James Webb Space Telescope nailing secondary mirror implementation
The James Webb Space Telescope achieved another major milestone today, successfully expanding its secondary mirror as it continues its journey through an unprecedented sequence of deployments en route to destination.
The 2.4-foot (0.74-meter) wide side mirror is mounted on a tripod facing main mirror. Its job is to focus the light captured by the gold-coated main mirror into an opening in the center of the main mirror. Through this slit, light reaches a third mirror, which reflects it to the telescope’s instruments.
The space travel side mirror is placed on top of the main mirror, attached to three 26 feet (8 m) long legs that form its support.
On Wednesday (January 5), operators at Webb’s operations center at the Space Telescope Science Institute in Baltimore released the pins that hold the legs in place during launch. After first doing a very small move to make sure the motors were working properly, they then began the deployment process, in which the pins expand and fall into place within 10 minutes. NASA streamed the exercise live with commentary on its television channel.
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Confirmation that the mirror was in place arrived around 11:30 a.m. EST (1630 GMT). It then took the operators an additional 30 minutes to lock the tripod in place with multiple latches to ensure it would remain stable for the duration of Webb’s at least ten-year scientific mission.
“This is unbelievable. We are now at a point about 600,000 miles away [1 million kilometers] from Earth, and we actually have a telescope, “Bill Ochs, James Webb . Space Telescope project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in an online stream. “So congratulations everyone.”
“Once it’s latched, it’s done and we’ll never go back and tweak this again,” added Webb’s deputy director of operations, Julie van Campen, also of NASA Goddard.
The secondary mirror rollout came just a day after operators completed the most challenging part of Webb’s build sequence – the unfolding and stretching of a telescopic tennis court-sized sunshade.
On Thursday (January 6), the operator will open a radiator on the back of the telescope, designed to remove heat from scientific instruments. They will then move on to assembling the main 21-foot (6.4 m) mirror, which due to its size also has to be folded to launch.
“For the first 12 days after launch, we focused on deploying spacecraft systems such as solar arrays, communications systems and sun visors,” said Van Campen. “Today, we switched gears and switched to telescope optics. And then, in the final part of the run, we’ll shift gears again and focus on that. scientific devices.”
The telescope’s deployment sequence is a source of anxiety with some describing it as nerve-wracking. Webb’s Scientific Objectives, to see the first stars and galaxies form in the universe in the first hundreds of millions of years Big Bang, which required an observatory of unprecedented size and complexity. For this reason, the telescope is so large that no current rocket can launch it without folding it first. Mission Engineers and technology stretched to their limit, which leads to a lot of ingenious technical solutions. Those solutions, which treat self-assembled telescopes in space like a transformer, have never been used in space before. However, the extensive testing program took years to complete.
“It has been extremely productive for the past 12 days,” says Van Campen. “We had moments of excitement and tension as we waited to see how things played out. But it’s going very well and we’re a little ahead of schedule.”
The telescope won’t be ready for science until this summer. It will take more than 100 days for Webb to cool down to an operating temperature of minus 400 degrees Fahrenheit (minus 235 degrees Celsius). Only in such extremely cold conditions can telescopes detect the faintest infrared signals from the most distant stars and galaxies.
Van Campen explains that operators cannot visually monitor deployments because none of the existing camera technology can survive extreme cold behind visor. Electronic interference from cameras can also affect scientific observations. Instead, operators use a computer-based visualization tool to receive telemetry data from the telescope.
The telescope is on its way Earth-sun Lagrange point 2 about 930,000 (1.5 million km) from our planet. At L2, Webb will orbit the sun hidden behind the Earth, held in a stable position by the delicate interplay of the two bodies’ gravity.
The telescope is expected to arrive at its destination by the end of January, fully deployed. The $10 billion mission, the most complex and expensive space observatory ever built, is expected to revolutionize astronomy, providing deeper insights into star and planet formation, the chemistry of exoplanets, and the behavior of comets and asteroids at the outer edges of the Earth. solar system.
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