In Orbiter Processing Facility Bay 1, technicians work on the Forward Reaction Control System (FRCS) of space shuttle Atlantis as it sits in the transfer aisle prior to installation. The FRCS provides the thrust for attitude (rotational) maneuvers (pitch, yaw and roll) and for small velocity changes along the orbiter axis (translation maneuvers). Processing of Atlantis is under way for mission STS-115, the 19th flight to the International Space Station.