Each time the space shuttle rises from its launchpad at Cape Canaveral, Fla., an Air Force officer waits anxiously for the first 2 minutes to pass safely. If the spaceship were to veer off course and endanger a populated area, this range safety officer would bear the terrible responsibility of flipping a pair of switches under a stenciled panel reading “Flight Termination.” The first switch arms explosives on the shuttle’s two solid rocket boosters. Flipping the second switch would detonate them, destroying the shuttle and crew.

“If something happens when it’s just off the pad, there’s only a couple of seconds [to react],” says Bryan O’Connor, a former shuttle commander and NASA’s chief of safety and mission assurance.