STS-80
Report # 20 
 Thursday, November 28, 1996, 6 a.m. CST 
 
 Columbia's five astronauts spent the day preparing for the first of
two planned spacewalks that will begin tonight and refined the
distance to the ORFEUS-SPAS astronomy satellite trailing the orbiter
by about 20 nautical miles.

  Mission Specialists Tammy Jernigan, Tom Jones and Story Musgrave
conducted a thorough check of the tools that Jernigan and Jones will
be using for their spacewalk which is scheduled to start shortly after
8 p.m. central time.  The three astronauts also prepared the middeck
for the spacewalk.  The schedule calls for the airlock to be
depressurized beginning about 8:16 p.m., followed soon after by the
hatch opening to start the spacewalk.

  The first extravehicular activity is designed to test a telescoping
crane which will be used during the assembly of the International
Space Station to move large components from module to module.  The two
astronauts will use the crane to move a simulated space station
battery back and forth around the cargo bay.  The second spacewalk by
the two will be conducted Saturday night.

  Near the end of the crew's day -- about 3:15 this morning --
Commander Ken Cockrell and Pilot Kent Rominger fired the small
thruster jets onboard to refine Columbia's distance to the ORFEUS-SPAS
and to maintain that separation at about 20 nautical miles.  The three
instruments mounted on the small satellite continue to function well
and should have made more than 200 observations by the end of the day
Thursday.

  Crew sleep begins at 7 a.m. and ends with a wakeup call from Mission
Control at 2:56 p.m. today.

  Columbia's 21st voyage in space continues to be troublefree for the
oldest orbiter in the shuttle fleet.  The current altitude is about
220 statute miles, equating to an orbital period around the Earth of
one hour 31 minutes.

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