Before any shuttle crew lifts off into space, they must go through a “Terminal Countdown Demonstration Test” which simulates the final hours of a launch countdown. It serves as a practice exercise for both
the crew and the launch team. Everyone rehearses launch-day time lines and procedures. The test actually simulates ignition and automated shutdown of the shuttle’s main engines.
By that time, the shuttle has already been removed from its protective covering at the Vehicle Assembly Building and
rolled out to launch pad 39-A.
After the practice countdown reaches “T-0,” the astronauts are briefed on emergency procedures. The shuttle is equipped with a slide-wire system which the crew can use to escape if a malfunction occurs before ignition. The final test also simulates real-time failures of both the vehicle and ground systems.
When Columbia’scommander and crewarrived at Kennedy Space Center to report for their terminal countdown demonstration test, everyone was in high spirits. Successfully completing one of their last pre-launch protocols, the crew and the shuttle were ready for a January 16, 2003 launch.