STS-118 Mission Specialist Dave Williams is helped adjusting his helmet as he suits up for launch.

In the Operations and Checkout Building, STS-118 Mission Specialist Dave Williams is helped adjusting his helmet as he suits up for launch. Williams, who is making his second spaceflight, represents the Canadian Space Agency. Space Shuttle Endeavour's STS-118 mission is the 22nd shuttle flight to the International Space Station. It will continue space station construction by delivering a third starboard truss segment, S5, and other payloads such as the SPACEHAB module and the external stowage platform 3. The 11-day mission may be extended to as many as 14 depending on the test of the Station-to-Shuttle Power Transfer System that will allow the docked shuttle to draw electrical power from the station and extend its visits to the orbiting lab. NASA/Kim Shiflett