Rehearsals and training at the Space Telescope Science Institute are critical to make sure that the assembly process goes smoothly and any unexpected anomalies can be dealt with. NASA/STScI, CC BY
After testing came the rehearsals. The telescope will be controlled remotely by commands sent over a radio link. But because the telescope will be so far away – it takes six seconds for a signal to go one way – there is no real-time control. So for the past three years, my team and I have been going to the Space Telescope Science Institute in Baltimore and running rehearsal missions on a simulator covering everything from launch to routine science operations. The team even has practiced dealing with potential problems that the test organizers throw at us and cutely call “anomalies.”
Some alignment required
The Webb team will continue to rehearse and practice until the launch date in December, but our work is far from done after Webb is folded and loaded into the rocket.
We need to wait 35 days after launch for the parts to cool before beginning alignment. After the mirror unfolds, NIRCam will snap sequences of high-resolution images of the individual mirror segments. The telescope team will analyze the images and tell motors to adjust the segments in steps measured in billionths of a meter. Once the motors move the mirrors into position, we will confirm that telescope alignment is perfect. This task is so mission critical that there are two identical copies of NIRCam on board – if one fails, the other can take over the alignment job.
This alignment and checkout process should take six months. When finished, Webb will begin collecting data. After 20 years of work, astronomers will at last have a telescope able to peer into the farthest, most distant reaches of the universe.
This story was originally published with The Conversation. Read the original here.
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