STS-77 Mission Control Center 
Status Report #14

Saturday, May 25, 1996; 6 p.m. CDT

Endeavour returned to the small, cylindrical PAMS-STU satellite this
morning holding position about 1,700 feet behind it for more than six
hours as scientists studied the experimental craft's stability and
orientation.

Through video of the satellite taken by Endeavour's crew and
information gleaned from the shuttle's radar system, experimenters
reported the satellite was stabilizing using natural aerodynamic
forces, although stabilization appeared to occur slower than
anticipated.  PAMS-STU studies the use of weighting and the Earth's
magnetic field to stabilize a small satellite in orbit instead of
using costly and complex steering jets.

A third and final rendezvous with PAMS-STU for further observations is
scheduled for Monday, one day later than originally
planned. Scientists requested the final encounter be postponed 24
hours to allow time to evaluate the Attitude Measurement Systems, a
laser- based system designed to provide highly accurate readings of
PAMS-STU behavior.

Although scientists reported good results today from the PAMS-STU
visual and radar observations, they experienced some difficulty
tracking the satellite with the AMS. The system did appear to track
the satellite for extended periods several times this morning, but
investigators want to be sure the laser system is tracking the
appropriate reflector targets on the satellite. The AMS should provide
data on the PAMS-STU stability accurate to one-tenth of one degree.

The crew began a sleep period at 1:30 p.m. Central time and will
awaken for Day 8 of STS-77 at 9:30 p.m. With the final PAMS-STU
rendezvous rescheduled to Monday, the crew will perform activities on
Sunday that had originally been planned for Monday.

In addition to a slate of experiment work in the Spacehab module,
Sunday's schedule includes a crew news conference at 6:40 a.m. Central
time.  The astronauts will discuss their mission with media in the
United States and Canada.

Endeavour, in a 177 by 172 mile-high orbit, is in excellent mechanical
condition with no system problems being tracked by flight controllers.

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