astronauts shown here are training on the electrical section
of Hubble. This is a full-size mockup of the section of Hubble
that houses the electrical components, such as transmitters,
batteries, tape recorders, and electronics to operate other
parts of Hubble. Astronauts come to Goddard several times prior
to each mission to familiarize themselves with Hubble's components
and the tools required to service them.