STS-79 Mission Control Center
Status Report #17

Tuesday, September 24, 1996, 6 a.m. CDT

Atlantis is flying solo once again after undocking from the Mir Space
Station at 8:33 p.m. central time yesterday to complete five days of
joint operations between the American astronauts and the Russian
cosmonauts.

As Atlantis/Mir flew over the Ural Mountains of central Asia, the
docking hooks and latches that joined the vehicles together were
commanded open and Atlantis drifted slowly away from Mir. Pilot Terry
Wilcutt then initiated a tail-forward flyaround of the Russian outpost
at a radial distance of about 400 feet. After one and one-half
revolutions around Mir, Atlantis' jets were fired in a separation
maneuver to enable Atlantis to break away from Mir until it returns in
January for the fifth docking on the STS-81 mission.

STS-79 Commander Bill Readdy told flight controllers in Houston it was
"kind of sad" to be leaving Mir behind. Astronaut Shannon Lucid,
leaving the complex that was her home for six months, bid a final
farewell to Mir 22 Commander Valery Korzun and Flight Engineer
Alexander Kaleri and U.S. astronaut John Blaha, who is beginning his
four-month mission on Mir. Blaha thanked Atlantis' astronauts for
helping him set up shop on the Mir for his lengthy research mission.

On board Atlantis, the six-member crew is settling back into its
normal routine with a fairly light schedule for the remainder of the
day. After completing some housekeeping chores and experiment status
checks, the astronauts are enjoying four hours of off-duty time to
relax after a busy five days of activities aboard the Mir,
transferring tons of equipment, water and logistical supplies to the
Russian station and hauling over a ton of gear and experiments back to
the Shuttle.

Early this morning as Atlantis flew over the United States, the crew
took time to talk with anchors for the CBS "Up to the Minute" network
news broadcast.

The astronauts will begin a planned nine-hour sleep period just before
1 p.m. Central time today. Atlantis is in excellent condition,
circling the Earth every 90 minutes.

During routine STS-79 postflight inspections of the Reusable Solid
Rocket Motors, contractor and NASA engineers observed erosion in the
right hand nozzle of a different nature than is typically observed in
the nozzles. Typically, about half of the carbon phenolic material
that lines the nozzle erodes during the flight of the motors. On
STS-79, the right hand nozzle had the typical erosion, but also had
several troughs eroded into the insulation which sloughed off an
additional three-eighths of an inch of insulation.

The nozzle insulation varies in thickness --- 1 1/2 to 3 1/2 inches
along the nozzle surface. It is backed by a glass cloth phenolic and
metal. The nozzles are en route to the RSRM prime contractor facility
in Utah where they will be disassembled and thoroughly inspected. A
team of NASA and Thiokol engineers and managers has been formed to
determine the cause of the erosion.

The next STS-79 status report will be issued at 5 p.m. Central time
today.

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