February 3, 2003	Monday	Zilhaj 1,1423

HAMBURG, Feb 2: German space experts said on Sunday the inquiry into the space shuttle Columbia disaster would focus on the heat shield, with damage to insulation tiles during the launch just one of the possible explanations for the accident.

Not only will the US space agency NASA mount an inquiry, but congressional and government investigations are expected.

Heinz-Hermann Koelle, 77, who was chief planner on the US Apollo programme and was later professor of space studies in Berlin, said the craft “undoubtedly” suffered structural failure as a consequence of a heat shield defect.

“It will take two to three months to settle the cause,” he forecast. Koelle’s analysis suggested five possible reasons for the tragedy:

(1) Damage to the tiles on the leading edge of the left wing during launch: “Apparently a piece of insulating foam from the fuel tank broke off during the launch,” said Koelle. “They seemed to think the risk was slight. Otherwise they could have aborted the launch.”

“The astronauts could also have been rescued from space using a second shuttle.”

(2) Maintenance errors on the ground: “People sometimes work unreliably, so that can’t be ruled out.”

(3) Material fatigue: “The Columbia was 20 years old, so that is possible.”

(4) A guidance error that exposed a weaker part of the shuttle to friction: “Re-entry into the atmosphere is the most critical phase of landing. The shuttle is supposed to descend into a lower orbit with its nose up so that the underside can take the extreme heat.”

“This manoeuvre is automated, but the pilot has to intervene if something goes wrong.”

(5) An explosion of a tyre in the undercarriage could have damaged the heat shield. Koelle said he had seen reports that sensors were no longer displaying tyre pressure shortly before the crash. This suggested problems in one or more of the eight wheels.

The seven astronauts would have known the craft was crashing from growing noises or vibrations, Koelle said.

“I don’t know how much a human being can handle in the space of a minute, but they did know ‘We’re done for’,” he said.

Koelle, who retired in 1991, worked from 1955 to 1965 on Apollo rockets, the predecessors to today’s shuttles.

Ernst Messerschmid, a former German astronaut, concurred, saying, either the heat shield failed or the crew lost control of the flight angle. “I would not say an explosion was very likely, but rather that they lost a major system and the shuttle gradually broke apart.”

Monika Auweter-Kurtz of Stuttgart University’s Institute of Space Flight Systems criticised the heat shield used on the shuttle.

“Technological development of the space shuttles was frozen in 1974,” she said. “A modern vehicle would definitely have been far safer.”

Another Berlin space expert, Fabian Eilingsfeld, noted, “If something is lost from the heat shield, the aluminium structure beneath cannot handle the thermal strain.” The nose and leading edges of the wings were built to stand 1,650 degrees centigrade.

Eilingsfeld, whose academic area is space tourism, recalled heat shield damage on the maiden shuttle flight nearly 22 years ago.

“Back then, in April 1981, there were news photos that clearly showed heat shield tiles missing. They fell off during launch,” he said. Eilingsfeld said the crash might set back by years plans to regularly take paying passengers into space.

“There have been efforts recently to raise finance for sub-orbital travel,” he said. “The disaster could lead to major delays.”—dpa