STS-51 marked the fourth launch pad abort in the shuttle program and the third for the orbiter Discovery. At just 3 seconds away from liftoff, the engines were shut down due to a faulty fuel flow sensor. This article was reprinted from the September 1993 issue of Countdown Magazine.

On July 12, 1985, the space shuttle program experienced its second launch pad abort. Discovery and the STS-51F crew were just 3 seconds from liftoff when the #2 engine failed causing a shutdown of all three engines. STS-51F would later experience another abort but this one at five minutes into ascent. The second abort was unrelated to the first and resulted in a safe abort-to-orbit scenario.