” And we do not do them at one time. The mirror control system is designed to run only one actuator at a time. That way is both simpler (in terms of the complexity of the control electronics) and safer (given that sensing units and computer systems can closely keep track of each private actuator as it works). To limit the quantity of heat put into Webbs really cold mirrors from the actuator motors, each actuator can just be operated for a brief duration at a time. Thus, those big 12.5-millimeter moves for each segment are broken up into lots of, lots of short relocations that take place one actuator at a time. Scripts sent from the Mission Operations Center will direct this process under human guidance, gradually and progressively moving one actuator at a time, taking turns in between segments. At full speed, it takes about a day to move all the sectors by just 1 millimeter. Its about the exact same speed at which turf grows!
” This might not be the most interesting period of Webbs commissioning, however thats okay. We can make the effort. During the days that were gradually deploying the mirrors, those mirrors are also continuing to slowly cool down as they radiate heat away into the cold of space. The instruments are cooling, too, in a carefully regulated and progressive manner, and Webb is likewise continuing to gently coast outwards towards L2. Slow and stable does it, for all these progressive procedures that get us every day a bit better to our ultimate goal of mirror positioning.”
— Marshall Perrin, deputy telescope scientist, Space Telescope Science Institute
Animation of the James Webb Space Telescope mirror alignment and phasing procedure. Credit: NASAs Goddard Space Flight Center
” To support the movable mirrors during the flight to area, each of them has on its back three rigid metal pegs which can nestle into matching holder sockets in the telescope structure. These initial implementations are by far the biggest relocations Webbs mirror actuators will ever make in area.
Credit: NASAs Goddard Space Flight Center
With major deployments total, Webb continues its journey to its last halo orbit around L2. In the meantime, there are a number of smaller releases in the next number of weeks, which make up the start of a several-month stage of lining up the telescopes optics. This week, we have actually started the process of moving the mirror sections (all secondary plus main) out of their stowed launch positions. For more details, here is Marshall Perrin from the Space Telescope Science Institute, house of the Webb Mission Operations:
” To support the movable mirrors during the trip to space, each of them has on its back three stiff metal pegs which can nestle into matching holder sockets in the telescope structure. Before launch, the mirrors were all placed with the pegs held tight in the sockets, offering extra support.
” Getting there is going to take some perseverance: The computer-controlled mirror actuators are developed for extremely small motions determined in nanometers. These initial deployments are by far the largest moves Webbs mirror actuators will ever make in space.
The mirror control system is developed to operate just one actuator at a time. To restrict the amount of heat put into Webbs extremely cold mirrors from the actuator motors, each actuator can only be run for a brief period at a time. Throughout the days that were slowly deploying the mirrors, those mirrors are likewise continuing to gradually cool off as they radiate heat away into the cold of space.
