Space Shuttle Atlantis is poised and ready on Launch Pad 39A for a fourth launch attempt on mission STS-101.

After rollback of the Rotating Service Structure, Space Shuttle Atlantis is poised and ready on Launch Pad 39A for a fourth launch attempt on mission STS-101. At the top of the photo can be seen the Gaseous Oxygen Vent Hood, often called the "beanie cap." The hood helps vent gaseous oxygen vapors away from the Space Shuttle. The hood will be raised and retracted two and a half minutes before launch. Abutting the side of Atlantis is the orbiter access arm with the environmental chamber known as the White Room at the end. The White Room provides access to the crew compartment. In the background of the photo is the Atlantic Ocean. This will be the third assembly flight to the International Space Station. Liftoff of Space Shuttle Atlantis for the 10-day mission is scheduled for about 6:12 a.m. EDT from Launch Pad 39A. Landing is targeted for May 29 at 2:19 a.m. EDT. This is the 98th Shuttle flight and the 21st flight for Shuttle Atlantis