Bill Readdy, NASA's associate administrator for space flight, said "it appears that the window extending from March 11 to April 6 honored all the constraints that we know," including a daylight launch and daylight external tank separation.

He noted, however, that the accident investigation board has not yet submitted its final report, expected in late August, and added that there "will likely be adjustments."

NASA Deputy Administrator Fred Gregory said the agency "will be responding almost to the letter the recommendations of the board."

Another 27-member independent commission charged with controlling flight operations "will tell us if we've gone down the long path or not," Gregory added.

Readdy expressed confidence that "the space program will come back smarter and safer" once the board presents its final report, eagerly awaited some eight months after the space shuttle Columbia broke apart in midair, killing all seven astronauts on board.

Investigators are convinced that a foam panel that came off during takeoff on January 16 pierced the heat-insulating skin around the shuttle, letting in boiling gases.

The report is to set out the sequence of events between takeoff and the disaster as Columbia re-entered the Earth's atmosphere before it was to land at Florida's Cape Canaveral.

SPACE.WIRE