This was a reflight of the STS-83 Microgravity Science Laboratory (MSL) mission. MSL was originally launched on 4 April 1997 at 2:20 pm EST and was intended to be on orbit for 15 days, 16 hours. The mission was cut short due to a problem with Fuel Cell #2 and Columbia landed on 8 April 1997 after 3 days 23 hours.

The primary payload on STS-83 was the Microgravity Science Laboratory (MSL). MSL was a collection of microgravity experiments housed inside a European Spacelab Long Module (LM). It built on the cooperative and scientific foundation of the International Microgravity Laboratory missions (IML-1 on STS-42 and IML-2 on STS-65), the United States Microgravity Laboratory missions (USML-1 on STS-50 and USML-2 on STS-73), the Japanese Spacelab mission (Spacelab-J on STS-47), the Spacelab Life and Microgravity Science Mission (LMS on STS-78) and the German Spacelab missions (D-1 on STS-61-A and D-2 on STS-55).