The James Webb Space Telescope has traveled to the second Lagrange point for 3 days, but it is about to perform its most dangerous operation yet.
The telescope will begin to extend its primary & secondary mirrors, as well as its incredibly delicate sun-shield, in “reverse origami” over the next 2 weeks, according to The Verge. Deployment is extremely risky for a variety of reasons, the most important of which is that no one has ever attempted something like this in space before.
“Sometimes we call Webb the ‘transforming telescope,'” Amy Lo, James Webb space telescope alignment engineer at Northrop Grumman, the telescope’s main contractor, told The Verge this week. And that’s an apt description.
The size of the telescope – its primary mirror is 21.5 feet tall & its sun shield is about size of a tennis court – meant it couldn’t be sent into space fully deployed.
In order to fit on top of Ariane 5 rocket, which sent it into space on Christmas Day, it had to be carefully folded up & designed with hundreds of additional mechanisms that could un-fold the telescope into a functional form once it was launched into space. .
This transformation is now underway & will require a lot of mechanical operations to be successful, & failure in any one could be fatal for the entire mission. When people talk about 344 single points of failure on Webb, almost all of them will be attempted within the next 2 weeks.
Webb has traveled beyond the Moon’s average altitude, so it’s beyond our reach. If something goes wrong, there is no way to go there & fix it so that it can continue its mission.
“In fact, I strongly believe that its not possible to-make-it simple within the constraints that we have,” Thomas Zurbuchen, associate administrator of the NASA Science Mission Directorate, told The Verge. “It is what it is.
The un-folding procedure has been tested repeatedly on Earth to make sure everything works properly & NASA has some contingencies in case something breaks up there.
But these fixes are limited, and for most of deployment sequence, each ex-tended beam, pulley, winch, & gear will need to perform exactly as designed for the deployment to be successful.
Otherwise, Webb will be a useless $10 billion human artifact adrift in space. If all goes as planned, however, telescope will be ready to observe distant cosmos with its massive primary mirror.
Webb’s iconic golden honeycomb shaped primary mirror has a light collecting area 6.25 times that of Hubble telescope & uses infrared sensors that can see the earliest galaxies & stars that formed in the early universe.
the next two weeks will have a lot of people struggling. But nothing worth doing is easy, & reward for successful Webb Telescope deployment will be worth both the wait & all of our current anxiety.