After 20 years of work, the James Webb Space Telescope is finally in space. NASA and the ESA successfully launched the next-generation observatory on Christmas Day, fulfilling the agency’s commitment to beginning the mission in 2021. While the Ariane 5 rocket performed perfectly, there are still many trials ahead for Webb — hundreds of things have to go right in the coming months to make the telescope fully operational.
The coming month will be stressful for astronomers around the world as Webb deploys more than 40 major systems. And it’s not just about turning things on — Webb has to physically change shape like a Transformer. The final configuration of the Webb telescope will measure about 66 by 44 feet (20 by 14 meters), including the sunshield. However, Webb was loaded aboard a rocket that was only 5.4 meters in diameter. Thus, the observatory was folded up and secured to withstand the extreme forces of launch. If even one thing fails to unfurl correctly, the mission could be in jeopardy.
Some of the most vital deployments have already happened. Shortly after separating from the launch vehicle, Webb deployed its solar panel to supply the observatory with 2 kW of power. The following day, NASA successfully unfolded the main communication array, which has a high-gain antenna that will beam 28.6GB of data to Earth twice per day.
The next major hurdle is the sunshield, which is essential to Webb’s infrared observations. The sunshield will ensure solar radiation doesn’t heat the instruments beyond their operating temperature of -369.7 degrees Fahrenheit (-223 Celsius). That’s also why it’s going way out to the Earth-Sun L2 Lagrange point a million miles away. There, on the far side of the moon, the telescope’s instruments can remain nice and frosty.
Here it is: humanity’s final look at @NASAWebb as it heads into deep space to answer our biggest questions. Alone in the vastness of space, Webb will soon begin an approximately two-week process to deploy its antennas, mirrors, and sunshield. #UnfoldTheUniverse pic.twitter.com/DErMXJhNQd
— NASA (@NASA) December 25, 2021
As Webb gets closer to L2 in the coming weeks, NASA will move on to deploying the secondary and primary mirrors. The secondary mirror (so-called because it’s the second surface light hits as it’s bounced down into the telescope’s instruments) is a single element of beryllium and gold. The primary mirror will be a greater challenge. The Korsch-style mirror consists of 18 hexagonal segments with the same beryllium-gold surface. To fit inside the rocket, NASA had to design the mirror with “wings” to fold down three segments on the left and right sides. Hubble famously had a flaw in its primary mirror, but NASA was able to fix it with a service mission. However, Webb won’t have any service missions — there’s currently no way to reach it with a spacecraft on the far side of the moon.
We may have seen our last glimpse of Webb on Christmas, but the data it sends back could keep astronomers busy far into the future. We should know in about a month if all the major deployments went well. The first images from Webb should appear in about six months.
Now read:
- NASA’s James Webb Space Telescope Will Finally Launch Soon
- NASA Completes Final Test on Webb Telescope’s Winged Mirror
- NASA Pauses Work on James Webb Space Telescope Due to COVID-19 Pandemic
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