A top NASA official says the U.S. space agency is working to recover pieces of heat-resistant tiles from the scattered remains of space shuttle Columbia, which could explain what caused it to disintegrate shortly after re-entering the earth's atmosphere.
Key to finding out what caused Columbia to disintegrate could be finding out what caused the temperature on the left side of the shuttle's fuselage to climb rapidly, just minutes before Columbia broke into pieces and fell to Earth.
"There's some other missing link that we don't have yet, that is contributing to this temperature increase, and we've got to go find that," said program manager Ron Dittemore. He said NASA is hoping to recover pieces of the shuttle's heat-resistant tiles, which he believes will hold answers. "That missing link is out there, and we just need to be persistent and go find it," he said.
One possible theory now being explored involves an incident just after liftoff on January 16, when a piece of hardened foam insulation struck Columbia's left wing. At the time, NASA engineers judged it to be of no concern to the overall safety of the shuttle. But investigators are looking into whether it may have set off a chain of events that ultimately caused the shuttle to break up under the extreme heat and pressure of re-entering the earth's atmosphere just minutes before landing.
"We want to know if we made any erroneous assumptions. We want to know if we weren't conservative enough. We want to know if we made any mistakes. And so, we are redoing the complete analysis," said Mr. Dittemore.
It may be months, or longer, before the cause of the Columbia disaster is determined. For the moment, Mr. Dittemore describes it as a mystery. "We may never know the exact root cause. Because we may never gather all the evidence to pin point it happened at this location for this cause. We may never know that," he said.
As the investigation continues, so do efforts to recover the remains of the six Americans as well as the man who had become Israel's first astronaut. On Tuesday, President Bush will attend a memorial in honor of all seven at the Johnson Space Center near Houston.