Webb is fully deployed for the last time on Earth. Next time will be in space

The main mirror of the highly anticipated James Webb Space Telescope (JWST) was last opened on Earth ahead of the observatory’s launch, currently scheduled for October 31, 2021.

In some of the last checks before the telescope headed for space, engineers ordered the 18 hexagonal mirrors to fully extend and lock into place, just as they will once the Webb telescope reaches its destination in space.

“Over the past few months, we’ve completed almost all of our post-environmental testing related deployments,” Bill Ochs, project manager for JWST at NASA, said at a press briefing this week. “This includes things like the mirror, the solar panel, as well as the very complex and difficult final deployment of the sunshade, which is now folded up and being put into final storage.”

Ochs said the engineering and science teams had also completed the final tests of the ground segment where they commanded the observatory from the telescope’s mission operations center at the Space Telescope Science Institute in Baltimore, Md.

Deployment, operation and tuning of Golden Mirrors requires 132 individual actuators and motors in addition to complex backend software to support it. Proper deployment in space is of crucial importance to allow individual mirrors to function as a single, functional and massive reflector.

Deployment to Earth, however, involves supporting the mirrored panels of a crane in a way that simulates the weightless environment in space.

“We actually have this mirror float like it does in space,” explained Scott Willoughby, program director for Northrop Grumman. “We designed the mirror wings to work in space, but we have to test them in the field – and gravity can be quite humbling.”

Once the fenders are fully extended and in place, extremely precise actuators at the rear of the mirrors position and bend or flex each mirror to a specific “prescription”. Tests of each actuator and their expected movements were carried out in a final functional test earlier this year.

“We are getting very close to the expedition and launch,” said Greg Robinson, program director for JWST in NASA’s science missions directorate. “Over the past year – this pandemic year – our employees have learned to live and work together like we never imagined. But we’ve made it all happen… and now we’re just doing all of these “last” – the last tests, the last deployments we’ll ever do on Earth, the last tie-up.

The plan is for JWST to be placed inside a large temperature-controlled sea container and taken on a ship from the Northrup Grumman facility where it is now located in California to the European rocket facility in Kourou. in French Guiana. The trip will last approximately two weeks and will involve passage through the Panama Canal.

JWST will be launched aboard an Ariane 5 rocket. However, the generally reliable Ariane 5 has encountered problems in two previous launches with a “Separation less than the nominal value of the fairing.” The rocket was grounded for months to fix the issue, and with two more launches on the manifesto before JWST, this issue could potentially delay the launch of the high-level space telescope in October, but maybe only for a few weeks. .

“They are getting the rocket ready for the next launch, the first of three,” Robinson said. “Once they launch, we will be able to launch in about four months after that.”

However, Robinson said at the end of NASA and Northrup Grumman, everything is fine and they are not running problems.

“Right now we are not working any privileges,” he said. “We’re getting closer to the goal line and just need to hit it. We’re in a great place, but we have several reviews ahead of us to move on to the next steps. “

Read more / watch: NASA, Space News, Webb Media Day presentation