WASHINGTON - One day before the Columbia disaster, senior NASA engineers worried that the shuttle's left wing might burn off and cause the deaths of the crew, describing a sequence of events much like the one investigators believe happened.
They never sent their warnings to NASA's leaders, according to dozens of pages of e-mails NASA released yesterday.
"Why are we talking about this on the day before landing and not the day after launch?" wrote William C. Anderson, an employee for the United Space Alliance LLC, a NASA contractor, less than 24 hours before the shuttle broke apart.
Two days earlier, one frustrated engineer had asked, "Any more activity today on the tile damage or are people just relegated to crossing their fingers and hoping for the best?"
After intense debate - by phone and e-mail - the engineers, supervisors and the head of the space agency's Langley research facility in Hampton, Va., decided against taking the matter to top NASA managers.
Jeffrey V. Kling, flight controller at Johnson Space Center's mission control in Texas, foresaw with haunting accuracy what might happen to Columbia during its fiery descent if superheated air penetrated the wheel compartment.
Kling wrote just 23 hours before the disaster that his engineering team's recommendation in such an event "is going to be to set up for a bailout (assuming the wing doesn't burn off before we can get the crew out)."
The e-mails describe a far broader discussion about the risks to Columbia than the concerns first raised three days earlier by Robert Daugherty, NASA senior research engineer at Langley. He was concerned most about the safety of the shuttle if it landed with flat tires or wheels damaged from extreme heat.
Daugherty was responding to questions Jan. 27 from Carlisle Campbell, NASA engineer at the Johnson Space Center, about how re-entry heat could damage the shuttle's tires. One day into the debate, Daugherty expressed frustration to Campbell about the apparent lack of interest with his remark about keeping fingers crossed.
Among the messages was one from Daugherty's boss at Langley, Mark J. Shuart, to another Langley supervisor, Doug Dwoyer, calling Daugherty "the kind of conservative, thorough engineer that NASA needs."
One e-mail, from R.K. "Kevin" McCluney, a shuttle mechanical engineer at the Johnson Space Center, described the risks that could lead to "LOCV" - NASA shorthand for the loss of the crew and vehicle.
McCluney ultimately recommended no action unless there was a "wholesale loss of data" from sensors in the left wing, in which case controllers would need to decide between a risky landing and bailout attempt.
"Beats me what the breakpoint would be between the two decisions," McCluney wrote.
Investigators have reported such a wholesale loss of sensor readings in Columbia's left wing, but it occurred too late to do anything - as the shuttle was racing through Earth's upper atmosphere and moments before its breakup.
NASA has considered a bailout by a shuttle crew feasible only during level, slow flight at 20,000 feet or lower. Columbia broke up at 207,000 feet while flying 18 times the speed of sound, roughly 12,500 mph.
Many of the e-mails NASA released yesterday were gathered at the direction of Ronald Dittemore, shuttle program manager at the Johnson Space Center. In a message he wrote the day that news organizations first reported Daugherty's concerns, Dittemore asked for copies of the e-mails "so that I can see the traffic and get a feel for the conversations."
Daugherty's concerns - and the subsequent debate among other engineers - took place days after engineers from the Boeing Co., another NASA contractor, had assured that Columbia could return safely despite possible damage to its left wing on liftoff from insulation peeling off its external fuel tank.
In response to Dittemore's request for the e-mails, Robert C. Doremus, a NASA employee at Johnson, summarized the earlier exchanges Feb. 11 and concluded that Daugherty and three other engineers, on the afternoon before the breakup, agreed "we were doing a 'what-if' discussion and that we all expected a safe entry."
The e-mails also disclose that Dwoyer, a middle manager at Langley, wrote to the director of the research center, Del Freeman, and asked whether Freeman should contact William F. Readdy, NASA's associate administrator for space flight.
NASA officials said yesterday that Freeman never contacted Readdy and considered the matter resolved after he discussed the matter with Langley engineers.
They never sent their warnings to NASA's leaders, according to dozens of pages of e-mails NASA released yesterday.
"Why are we talking about this on the day before landing and not the day after launch?" wrote William C. Anderson, an employee for the United Space Alliance LLC, a NASA contractor, less than 24 hours before the shuttle broke apart.
Two days earlier, one frustrated engineer had asked, "Any more activity today on the tile damage or are people just relegated to crossing their fingers and hoping for the best?"
After intense debate - by phone and e-mail - the engineers, supervisors and the head of the space agency's Langley research facility in Hampton, Va., decided against taking the matter to top NASA managers.
Jeffrey V. Kling, flight controller at Johnson Space Center's mission control in Texas, foresaw with haunting accuracy what might happen to Columbia during its fiery descent if superheated air penetrated the wheel compartment.
Kling wrote just 23 hours before the disaster that his engineering team's recommendation in such an event "is going to be to set up for a bailout (assuming the wing doesn't burn off before we can get the crew out)."
The e-mails describe a far broader discussion about the risks to Columbia than the concerns first raised three days earlier by Robert Daugherty, NASA senior research engineer at Langley. He was concerned most about the safety of the shuttle if it landed with flat tires or wheels damaged from extreme heat.
Daugherty was responding to questions Jan. 27 from Carlisle Campbell, NASA engineer at the Johnson Space Center, about how re-entry heat could damage the shuttle's tires. One day into the debate, Daugherty expressed frustration to Campbell about the apparent lack of interest with his remark about keeping fingers crossed.
Among the messages was one from Daugherty's boss at Langley, Mark J. Shuart, to another Langley supervisor, Doug Dwoyer, calling Daugherty "the kind of conservative, thorough engineer that NASA needs."
One e-mail, from R.K. "Kevin" McCluney, a shuttle mechanical engineer at the Johnson Space Center, described the risks that could lead to "LOCV" - NASA shorthand for the loss of the crew and vehicle.
McCluney ultimately recommended no action unless there was a "wholesale loss of data" from sensors in the left wing, in which case controllers would need to decide between a risky landing and bailout attempt.
"Beats me what the breakpoint would be between the two decisions," McCluney wrote.
Investigators have reported such a wholesale loss of sensor readings in Columbia's left wing, but it occurred too late to do anything - as the shuttle was racing through Earth's upper atmosphere and moments before its breakup.
NASA has considered a bailout by a shuttle crew feasible only during level, slow flight at 20,000 feet or lower. Columbia broke up at 207,000 feet while flying 18 times the speed of sound, roughly 12,500 mph.
Many of the e-mails NASA released yesterday were gathered at the direction of Ronald Dittemore, shuttle program manager at the Johnson Space Center. In a message he wrote the day that news organizations first reported Daugherty's concerns, Dittemore asked for copies of the e-mails "so that I can see the traffic and get a feel for the conversations."
Daugherty's concerns - and the subsequent debate among other engineers - took place days after engineers from the Boeing Co., another NASA contractor, had assured that Columbia could return safely despite possible damage to its left wing on liftoff from insulation peeling off its external fuel tank.
In response to Dittemore's request for the e-mails, Robert C. Doremus, a NASA employee at Johnson, summarized the earlier exchanges Feb. 11 and concluded that Daugherty and three other engineers, on the afternoon before the breakup, agreed "we were doing a 'what-if' discussion and that we all expected a safe entry."
The e-mails also disclose that Dwoyer, a middle manager at Langley, wrote to the director of the research center, Del Freeman, and asked whether Freeman should contact William F. Readdy, NASA's associate administrator for space flight.
NASA officials said yesterday that Freeman never contacted Readdy and considered the matter resolved after he discussed the matter with Langley engineers.