Shuttle probe focuses on vent as possible source of ice

By Paul Recer, Associated Press, 2/10/2003

OUSTON - Investigators of the space shuttle Columbia disaster are searching for evidence that a block of ice big enough to damage Columbia's wing may have formed on a waste-water vent, spokesmen at the Johnson Space Center said yesterday. A similar problem plagued an earlier shuttle flight.

They also are looking closely at what could be two key pieces of Columbia debris: a 2-foot piece of one wing, including an attached chunk of thermal tiles, and a 300-pound cover of a landing gear compartment, possibly the site of a sudden temperature rise moments before the shuttle broke apart.

One day after Columbia's Jan. 16 launch, military radar detected an object moving rapidly away from the shuttle. NASA said it did not know what the object was, but the possibility that it could have been ice from a vent sent investigators back to a detailed search for evidence that the shuttle may have formed ice throughout its mission.

Admiral Hal Gehman, head of a board investigating the Columbia accident, said yesterday that the object detected near the shuttle could have come from the spacecraft and could be ice. He said the US Space Command of the Air Force, which monitors objects in space, is providing data on the object to the investigators.

''It's too early to say if they mean anything,'' Gehman said of the reports.

The waste-water vent, which is under the shuttle cabin in front of the left wing, is used to expel into space surplus water generated from the shuttle's fuel cell power system and urine.

Usually the water shoots out into the cold vacuum of space as a spray of crystals, but on at least one shuttle mission, in 1984, the water formed a basketball-sized chunk of ice on the lip of the vent. At the time, NASA engineers were so concerned the ice could damage the shuttle wing during reentry that they ordered the astronauts aboard Discovery to use the shuttle's robot arm to break off the ice.

That heavy robot arm, which wasn't necessary for Columbia's 16-day science mission, was left off so more experiments could be added, and the water vent could not be seen from the cabin by the seven astronauts. NASA spokesman Kyle Herring said it's possible ice could have formed and not been detected, even though heaters were installed on the waste-water dump valve after the 1984 mission.

When Columbia fired its rockets to drop out of orbit, it could have sent any accumulated ice slamming into the wing, where data suggest there was severe damage to the thermal protection tiles. The theory is one of a number of scenarios being probed by engineers.

Gehman said that although he and the other members of the Columbia investigation board were appointed by NASA, they have the authority to conduct testing in laboratories not affiliated with the space agency.

He said yesterday that the board will split up into three teams and that each will gather data at different NASA centers, speeding up the investigation. The board has 60 days to complete its work. Some critics said the board needs more time, noting that the commission that investigated the 1986 Challenger accident required 120 days.

NASA administrator Sean O'Keefe said yesterday that no theory has been excluded. ''Nothing is off the table,'' he said on CNN.

More than 12,000 pieces of debris have been found in Texas and Louisiana, including what appears to be a hatch door with a hydraulic opening and closing mechanism that was found yesterday. O'Keefe said the debris will be transported to Kennedy Space Center in Florida starting this week, where investigators will attempt to reassemble it.

''There is certainly no way we are going be able to reconstruct it. The pieces are just absolutely mangled,'' O'Keefe said.

This story ran on page A11 of the Boston Globe on 2/10/2003.
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