Mission Control Status Report #13
8 a.m. CDT  Thursday, October 26, 1995

  Research work continued on schedule overnight aboard Columbia as the
crew also continued a schedule of staggered half-days off duty to
relax from the around-the-clock operations.

  Mission Specialist Cady Coleman and Payload Specialist Fred Leslie
each had a half-day off during the night. The Red Team of crew members
is now at work aboard Columbia, having begun their 12-hour shift at
6:38 a.m.  CDT

  Although it had no effect on the research work, a ground system
problem caused two extended communications outages between Columbia
and the ground during the night. The time frame for the outages was
known in advance by Mission Control and the crew was informed. All
data from the experiments and the shuttle itself during the
communications loss was recorded aboard Columbia and has since been
played back to the ground.

The communications loss was due to an equipment failure at the ground 
  terminal for NASA's tracking and communications satellites. The
failure prohibited communications using the eastern Tracking and Data
Relay Satellite (TDRS-E), a satellite stationary above the Atlantic
Ocean used during about the last one-third of each orbit by
Columbia. On two successive orbits during the early morning hours,
communications were unavailable on TDRS-E, the first time for about 36
minutes and the second time for about 27 minutes, while the ground
equipment was being repaired.

  On NASA Television today, Mission Update will air at 11 a.m. CDT; an
STS- 73 Mission Status Briefing is scheduled for 12 noon; a press
conference regarding the Ulysses solar probe will air at 1p.m.;
highlights from the day aboard Columbia will air on the Flight Day
Video File at 3:30 p.m.; and Columbia Commander Ken Bowersox will be
interviewed by WISH-TV, Indianapolis, at 5:03 p.m.

  Columbia is in a 169 by 165 mile orbit, completing a revolution of
Earth every 90 minutes. The spacecraft remains in excellent condition,
and there are no issues of concern in Mission Control regarding its
performance.