STS-80 Day 12 Highlights

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On Saturday, November 30, 1996, 6:00 a.m. CST, STS-80 MCC Status Report # 25 reports:

Columbia's astronauts concluded their 11th day in space with discussions about troubleshooting measures they may undertake this afternoon to open a balky airlock hatch if the shuttle mission management team decides this morning to proceed.

The failure of the hatch to properly open caused the cancellation of Thursday's planned spacewalk by Mission Specialists Tammy Jernigan and Tom Jones. Since that time, NASA engineers and managers have continued to collect and analyze data on what may have caused the failure. The leading candidate is a misalignment of the hatch against the airlock seal. While this is the most likely reason for the problem, the engineering team has been evaluating a number of possible causes.

While discussions on the ground continued, Columbia was maneuvered into an attitude that will keep sunlight on the hatch in hopes that warming it will assist in any procedure attempted.

The crew will be asleep when the mission management team meets and will not be informed of the decision until Mission Control's wakeup call at 2:56 p.m. today. If managers decide to proceed with troubleshooting, the two astronauts would climb into their suits and depressurize the airlock. If the hatch opens, they would proceed with the spacewalk as originally planned.

Early this morning, Commander Ken Cockrell, Pilot Kent Rominger and Mission Specialists Story Musgrave, Jernigan and Jones talked to fellow Astronaut John Blaha aboard the Russian Space Station Mir. The conversation centered on each other's missions and well wishes for safe, successful flights.

Meanwhile, Columbia continues to lead the ORFEUS-SPAS astronomy satellite by a comfortable 20 nautical miles. The satellite continues in its observations of the origins and makeup of distant stars. The satellite is scheduled to be retrieved by the crew on December 3 for the return trip to Earth at the end of Columbia's mission.

On Saturday, November 30, 1996, 10:00 a.m. CST, STS-80 MCC Status Report # 26 reports:

The STS-80 Mission Management Team concluded at its 8 a.m. meeting today that around-the-clock analysis and testing so far has not identified a most likely cause of a jammed hatch that has prevented astronauts aboard the orbiter Columbia from conducting the first of two planned space walks.

The MMT, chaired by Loren Shriver, Shuttle Launch Integration Manager, asked engineering analysis teams at JSC, the Kennedy Space Center, and at Rockwell in Downey, Calif., to continue efforts to identify the likely cause of the hatch problem and report back at 2 p.m. today.

Investigations continue to center on possible problems with the linkage and latch mechanisms located on the payload bay side of the airlock hatch (called the "B" hatch) or with the gear actuator mechanism driven by crew operated handles on either side of the hatch. Analysis teams also are looking at the possibility of a small misalignment of the hatch with respect to the orbiter structure which might have resulted at installation or which could be caused by slight deformation of the orbiter structure in space.

A decision to proceed with a spacewalk today will hinge on progress in the next few hours before the crew awakens at identifying a likely cause of the problem and assuring that any corrective action attempted will not adversely affect the safe operation and sealing of the hatch. The crew wakeup is scheduled for 2:56 p.m. CST.

NASA managers are viewing the hatch problem not only from the perspective of completing the two space walks scheduled for the flight, but also to develop a plan for opening the hatch in the unlikely event that a contingency EVA becomes necessary, for example, to close and latch the payload bay doors before entry.

If additional time is required for analysis and testing of the airlock hatch, a decision could be reached at the 2 p.m. MMT to defer the EVA decision for another 24 hours and to look at dropping a second EVA originally planned to follow two days after the initial EVA.

An STS-80 mission status briefing is planned for 4 p.m. today at the Johnson Space Center and on NASA Television.

On Saturday, November 30, 1996, 6:00 p.m. CST, STS-80 MCC Status Report # 27 reports:

After a day of extensive ground analysis and testing of a balky airlock hatch on Columbia, STS-80 mission managers decided to cancel the two spacewalks that had been planned for astronauts Tammy Jernigan and Tom Jones.

Spacecraft communicator Dominic Gorie relayed the news to Jernigan and Jones as the crew was awakened at 2:56 p.m. Central time for the astronauts' 12th day in space.

After detailed engineering analysis, shuttle managers could not conclusively identify the problem that was causing the hatch handle to jam and not allowing the hatch to open. Since the exact nature of the problem could not be determined, managers decided it would not be prudent to attempt the two planned spacewalks and risk unecessary damage to the hatch or seals.

Mission Operations Representative Randy Stone said one possible suspect for the airlock hatch failure could be a mechanical problem in the hatch handle's gearbox, a problem that cannot be fixed in orbit. Stone said shuttle program officials are considering the possibility of rescheduling the spacewalks on a future flight. The spacewalks were designed to test tools and to refine techniques for the assembly of the International Space Station, which is scheduled to begin in about a year.

Although the planned spacewalks have been canceled, engineers are continuing an analysis of the problem to be as prepared as possible in the highly unlikely event a contingency spacewalk is needed later in the flight. Also, flight planning will minimize the use of mechanical systems aboard Columbia which could require repair on such a contingency spacewalk. With all other shuttle systems in excellent shape, Columbia is scheduled to remain in orbit for the full 16 days planned for STS-80, and managers will meet Monday to decide on a possible extension of the flight to allow additional astronomical observations by the German ORFEUS-SPAS satellite.

Because of the cancelled spacewalks, the crew is spending a quiet day in orbit, conducting secondary experiments and exercising. They will go to sleep at 7:56 a.m. Sunday.

Columbia is in a 223 by 212 statute mile orbit, leading the ORFEUS-SPAS satellite by 27 miles.

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