Confirmation came from mission managers at 7:24 a.m. EST today that a Sunday launch for space shuttle Atlantis had been cancelled. At approximately 6:50 a.m. EST this morning, the third of four liquid hydrogen sensors on the LH2 fuel tank of NASA’s space shuttle Atlantis failed its simulated tests. This was in violation of the revised criteria put forth by mission managers yesterday which stated that all four sensors must be working properly throughout the duration of the launch proceedings for the launch to continue.
“Two or three minutes after [a simulated test] was done they were all ‘dry’,” said NASA Test Director, Doug Lyons, “then we saw system number three go from ‘dry’ to ‘wet,’ which was a failure.”
As was stated by the mission managers during the press conference on Saturday, Dec. 9, if a scrub were to occur the launching proceedings would become a series of testing exercises to troubleshoot the sensors. All indications point to the malfunctions being caused by an open circuit somewhere in the wiring between the shuttle and the fuel tanks. Mission managers will convene today at 9 a.m. EST to discuss when another launch may be attempted.
The malfunctioning sensors have been behind the grounding of Atlantis since Thursday, Dec. 6, when two of them failed simulated tests. Mission STS-122, in which Atlantis delivers a payload consisting of the European Space Agency’s Columbus laboratory module to the International Space Station, has been consistently postponed ever since.