STS-82
Report # 11 
Sunday, February 16, 1997, 8:30 A.M. CST 
 
Mission managers decided this morning to add a fifth spacewalk to Discovery's flight to 
refurbish the Hubble Space Telescope to allow flight controllers and the astronauts time to 
repair  tattered thermal insulation on the12-ton observatory. The decision came after 
astronauts Mark Lee and Steve Smith completed a 7 hour 11 minute spacewalk to replace 
various components on the telescope.

The revised plan calls for Greg Harbaugh and Joe Tanner to conduct the fourth spacewalk 
of the flight tonight to replace a Solar Array Drive Electronics package and to replace covers 
on Hubble's magnetometers near the top of the telescope. They will also repair ripped 
thermal insulation on the light shield of Hubble below the areas where the magnetometers 
are located. On Monday night, Lee and Smith will venture into Discovery's cargo bay again 
to repair additional thermal insulation which has degraded on three key equipment bays 
near the middle of the telescope. 

Hubble's redeployment will be shifted one day from Tuesday to Wednesday with 
Discovery's landing at the Kennedy Space Center still planned for early Friday morning 
before dawn.

The third spacewalk began at 8:53 p.m. Central time Saturday evening. Lee and Smith 
removed and replaced a Data Interface Unit which provides command and data interfaces 
between Hubble's data management system and other subsystems.  They also replaced an 
old reel-to-reel style Engineering and Science Tape Recorder with a new digital Solid State 
Recorder (SSR) that will allow simultaneous recording and playback of data

The final task for Lee and Smith was the changeout of one of four Reaction Wheel 
Assembly units that use spin momentum to move the telescope toward  a target and 
maintain it in a stable position. All of the new components are reported to be in excellent 
condition.

Discovery's small maneuvering jets were then fired for about 20 minutes to gently raise 
Hubble's altitude. The reboost maneuver by Commander Ken Bowersox and Pilot Scott 
Horowitz was the third in the past two days. Lee and Smith returned to Discovery's  
airlock at 4:04 A.M., with 21 hours 20 minutes of spacewalk servicing time having been 
logged during the first three excursions in the Shuttle's cargo bay.

The astronauts will begin an eight hour sleep period at 9:25 a.m. this morning and will 
receive a wake up call at 5:25  p.m. to begin the seventh day of the mission.

Discovery and the Hubble Space Telescope continue to orbit the Earth every 90 minutes at 
an altitude of  374 statute miles with all of the Shuttle's systems still operating in flawless 
condition.

The next STS-82 status report will be issued at 5 P.M. Central time.




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