Technicians prepare to move an aft access platform into place behind shuttle Atlantis following the installation of the spacecraft's three main engines.

In Orbiter Processing Facility-1 at NASA's Kennedy Space Center in Florida, technicians prepare to move an aft access platform into place behind shuttle Atlantis, following the installation of the spacecraft's three main engines. Shown is the right-hand orbital maneuvering system (OMS) pod and engine taken from the right-hand access arm.

Atlantis is being prepared for the "launch on need," or potential rescue mission, for the final planned shuttle flight, Endeavour's STS-134 mission. For more information, visit www.nasa.gov/shuttle. Photo credit: NASA/Kim Shiflett