STS-82 Day 5 Highlights

Back to STS-82 Flight Day 04 Highlights:

On Saturday, February 15, 1997, 7:00 a.m. CST, STS-82 MCC Status Report # 9 reports:

Early this morning, astronauts Greg Harbaugh and Joe Tanner completed a 7 hour, 27 minute spacewalk in the cargo bay of the Shuttle Discovery to replace and install several new engineering components in the Hubble Space Telescope.

After being awakened late Friday afternoon, Harbaugh and Tanner completed the checkout of their spacesuits well ahead of schedul, allowing them to start the second spacewalk of the flight at 9:25 p.m. Central time, almost one hour ahead of schedule.

Harbaugh and Tanner went right to work, replacing a degraded Fine Guidance Sensor and a failed Engineering and Science Tape Recorder with new spares. Payload controllers verified that the new Fine Guidance Sensor and the new tape recorder were healthy and ready to support the telescope's scientific efforts. The astronauts also installed a new unit known as the Optical Control Electronics Enhancement Kit, which will further increase the capability of the new Fine Guidance Sensor.

During the spacewalk, the astronauts and flight controllers took note of cracking and wear incurred by thermal insulation which protects several areas of the telescope. The part of the telescope which is in the direction of travel and always exposed to the sun has experienced slight cracks and delamination during almost seven years of time on orbit. Flight controllers and Hubble project managers are evaluating whether some repair work might be performed to certain portions of the telescope's insulation during the final spacewalks of the flight.

As Harbaugh and Tanner neared the end of their work in the cargo bay, Discovery's small maneuvering jets were fired for about 20 minutes to gently raise Hubble's altitude by about 1.8 nautical miles. The reboost effort by Commander Ken Bowersox and Pilot Scott Horowitz will be performed again near the end of the final two spacewalks and should raise Hubble's altitude by a total of about five nautical miles. Harbaugh and Tanner returned to Discovery's airlock at 4:52 A.M., with more than 14 hours of spacewalk servicing time having been logged during the first two excursions in the Shuttle's cargo bay.

The astronauts will begin an eight-hour sleep period at 9:25 this morning and will be awakened at 5:25 this afternoon for the third spacewalk by Mark Lee and Steve Smith. They will replace an ailing Data Interface Unit, swap out another science and engineering tape recorder for a new solid state recorder and will replace a faulty Reaction Wheel Assembly for a new unit to help steer the telescope to its targets.

Discovery and the Hubble Space Telescope continue to orbit the Earth every 90 minutes at an altitude of approximately 370 statute miles with all of the Shuttle's systems still operating in excellent condition.

On Saturday, February 15, 1997, 5:00 p.m. CST, STS-82 MCC Status Report # 10 reports:

With two spacewalks complete, the STS-82 crew has met the minimum success criteria for the second Hubble Space Telescope servicing mission, but still has plenty of work left to do.

Tonight, astronauts Mark Lee and Steve Smith will leave the crew cabin for their second spacewalk of the flight. Lee and Smith are scheduled to install a new Data Interface Unit in HST and swap out a science and engineering tape recorder with a new solid state recorder. Unlike the older reel-to-reel recorder, the new digital recorder has no reels, no tape or moving parts to wear out and unlimited lifetime. Data is digitally stored in computer-like memory chips until HST's operators at the Goddard Space Flight Center play it back. Lee and Smith also will replace a Reaction Wheel Assembly that failed late last year with a new unit to help steer the telescope to its targets.

The Hubble Space Telescope was designed for on-orbit servicing with three maintenance scenarios in mind. They are incorporating technological advances into the science instruments as was done with the installation of the Space Telescope Imaging Spectrograph and the Near Infrared Camera and Multi-Object Spectrometer, replacing items such as the tape recorders and reaction wheels which normally degrade over time; and correcting random equipment failures or malfunctions.

If there is time during the spacewalk, Lee and Smith may perform some simple operations to assist engineers in planning for the possibility of performing some repairs to the aging thermal covering of the telescope. Controllers and astronauts have noticed areas on the telescope where the insulation is peeling. The tasks include bringing materials that could be used for the repair back into the crew cabin, assessing how brittle the insulation is and testing how well Kapton tape adheres to the insulation.

The spacewalk is officially scheduled to begin at 10:20 p.m., but for the first two EVAs, crew members completed their preparations early so that they were ready to begin between 9 and 9:30 p.m.

Also during the sixth day of the mission, Commander Ken Bowersox and Pilot Scott Horowitz will fire the small steering jets in the next phase of the effort to reboost the telescope. The first reboost burn raised Hubble's altitude by about 1.8 nautical miles, and a second unplanned burn, which was required to move Discovery a safe distance from some orbital debris, raised the orbit another half mile. Overall, flight controllers plan to raise HST's orbit about 7 statute miles.

Go to STS-82 Flight Day 6 Highlights: