Webb Aft Momentum Flap release. Credit: NASAs Goddard Space Flight Center Conceptual Image Lab
Quickly after 9 a.m. EST today (December 30, 2021), the Webb group finished release of the observatorys aft momentum flap. In a procedure that took about eight minutes, engineers launched the flaps hold-down gadgets, and a spring brought the flap into its final position.
The aft momentum flap assists decrease the fuel engineers will need to use throughout Webbs lifetime, by helping to preserve the observatorys orientation in orbit. As photons of sunshine hit the big sunshield surface, they will put in pressure on the sunshield, and if not appropriately balanced, this solar pressure would cause rotations of the observatory that should be accommodated by its response wheels. The aft momentum flap will sail on the pressure of these photons, stabilizing the sunshield and keeping the observatory stable.
Just as a ships mast must be set in position and the rigging established prior to the ship unfurls its sails, Webbs pallet structures, momentum flap, and mid-booms will soon all remain in place for Webbs silver sunshield to unfold. The next actions in Webbs prepared deployment timeline are detailed here.
By NASA
December 30, 2021