HOUSTON - Before the shuttle Columbia's fatal descent, a NASA engineer complained in e-mails that the agency was not paying more attention to problems he feared might occur during re-entry in the event of a breach near its left landing-gear compartment.
In a message dated three days before the disaster Feb. 1, the engineer told a co-worker at the space agency's Langley Research Center in Virginia that his efforts to share his concerns were being treated "like the plague."
He suggested that others, at NASA's Ames Research Center in Mountain View, Calif., could run landing simulations in secret to determine how the shuttle would perform if both tires on its left side were damaged by extreme heat.
"Since no Orbiter Program Management is 'directing' the sim [simulation] community to do this, it might need to be done 'at night,'" Robert Daugherty wrote in e-mails made public by the National Aeronautics and Space Administration yesterday.
In addition to the e-mails, NASA released three reports that show how the agency analyzed the potential for damage from debris that hit the orbiter's left wing during launch Jan. 16. The debris appears to be foam insulation from the outer layer of the shuttle's external tank.
NASA says Columbia might have been hit by three pieces of debris, though videos show only two of the chunks hitting the wing.
NASA spokesman James Hartsfield in Houston said it's not clear whether the pieces came from a single chunk that separated into three or whether they were three independent segments that broke loose from the same area of the tank.
In any case, Hartsfield said, the number of pieces does not change the conclusion of the analysis, which was that any potential damage from the debris would not endanger the shuttle.
He said the evaluation, performed by Boeing Co. for NASA, postulated the worst possible circumstance based on a piece of debris weighing up to 2.67 pounds. The debris could be as large as 20 inches long, 16 inches wide and 6 inches deep - roughly the size of a briefcase - without causing trouble, the evaluation found.
The detailed analysis considers multiple points of impact at varying angles, always reaching the conclusion that none would cause enough damage to endanger the ship and its crew.
By focusing on the impact of the largest possible piece, Hartsfield said, the agency ruled out any potential for trouble from smaller chunks.
"If the worst-case scenario was not a safety of flight issue, then, logically, it would not be an issue with the smaller pieces," he said.
Hartsfield said no concerns were brought to managers about the debris analysis during the mission and that he directed inquiries about the newly released e-mails to Langley.
NASA officials have said that the issues described in the internal e-mails were "what if" situations being discussed by diligent engineers. Their concerns were never acted upon because flight controllers at the Johnson Space Center agreed with the Boeing analysis that the debris was not a danger.
Robyn Suriano writes for the Orlando Sentinel, a Tribune Publishing newspaper.