Webb Telescope Pathfinder
NASA’s Webb Space Telescope pathfinder fully assembled, inside the giant clean room at Goddard Space Flight Center in Greenbelt, Maryland.

Teams of engineers built and aligned the pathfinder telescope to rehearse assembly and testing before the actual telescope is built. After the team installs the test sensors and completes their final close out, the pathfinder telescope will be shipped to NASA’s Johnson Space Center in Houston, Texas for cryo-optical testing.

Text credit: NASA/Laura Betz,  Image credit: NASA/Chris Gunn

source NASA