NASA Goddard Engineers Testing Webb Telescope's OSIM and BIA Instruments

Several critical items related to NASA's next-generation James Webb Space Telescope are being tested in the giant thermal vacuum test chamber at NASA's Goddard Space Flight Center, Greenbelt, Md.

These photos show the OTE (Optical Telescope Element) Simulator or OSIM wrapped in a silver blanket on a platform, being lowered down into a vacuum chamber (called the Space Environment Simulator, or SES) by a crane to be tested to withstand the cold temperatures of space.

The OSIM simulates the Webb telescope for the purposes of testing the science instruments that will fly on the observatory. The OSIM itself will never fly into space, but it is a vital part of the testing program to verify that the science cameras and spectrographs will function as planned.