STS-125/HST SM-4 Status Report No. 09 (Forwarded)

STS-125 MCC Status Report #09
Mission Control Center, Houston, Texas
Thursday, May 15, 2009, 5 p.m. CDT

Mission Specialists Michael Good and Mike Massimino spun up the Hubble Space
Telescope with six new gyroscopes and a new battery during a 7-hour,
56-minute spacewalk. Friday's was the eighth longest spacewalk in history.

The second of the mission's five spacewalks began at 7:49 a.m. CDT, and by
3:15 p.m. the team had accomplished all of the planned objectives. Those
included replacement of all three rate sensing units (RSUs). Each rate
sensing unit contains two gyroscopes, which help the telescope point itself.
The spacewalkers couldn't get one of the three units into its slot, but they
were able to install a spare that was carried on board because of the tight
tolerances involved.

Good and Massimino removed one of the original battery modules from Bay 2 of
the telescope and replaced it with a new unit. The module in Bay 3 is
scheduled to be replaced by Mission Specialists John Grunsfeld and Andrew
Feustel on Monday. The batteries provide power to the telescope when it
passes into the Earth's shadow and its solar arrays are not exposed to the
sun.

Ground controllers at the Space Telescope Operations Control Center at
Goddard Space Flight Center in Maryland confirmed that all six gyroscopes
and the new battery passed preliminary tests.

Commander Scott Altman and Mission Specialist Megan McArthur completed a
robotic arm inspection of 40 shuttle heat shield tiles that weren't in full
view during Tuesday's inspection. Based on imagery analysis, mission
managers cleared all of Atlantis' thermal protection systems until a final
pre-landing inspection on Tuesday.

The last item on today's schedule for the crew is the review of the
procedures for tomorrow's spacewalk, the third of the mission. That
spacewalk will see Grunsfeld and Feustel install a new Cosmic Origins
Spectrograph and Advanced Camera for Surveys.

Because Friday's spacewalk was longer than planned, the crew will go to bed
an hour later at 8:31 p.m. and awaken an hour later at 4:31 a.m. Saturday.
The next status report will be issued after the start of the crew's next day
on orbit, or earlier if events warrant.