Nasa cancelled its second launch attempt of space shuttle Atlantis after a sensor in an emergency engine cutoff system failed again on Sunday, once more delaying Europe’s major contribution to the International Space Station.
Atlantis and its seven astronauts — five Americans, one German and one French — are due to deliver Europe’s Columbus science laboratory module to the space station.
The sensors in the shuttle’s external fuel tank are part of a backup system to cut off the shuttle’s main engines in case of an emergency during the climb to orbit. Two of the four sensors in ship’s hydrogen tank failed during Nasa’s first launch attempt on Thursday.
”The ground rules that were laid out before we went into [Sunday’s] launch attempt were that we would have to have four sensors that were mandatory for launch,” launch commentator George Diller said.
”According to the plan that was laid out, the rest of the morning as it was laid out, is probably going to evolve into a tanking test,” Diller said.
Nasa did not immediately reschedule Atlantis’ launch, although the next earliest opportunity is at 19.55pm GMT on Monday. Nasa has until Thursday or Friday for launch attempts this year.
The sensors, which operate like dipsticks to determine fuel levels, are part of a backup system to cut off the shuttle’s three hydrogen-burning main engines if the tank runs dry due to a leak or other problem.
Running the engines without propellant could cause their pumps to break and possibly trigger a catastrophic explosion. – Reuters