The James Webb Space Telescope started its journey to a location over a million kilometers from Earth, where it will start its science mission in roughly six months. Ken Sembach is the director of the Space Telescope Science Institute. Science will not be the same after today.
Sembach said those words roughly an hour before the launch, well before any last minute glitch could have delayed matters, and long before the complicated series of events that would see parts of the observatory unfold from their compact launch configuration. The people gathered at the Space Telescope Science Institute seemed relaxed despite the long delays and the fact that they were gathered to watch the launch. Until you asked how they were feeling.
So far, that confidence appears to be in good shape. The launch went forward without delay, and each step along the way, from separation of solid rocket boosters to release of the fairing, went exactly as planned. The telescope's solar panel deployed in the video from the rocket's second stage, after controllers here indicated it was fully powered.
What will happen in the future?
Scott Friedman, the scientist who is in charge of the telescope's commissioning, went over all the additional hurdles that have to be cleared before it can be used. The sunscreen will be extended to its full width over the first few weeks, and then the screen's multiple layers will separate and be pulled to a tension to stretch them into their final form. The instrument package will be extended away from the "hot side" of the telescope.
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There's a solar panel, communication equipment, and all the hardware needed to function as a spacecraft on the hot side. They have to be separated from the equipment so that they don't generate heat that can swamp signals in the telescope.
The cool side will begin to deploy after the sunscreen, with a small secondary mirror that's housed on booms in front of the primary mirror. The two wings of the primary mirror, folded back to fit in the launch fairing, will then extend and place the primary mirror in its final configuration. A "momentum flap" will be extended to counteract the radiation pressure from sunlight.
One of the instruments will need to be at seven degrees to start cooling, but a panel that acts as a radiator will extend, allowing the cooling to begin. It will take 96 days to cool down.
The final configuration will be in about two weeks after launch. The mirrors have to move a bit more than a millimeter to get to their final position. The control of the mirrors is handled by the motors that manage this, so they can only move slowly. It will take the mirrors 10 days to traverse that small distance.
The controllers will begin to make the necessary adjustments to get the instrument in its operating configuration once that's all done.
There are lots of anxious moments to come, but significant hurdles have been cleared. The Webb is in space and communicating with Earth.
