STS-77 Mission Control Center 
Status Report #4

Monday, May 20, 5 p.m. CDT

With the free-flying Spartan spacecraft trailing Endeavour by about 21
nautical miles, and the jettisoned Inflatable Antenna Experiment
leading by a distance of more than 100 nautical miles, the six
astronauts on board Endeavour have begun a planned eight-hour sleep
shift.

Early this morning, Mission Specialists Mario Runco used the
Shuttle's robot arm to deploy the Spartan and its Inflatable
Antenna Experiment from Endeavour's payload bay.  At 8:38
a.m. Central time, the antenna structure inflated to its full 92 foot
length supporting a 50 foot diameter dish.  Cameras and sensors on the
Spartan spacecraft took precise measurements of the smoothness of the
antenna dish surface.  IAE was jettisoned about 90 minutes later
according to plan.

The antenna continues to move ahead of Endeavour at the rate of 50 to
60 nautical miles with every revolution of the Earth, and at 3:30
p.m. was approximately 85 nautical miles in front of, and below
Endeavour.  Due to IAE's dynamic characteristics -- its large size
but relatively light weight -- an exact orbital lifetime is difficult
to predict, but flight controllers estimate that it should reenter the
Earth's atmosphere within the next 17 to 24 hours.

The IAE may be visible in the early morning skies over the United
States early Tuesday morning, in those areas where the Shuttle is
predicted to be visible. Viewing opportunities for the antenna will
precede the Shuttle by about one to two minutes.

Tuesday morning, about 9 a.m. Central time, Endeavour will rendezvous
with the Spartan spacecraft, retrieving it about one hour later before
Marc Garneau uses the robot arm to place it back in the payload bay
for its return to earth.

Studies with a variety of experiments housed in the Spacehab science
module -- including the Commercial Float Zone Furnace -- will continue
as the crew sleeps. The CFZF operates independently producing large
crystals for use in semiconductors and infrared sensors.

Endeavour is currently in a 176-mile high circular orbit, completing
one revolution of Earth every 90 minutes. The crew will receive a
wake-up call from Mission Control at 12:30 a.m. Tuesday.

The JSC Newsroom will remain open around the clock during the flight
of Endeavour.