Space shuttle Discovery will move back into the Vehicle Assembly Building (VAB) at Kennedy Space Center in Florida after tanking tests on 17 December, NASA says.

Abnormally frigid temperatures and high winds have slowed the testing process as the US space agency's engineers continue to attempt to determine the root cause of cracks in the tops of two 21-foot-long aluminium stringers during the shuttle's 5 November launch preparations.

Programme managers will move Discovery back to the VAB to perform additional image scans on the external tank, four or five days after the initial, outdoor tanking tests, NASA says. Once in the VAB, technicians will collect X-ray data on stringers on the back side of the external tank midsection, called the intertank, which is not accessible at the launch pad. The test instrumentation and foam insulation on those areas of the intertank would be removed and the area would be prepared again for launch.

At the launch pad, crews are currently finishing installing 89 strain gauges and temperature sensors for the tanking test to record movement and temperatures from the intertank as it changes temperatures during the loading of propellants and emptying process. The tank holds super-cooled liquid oxygen and liquid hydrogen, which cause the tank to shrink by about half an inch as it is filled.

NASA will review the data gathered from the tanking test and additional image scans before determining the next course of action, the space agency says. Currently, managers plan to have Discovery back on the launch pad in January ahead of its next launch window, which begins 3 February.

Source: Flight International