A NASA safety engineer warned days before Columbia broke apart that he feared the shuttle was at risk for a devastating breach near its left wheel, and he suggested people in the U.S. space agency weren't adequately considering the threat.
"We can't imagine why getting information is being treated like the plague," the engineer wrote in one of a number of e-mails released Friday that describe greater concerns about Columbia's safety in the days before its breakup.
Other documents NASA released show that Columbia may have been struck by as many as three large chunks of foam that smashed against delicate insulating tiles as it took off, not just the one previously acknowledged.
Robert Daugherty, an engineer at NASA's Langley research facility, Va., did not indicate that he believed the breach would cause Columbia to break apart during its fiery descent. "No way to know, of course," he wrote.
But Daugherty warned in his e-mail on Jan. 29 about a possible breach near the seal of Columbia's wheel compartment that could have been caused by damage to the shuttle's thermal tiles there. He seemed mostly worried about the risks of pilots struggling to land Columbia with one or more tires damaged by extreme heat.
"It seems to me that if mission operations were to see both tire pressure indicators go to zero during entry, they would sure as hell want to know whether they should land with gear up, try to deploy the gear or go bailout," Daugherty wrote.
Meanwhile, as CBS News Space Consultant Bill Harwood the shuttle's fuselage remained essentially intact for at least a half minute after the commander's final transmission, according to sources familiar with an ongoing analysis of the last 32 seconds of telemetry from the doomed spacecraft. The astronauts almost certainly had some awareness of the unfolding disaster, but there is no insight at this point to indicate what they might have known, or when.
Analysis of the telemetry that was received is not complete. But officials say valid data continued flowing down for about five seconds after Air Force Col. Rick D. Husband's interrupted transmission. During that five-second period, two more right-firing thrusters ignited on command of Columbia's flight computers, joining the two already in operation to counteract an increasing aerodynamic drag on the left side of the vehicle, says Harwood.
Senior NASA officials have steadfastly supported assurances by The Boeing Co., a contractor, since the accident that Columbia was expected to be return safely despite possible tile damage along its left wing. They also have maintained that concerns expressed in e-mails among mid-level engineers such as Daugherty were part of a "what-if" analysis, and that even these engineers were satisfied with Boeing's conclusions.
"During the flight, no one involved in the analysis or the management team or the flight team raised any concerns," NASA spokesman James Hartsfield said Friday.
But the e-mails disclosed in Washington raise important issues about those safety assurances by Boeing, including underlying assumptions about the likelihood of damage from a large chunk of breakaway foam and whether damage to Columbia might have been caused by falling ice.
They also include references by Daugherty and another Langley employee, Mark J. Shuart, about the secrecy within National Aeronautics and Space Administration of the ongoing study of risks to Columbia. Shuart wrote Jan. 28 to two other employees that, "I am advised that the fact that this incident occurred is not being widely discussed."
The e-mails, which never were passed to senior mission controllers in Houston during Columbia's flight, will be turned over to the board investigating the accident, board spokeswoman Laura Brown said. All seven astronauts died in the breakup Feb. 1.
The e-mails had been sought since last week by news organizations under the Freedom of Information Act. Employees at NASA's headquarters here published them Friday with little fanfare on the agency's Web site.
Among the e-mails were two written after the breakup. Daniel D. Mazanek of the Spacecraft and Sensors Branch at Langley wrote Feb. 7 that the debris that struck Columbia might have been ice, not foam from the external fuel tank.
Boeing had calculated that a chunk of foam weighing 2.67 pounds was responsible. But Mazanek estimated that a chunk of ice the same size would have been more damaging because it would weigh 63.4 pounds, "the equivalent of a 500-pound safe hitting the wing at 365 mph."
Last week, NASA disclosed a similar e-mail by Daugherty. He wrote two days before Columbia's breakup about risks to the shuttle from "catastrophic" failures caused by tires possibly bursting inside the wheel compartment from extreme heat.
Daugherty was responding in that e-mail to a telephone call Jan. 27 from officials at the Johnson Space Center asking what might happen if Columbia's tires were not inflated when it attempted to land.
Daugherty cautioned in the e-mail disclosed earlier that damage to delicate tiles near Columbia's landing gear door could permit dangerous temperatures causing one or more tires to burst, perhaps ending with failures that would place the astronauts "in a world of hurt."