Safety considerations in a piloted spacecraft must take into account the possibility of an emergency at any stage of the flight, starting with the pre-launch countdown and ending with the vessel's return to Earth. Following the Challenger disaster in 1986, the crew compartment was found in the Atlantic Ocean. It appeared that at least some crewmembers survived the initial explosion and were alive before the impact with the water. But the seven astronauts had no way to escape, and their cloth uniforms offered no protection or survival capabilities. The National Aeronautics and Space Administration (NASA) proceeded to implement changes to the crew module and the astronauts' uniforms, making emergency evacuation and survival more likely during specific periods in the shuttle's mission.

In the event of an emergency on the launch pad, the astronauts can evacuate the shuttle up to 30 seconds before launch. The shuttle launch gantry is...