July 27, 2005

Astronauts Use Laser to Search for Shuttle Damage

HOUSTON -- Astronauts on the shuttle Discovery slowly scanned the wings and nose of their spacecraft with a laser-equipped robot arm on Wednesday to begin a critical safety inspection never before performed on a shuttle mission.

Maneuvering the computer-aided arm from within the orbiter, the astronauts looked for cracks that could pose a danger to the shuttle when it returns to the Earth's atmosphere for landing on Aug. 7 and builds up super-hot temperatures.

Television shots from space showed the procedure from the perspective of the laser, which is accompanied by a television camera, as the robot arm crept along the black edge of the wing.

The inspection is expected to take about seven hours. It is one of many safety measures put in place after the fatal Columbia disaster on Feb. 1, 2003, when a loose chunk of insulating foam at launch damaged the wing and caused the shuttle to disintegrate on re-entry over Texas, killing its seven astronauts.

Discovery launched on Tuesday from Florida in the first shuttle flight since Columbia.

The launch was smooth but not flawless. Video from one of an array of cameras at the takeoff showed a nick in heat-protective tiles near the nose landing gear and an unexplained piece of debris falling away from the exterior fuel tank.

The debris did not strike the shuttle, but the 1-inch (2.5 cm) gouge in the tile would require further study before it was known if it posed a danger, said flight operations manager John Shannon.

Because of schedule constraints, Wednesday's inspection would not include a look at the damaged tile, Shannon said. That likely would not happen until Friday, he said.

The laser, which will get as close as five feet to the orbiter, is on a 50-foot (15-meter) extension attached to the 50-foot-(15-meter)long robot arm used on previous shuttle flights.

It can detect minute cracks in the wings and nose cap, which are subjected to the most intense heat during landing.

The astronauts also will examine tiles around the crew cabin and tail, but using only a television camera.

Along with the laser and visual inspections, NASA has installed 176 damage-detecting sensors in the wings.

Tile damage to the shuttle is not unusual, but under new safety rules NASA must make sure that any problem does not hold the potential for a Columbia-like disaster.

"It's well documented that we have had 15,000 dings on shuttles, post-flight," Shannon said. But, he added, "we're going to look real close at this" damaged tile.

The shuttle is en route to the International Space Station and a planned docking on Thursday. NASA said Discovery was 177 miles above the earth early on Wednesday and trailing the station by 3,000 miles.

Before docking, Collins will park Discovery 600 feet away and put the shuttle in a slow back-flip while station crewmembers Sergei Krikalev and John Phillips snap photos of its underside in search of signs of damage.

Since Columbia, NASA has spent more than $1 billion on safety upgrades and worked to change a culture that investigators charged had become too casual about risk.

If NASA engineers determine there is dangerous damage to Discovery, the astronauts could try to repair it with experimental fixes they plan to test later in the flight.

In the worst case, the crew could take refuge on the International Space Station and await a rescue flight from shuttle Atlantis.

Also on Wednesday, astronauts Steve Robinson and Japan's Soichi Noguchi were to check out space suits they will wear later in the mission when they perform three space walks.

Other crew members on the 12-day mission include pilot Jim Kelly, Charles Camarda, Australia's Andy Thomas and Wendy Lawrence.