MISSION CONTROL CENTER
STS-63 Status Report #4


Saturday, February 4, 1995, 4:30 p.m. CST


Space shuttle Discovery continues to close in on the Mir space station in
anticipation of a planned rendezvous between the two orbiting spacecraft
on Monday morning. 

On the ground, flight controllers are assessing plans for up-close
maneuvers with Mir after a forward reaction control system thruster on
Discovery began leaking during a hot fire test earlier today. The
thruster's oxidizer supply line has been closed and Discovery has been
maneuvered to a nose-toward-the-sun attitude to warm the thruster. Flight
controllers report they are seeing a gradual increase in temperature on
the forward jet. 

Throughout the evening, flight controllers will continue to look at what
effect the failure may have on the planned rendezvous as well as their
options for restoring thruster operations. 

Discovery currently is approximately 4,000 nautical miles behind Mir,
closing that distance by about 190 nautical miles per orbit. 

The six astronauts on board Discovery spent a successful Flight Day 2 on
orbit using the shuttle's robot arm to lift the SPARTAN-204 satellite from
the cargo bay shortly after midnight for several hours studying the
shuttle glow phenomenon and shuttle steering jet firings. Crew members
also observed the successful deployment of several spheres and poles of
varying sizes that will be used to calibrate orbital debris-tracking
radars on the Earth.