The results of radar signature testing of sample T-seals from the space shuttle is consistent with radar data observed when an unidentified fragment broke loose from Columbia in orbit on day two of its mission and re-entered Earth's atmosphere, according to the Columbia Accident Investigation Board (CAIB).

Scientists at the Air Force Research Laboratory have spent the past few weeks gathering radar return data on various sample items from the leading edge of the shuttle's left wing and comparing the results to the observed radar signature of the mystery fragment, as well as its ballistic trajectory into the atmosphere.

"That T-seal that we did submit passed both the radar cross-section and the signature ballistics required that was tracked upon re-entry," CAIB member Rear Adm. Stephen Turcotte said during a briefing April 22. "So that did correspond exactly with what we saw [during] the mission."

The leading theory of Columbia's destruction has superheated gas entering a breach on the orbiter's left wing during re-entry Feb. 1, at or near reinforced carbon-carbon (RCC) panel number 8. The U-shaped RCC panels are held in place by the T-seals, which are bolted to the front of the wing with inconel fittings.