NASA opts to move forward to Thursday's shuttle launch
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: February 1, 2008
NASA managers today decided to press ahead with preparations for launch of the shuttle Atlantis Feb. 7 pending final work Monday to make sure a kinked Freon flex hose retracts as required when the ship's payload bay doors are closed for flight.
Assuming no other problems develop, engineers plan to restart Atlantis's countdown at 5 p.m. Monday for a launch attempt at 2:45:28 p.m. Thursday. This will be NASA's third attempt to launch Atlantis on a space station assembly mission following delays Dec. 6 and 9 because of problems with low-level fuel sensors in the shuttle's external tank.
Those problems were traced to a suspect wiring connector at the base of the tank that has since been modified to prevent the sort of intermittent continuity blamed for the December delays. Engineers are confident the sensor circuits will work properly when the tank is fueled for launch Thursday.
The Freon coolant line issue cropped up earlier this week when the shuttle's cargo bay doors were opened for routine payload processing. Engineers noticed one of four metal-jacketed flex hoses that carry Freon coolant to and from radiator panels mounted on the inside of the ship's cargo bay doors was sharply kinked.
The shuttle is equipped with two Freon coolant loops to dissipate the heat generated by the ship's myriad electronic systems. The concern in this case was the possibility that launch vibrations could damage a weakened flex hose enough to cause a leak.
While loss of a Freon coolant loop would not pose a safety of flight risk, it could force mission managers to shorten a flight and extensive tests were ordered to make sure the hose aboard Atlantis will function properly after launch.
As it turns out, engineers discovered a similar kink in a hose aboard Discovery late last year. That hose was removed and subjected to the sort of flexing it could expect to see over about a dozen door opening-closing cycles. A NASA spokesman said the hose continue to work normally with no signs of any internal damage.
As a result, NASA managers called off plans for a Saturday engineering meeting and decided to press ahead with launch preparations. When Atlantis's payload bay doors are closed overnight Sunday, engineers will manually guide the kinked line into its storage container, using an improvised tool when the right-side door closes far enough to limit access.
"They'll assist the hose as the door is closing for flight," the spokesman said. "They'll assist it by hand until it gets closed enough and then they'll use this pole. They'll use it as a guide, they won't put any pressure on it."
Assuming the hose retracts as required, engineers will start the countdown as planned Monday afternoon. The issue will be discussed again at management review Tuesday.