The use of automation in propellant loading for the Space Shuttle has significantly reduced human error and servicing time. For the STS-2 launch, 6 hours were required to load the Orbital Maneuvering System (OMS) tank and 4 hours to load the Reaction Control System (RCS) tank. This propellant loading was done manually until the STS-26R mission, when autosequencers were introduced. The autosequencers were developed during the downtime between the loss of the Orbiter Challenger and the return to flight. By the end of the Shuttle program, 3 hours were allocated for OMS loading, which included about 1.5 hours of sequencer run time. The RCS loading planned time was 45 minutes, but the sequencer actually finished this task in about 30 minutes.