25.01.2022
New space telescope reaches final stop million miles out
The world's biggest and most powerful space telescope has reached its final destination 1 million miles away
CAPE CANAVERAL, Fla. -- The world’s biggest, most powerful space telescope arrived at its observation post 1 million miles from Earth on Monday, a month after it lifted off on a quest to behold the dawn of the universe.
On command, the James Webb Space Telescope fired its rocket thrusters for nearly five minutes to go into orbit around the sun at its designated location, and NASA confirmed the operation went as planned.
The mirrors on the $10 billion observatory still must be meticulously aligned, the infrared detectors sufficiently chilled and the scientific instruments calibrated before observations can begin in June.
But flight controllers in Baltimore were euphoric after chalking up another success.
"We’re one step closer to uncovering the mysteries of the universe. And I can’t wait to see Webb’s first new views of the universe this summer!” NASA Administrator Bill Nelson said in a statement.
The telescope will enable astronomers to peer back further in time than ever before, all the way back to when the first stars and galaxies were forming 13.7 billion years ago. That's a mere 100 million years from the Big Bang, when the universe was created.
Besides making stellar observations, Webb will scan the atmospheres of alien worlds for possible signs of life.
“Webb is officially on station," said Keith Parrish, a manager on the project. “This is just capping off just a remarkable 30 days."
The telescope was launched from French Guiana on Christmas. A week and a half later, a sunshield as big as a tennis court stretched open on the telescope. The instrument's gold-coated primary mirror — 21 feet (6.5 meters) across — unfolded a few days later.
The primary mirror has 18 hexagonal segments, each the size of a coffee table, that will have to be painstakingly aligned so that they see as one — a task that will take three months.
“We’re a month in and the baby hasn’t even opened its eyes yet,” Jane Rigby, the operations project scientist, said of the telescope's infrared instruments. "But that's the science that we’re looking forward to.”
Monday's thruster firing put the telescope in orbit around the sun at the so-called second Lagrange point, where the gravitational forces of the sun and Earth balance each other. The 7-ton spacecraft will loop-de-loop around that point while also circling the sun. It will always face Earth’s night side to keep its infrared detectors as frigid as possible.
At 1 million miles (1.6 million kilometers) away, Webb is more than four times as distant as the moon.
The Webb is expected to operate for well over a decade, maybe two.
Considered the successor to the Hubble Space Telescope, which orbits 330 miles (530 kilometers) up, Webb is too far away for emergency repairs. That makes the milestones over the past month — and the ones ahead — all the more critical.
Spacewalking astronauts performed surgery five times on Hubble. The first operation, in 1993, corrected the telescope's blurry vision, a flaw introduced during the mirror's construction on the ground.
Whether chasing optical and ultraviolet light like Hubble or infrared light like Webb, telescopes can see farther and more clearly when operating above Earth's distorting atmosphere. That's why NASA teamed up with the European and Canadian space agencies to get Webb and its mirror — the largest ever launched — into the cosmos.
Quelle: abcNews
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James Webb telescope parked in observing position
Thirty days after it was launched, the James Webb telescope has arrived at the position in space where it will observe the Universe.
The Lagrange Point 2, as it's known, is a million miles (1.5 million km) from Earth on its nightside.
Webb was finally nudged into an orbit around this location thanks to a short, five-minute thruster burn.
Controllers back on Earth will now spend the coming months tuning the telescope to get it ready for science.
Key tasks include switching on the observatory's four instruments, and also focusing its mirrors - in particular, its 6.5m-wide segmented primary reflector.
"There's a pretty intensive effort to take all of those 18 segments from their current state and get them to act as one big mirror, and also to get the secondary mirror into its optimised condition," explained Charlie Atkinson, the chief engineer on Webb at Northrop Grumman, the American aerospace company that co-led the telescope's development with the US space agency (Nasa).
"We do this using the science images, which is why we need to get the science instruments activated and checked out with some initial calibration work," he told BBC News.
Webb, billed as the successor to the famous Hubble Space Telescope, was launched on 25 December by an Ariane-5 rocket from French Guiana.
Its overarching goals are to take pictures of the very first stars to shine in the Universe and to probe far-off planets to see if they might be habitable.
Europe's Ariane-5 gave the new observatory a near-perfect trajectory and velocity to get it out to L2. Even so, two course correction burns were necessary, with the third on Monday tipping Webb into its planned parking position.
The Lagrange Point 2 is one of five gravitational "sweet-spots" around the Sun and Earth where satellites can hold their position with few orbital adjustments, thus conserving fuel.
The other advantage is that Webb will not experience at L2 the big swings in temperature and light endured by space telescopes positioned much closer to Earth.
This is vital for the mission. It's designed to view the cosmos in infrared light and must maintain therefore constant super-cold conditions for its hardware.
Infrared light has waves that are just longer than those of visible light. "Seeing" in the infrared will allow the telescope to, for example, look through dust to image stars that would otherwise be obscured.
IMAGE SOURCE, NORTHROP GRUMMANWebb will now circle L2, keeping the Earth and the Sun in a near-straight line.
"L2 is pseudo-stable," said Jean-Paul Pinaud, who leads the Northrop engineers that keep Webb on track.
"The flight operations team is preparing routine station-keeping burns. They'll be doing those every 20 days or so with the trajectory calculations provided by our flight dynamics team. We'll set them up in a similar way, and then fire the thruster. But the burns will be quite small."
Hidden behind a big sunshield, Webb's optics and instruments will soon cool to about -230C (some sections of the telescope are already there). When that happens, controllers will switch on Webb's Near Infrared Camera (NIRCam) to take a picture of a test star to begin the process of aligning the big mirror.
"We know when we first focus on a star in space, we'll actually see 18 different spots of light because the 18 individual mirror segments won't be aligned," said Nasa instrument systems engineer Begoña Vila.
"But we'll adjust the mirrors to bring all the spots together to make a single star that's not aberrated and good for normal operations.
"It's a long process. It can take up to three months during commissioning, and we are ready to do that," she told BBC News.
Focusing involves driving small actuators, or motors, on the back of the 18 segments of the primary mirror to harmonise their curvature. The current misalignment, which is measured in millimetres, will be brought down to one measured in nanometres - a factor of a million improvement.
Similar adjustments will be applied to the 74cm-diameter secondary reflector which sits out in front of the primary mirror and is used to bounce light back towards the instruments.
IMAGE SOURCE, ARIANESPACESo far, the Webb mission has not put a step wrong. The launch and journey out to L2 passed off without incident.
And even the complex business of unfolding the telescope after it came off the top of the Ariane rocket was made to look like the easiest of rehearsals.
"We were thrilled with the precision and success of all those deployments," said Kyle Hott, the mission systems engineering lead at Northrop.
"It's pretty incredible to think that it was all just a concept on paper decades ago, and now it's actually here, arriving at L2. Morale is high and we're so very excited."
Quelle: BBC
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NASA's James Webb Space Telescope reaches new home a million miles from Earth
After a nail-biting 29 days of travel and ultra-precise deployments, the James Webb Space Telescope fired its thrusters one more time Monday to reach its final parking spot a million miles from Earth.
"Webb, welcome home," NASA Administrator Bill Nelson said in a statement after a five-minute burn added just 3.6 mph to the telescope's speed. "Congratulations to the team for all of their hard work ensuring Webb’s safe arrival at L2 today."
L2 refers to a kind of stable orbit known as a Lagrange point. Technically, Webb is now orbiting the sun and is staying in line with Earth about a million miles away.
"We’re one step closer to uncovering the mysteries of the universe. And I can’t wait to see Webb’s first new views of the universe this summer," Nelson said.
The arrival at L2 capped off a treacherous 29 days in which everyone involved in the $10 billion program — from scientists to NASA officials to companies involved in building the infrared telescope — readily admitted the technical challenges were daunting. Every single thing had to work perfectly in order to launch, deploy mirror segments, and reach its final position.
Mission partners NASA, the European Space Agency, and Canadian Space Agency described the process as "29 days on the edge." Officials before launch said there were potentially 344 points of failure during that period.
Moving forward, engineers will spend about three months aligning Webb's 18 gold-coated hexagonal mirrors to the final configuration.
Webb uses a massive, 21-foot primary mirror made up hexagonal tiles to study the cosmos. Its main capability is infrared observation, meaning it will be able to peer through obstacles like dust clouds to see the early phases of star formation. Scientists even hope to see the atmospheric compositions of promising far-off planets.
Webb is the successor to Hubble Space Telescope, which revolutionized science with the Hubble Deep Field that famously captured thousands of galaxies in a single image.
Total cost to NASA: $10 billion over its 25-year development history, which doesn't include costs incurred by ESA and CSA. Northrop Grumman was the prime contractor for the project while Lockheed Martin built the main infrared instrument known as Near Infrared Camera, or NIRCam.
The telescope took flight on Christmas Day with help from a European Ariane 5 rocket. The European Space Agency operates the liftoff site in French Guiana, a territory of France just north of Brazil.
Quelle: Florida Today
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THE JAMES WEBB SPACE TELESCOPE HAS ARRIVED AT ITS DESTINATION
Fully deployed, the James Webb Space Telescope arrived at its new home today, in a halo orbit around the Earth-Sun L2Lagrange point.
NASA’s newest space telescope has arrived at its new home in space. On Monday January 24th at 2:00 p.m. EST (19:00 UT), the James Webb Space Telescope (JWST) fired its thrusters for five minutes, putting it into the start of a halo (Lissajous) orbit around the Sun-Earth (L2) Lagrange point 1.5 million km (almost a million miles) beyond Earth's orbit. Engineers reported that the telescope is in good health.
“Webb, welcome home!” said Bill Nelson (NASA-Administrator) in a recent press release. “Congratulations to the team for all of their hard work ensuring Webb’s safe arrival at L2 today. We’re one step closer to uncovering the mysteries of the universe.”
They're not the only ones rejoicing. Amateurs and ground-based telescopes tracked JWST all the way to its destination:
THE PATH SO FAR
Launched on Christmas Day 2021 from the Guiana Space Center, JWST took just over 29 days to transit from Earth to L2. The Ariane 5 rocket launch was so accurate that less fuel than anticipated was required for the two planned mid-course correction burns. In fact, the rocket deliberately underpowered the launch by a small amount, so the observatory would not overshoot its target. (If it did, it would have had to rotate sunward to "put on the brakes," wasting precious fuel and exposing the optics to the Sun.) With the course correction burns complete, team engineers now estimate that JWST will have enough fuel to last well past its 10-year planned extended mission.
Fitting the 6.5-meter mirror observatory in the Ariane 5 rocket fairing necessitated the design of a telescope that could fold up in a stowed-away configuration for launch, then unfold once it was in space.
Along the way to L2, the observatory unfurled and tensioned its sunshield, unfolded its primary and secondary mirrors, and performed small correction burns, as controllers learned just how the telescope and components would react to the cold vacuum of space.
The controllers also issued the commands for 132 actuators on the primary and secondary mirrors to drive 18 mirror segments out of their stowed launch position for initial individual focusing and adjustment. They didn't move far — the primary segments moved only 12.5 millimeters. An additional 18 "radius of curvature" actuators drove out of their stowed launch position as well. These will bend the segments of the primary to give the parabolic mirror its initial curvature.
WELCOME TO L2
As an infrared telescope, the joint Canadian Space Agency/European Space Agency/NASA observatory must stay at a super-cold 40 kelvin (-233°C/-387°F) for scientific observations. The gigantic sunshield is crucial to keeping the observatory cold, as is the telescope's orbit: a a halo orbit around L2.
At L2, JWST will orbit the Sun in time with Earth, but 1.5 million km in the opposite direction from the Sun. This is the perfect location for an infrared space telescope, as it can stay permanently oriented away from the heat signatures of both the Sun and Earth.
“If Webb was exactly at L2, then it would be difficult to transmit data back to Earth, because there would be interference from the Sun,” says Heidi Hammel (NASA/GSFC). “This orbit also keeps the telescope out of the shadow of the Moon, as well as the Earth. Finally, this ‘halo orbit’ requires the least amount of fuel for ‘station-keeping’ (keeping the telescope in orbit there at L2).”
The potato chip-shaped orbit at L2 is meta-stable, meaning it has a saddle-shape gravity gradient similar to the balancing point on a ridge. Therefore, the telescope needs to use its thrusters for small station-keeping corrections once every three weeks to keep it in a six-month, 232,000 mile (374,000 km) wide orbit around L2.
WHAT'S NEXT FOR JWST
The telescope’s optics now need to reach their wavefront configuration, as the mirrors are moved in nanometer and micron increments to achieve alignment.
“The next major activity for Webb is the alignment of the primary mirror segments, so that they work together as one mirror,” says Hammel. “This long, complex process will likely take a few months. Throughout that time, the instruments (cameras and spectrographs) will continue to cool. After the optical alignment is complete, then the final commissioning of the instruments takes place.”
Expect to see the first light for James Webb around L+36 days (early February), with an initial calibration mosaic. It won't be pretty — yet. Further alignment will result in improved images, and we can expect the first science observations by this summer.
And you thought that collimating your Newtonian for a night’s worth of driveway observing was hard. Still, the deployment of JWST has gone by the numbers thus far. Now, it's time to get down callibration and commissioning in preparation for the ground-breaking science that JWST is set to deliver.
Quelle: Sky&Telescope
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Webb has arrived at L2
Today, at 20:00 CET, the James Webb Space Telescope fired its onboard thrusters for nearly five minutes (297 seconds) to complete the final post launch course correction to Webb’s trajectory. This mid-course correction burn inserted Webb toward its final orbit around the second Sun-Earth Lagrange point, or L2, nearly 1.5 million kilometres away from Earth.
The final mid-course burn added only about 1.6 metres per second – a mere walking pace – to Webb’s speed, which was all that was needed to send it to its preferred “halo” orbit around the L2 point.
Webb’s orbit will allow it a wide view of the cosmos at any given moment, as well as the opportunity for its telescope optics and scientific instruments to get cold enough to function and perform optimal science. Webb has used as little propellant as possible for course corrections while it travels out to the realm of L2, to leave as much remaining propellant as possible for Webb’s ordinary operations over its lifetime: station-keeping (small adjustments to keep Webb in its desired orbit) and momentum unloading (to counteract the effects of solar radiation pressure on the huge sunshield).
Now that Webb’s primary mirror segments and secondary mirror have been deployed from their launch positions, engineers will begin the sophisticated three-month process of aligning the telescope’s optics to nearly nanometre precision.
Webb is the largest, most powerful telescope ever launched into space. As part of an international collaboration agreement, ESA has provided the telescope’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 by Arianespace. ESA has also provided the workhorse spectrograph NIRSpec and 50% of the mid-infrared instrument MIRI, in collaboration with the University of Arizona. Webb is an international partnership between NASA, ESA and the Canadian Space Agency (CSA).
Quelle: ESA
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Update: 31.01.2022
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How NASA's James Webb Space Telescope will get ready for its first cosmic observations
Webb's instruments are being switched on as the telescope continues its commissioning.
With NASA's newest space observatory exactly on schedule in its commissioning phase, the science team outlined their plan to make the most of this $10 billion opportunity.
The James Webb Space Telescope arrived days ago at its destination at the Earth-sun Lagrange Point 2 (L2), which is about 930,000 miles (1.5 million kilometers) away from our planet.
The principal investigators of the Webb science team outlined their plan in a town hall Friday (Jan. 28) hosted online by the Space Telescope Science Institute (STScI) in Baltimore.
The town hall took place as engineers continued to work on getting the observatory up and running. A key milestone, turning on its science instruments, happened this week. Technicians also continue to align the mirrors and otherwise ready the observatory through five more months of commissioning.
Jonathan Gardner, Webb deputy senior project scientist at NASA Goddard Space Flight Center in Greenbelt, Maryland, walked through the last few months of preparations before giving a brief update on how things are going in orbit. In a few words, everything is going to plan, he noted.
"There were 50 major deployments; they have all been successful," he said of the telescope's mirror unfolding, as an example of the major milestones Webb achieved.
Meanwhile, amateurs and professionals alike area already sending back data from backyard observatories and professional locations. For example, he said, people have also been taking "light curves" at places such as the National Science Foundation's Green Bank Telescope.
Webb's brightness changes in a repeatable six-hour cycle as the observatory's solar array reflects a glint of sunlight back towards the Earth, during its regular spin, Gardner said. "The sunshield reflects the sunlight directly at the Earth, and [sometimes] has a glint and at other times, it's more diffuse light," Gardner said.
Commissioning is still going to take several more months, said Mike McElwain, Webb observatory project scientist at Goddard.
"We'll be aligning the telescope; that's about a three month process that we're planning to begin early next week," he said, noting that optical performance of the telescope will be assessed to (among other things) determine the amount of stray light being produced by the optics.
Optical commissioning will include several complex steps — sometimes sequentially and sometimes iteratively — such as identification of images, aligning different mirror segments, and eventually phasing the segments to within a fraction of a wavelength, McElwain noted.
To guide mirror alignment, the Webb team will focus each of the 18 primary mirror segments on a bright, distant star called HD 84406, which is part of the constellation Ursa Major ("the Great Bear").
An "additional layer of complexity" during commissioning, McElwain noted, is that the telescope's performance will change as it continues to cool. Eventually Webb's operating temperature will be about 45 Kelvin or degrees above absolute zero, which is equal to minus 379 degrees Fahrenheit (minus 228 degrees Celsius), but commissioning is ongoing as the telescope changes temperature.
Webb will always have a slight "jitter," though, due to expected reaction wheel and cryocooler vibrations. The telescope will drift very slightly over time, too, due to solar heating on the observatory. While these disturbances to the telescope are expected to be very tiny, engineers will periodically make adjustments as required, McElwain said.
The team is now getting ready to transition into science operations through commissioning the instruments, an activity that was set to begin last week as the instruments turn on, said Jane Rigby, Webb operations project scientist at Goddard.
The instruments coming alive will kick off, Rigby said, a "two-month intense period where we check out the science instruments and get them ready for science operations."
Commissioning shows that the instruments are able to be calibrated, she noted, but calibration will not complete during the commissioning period. "Each observing mode has specific quantitative criteria for science readiness that say, 'Okay, this looks ready to go,' " Rigby said. "It doesn't mean it is perfect, [but] it means that this looks like it is ready to start science operations."
Full calibration will wait until Cycle 1, the first round of early science, which is expected to take place after the six-month mark of the mission, around June 25. This means the instruments will be fully readied for operations amid this data collection, she said. (A sample of Cycle 1 observations include coronagraphic observations of debris desks around some brighter stars, and a star that has a transiting super-Earth planet.)
Around the same time will come an early release of observations, including the first images. There will be a set of showcase images "designed to be on the front pages of media all around the world," Rigby said. But all the commissioning data will go public at that time, including "the good, the bad, and the ugly." The Webb team has been quiet about exactly which images will be released at this time.
Rigby repeated past estimates suggesting that Webb will have roughly 20 years' worth of fuel on board, but said that estimate will need to be refined as the telescope performs periodic thruster firings to "dump momentum" from torque induced on the observatory from the solar wind.
"That angular momentum is taken up by the reaction wheels, but then we have to spin those reaction wheels down by by firing the thrusters," Rigby said, estimating this activity will take place every three weeks. But the limiting lifetime problem on Webb, she added, will likely be the health of the instruments rather than its fuel.
Normal science operations for Webb are already in the works, said Klaus Pontoppidan, Webb project scientist at STScI.
The "Cycle 1" proposals for early science, available on the STScI website, are already approved and scheduled, he said. Everything is in a long-range schedule and then every 10 days or so, the team draws up a shorter-range schedule that attempts to be flexible for unplanned events such as "targets of opportunity," meaning short-term phenomena in the sky like comets or supernovas.
"Cycle 2" proposals for operational science will likely be due in January 2023, assuming that the schedule continues to go to plan. An exact proposal submission date will be determined as commissioning proceeds, he said.
A comparison of the light collecting areas of the Hubble Space Telescope (left) and the James Webb Space Telescope. (Image credit: NASA's Goddard Space Flight Center)
Webb will likely be highly oversubscribed for telescope time given its ambitious science agenda, which goes from learning about the early universe to studying celestial objects.
The question-and-answer session included queries about increasing the amount of Webb's observing budget, any efforts to increase equity, diversity and inclusion in science proposals, and a previous proposal to rename the telescope.
Officials including Webb program scientist Eric Smith (at NASA Headquarters) encouraged participants in the community to continue raising such questions to the team to adjust future science cycle proposals.
In the case of Webb's renaming, though, that decision came down to NASA's senior team and the telescope team is focusing on the telescope's commissioning, he said.
Quelle: SC
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Update: 4.02.2022
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James Webb Space Telescope marks ‘exciting period’ in space exploration, U of A space historian says
The James Webb Space Telescope will be the subject of Robert Smith's upcoming book, which he expects to release late next year.
A University of Alberta historian has been documenting every phase of the James Webb Space Telescope for 22 years, and continues to follow it now that the the spacecraft has reached its final destination in space.
Robert Smith, professor of history in the department of history, classics, and religion, has spent the past four decades chronicling the development of NASA’s Hubble Space Telescope and James Webb Space Telescope. The James Webb Space Telescope, which has now reached its final destination in space, will be the subject of Smith’s upcoming book — which he expects to release late next year.
Smith’s book will cover the making of the telescope, along with early scientific results collected from the spacecraft.
“With the James Webb Space Telescope, I started following the telescope in about 2002 when serious work [on it] began,” Smith said. “With any luck, in a few months time there will be scientific results secured from the James Webb Space Telescope… so one of the major themes for the latter section of the book will be how scientific observations that have actually been made matched up with what people have expected [the telescope] to be doing.”
This book is likely his last on a space telescope, due to the sizeable scale of such projects.
Smith has been documenting space history for the majority of his career. After completing the equivalency of a master’s degree in applied mathematics and theoretical physics, the history of science sparked his interest.
“At that point, I switched and I worked on really the history of astronomy in the early 20th century,” he explained. “‘Are there other galaxies in space besides our Milky Way galaxy’ and ‘is the universe expanding’ were the types of subjects of my PhD dissertation. From there I got interested in the development of telescopes.”
This lead Smith to working at the National Air and Space Museum in Washington, D.C. for 15 years, where he was involved in the Space Telescope History Project. This project introduced him working with space telescopes.
“I became fascinated with these kinds of very large-scale projects involving interactions between science, technology, politics, and trying to establish how a project in somebody’s head actually moves forward and leads to an operating telescope or operating observatory,” he said.
“So my route into space came via the astronomy and the tools that astronomers were developing to pursue astronomy. And because you can do a lot of fun space [research] with telescopes… I became extremely interested in space telescopes.”
Smith described the work being done with the James Webb Space Telescope as an exciting period for space exploration.
“It is an exciting period, because one of the lessons of the history of astronomy is when a big new telescope is built, [a telescope that] is more powerful in certain ways than any telescope that has been built before, new things are found,” Smith said. “So you can have what is called the conscious expectation of the unexpected — you don’t know what you’re going to find necessarily, but you expect to find new stuff.”
For students interested in space history and exploration Smith recommended checking out the courses he is teaching at the U of A, and taking advantage of the historical literature currently available on the subject.
“There’s a lot of really interesting books that are available that people can read — when I started off in the 1980s there was much less solid historical literature available than is the case now,” he said. “So if anybody is interested, they’re welcome to send me an email; I can write back with some suggestions of further reading that they might like to pursue if they want to get themselves up to speed.”
Quelle: University of Alberta
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Update: 8.02.2022
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NASA's James Webb Space Telescope is cooling down for its next trick: Observing the universe
The telescope's chief scientist discussed its nearly 40 days in space so far.
It's been a whirlwind 38 days in space for the James Webb Space Telescope, but its chief scientist says the mission is well on track to uncover the universe soon.
"The telescope is cold ... the instruments are cooling," John Mather, a Nobel laureate and astrophysicist who also works at NASA's Goddard Space Flight Center in Greenbelt, Maryland, said during a livestreamed Explore Mars event Thursday (Feb. 3).
Webb needs to be very cold for its infrared instruments to pick up subtleties in galaxies, exoplanets and other objects it is examining, and Mather said individual photons (particles of light) are starting to register in the telescope's detectors. "No images to show you yet," he said, "but it will be soon, I hope."
Mather told participants about the epic journey Webb has taken so far to a distant location known as Lagrange Point L2, which balances out several gravitational forces to allow the telescope to orbit a point in space with a minimum of fuel.
In about five more months, Webb will begin an ambitious science program covering all aspects of astrophysics, but it must pass a rigorous commissioning period first, he noted.
Right now, a key activity is aligning the 18 hexagonal elements of the primary mirror. For the time being, they are working as 18 separate telescopes, but will soon need to act as a single mirror looking at the deep universe, Mather explained.
"First, we have to find the images that all of those 18 different hexagons are making then figure out which one is which, and then start sending commands to the little motors that move the viewers around to get them in the right place," he said.
"Then surely, we get them lined up so they do a nice sharp image with a near-infrared camera. Then we have to check that the other three instruments are also in focus."
One of the instruments isn't even turned on yet (the mid-infrared instrument), so the process hasn't started yet. It will be ready about four months after the Dec. 25 launch, while the others should be available two months post-launch. "Then we're ready to start announcing our first results around the summer solstice next year," Mather said.
Mather said the images Webb produces, since they are largely in infrared, will be different than what we are used to with the long-running Hubble Space Telescope that uses different infrared wavelengths, along with visible light.
"We can see into and through the dust clouds using infrared because the infrared will go around the grains instead of bouncing off," Mather explained. So in other words, Webb will be able to peer deep into dust clouds where exoplanets are forming, or to look at the hearts of dust-filled galaxies. "It will still be beautiful pictures, but it'll be different," he noted.
Closer to home, he promised Webb will turn its attention to solar system objects like Mars or Jupiter's moon Europa, which are targets of more robotic exploration in the 2030s and beyond. Webb will also bring some attention to Earth-sized planets orbiting M-dwarf stars, which may be habitable depending on the radiation environment.
n seeking life in distant areas of the universe, Webb will not be able to give definitive answers but can give us some pointers, Mather said during the question and answer period.
"We do not expect to see oxygen with this observatory; it's too hard," he said of looking at Earth-sized planets for signs of life. "We're not looking at the correct wavelength to be able to do it. But we do expect to be seeing presence of water vapor in little planets' atmospheres."
Webb may also be able to assist with dating stars in globular clusters, Mather said in response to another question, that would help us with understanding stellar ages and the evolution of the universe at large. Examples of other forthcoming investigations he pointed to included looking at young solar systems in nebulas or gas clouds, and using supernovas to assess the expansion rate of the universe.
Quelle: SC
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Update: 11.02.2022
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NASA to Discuss Webb Telescope Progress, Mirror Alignment
NASA will hold a media teleconference at 11 a.m. EST on Friday, Feb. 11, to share progress made in the early stages of aligning the James Webb Space Telescope’s mirrors. The agency will livestream audio of the teleconference on its website.
Engineers and scientists will review the first weeks of the months-long alignment process and discuss early imagery that shows how the Webb team has identified starlight through each of telescope’s 18 hexagonal mirror segments. NASA will make this imagery available at 10:30 a.m. before the call on the Webb telescope blog.
Teleconference participants include:
- Lee Feinberg, Webb optical telescope element manager, NASA’s Goddard Space Flight Center in Greenbelt, Maryland
- Marshall Perrin, Webb deputy telescope scientist, Space Telescope Science Institute in Baltimore
- Marcia Rieke, principal investigator for the NIRCam instrument and regents professor of astronomy, University of Arizona in Tucson
To ask questions during the teleconference, media must RSVP no later than two hours prior to the event to Natasha Pinol at: natasha.r.pinol@nasa.gov. NASA’s media accreditation policy is available online.
The Webb team has begun to fine-tune the telescope using images captured by its Near-Infrared Camera (NIRCam). The early engineering imagery produced during this stage in the process, called “segment image identification,” stitches together more than 1,000 images to form 18 unfocused versions of a single star. This serves as the starting point for gradually aligning Webb’s mirror segments into one precise system.
Following the telescope’s alignment over the next several months, the Webb team will then move on to prepare the instruments for science observations and release the mission's first science images and data in the summer.
Webb, an international partnership with ESA (European Space Agency) and the Canadian Space Agency, launched Dec. 25 from Europe’s Spaceport in Kourou, French Guiana. After unfolding into its final form in space and successfully reaching its destination 1 million miles from Earth, the observatory is now in the months-long process of preparing for science operations.
Webb will explore every phase of cosmic history – from within the solar system to the most distant observable galaxies in the early universe, and everything in between. Webb will reveal new and unexpected discoveries and help humanity understand the origins of the universe and our place in it.
NASA has a digital media kit for web as well as image and video galleries online. The public also can follow Webb’s progress via a “Where is Webb?” interactive tracker.
Quelle: NASA
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Quelle: NASA, Twitter