STS-121 (July 4–17, 2006), was a return-to-flight test mission and assembly flight to the International Space Station. During the 13-day flight, the crew of Space Shuttle Discovery tested new equipment and procedures that increase the safety of space shuttles, repaired a rail car on the International Space Station and produced never-before-seen, high-resolution images of the Shuttle during and after its July 4 launch. Wilson supported robotic arm operations for vehicle inspection, Multi-Purpose Logistics Module installation and EVAs and was responsible for the transfer of more than 28,000 pounds of supplies and equipment to the ISS. The crew also performed maintenance on the space station and delivered a new Expedition 13 crew member to the station. The mission was accomplished in 306 hours, 37 minutes and 54 seconds.