The sunshield of the James Webb Space Telescope is fully unfurled.
The newly launched NASA observatory – which includes Canadian contributions – passed this engineering milestone on Tuesday (Jan. 4), less than two weeks after launching on a flagship mission to better understand the universe’s evolution and various cosmic objects.
The overall cost is around $10 billion USD ($12.7 billion CAD), and the mission launched far over budget after an approximate 14-year delay. But with the budget and engineering challenges in the past, astronomers around the world are now eager to get their hands on the observatory.
The unfolding of Webb’s sunshield went far faster than anticipated, with engineers blowing past initial estimates of three days by completing the operation in only about one day. The procedure called for tensioning five sunshield layers in a sequence, and the work had been slightly delayed by minor engineering issues around the new year – as well as NASA’s desire to give the team a rest after working through the holidays, including a Christmas Day launch.
“Yesterday, we did not think we were going to get through the first three layers,” Keith Parrish, observatory manager for Webb, said during a live NASA webcast during Tuesday’s (Jan. 4) deployment. “But the team just executed everything flawlessly. We were only planning to do one yesterday, but that went so well, [so] they said, ‘Hey, can we just keep going?’ And we almost had to hold them back a little bit.’ “
So far, the only issues that engineers have been working on with Webb have been minor: an overheating problem with the motors – quickly resolved by moving the telescope to place them more into a shade – and a solar array duty cycling issue addressed with a manual reset, verified by simulation at the factory to make sure the voltage adjustment would work for real.
Given the small issues, Webb engineers struck a note of optimism when speaking with reporters about their work on Monday (Jan. 3), just when the tensioning of the sunshield was at a beginning.
“I don’t expect any drama … the best thing for operations is boring, and that’s what we anticipate over the next three days – be boring,” Webb project manager Bill Ochs, who is based at NASA Goddard Space Flight Center, told reporters back when the sunshield deployment was expected to take three days.
Ochs said the team – working 12-hour shifts and making sure to take breaks where needed – will “breathe a sigh of relief” when the tensioning is complete, but he emphasized that all work done will be done to a preplanned sequence. “It’s done in a very methodical, logical, calm fashion,” he said.
Some emotions did show during the live webcast, however. When the final layer was tensioned at 12:09 p.m. EST, control teams broke into applause and cheers. On the webstream, one of the managers addressed the team with congratulations. “We still have got a lot of work to do, but getting the sunshield deployed is really, really big,” the manager was heard saying.
Webb is rapidly approaching a million kilometers from Earth as it flies to its ultimate destination, a Lagrange point roughly 1.5 million miles (2.4 million km) from our planet. The distant location is meant to include a minimum of interference from stray sunlight, and the sunshield is a key element in protecting the telescope as well as it performs infrared observations.
The sunshield’s deployment has been tested on Earth to see how well it will perform in space, as indicated in this example 2014 video from Northrop Grumman. While the test deployments, as the video indicated, gave “important insights” in understanding how the telescope would behave in space, it was impossible to fully simulate the deployment under our planet’s conditions – making the successful work an engineering marvel.
The work is by no means finished for Webb, as deployment work will continue for the next several weeks to get the telescope ready for observations later in 2022. Next in the sequence is heating up the motors and deploying the secondary mirror system, according to Parrish during the broadcast.
Canada’s role in Webb includes a fine guidance sensor to assist with pointing, and the Near-Infrared Imager and Slitless Spectrograph that allows for detailed studies of objects ranging from exoplanets to galaxies. Canada is allotted a guaranteed share of observing time and will be among the countries that are first to use the observatory when it becomes operational, which is anticipated to be around the summer.