The space shuttle is a reusable orbital vehicle that jettisons two solid rocket boosters and an external fuel tank before entering Earth orbit. The shuttle flew a total of 135 missions between 1981 and 2011. In 1986, the Challenger was destroyed by an explosion, resulting in the loss of all seven crew members. In 2003, the Columbia disintegrated during re-entry, resulting in the loss of all seven crew members. The other 133 launches and landings were successful, logging over 21,000 orbits of Earth and over 8,000 days of manned spaceflight.