STS-103
Report # 09 
 Thursday, December 23, 1999 - 11:30 p.m. CST 
 
 The Hubble Space Telescope received a new advanced computer Thursday from
space-walking Discovery astronauts Mike Foale and Claude Nicollier.  Their
8-hour, 10-minute space walk, the third longest in history, also saw
replacement of a 550-pound fine guidance sensor.

Flight controllers said all major activities of the space walk, the second
of three on consecutive days of Discoveryís space telescope repair and
improvement mission, had been accomplished.  Controllers reported that
power was reaching both of the new pieces of equipment.

ìThe brains of Hubble have been replaced,î said Mission Specialist John
Grunsfeld, who worked Thursday in Discoveryís cabin with the space-walking
crew members outside.  About 30 minutes later Hubble began thinking with
those new brains.  At an evening mission status briefing, John Campbell,
Hubble Space Telescope program manager, said the functional checkout of
the new computer showed it was functioning well. Checkout of the Fine
Guidance Sensor, is continuing.

The length of Thursdayís space walk made it the third longest in history,
behind only the 8-hour, 15-minute effort on Wednesday by Payload Commander
Steve Smith and Grunsfeld and an 8-hour, 29-minute space walk by three
Endeavor astronauts on STS-49 on its Intelsat rescue mission in May 1992. 

Replacement of one of Hubbleís two S-band transmitters is a highlight of
Fridayís space walk by Smith and Grunsfeld. The transmitter to be replaced
had failed.  The second transmitter was able to carry the load alone, so
no science was lost. The transmitters are considered very reliable, and
unlike most of the equipment aboard Hubble, they were not designed to be
changed out in orbit. Special tools were developed to enable astronauts to
do the job more easily.  Installation of a Solid State Recorder to replace
a less reliable and less capable 10-year-old recorder is the second major
item on the schedule.

Also on the timeline of the space walk, scheduled to begin at 1:50 p.m.
CST, is installation of new insulation on equipment bay doors. The
spacewalk could, like its two predecessors on STS-103, begin earlier if
the crew completes preparations early.  Flight controllers are anxious to
end this third space walk at 8 p.m. as scheduled.

Discovery remains is in excellent condition, in an orbit with a high point
of 380 statute miles and a low point of 364 miles. The next status report
will be issued at 11 a.m. Friday, or as events warrant.