Inside Endeavour's opened payload bay a worker installs a wiring modification called the Station to Shuttle Power Transfer System.

Inside Endeavour's opened payload bay, a worker installs a wiring modification called the "Station to Shuttle Power Transfer System," or SSPTS. The SSPTS allows the space shuttle to stay docked at the International Space Station longer by providing its power and preserving its consumables. Endeavour is scheduled for mission STS-118 in June. It will be the orbiter's first shuttle flight in nearly five years. The vehicle has undergone an extensive modification period, including the addition of all of the return-to-flight safety modifications added to both Discovery and Atlantis. The June mission will deliver another starboard solar array, S5, to the International Space Station. Photo credit: NASA/Kim Shiflett