NASA Space Shuttle Discovery At The Smithsonian Udvar-Hazy Air And Space Museum Editorial Photo

Discovery was the third Space Shuttle orbiter vehicle to fly in space. It entered service in 1984 and retired from spaceflight as the oldest and most accomplished orbiter. Discovery flew on 39 Earth-orbital missions, spent a total of 365 days in space, and traveled almost 240 million kilometers (150 million miles) more than the other orbiters. It shuttled 184 men and women into space and back, many of whom flew more than once, for a record-setting total crew count of 251.