Mission Control Center
Status Report # 06
Wednesday, December 22, 1999 - 10:30 a.m. CST
With the Hubble Space Telescope
securely latched in the payload bay, the astronauts board Discovery
today will turn their attention to the primary objective of their flight
-- restoring the capability of the 12.5-ton telescope to observe the
Astronauts Steve Smith and John Grunsfeld are scheduled to begin the
first of three planned maintenance spacewalks today at about 1:40 p.m.
The crew was awakened this morning to the song "Hucklebuck"
performed by Beau Jocque and the Zydeco Hi-Rollers, a tune that the
spacewalkers heard many times while training hundreds of hours for the
mission in the 6.5-million gallon water tank at the Johnson Space Center
Although not scheduled to begin until 1:40 p.m., Smith and Grunsfeld
could begin the planned six-hour spacewalk earlier if they complete
preparations ahead of schedule. Once outside Discovery's cabin, the
first task they will perform will be to replace the telescope's three
Rate Sensor Units, each of which contains two gyroscopes. Of the six
gyroscopes currently installed in Hubble, four have failed. At least
three operable gyroscopes are needed to point the telescope with the
accuracy required to track its astronomical targets.
After the rate sensor units
have been installed, the two spacewalkers will then open valves on the
telescope's Near Infrared Camera and Multi-Object Spectrometer to purge
nitrogen coolant from that instrument in preparation for its servicing
on the next Shuttle maintenance mission. Next, they will install six
Voltage/Temperature Improvement Kits for the Hubble's batteries that
will increase the batteries' efficiency and reduce a potential for them
to overcharge and overheat. If those tasks are completed and the spacewalkers
have extra time, they may perform some additional small jobs such as
installing handrail covers and inspecting brackets.
While Smith and Grunsfeld are outside, inside the cabin European astronaut
Jean-Francois Clervoy will control Discovery's robotic arm, maneuvering
the spacewalkers into position to work on the telescope. Discovery's
other spacewalking team, astronaut Mike Foale and European astronaut
Claude Nicollier, also will assist from inside the cabin. Foale and
Nicollier are scheduled to perform the mission's second spacewalk tomorrow.
Smith and Grunsfeld are planned to again venture outside on Friday for
the flight's third and final spacewalk.
Discovery remains in near-perfect
condition with no mechanical problems of concern to flight controllers,
as has been the case since its launch on Sunday. It is orbiting at an
altitude of 380 by 365 statute miles. The next Mission Control Center
status report will be issued at 10 p.m. or as events warrant.
NASA Johnson Space Center
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