A thermal protection system technician secures a newly installed heat shield tile in place under Atlantis.

In Orbiter Processing Facility-1 at NASA's Kennedy Space Center in Florida, a thermal protection system technician secures a newly installed heat shield tile in place under space shuttle Atlantis with a pressure fitting to ensure a tight bond.

The tiles are part of the Orbiter Thermal Protection System that protects the shuttle against temperatures as high as 3,000 degrees Fahrenheit, which are produced during descent for landing. Atlantis is being prepared for the STS-135 mission, which will carry the Raffaello multi-purpose logistics module packed with supplies, logistics and spare parts to the International Space Station. STS-135 is targeted to launch June 28, and will be the last flight for the Space Shuttle Program. Photo credit: NASA/Jack Pfaller