Orbiter Docks With ISS; Power Transfer System Activated
A detailed inspection
Friday of the heat shield of the shuttle Endeavour detected a
potentially worrisome gouge in the tiles near the orbiter's
starboard main landing gear door.
"What does this mean? I don't know at this point," said mission
management team chairman John Shannon.
The damage was detected shortly after Endeavour docked with the
International Space Station at 1404 EDT Friday. Astronauts will use
the orbiter's robotic arm to take a closer look at the suspect area
Sunday, using laser sensors to measure the exact size and depth of
NASA says the damage may have been caused by a chunk of ice
falling from the shuttle's external tank during launch. If it was
ice -- which is much more dense than the foam insulation that
struck the leading edge of a wing on Columbia in 2003, that led to
the loss of the orbiter -- engineers believe it may have
pierced the tile and broken up, causing the three-inch-square
The agency says if necessary, astronauts on Endeavour will
conduct a spacewalk to patch the damage -- a process devised in the
aftermath of the Columbia tragedy.
Images taken during Endeavour's launch Wednesday night show a
white object falling away from the shuttle 58 seconds after
liftoff, and several streaks were seen near the gouge.
In all, nine pieces of debris, primarily foam, fell from the
fuel tank; three are believed to have struck the orbiter. Shannon
said further examination could reveal more damage, although such
hits are relatively common during launch.
Meanwhile, the STS-118 and Expedition 15 crews are conducting
joint operations aboard Space Shuttle Endeavour and the
International Space Station.
For the first time ever, the crews also activated the
Station-to-Shuttle Power Transfer System (SSPTS) Friday. The SSPTS
is designed to reroute power from the station to a visiting
If the transfer system works as expected, mission managers could
elect to extend STS-118’s mission from 11 to 14 days and
increase the number of spacewalks from three to four. A decision on
a possible extension could occur Sunday.
The two crews are preparing for STS-118's first spacewalk, which
is set to begin at 1231 EDT Saturday. The spacewalkers will assist
in the installation and activation of the Starboard 5 (S5) truss.
Friday’s preparations included transfer of spacewalk
equipment and the review of procedures. Also, the two crews used
the shuttle robot arm to lift the S5 out of the payload bay and
hand it off to the station robotic arm.
The two spacewalkers, Mission Specialists Rick Mastracchio and
Dave Williams, will enter the station’s Quest airlock where
they will spend the night. This procedure is performed to help
prevent decompression sickness.