Stormy weather in Texas forced the Columbia Accident Investigation Board to delay a critical test designed to find out whether foam debris could have caused the kind of wing leading edge damage that doomed the shuttle and its crew during re-entry.

The test, a potentially critical milestone in the shuttle investigation, had been planned for this afternoon at the Southwest Research Institute in San Antonio. But heavy rains grounded CAIB investigators in Houston and delayed work to prepare a wing leading edge mockup for the test. As a result, the test was delayed to Friday, between noon and 5 p.m., weather permitting.

"I know everybody there is disappointed, we're disappointed as well," said CAIB member Scott Hubbard, who is overseeing the test. "But in the interest of doing a really correct test and doing it in the manner in which we'd been planning to do, we felt this was the best decision."

Hubbard, other members of the CAIB and key NASA personnel were grounded in Houston by heavy rains. Hubbard spoke to reporters gathered at the Southwest Research Institute by telephone.

"This is like a launch delay," he said. "We had several other things I wanted to do at the test site, particularly I wanted to personally discuss and inspect a few features of the test plan. We don't have a signed test plan yet and just like in a space launch where there are go/no-go criteria, one of our go/no-go criteria is a signed test plan and I needed to put my personal eyes on a few areas and discuss them with the crew there to be sure we are all ready to go.

"This is a complex test with hundreds of sensors and a lot of other features, so seeing we were unable to get there and we had another delay at both ends it seemed like the right thing to do to not rush it and to be sure we had everything exactly correct."