Two days before the Columbia disaster, NASA engineers wrote a memo detailing their concerns about damage caused to the orbiter's left wing when a chunk of foam smashed into it, eighty seconds after lift-off.

MSNBC reports the engineers who wrote the memo and distributed it to operations centers around the world believed the seven-inch long [note: some reports said, "7 feet." We don't know which is accurate --ed.] by 30-inch wide gash posed a "significant danger" to the Columbia upon landing.

NASA's Shuttle Program Director, Ron Dittemore, indicated in Sunday's news conference that the preliminary investigation into Saturday's shuttle disaster is beginning to focus on the left landing gear well, a junction point for temperature sensors that began to fail seven minutes before the orbiter broke up over East Texas.

"It's very interesting," said Dittemore, "(Saturday), we told you that we lost instrumentation readings on the trailing edge of the left wing. The wires for those sensors junction in the wheel well."

"It's looking more and more like a thermal event," said Dittemore, "more than a structural event. But I caution you, it's still early in the investigation."

FMI: www.nasa.gov, www.spaceflight.nasa.gov