Once
the telescope is in the shuttle's cargo bay, the astronauts can
begin replacing instruments and equipment. They will accomplish their tasks while at least
one of them is attached to the shuttle arm. The arm serves as
a dolly, allowing the astronaut to move conveniently from one
location to another.
The first parts of the telescope to be
replaced are the four large, flexible solar arrays, which have
powered Hubble for over 8 years. Radiation and debris take their toll on the sensitive electronics in the
panels, which gradually makes them unreliable. To ensure an uninterrupted
supply of energy for the remainder of the mission, new solar arrays
are the first priority.
Although the new arrays are one-third smaller
than the old ones, they produce slightly more power, thanks to new
technology. Their smaller size will reduce the effects of atmospheric
drag on the spacecraft. The new arrays don’t roll up like the
old, flexible ones; they are rigid and therefore less susceptible
to extreme temperatures.
Once removed, the old solar arrays will
be stored in the shuttle’s cargo bay and returned to Earth,
as will all the replaced components.
