STS-77 Mission Control Center
Status Report #18

Monday, May 27, 1996 -- 5 p.m. CDT

Endeavour's third and final encounter with a satellite deployed from
the shuttle five days ago was highlighted by almost eight hours of
formation flying, with science investigators reporting they obtained
the best measurements yet on the stability of the PAMS-STU satellite.

For seven hours and 45 minutes, Pilot Curt Brown held Endeavour in
position less than 1,600 feet behind PAMS-STU, as video cameras and
other instruments documented the satellite's behavior.

The Attitude Measurement System (AMS), a laser-based instrument in
Endeavour's payload bay, consistently locked on to the satellite today
and attained highly accurate readings. During two previous encounters,
the AMS experienced some difficulty accurately tracking the satellite.
With AMS performing so well, the stationkeeping activities were
extended about an hour and 10 minutes to allow scientists to gather as
much information as possible.

PAMS-STU appeared to be very stable, demonstrating the concept of
using aerodynamic forces and the Earth's magnetic field to naturally
control a small satellite in orbit, without a need for thrusters.

Based on the satellite's stability, flight controllers revised their
estimate of its orbital lifetime, predicting that it could remain in
orbit until January 1997.  Initial estimates predicted an orbital
lifetime of several weeks.  PAMS-STU is expected to burn up when it
reenters the Earth's atmosphere.

As Endeavour held position with the satellite today, Commander John
Casper spoke briefly with astronaut Shannon Lucid, marking her 65th
day on board Russia's Mir space station.

The six-member Endeavour crew will awaken at 9:30 p.m. central time
today to begin what should be its final full day on orbit.  Flight Day
10 will see the astronauts perform routine activities for the day
before landing.  Casper, Brown and Mission Specialist Dan Bursch will
conduct a checkout of systems to ensure the orbiter is in top shape
for its return to Earth early Wednesday morning.  The astronauts also
will begin to deactivate some of the experiments housed in the
Spacehab module, and stow some of the equipment they have used over
the past nine days on orbit.

The JSC newsroom will remain open 24 hours to support the STS-77
mission.