“30 days of terror”: The James Webb telescope’s troubles are just getting started - Inverse
The bumps on the long and winding road keep coming for NASA’s flagship James Webb Space Telescope mission.“This telescope is not designed to be a serviceable mission,” Heidi Hammel, an interdisciplinary scientist on the James Webb Space Telescope project, tells Inverse.It’s not just the rocket launch, which Hammel admits is always a little nerve-wracking, “We’re putting this precious telescope that we’ve been building for 20 years now on top of a big, giant rocket and lighting the fuse.”.
The bigger the primary mirror, the more powerful the telescope: One reason scientists are excited about the Webb is that its primary mirror is 21-feet in diameter, compared to Hubble’s seven feet.So the Webb primary mirror is built of 18 segments, each of which can be individually adjusted, and which are divided into two foldable wings and a central section to make for a compact launch configuration.
The tennis court-size sunshade assembly also rolls up and folds for launch — but must unfold in just the right manner once the telescope is aloft.
Folded up for launch like space telescope origami, “there are cables and wires and pulleys and little actuators that pop so that things open,” Hammel says.
All of those things must go off without a hitch while the telescope speeds away to a point a million miles from Earth, a month-long journey you might call the 30 Days of Terror, though NASA, Hammel says, prefers the more palatable “30 Days on the Edge.”.Beginning during its third day in space and continuing over the next week, the Webb will slowly deploy its layers of sunshade and begin positioning the tower structure that supports the segmented primary mirror.A NASA animation showing all of the steps the James Webb Space Telescope must take to successfully deploy its components during its 30 day journey Lagrangian point 2.It’s not just that the telescope will be inaccessible once in operation; it’s beyond human reach once it leaves the launch pad.
A lot of other things could go wrong, she says, like the wings of the primary mirror failing to swing into position, and the telescope could still work, if not at full capacity?“If we don’t fire the rockets to get into the L2 orbit, and we miss that, it just kind of goes out forever into the cosmos,” Hammel says, which would certainly be suboptimal.“Then we have to go to the next phase, which is the multi-instrument alignment phase,” Hammel says, another week of careful work more finely aligning each mirror segment to ensure images are focused for all four instruments on the Webb.As someone who has been on the Webb project since 2002, waiting five months to start the science doesn’t bother Hammel anymore than waiting five days to launch