What appears to be a unique selfie opportunity was actually a critical photo for the cryogenic testing of NASA’s James Webb Space Telescope.
Taken at NASA’s Johnson Space Center in Houston, the photo was used to verify the path light will travel between the mirrors of the telescope.
During Webb’s extensive cryogenic testing, engineers checked the alignment of all the telescope optics and demonstrated the individual segments of the primary mirror can be properly aligned to each other and to the rest of the system.
This all occurred in test conditions that simulated the space environment where Webb will operate, and where it will collect data of never-before-observed portions of the universe. Verifying the optics as a system is a very important step that will ensure the telescope will work correctly in space.
This photo, snapped by Ball Aerospace optical engineer Larkin Carey, verified the line of sight. The image was compared with one collected once the telescope was cold inside the chamber, to ensure any observed obscurations would not be present during science data collection on orbit.
In the photo, Carey is harnessed to a “diving board” over the primary mirror. All tools (including the camera) were tethered, and all safety protocol for working over the mirror were closely followed. Carey faced upwards and took the photo of the secondary mirror, which is reflecting him as well as the primary mirror below.