Vapor trails follow space shuttle Atlantis as it approaches Runway 15 on the Shuttle Landing Facility for the final time.

Vapor trails follow space shuttle Atlantis as it approaches Runway 15 on the Shuttle Landing Facility at NASA's Kennedy Space Center in Florida for the final time. A vapor trail, known as a contrail, is a cloud of water vapor that condenses and freezes around the small particles in aircraft exhaust. Atlantis marked the 26th nighttime landing of NASA's Space Shuttle Program and the 78th landing at Kennedy. It also was the final mission for the shuttle program.

STS-135 was the 33rd and final flight for Atlantis, which has spent 307 days in space, orbited Earth 4,848 times and traveled 125,935,769 miles. For more information on the space shuttle era, visit www.nasa.gov/mission_pages/shuttle/flyout. Photo credit: NASA/Sandra Joseph and Kevin O'Connell