Webb Telescope, from Launch to Deployment, Means ‘29 Days on Edge’
Dec. 26, 2021 (EIRNS)—Now that the James Webb Space Telescope is making its way to the L2 point of its orbit since its Dec. 25 launch from Kourou, French Guiana, the real nail-biting portion of its mission begins. It will take it approximately 29 days to get there, and it has “50 major deployments ... and 178 release mechanisms to deploy those 50 parts,” Webb Mission Systems Engineer Mike Menzel, of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a briefing video, “29 Days on the Edge” that NASA posted in October. “Every single one of them must work,” Menzel said. “Unfolding Webb is hands-down the most complicated spacecraft activity we’ve ever done.”
The deployment schedule is flexible, and may shift as needed. The first two steps have been successfully implemented—turning its high-gain antenna toward Earth for communications, and a 65-minute thruster burn to put it on the trajectory for L2.
Next on the schedule is unfolding its five-layer sunshield—almost the size of a tennis court—designed to protect Webb's giant mirror and instruments from the Sun’s heat, which need to be kept at −370° Fahrenheit (−188° Celsius) in order to operate, the shield will always be positioned between the telescope and the Sun.
“The sunshield structure has 140 release mechanisms, 70 hinge assemblies, 400 pulleys, 90 cables and 8 deployment motors, all of which have to work properly for the five layers to deploy as planned,” describes systems engineer Krystal Puga in the video.
In about 10-14 days, the secondary and then primary mirrors will unfold and begin to take their final configuration.
At about two months out, each of the individual hexagon mirrors that comprise the primary mirror will be aligned to fine-tune the focus. This will be a painstaking process, with one scientist estimating that “we move those mirrors literally slower than grass grows as we’re lining them up so incredibly precisely.”