After launch and during the first month in space, on its method to the 2nd Langrange point (L2), Webb will undergo an intricate unfolding series. Credit: NASA, ESA, CSA, Joyce Kang (STScI).
” There are 50 major releases that change Webb from its stowed, launch configuration into an operational observatory. The sunshield deployment series started with the forward, then aft, UPSs mechanical release from the telescope and motorized lowering into position. The telescope and science instruments, installed on a deployable tower assembly, were then mechanically released and raised. There is a momentum flap connected to the end of the aft UPS that is launched and placed, whose function is to stabilize the solar pressure on the deployed sunshield. The sunshield covers are released by means of retraction of membrane release devices and roll out of the way, readying the system for the deployment of the sunshield layers. The telescopic mid-booms sequentially press out from the spacecraft bus perpendicular to the telescope line of sight, pulling the folded stack of sunshield layers out into the final, but still untensioned, setup. Each sunshield layer is tensioned into position, starting with the Sun-facing layer initially and completing with the telescope-facing layer. The deployed sunshield starts a fast cooldown of the telescope and the science instruments, however on-board heaters within the science instruments will be utilized to manage their cooldown and prevent contamination.
” While these steps have actually been checked on the ground and operationally practiced in the Mission Operations Center, these critical activities need to be carried out for a successful objective. Finest wishes to our group, and stay cool, Webb!”.
— Michael McElwain, Webb observatory job researcher, NASAs Goddard Space Flight Center.
Credit: NASAs Goddard Space Flight Center Conceptual Image Lab
With Webbs very first significant structural releases finished and the observatorys Deployable Tower Assembly extended, we are taking a step back to find out more about Webbs sunshield. Observatory Project Scientist Michael McElwain, from NASAs Goddard Space Flight Center, provided these ideas:
” The Webb telescope and science instruments are all set to go into the shade, never ever once again to see direct sunlight. Among Webbs unique design functions is using passive cooling by a five-layer sunshield to reach the telescopes operational temperatures of 45 Kelvin (-380 degrees Fahrenheit). The enormous sunshield has to do with 70 by 47 feet (21 by 14 meters) when released, or approximately the size of a tennis court. The sunshield geometry and size were identified such that the telescope can point within a field of regard that covers 40% of the sky at any time and can observe anywhere in the sky over 6 months. This innovative architecture makes it possible for Webbs sensitivity to be limited by the natural sky background (mostly zodiacal light) rather than being jeopardized by thermal radiance of the observatory itself, for all wavelengths shorter than 15 microns, for the duration of the objective.
” For launch, the sunshield was folded like a parachute and stowed onto the forward and aft unitized pallet structures (UPSs). Both the telescope and sunshields support structures are mechanically connected to each other and the spacecraft bus in order to fit within the Ariane 5s fairing and stand up to the dynamic launch environment.
One of Webbs unique style features is utilizing passive cooling by a five-layer sunshield to reach the telescopes functional temperature levels of 45 Kelvin (-380 degrees Fahrenheit). The sunshield release series began with the forward, then aft, UPSs mechanical release from the telescope and motorized lowering into position. The sunshield covers are released via retraction of membrane release devices and roll out of the way, preparing the system for the implementation of the sunshield layers. The released sunshield starts a fast cooldown of the science and the telescope instruments, however on-board heaters within the science instruments will be utilized to control their cooldown and avoid contamination.