MISSION CONTROL CENTER
STS-67 Status Report #3

Thursday, March 2, 5 p.m. CST

Activation and calibration of the Astro-2 ultraviolet telescopes are
continuing slightly behind schedule following a steering jet leak that
has twice forced closure of the instruments protective doors.

The leak is in a reaction control system thruster designated R4R, a
jet in the right aft orbital maneuvering system pod that is aimed to
the right of the shuttle. Flight controllers worked with the crew to
close the manifold that supplies oxidizer and fuel to that jet, which
effectively stopped the leak.

The doors on the Hopkins Ultraviolet Telescope, the Wisconsin
Ultraviolet Photo- Polarimeter Experiment and the Ultraviolet Imaging
Telescope were first closed to protect the instruments from any
remaining oxidizer coming out of that jet after the manifold was
closed. Once the thruster's propellant lines had been evacuated, the
telescope doors were reopened. The doors were briefly closed again
while residual propellant downstream of the closed manifold
dissipated, but are now open and all scheduled operations have
resumed.

During the period the doors were closed, flight controllers and the
crew used the time to complete a number of other activation and
calibration activities that did not require the telescopes to acquire
celestial targets.

The failed jet, which is not being used to position the orbiter for
its science operations, is not a safety hazard in any way, and does
not affect the mission duration. The flight control team is looking at
options in dealing with the jet, but has not yet decided whether any
additional actions will be necessary.

The Red Team -- Commander Steve Oswald, Pilot Bill Gregory, Mission
Specialist John Grunsfeld and Payload Specialist Ron Parise -- is now
on duty. The Blue Team -- Payload Commander Tammy Jernigan, Mission
Specialist Wendy Lawrence and Payload Specialist Sam Durrance -- is in
its sleep shift.

Endeavour is in an orbit with a high point of 190 nautical miles and a
low point of 188 nautical miles, completing one orbit every 91
minutes.