Under tow by a tractor the orbiter Discovery turns toward the Orbiter Processing Facility.

Under tow by a diesel-powered tractor, the orbiter Discovery turns toward the Orbiter Processing Facility. Umbilical lines for coolant and purge air are still attached. Discovery landed at the SLF at 9:14 a.m. EDT, completing mission STS-121. Discovery traveled 5.3 million miles, landing on orbit 202. Mission elapsed time was 12 days, 18 hours, 37 minutes and 54 seconds. Main gear touchdown occurred on time at 9:14:43 EDT. Wheel stop was at 9:15:49 EDT. During the mission, the STS-121 crew tested new equipment and procedures to improve shuttle safety, and delivered supplies and made repairs to the International Space Station. Photo credit: NASA/Jim Grossmann