HOUSTON ? The vital heat shield protecting NASA's space shuttle Endeavour appears in good shape after launch despite three apparent debris hits, mission managers said Thursday.
Cameras mounted to Endeavour's external tank caught nine pieces of foam insulation break off during liftoff, three of which appeared to strike the orbiter, said John Shannon, STS-118 mission management chairman, during a briefing here at the Johnson Space Center. None of the impacts are believed to have caused significant damage, he added.
Shannon said one fragment popped free about 24 seconds after Endeavour's Wednesday launch and appeared to hit the end of the shuttle's aft-mounted body flap.
A second piece separated about 58 seconds into the flight and appeared to cause a spray of material on Endeavour's starboard wing. The third fragment separated near the three-minute mark, much too late to cause significant damage.
But the foam incidents did not appear to be severe in images relayed to Earth by Endeavour's fuel tank camera, Shannon said.
"I would tell you that the picture was extremely underwhelming," Shannon said of the apparent starboard wing hit. "The report initially was that you got a spray of debris from this area and of course that brings up images of Columbia?this was not even remotely of the same magnitude."
A briefcase-sized piece of foam fell from the shuttle Columbia's fuel tank during its 2003 launch, piercing the heat shield and leading to the loss of the orbiter and its seven-astronaut crew.
During Endeavour's rendezvous with the International Space Station (ISS) at 1:53 p.m. EDT (1753 GMT) tomorrow, astronauts aboard the orbital laboratory will take detailed photographs of the three impact points before the orbiter docks. The images, as well as data taken from the shuttle crew's heat shield inspection today, will be analyzed by engineers on Earth.
Commanded by veteran astronaut Scott Kelly, the STS-118 crew's major tasks include attaching a starboard (S5) truss spacer to the ISS, delivering fresh cargo and shuffling space station components to make way for further construction.
Endeavour's crew awoke to an alarm last night, which turned out to be the failure of an oxygen tank pressure sensor. Liquid oxygen is used in Endeavour's fuel cells to help generate electricity for the shuttle, but must gently boiled into gas by heaters when power is needed.
"With the failure we're going to have to use manual heater control. The automatic heater control is not functional on that tank," said Matt Abbott, NASA's STS-118 lead shuttle flight director.
Because of the faulty sensor, the astronauts will need to turn on the heaters via flight deck controls about once every hour to keep feeding the shuttle's electricity-generating fuel cells.
"It's just a matter of flipping the switch on, flipping the switch off," Abbott said of the procedure, which should not impact the crew's busy ISS construction schedule during their 11-to-14-day mission. "It will require some babysitting."
Endeavour's STS-118 mission marks the first time in space for three mission specialists, including teacher-astronaut Barbara Morgan as well as Alvin Drew and Tracy Caldwell. Shuttle pilot Charlie Hobaugh and mission specialists Dave Williams and Rick Mastracchio round out the crew.
The astronauts awoke early Thursday to the song "Where My Heart Will Take Me" by Russell Watson, the theme to "Star Trek: Enterprise," chosen for Mastracchio.
"They're having a great time," Abbott said of the rookies, adding that every one of the crew members looks like "they're having a ball."
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- VIDEO: Endeavour's STS-118 Mission Profile
- Complete Space Shuttle Mission Coverage