As astronauts aboard the Space Shuttle Endeavour replaced a faulty gyroscope on the International Space Station (ISS) during a spacewalk today, senior mission control officials back on Earth debated their options in responding to a small gouge in the underside of the orbiter discovered yesterday. NASA announced this morning that its experts are considering a number of responses to the gash, caused by a ricocheting piece of insulating foam from the shuttle's external fuel tank shortly after lift-off. With two more spacewalks planned this week, the space agency could order astronauts to attach a temporary shielding panel over the hole, or apply a coating of special protective paint over it, or fill the 3.5-inch gouge with a hardening glue.
The damaged area, near the shuttle's right main landing gear door, was identified during an inspection routine performed prior to the docking maneuver that joined the Endeavour with the ISS. Educator-astronaut Barbara Morgan assisted in a procedure using a laser-imaging device attached to the shuttle's robotic arm to beam 3-D pictures of the gash down to the Mission Control Center in Houston yesterday. Early word from NASA managers is that the damage is not critical to the safety of the ship when it descends through the atmosphere on re-entry for landing.
In the meantime, routine mission work continues as planned. Today, the crew of Endeavour is busy off-loading tons of cargo for the ISS and swapping out one of the control moment gyroscopes that determines the altitude of the space station. Yesterday, they carried out the centerpiece of the mission, known as STS-118, by attaching an enormous truss to the solar-array wings of the ISS, NASA said in a separate statement. Unrelated to the damaged thermal tile, the space agency decided to extend Endeavour's stay at the ISS by two days, bringing the visit to 10 days. The decision was made upon the successful connection of a new power coupling, called the Station-to-Shuttle Power Transfer System, which enables the shuttle to run on electricity supplied from the very solar array the astronauts are augmenting.
Endeavouris now scheduled to undock from the ISS on 20 August and land in the United States two days later. A number of educational programs will be presented from the orbiting platforms by Morgan in the days ahead.