Hubble Simulator
The Vehicle Electrical System Test (VEST) facility combines an exact duplicate of the Hubble Space Telescope's electrical system, which was designed in the 1980s, with simulators that mimic other components ― such as the batteries, solar arrays, pointing control, and instruments ― to create a full replica of Hubble. It is used to safely test software changes to the telescope on the ground before sending them on to Hubble in orbit.
On June 11, 2019, the Hubble team used this simulator to test upgraded flight software that was later uploaded to the actual spacecraft. Attempting to diagnose equipment that would not properly start are Ron Stattel, flight software engineer (front); Bob Smith, electrical engineer (back, left); Doug Grimes, flight ops supervisor (back, right); and Shirley Duhaney, flight software test lead (seated).
Credits: NASA Goddard / R. Roth