STS-77 Day 7 Highlights
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- On Saturday, May 25, 1996, 6:30 a.m. CDT, STS-77 MCC Status Report # 13
reports:
- Endeavour returned to the small, cylindrical PAMS-STU satellite
today and began eight hours of station-keeping about 1,800 feet away
that will conclude about 11 a.m.
- The second rendezvous with the Passive Aerodynamically Stabilized
Magnetically Damped Satellite (PAMS) began shortly after the crew was
awakened to the song "Down Under" performed by Men At Work, in honor
of Australian-born Mission Specialist Andy Thomas.
- Commander John Casper and Pilot Curt Brown performed a series of
thruster firings over the course of several hours that allowed
Endeavour to close in on the 2 foot by 3 foot satellite. The PAMS
Satellite Test Unit was deployed from a canister in the rear of the
payload bay Wednesday to begin a study into the use of aerodynamic
stabilization to maintain a spacecraft's attitude on orbit. The
rendezvous took place as other crewmembers monitored science
experiments ongoing in the SPACEHAB module and on the middeck of the
orbiter.
- Casper and Brown pulled to within less than 2,000 feet behind
PAMS-STU on time at 3 a.m. today where the astronauts began to take
attitude measurements of the satellite's stability by reflecting laser
light on the satellite. The images returned by reflectors on the
PAMS-STU satellite are being recorded by the Attitude Measurement
System in Endeavour's cargo bay for analysis.
- Today's rendezvous is the second of three planned visits to the
satellite since its deployment, and the third of a record four planned
during the mission. The final rendezvous with the PAMS-STU, planned
for tomorrow, could be rescheduled for Monday depending on the results
of this morning's exercise.
- Just as Endeavour approached the satellite, a commanding problem was
seen with the Space Experiment Facility in the SPACEHAB module and
Thomas began troubleshooting procedures called up from the Payload
Operations Control Center. A few hours later, payload officials said
the device had failed. SEF was one of several materials processing and
crystal growth experiments that make up the flight's science
investigations.
- Endeavour continues to provide a stable platform for the scientific
investigations being conducted on board. The six-astronaut crew will
go to sleep at 1:30 this afternoon and will be awakened at 9:30
tonight.
- On Saturday, May 25, 1996, 6 p.m. CDT, STS-77 MCC Status Report # 14
reports:
- 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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