STS-80
Report # 28 
Sunday, December 1, 1996  6 a.m. CDT 
 
 Columbia's astronauts spent a relatively quiet day monitoring
experiments on board and carrying out two rendezvous burns to maintain
a stable distance from the free-flying ORFEUS-SPAS astronomy
satellite.

  Late yesterday afternoon, the crew was notified that the two planned
spacewalks for the mission were canceled following extensive ground
analysis and testing of the balky airlock hatch. Mission managers
could not conclusively identify the problem that was causing the hatch
to jam, and decided not to risk unnecessary damage to the hatch or
seals. The engineering analysis will continue even though the
spacewalks have been canceled in case a contingency spacewalk is
needed later in the flight.

  The spacewalks were designed to test tools and maintenance
procedures that would be used during and after the assembly of the
International Space Station, scheduled to begin one year from now.

  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 for additional astronomical observations by the German
ORFEUS-SPAS satellite.

  The five astronauts will end a nine-hour sleep period with a wakeup
call from Mission Control at 4:56 p.m. central time to begin the
thirteenth flight day of the mission. The crew's sleep shift is moving
later to accommodate a morning landing on December 5.

  Columbia is in a 223 by 212 statute mile orbit, leading the
ORFEUS-SPAS satellite by 25 miles.

  NASA Johnson Space Center Mission Status Reports and other
information are available automatically by sending an Internet
electronic mail message to jscnews-request@listserver.jsc.nasa.gov. In
the body of the message (not the subject line) users should type
"subscribe" (no quotes). This will add the email address that sent the
subscibe message to the news release distribution list. The system
will reply with a confirmation via E-mail of each subscription. Once
you have subscribed you will receive future news releases via e-mail.