With the Rotating Service Structure rolled back, Space Shuttle Atlantis stands ready for launch on mission STS-110. The Orbiter Access Arm extends from the Fixed Service Structure (FSS) to the crew compartment hatch, through which the STS-110 crew will enter Atlantis. Above the golden external tank is the vent hood (known as the "beanie cap") at the end of the gaseous oxygen vent arm. Vapors are created as the liquid oxygen in the external tank boil off. The hood vents the gaseous oxygen vapors away from the Space Shuttle vehicle. The RSS provides protected access to the orbiter for changeout and servicing of payloads at the pad. The structure has access platforms at five levels to provide access to the payload bay. The FSS provides access to the orbiter and the RSS. Mission STS-110 is scheduled to launch April 4 on its 11-day mission to the International Space Station