STS-55
However, this date slipped to early March 1993 due to concerns with the tip-seal retainers in the main engines' oxidizer turbopumps.Further delays were caused by the burst of a hydraulic flex hose in the aft compartment during the Flight Readiness Test (FRT).[2] Columbia carried to orbit the second reusable German Spacelab D-2 and demonstrated the shuttle's ability for international cooperation, exploration, and scientific research in space.They also successfully completed an in-flight maintenance procedure for collection of orbiter waste water, which allowed the mission to continue.These experiments allowed students and amateur radio operators from around the world to talk directly with the Space Shuttle in orbit and participated in a SpaceMedicine conference with the Mayo Clinic.