James Webb Space Telescope About to Perform Critical Transformation
The James Webb Space Telescope is three days into its journey to the second Lagrange point but it is about to attempt its most perilous operation yet.
The telescope will begin extending its primary and secondary mirrors, along with its incredibly delicate sunshield, in a "reverse origami" over the next two weeks, according to The Verge. The deployment is very high risk for a number of reasons, the biggest of which is that nobody has attempted something like this before in space.
“We sometimes call Webb the ‘Transformer Telescope,’” Amy Lo, a James Webb Space Telescope alignments engineer at Northrop Grumman, the telescope's primary contractor, told The Verge this week. And it's an apt description.
The size of the telescope—its primary mirror is 21.5 feet tall and its sunshield is about the size of a tennis court—meant that it could not be sent into space fully deployed.
In order to fit on top of the Ariane 5 rocket that sent it into space on Christmas day, it had to be carefully folded up and designed with hundreds of additional mechanisms that could unfold the telescope into a functional form once it had been launched into space.
That transformation is now underway and will require many mechanical operations to succeed, and a failure among any of them could be fatal to the entire mission. When people talk about the 344 single points of failure on Webb, nearly all of them are going to be attempted in the next two weeks.
Webb has already traveled beyond the average altitude of the Moon, so it is effectively out of our reach. If something goes wrong, there is no way to go up there and fix it so it can continue its mission.
"I actually strongly believe it’s not possible to make it simpler within the constraints that we have,” Thomas Zurbuchen, associate administrator for NASA's science mission directorate, told The Verge. “This is what it is."
The unfolding procedure has been repeatedly tested on Earth to ensure that everything will work smoothly, and NASA does have some contingencies in case something does get stuck up there.
But those fixes are limited, and for most of the deployment sequence, every extended beam, pulley, winch, and gear will have to work exactly as designed for the deployment to be successful.
If not, Webb will be a useless, $10 billion human artifact adrift in space. If all goes according to plan, however, the telescope will be ready to observe the distant cosmos with its massive primary mirror.
Webb's iconic golden honeycomb-shaped primary mirror has 6.25 times as much light-collecting surface area as Hubble and uses infrared sensors that are capable of seeing the earliest galaxies and stars to form in the early universe.
Needless to say, the next two weeks will have a lot of people on edge. But nothing worth doing is easy, and the reward for a successful deployment of the Webb telescope will be worth both the wait and all of our current anxiety.
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