Adm. Harold Gehman chairman of the Columbia Investigation Accident Board is shown some of the tiles recovered from Columbia.

In the RLV Hangar, Adm. Harold Gehman, center, chairman of the Columbia Investigation Accident Board, is shown some of the tiles recovered from Columbia. Gehman and other board members are visiting KSC as part of the ongoing investigation. With Gehman are U.S. Representatives Tom Feeney (far left) and Dave Weldon (next to him). Recovery efforts as of May 5 included 82,500 pieces of debris weighing 84,800 pounds, almost 40 percent of the total dry weight of the shuttle. About 25,000 personnel took part, utilizing almost 1.5 million total man-hours in the recovery effort and involving more than 130 federal, state and local agencies. The operation was also supported by more than 270 organizations that included businesses and volunteer groups.