In NASA Kennedy Space Center's Orbiter Processing Facility bay 3, STS-121 Pilot Mark Kelly and Mission Specialist Stephanie Wilson work with equipment that will be on the mission. The crew is at Kennedy to take part in the crew equipment interface test, which provides hands-on experience with equipment to be used on-orbit. Launch of Space Shuttle Discovery on mission STS-121, the second return-to-flight mission, is scheduled no earlier than May.