'World's Most Magnificent Time Machine,' the James Webb Space Telescope, Leaving Houston

Image Credit: NASA

Via space.com by Sarah Lewin

It survived a hurricane and is now off to earthquake territory: The James Webb Space Telescope has come out of its deep freeze and will soon leave Houston to unite with its sun shield and spacecraft bus in California to prepare for a 2019 launch.

NASA officials updated media on the megatelescope's status and described trials yet to come in a teleconference yesterday (Jan. 10) from Johnson Space Center in Houston.

"We're extremely elated to be here, especially after the successful completion of our cryovacuum and optical testing of the world's most magnificent time machine, the Webb telescope," Mark Voyton, the manager for the Optical Telescope Element and Integrated Science Instrument Module, said during the news conference.

The telescope's mirrors and instrumentation emerged from Johnson's enormous cryovacuum chamber, Chamber A, two months ago after a series of tests to confirm its enormous primary mirror — consisting of 18 hexagonal segments — and its science instruments could work to focus and track starlight in the airless cold of space. When it launches, Webb will be the largest space telescope in the world. With seven times the collecting area of the Hubble Space Telescope and ultracool operating temperatures, it will be able to detect infrared light from the earliest stars and galaxies and even analyze the atmospheres of distant planets passing in front of their stars.

"It's really a pleasure to be hosting this event at Johnson Space Center, now that this very demanding test of the James Webb telescope and science instruments has been successfully completed," Ellen Ochoa, director of Johnson Space Center, said during the news conference. "Goddard Space Flight Center [in Maryland] determined a number of years ago that our Chamber A would be the best choice for this test, once it had been modified to support the extremely cold temperatures and the other requirements that were needed for the test."


The telescope's instruments were built and tested at Goddard, but traveled to Houston for access to the huge Chamber A — which was adapted for Webb after testing Apollo's command and service modules in the 60s and 70s and several other missions over the years. For Webb, the chamber was cooled for more than a month to 20 kelvins (minus 424 degrees Fahrenheit, or minus 253 degrees Celsius), tested for a month, and finally returned to room temperature over the course of another month. This was the longest — and maybe most complex — testing done in Chamber A, NASA officials said.

During that time, Hurricane Harvey hit — but "the telescope did not know, the chamber did not know that there was an event going on outside its environment," Jonathan Homan, project manager for Webb's Chamber A test team at Johnson, said during the news conference.

"We had spent probably more than a month to get the chamber and the telescope down to test temperatures, and we were ready for testing — it was a primary part of optical testing," he added. "It maintained [its minimum temperature], held those conditions without any incident. With that, that meant that helium refrigerators were operating, cryogenic liquid nitrogen systems were operating, vacuum systems were operating, lots of telemetry, data systems, control systems were operating," although the building "took some water hits."

Although the storm was much fiercer than expected, he said, the Johnson and Goddard teams had planned well enough that they were able to keep personnel and hardware safe and avoid any interruption to testing. And afterward, he and others added, many of the Webb team volunteered in the community to help Houston recover.

Before it came to Houston, Webb's mirrors and instruments were subjected to violent shaking, pressure and chill to mimic the dramatic changes of launch. Now that it has proven its mirrors and instruments can align, focus and track an artificial star in Houston's cold vacuum, it will head to reunite with its tennis court-size sun shield and the rest of the spacecraft at Northrop Grumman's Aerospace Systems facility in California — probably starting the moving process in late January or early February, officials said. There, it will be vibrated, stuck in another vacuum and blasted with sound, its sun shield fully deployed in a simulated zero-gravity environment and more, before it's finally packed up and shipped to French Guiana, where it will eventually launch.

"It's a very, very exciting time, but we still have a lot of work in front of us; there's a lot of excitement ahead," Bill Ochs, the telescope's project manager at Goddard, said at the news conference. "We all hope it's going to be very boring, because boring is good, and we hope that when we launch … the only excitement should be when we see science."

During Webb's very long development process, "we've survived almost every major natural event, except for a couple — and those are the ones that kind of occur in California," Ochs said. "So we're worried about those," he added with a laugh.

Source