Cape Canaveral, Florida -- NASA has postponed the launch of space shuttle Discovery on its final mission, to no earlier than 30 Nov, to allow engineers and technicians time to diagnose and repair a hydrogen gas leak detected while filling the external tank last Friday morning (4 Nov).
US space agency NASA said in a 5 Nov statement that the team will also assess a foam crack on the external fuel tank's liquid oxygen intertank flange. The crack was discovered during de-tanking operations.
Discoevery had been scheduled to take off Thursday 3 Nov, but storms prevented the launch.
The gas leak discovered on Friday was at the Ground Umbilical Carrier Plate, an attachment point between the external tank and a 7-inch pipe that carries gaseous hydrogen safely away from Discovery to the flare stack, where it is burned off.
"We always place safety first," said NASA Associate Administrator for Space Operations Bill Gerstenmaier, in the NASA statement. "It is essential we repair this hardware before we fly the mission, and we will take the time to properly understand and fix the failure before we launch."
Mission managers will look closely at the crack in the external tank foam that developed as super-cold liquid hydrogen and liquid oxygen were being drained from the tank. The 15-storey tall, orange external tank shrinks and expands as its temperature changes from the effects of the propellants. That change can cause the foam insulation on the outside to crack.
Mike Moses, chair of the Mission Management Team, said the crack did not develop until after the launch attempt was called off. However, he said the team will analyse the crack carefully.
The six astronauts for Discovery's 11-day STS-133 mission will deliver the Permanent Multipurpose Module (PMM) to the International Space Station. The PMM was converted from the multi-purpose logistics module Leonardo. It can hold microgravity experiments in areas such as fluid physics, materials science, biology, and biotechnology.
The mission will feature two spacewalks to do maintenance work and install new components.
Commander Steve Lindsey leads the veteran crew, which consists of pilot Eric Boe and Mission Specialists Alvin Drew, Tim Kopra, Michael Barratt and Nicole Stott.
STS-133 is the final shuttle mission planned for 2010, Discovery's 39th and final scheduled flight; and the 35th shuttle mission to the station.
PIC: The crack in the fuel tank's foam insulation foam, discovered as liquid hydrogen and oxygen were drained from the tank.