Engineers warned of shuttle wing burning
By Richard Stenger
(CNN) -- The day before the Columbia broke up, space shuttle engineers expressed concern that its left wing might burn off and lead to the complete loss of the orbiter.
The warnings, documented in a volley of NASA e-mails released on Wednesday, reflect uncanny similarities to what may have actually taken place.
The shuttle shattered as it re-entered the atmosphere February 1, minutes after developing problems with its left wing, which had been struck by external fuel tank debris 16 days earlier at liftoff.
"Why are we talking about this on the day before landing and not the day after launch?" asked Bill Anderson of the United Space Alliance LLC, the primary space shuttle contractor, in a January 31 memo to senior shuttle engineers.
While the group focused on how to manage an emergency landing if the landing gear were damaged, Anderson cautioned that the stakes could be much higher.
"If the wing is off, or has a big hole in it, you're not going to make the runway and the gear question is moot," he said.
Hours earlier, Jeffrey Kling, a flight controller at NASA's Johnson Space Center, had outlined possible landing problems if launch debris had breached a shuttle landing gear wheel well.
He warned that a breach, by allowing super hot gas to bore into the orbiter, could blow off the gear door and even affect the interior aluminum structure of the wing, with dire consequences.
"Ultimately our ... recommendation in that case is going to be to set up for a bailout (assuming the wing doesn't burn off before we can get the crew out)," he said.
In such a scenario, he wrote, the orbiter could register a temperature increase and lose sensor readings involving tire pressure and hydraulics.
The next day, Kling was among the flight controllers in Mission Control who reported the abrupt, mysterious loss of a sequence of sensor readings in the left wing, shortly after a temperature rise was detected in the left wheel well.
Despite their concerns, the discussions were not forwarded to top NASA management, who had signed off earlier on a launch debris assessment that determined there was no landing risk.
Even if scraps of tank foam had struck thermal tiles that protect the shuttle underbelly from the intense heat of atmospheric re-rentry, the damage would have been minimal, according to the analysis.
The conclusion did little to comfort some, including NASA engineer Robert Daugherty, who had raised landing concerns in an earlier NASA e-mail exchange.
"Any more activity today on the tile damage or are people just relegated to crossing their fingers and hoping for the best?" he wrote January 28.
The space agency and an independent investigation board maintain that launch debris is only one of many theories they are studying to find out what went wrong.