mission specialists Mike Massimino and
Mike Good are conducting the mission’s
fourth spacewalk today, continuing
repairs and improvements that will
extend the Hubble Space Telescope’s life
into the next decade. The spacewalk
began at 9:45 a.m. EDT.
The bulk of the spacewalk will be spent
working with the telescope’s Space
Telescope Imaging Spectrograph, or STIS.
Massimino and Good will replace a
low-voltage power supply board, which
contains a failed power converter. Due
to this power supply failure, STIS has
been in “safe mode” since August 2004.
The spacewalkers also will install one
of two new protective thermal insulation
panels delivered by space shuttle
Atlantis. This insulation will be
installed on the telescope’s bay 8 door.
Today’s spacewalk is scheduled to last