This is the Vehicle Electrical System Test facility, or VEST, an exact
duplicate of the Hubble's electrical system. It is used to ensure
compatibility of new instruments and software with the telescope's existing
systems. This area on Hubble also houses batteries which will be upgraded on
the Servicing Mission.
In September 2008, shortly before the planned launch of Servicing Mission 4,
Hubble's Science Data Formatter failed, delaying the launch. The Science Data
Formatter had a backup unit, but it was a complicated procedure to switch over
to this backup unit. The switch-over procedure was tested on the VEST.
At left is the High Fidelity Mechanical Simulator
(HiFi) and the white cylinder near the center of the picture is the Cosmic Origins Spectrograph.