The fragile heat shield of the space shuttle Discovery is seen in this view from a camera mounted to its external fuel tank as the two separate following a successful Aug. 28, 2009 launch into orbit on STS-128.
Credit: NASA TV.
This story was updated at 12:13 a.m. EDT, Aug. 30.
Astronauts aboard the space shuttle Discovery inspected their spacecraft?s vital heat shield for damage today as they chase down the International Space Station for a Sunday rendezvous.
Shuttle commander Rick Sturckow and his crew used a sensor-tipped pole attached to Discovery?s robotic arm to conduct the six-hour survey of heat shield panels lining the shuttle?s wing edges and nose cap. The inspection has been a standard chore for astronauts since the 2003 Columbia disaster to seek out any damage caused by fuel tank debris during the launch into orbit.
?It?s a thorough process that we go through and we have a lot of confidence now that we can determine any damage that the shuttle might have,? said Discovery astronaut Patrick Forrester, lead shuttle arm operator for the flight, in a NASA interview.
The inspection was expected to last most of the night. Discovery is due to dock at the space station late Sunday at 9:03 p.m. EDT (0103 Aug. 31 GMT).
Shuttle flight director Tony Ceccacci said that, so far, Discovery appears to be in fine shape since its midnight launch Friday. A blown fuse at a communications station in New Mexico did delay some of the survey data from reaching Mission Control, but was fixed promptly, he added.
Shuttle health check
Discovery lifted off late Friday from NASA?s Kennedy Space Center in Florida at 11:59 p.m. EDT (0359 Aug. 29 GMT) to begin a 13-day resupply flight to the International Space Station. Because the shuttle launched at night, Discovery astronauts were unable to photograph their foam-covered external fuel tank as it separated from the shuttle once the spacecraft reached orbit.
Sturckow, however, did fire Discovery?s thrusters to guide the shuttle over the 15-story fuel tank so a belly-mounted digital camera equipped with a flash could photograph it. Those images were beamed back to NASA?s Mission Control in Houston a few hours after launch.
?It?s great to be back in space,? Sturckow, who is making his fourth spaceflight, told Mission Control Saturday.
William Gerstenmaier, NASA?s chief of spaceflight operations, said early Saturday that a preliminary look at launch video of Discovery?s liftoff found few or no signs of serious fuel tank foam debris shedding.
?We didn?t see anything really abnormal,? Gerstenmaier said. ?In fact, I didn?t see any foam loss.?
NASA analysts will review the video, as well as radar data and imagery in more detail to be sure, he added.
NASA has kept a close watch on fuel tank foam debris and shuttle heat shield health since the Columbia tragedy. During Columbia?s February 2003 flight, a large piece of fuel tank foam fell during launch and damaged the shuttle?s wing, leading to the spacecraft?s destruction during re-entry two weeks later. Seven astronauts were killed.
Since then, NASA developed new heat shield inspection methods and repair tools for shuttle missions. Shuttle astronauts now routinely inspect their spacecraft heat shields twice, once after launch and again before landing, to make sure their vehicles are in good health. Astronauts aboard the International Space Station also take photographic surveys of incoming shuttles just before docking as another safety measure.
The data and imagery from all of those surveys are exhaustively reviewed by engineers and analysts on Earth to be sure a shuttle is fit to return home.
Tonight, Discovery?s six-man, one-woman crew will also check the spacesuits to be used during the three excursions planned during the shuttle?s time at the International Space Station. Discovery is delivering a new crewmember and a cargo pod packed with about 15,200 pounds (6,894 kg) of science equipment and fresh supplies.
The shuttle is also delivering a new space treadmill named after television comedian Stephen Colbert, who won an online NASA poll to have a new station room named after him but got the exercise gear instead as a consolation prize.
So far, the only glitch that has popped up on Discovery is the failure of one of two small forward thrusters on the shuttle?s nose. Engineers believe a leaky fuel valve caused the failure and shut down the manifold controlling both thrusters for the duration of Discovery?s 13-day flight. Discovery has six of the small thrusters, two forward and four aft, and 44 thrusters in all.
The glitch should not impact Discovery?s mission other than requiring astronauts to use a bit more propellant during other shuttle thruster firings, as well as rely more on Russian thrusters on the space station for attitude control once both spacecraft are docked, NASA officials said.
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SPACE.com is providing complete coverage of Discovery's STS-128 mission to the International Space Station with Managing Editor Tariq Malik in New York. Click here for shuttle mission updates and a link to NASA TV.