webb will be a significant life event – I’ll be elated of course when this is successful, but it will also be a time of deep personal introspection. Twenty years of my life will all come down to that moment,” said Mark Voyton, Webb observatory integration and test manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “We’ve come a long way and worked through so much together to prepare our observatory for flight. The telescope’s journey is only just beginning, but for those of us on the ground who built it, our time will soon come to an end, and we will have our opportunity to rest, knowing we put everything on the line to make sure our observatory works. The bonds we formed with each other along the way will last far into the future.”
Opening NASA’s New Eye on the Cosmos
After launch, Webb will undergo an action-packed six-month commissioning period. Moments after completing a 26-minute ride aboard the Ariane 5 launch vehicle, the spacecraft will separate from the rocket and its solar array will deploy automatically. After that, all subsequent deployments over the next few weeks will be initiated from ground control located at STScI.
Webb will take one month to fly to its intended orbital location in space nearly one million miles away from Earth, slowly unfolding as it goes. Sunshield deployments will begin a few days after launch, and each step can be controlled expertly from the ground, giving Webb’s launch full control to circumnavigate any unforeseen issues with deployment.
Once the sunshield starts to deploy, the telescope and instruments will enter shade and start to cool over time. Over the ensuing weeks, the mission team will closely monitor the observatory’s cooldown, managing it with heaters to control stresses on instruments and structures. In the meantime, the secondary mirror tripod will unfold, the primary mirror will unfold, Webb’s instruments will slowly power up, and thruster firings will insert the observatory into a prescribed orbit.
Once the observatory has cooled down and stabilized at its frigid operating temperature, several months of alignments to its optics and calibrations of its scientific instruments will occur. Scientific operations are expected to commence approximately six months after launch.
‘Flagship’ missions like Webb are generational projects. Webb was built on both the legacy and the lessons of missions before it, such as the Hubble and Spitzer space telescopes, and it will in turn provide the foundation upon which future large astronomical space observatories may one day be developed.
“After completing the final steps of the James Webb Space Telescope’s testing regimen, I can’t help but see the reflections of the thousands of individuals who have dedicated so much of their lives to Webb, every time I look at that beautiful gold mirror,” said Bill Ochs, Webb project manager for NASA Goddard.
The James Webb Space Telescope will be the world's premier space science observatory when it launches in 2021. Webb will solve mysteries in our solar system, look beyond to distant worlds around other stars, and probe the mysterious structures and origins of our universe and our place in it.
Quelle: NASA