Is JWST Finally Ready

The long-delayed James Webb Space Telescope has finally been completed and is undergoing final testing before being made ready for launch in March 2021

Published on 29th Oct, 2019

We haven’t talked about JWST in a while and it’s time for an update. Most of us have long ago given up waiting for this mission to launch, I mean it was supposed to happen in 2007, then 2009 then 2018 and now NASA has said “for sure absolutely positively JWST will launch in March 2021. I promise. Pinky swear and hope to die.” Well it looks like things might actually happen. Maybe. At least they put the thing together. Incredibly, JWST is now costing around the 9 billion dollar mark, a cost comparable to building an aircraft carrier. I’ve already given you my opinions on this, I think ‘whatever, I’d rather have this than another aircraft carrier’, but you’d think when that much money is at stake, the project could move along a little faster. Many of you have understandably pointed out that this looks like just another military contractor gouging the U.S. Taxpayer for all they can and I’m finding it very difficult to defend the way this project has been funded. JWST is being paid via something called a cost-plus contract which means that Northrop Grumman, the main contractor for JWST isn’t on the hook financially for cost overruns and delays. NASA uses these types of contracts whenever there is insufficient experience in building something that would make committing money to the project extremely risky. NASA used cost-plus contracts a lot during the Apollo program where basically nothing existed or built prior for space use so they aren’t anything new. And really, JWST is a lot like Apollo when it comes to new stuff needed to do the science required of it. For example, the onboard near and mid-infrared detectors, sunshield materials, microshutters and wavefront sensing and control all had to be invented and then approved by NASA before they could be included in the telescope. Lightweight cryogenic mirrors, cryogenic detector readout application-specific integrated circuits, cryogenic heat switches, a cryocooler for the mid-infrared instrument, and a large precision cryogenic structure (including the primary mirror backplane materials and design) - ll of this stuff has never before been on any satellite or space hardware ever. The microshutters are particularly amazing and I believe will absolutely spawn technology spinoffs on both Earth and space-based telescopes. Microshutters are tiny doorways the width of a few hairs that will allow scientists to remotely and systematically block out unwanted light and view the most distant stars and galaxies humans have ever seen. The James Webb Space Telescope will be the first to use this technology but they will prove extremely useful in a lot of other optical applications where you need to block out a bright thing to see a dim thing. Still though, I get the impatience and frustration, I feel it too. I think this thing could have been built a lot cheaper if Northrop Grumman had been held at least somewhat accountable for their management of the project but it’s too late for all that now. Here we are in 2019, and it looks like we finally have a completed telescope. So early this week, NASA announced that JWST is assembled and passed a crucial first test for the completed telescope: they successfully deployed the Sun shield for the first time. This is a big deal, maybe the biggest deal because if that thing doesn’t unfurl, JWST is in deep doo doo (that’s actually in the mission vocabulary - deep doo doo, it’s one of the milestones to officially avoid). Anyway, they did the test by simulating the null gravity of space by attaching special pulleys that compensated for the pull of Earth’s gravity. It doesn’t do any good to try to unfurl this thing under gravity because it’ll get hung up. Interestingly, in previous unfurling tests before they attached it to the telescope, they turned it in all kinds of different directions (hung it upside down, moved it sideways), to make sure things didn’t get hung up unexpectedly. Those tests by the way were the ones that caused the most recent delay in the mission. Somebody forgot to remove some screws and made some other rookie mistakes when testing the unfurling that caused NASA to move the timeline back a few more years. Probably more than any other component on JWST, the five-layer, tennis court sized Sun shield is the most critical to the mission and the most fragile. If this thing doesn’t deploy, then the electronics, detectors and everything else needed for JWST to see what it needs to see won’t get cool enough to work properly. This thing gets hung up anywhere along the way, and the whole thing is useless. It’s a little worse than that though because the telescope itself is so big it has to be folded in on itself in a variety of ways to fit in the rocket. The enormous primary mirror assembly has to be folded up, you can see that in this image. The secondary tower assembly has to be bunched up and of course all five layers of the Sun shield are rolled up and stowed to fit inside the rocket fairing. Many components have already been individually tested for the space environment, including shock testing for launch and cryogenic testing for operating in the cold of space and so far everything has passed so that’s good. What’s next for these guys is they are gonna painstakingly roll the sun shield back up into it’s stowed position for flight, Then, the entire observatory will be subjected to comprehensive electrical tests and one more set of mechanical tests that emulate the launch vibration environment. Then they are going to deploy the whole thing one more time and stow it on the ground, before its flight into space. But wait that’s not all! After that, which should happen over the course of the first half of this year, they are gonna put the whole thing on a barge and sail it from California to the launch site at French Guiana where it will be put on the Arianne V rocket to go up into space. No shortage of tense moments here when it comes to this mission and all that’s nothing compared nervousness I’m gonna feel during the actual launch and deployment phase. Once launched and JWST heads to the L2 point where it will do it’s work, NASA will take about two weeks to fully deploy the telescope. It’ll take about a month after launch to get where it’s going then they will start to take first light images sometime in late 2021. At least that’s the story so far, I will keep you posted.