Internal e-mails among NASA engineers and contractor personnel in the days prior to Columbia's disastrous reentry provide deepening evidence that serious concerns about the left wheel well and the survivability of the left wing were widespread and growing during the final days of the flight.

None of the information on serious, but survivable, landing gear issues was shared with mission commander USAF Col. Rick Husband, and it will be up to the accident board to determine if more dire projections were elevated properly within NASA management.

In a stance sure to spark debate downstream, NASA Administrator Sean O'Keefe told the House Science Committe, "It sure looks like that dialogue went on at the exact right levels for the operational considerations involved."

The concerns and projections continued to be aired four days after NASA's Mission Management Team sided with a Boeing assessment that safety of flight was not an issue in connection with external tank debris assessments.

Adm. (ret.) Harold W. Gehman, Jr., who heads the independent Columbia Accident Investigation Board (CAIB), said Boeing's foam debris risk analysis is being reviewed from several aspects, including any potential for a conflict of interest in the way Boeing employees made their findings. Lockheed Martin input on the potential for debris from its external tank also is being similarly scrutinized.

Other developments include: