Subsequent investigations revealed that a cabin vent valve had accidentally opened and depressurised the capsule when the service module was jettisoned at an altitude of 168 km, causing the crew to fall unconscious and suffer cardiac arrest in less than a minute.

At 11.39am Challenger lifted off, and seventy-three seconds later the Shuttle began to disintegrate following a huge fireball. All seven members of crew were killed, and the disaster led to NASA suspending all Space Shuttle missions for over two and a half years.