STS-75 Mission Control Center 
Status Report # 11

Tuesday, February 27, 1996, 10 a.m. CST

Columbia's crew is preparing to move into the second major portion
of the STS-75 mission activating the United States Microgravity
Payload, or USMP, after completing work with several experiments
associated with the tethered satellite portion of the flight.

The USMP experiments will gather data on various materials science
investigations including crystal growth, materials solidification and
fluid dynamics.  TSS-related experiments have been operated by the
crew throughout the night gathering data on the orbiter's payload
environment.  Investigations included measuring glow and
electrodynamic phenomena around the orbiter surfaces during thruster
firings.  At about 2:30 this afternoon, the crew will begin shifting
to USMP operations for the remainder of the flight.

In the meantime, tethered satellite payload and ground controllers are
taking snapshots of data from the satellite sending data through
available ground stations around the world.  Commands were scheduled
to be sent directly to the satellite during several passes throughout
the day over Houston as it passed within range of the Electronics
Signal Test Lab at the Johnson Space Center.  Data collection will
continue as long as the TSS batteries remain fuctioning, about 24 - 48
hours.

Initial configuration data received from TSS indicates that the
thruster valves, which were commanded to a closed position as the
satellite was being reeled out from Columbia, are open and that no
gaseous nitrogen remains on board.  Additionally, two of four
stabilizing gyros on the satellite give indications of being in the
"off" position.  This and all other data gathered during dumps
to the ground stations will be gathered for post-flight analysis.

The satellite unexpectedly separated from Columbia about 7:30 p.m. CST
Sunday as the tether broke within the mast.  The latest information on
the satellite shows it trailing Columbia at a distance of 8,500
nautical miles, in an orbit 221 nm by 170 nm.  Columbia remains in an
orbit 30-40 miles lower than the satellite causing the distance
between the two spacecraft to increase by about 350 nm per orbit.

With the TSS operations winding down, the crew will begin
concentrating its attention on the remaining payload activity and
Commander Andy Allen will begin shifting his schedule to match that of
the Red Team of astronauts which includes Pilot Scott Horowitz,
Mission Specialist Maurizio Cheli and Payload Specialist Umberto
Guidoni.  Mission Specialist Jeff Hoffman has shifted his schedule to
match the Blue Team of mission specialists Claude Nicollier and
Franklin Chang-Diaz.