"Columbia" accident
Fueling of "Discovery's" External Tank in preparation for launch began at 11:50 GMT. By 12:50, it had been confirmed that initial tests on Engine Cutoff (ECO) sensors in the External Tank had been conducted successfully. ECO sensor failures had caused a number of delays to recent Shuttle launch attempts, and STS-124 is the first mission to use a modified tank, which is intended to eliminate such faults. At the time at which tanking began, weather forecasters predicted an 80 percent chance of acceptable conditions at the scheduled launch time. Fuelling was completed, and topping up of cryogenic propellant began, at 15:36. In addition to the ECO sensor modifications, this was the first mission to use an External Tank manufactured after the 
 in 2003, and therefore the first tank to have all safety enhancements built into it, rather than retrofitted.
Space Shuttle Discovery launches on mission STS-124