The mission also will fly a system to investigate the potential for robotically refueling existing spacecraft and return a failed ammonia pump module to help NASA better understand the failure mechanism and improve pump designs for future systems.
In late December, the agency's Space Operations Mission Directorate requested the shuttle and International Space Station programs take the necessary steps to maintain the capability to fly Atlantis on the STS-135 mission.
The Authorization Act of 2010 directs NASA to conduct the mission, and baselining the flight enables the program to begin preparations for the mission with a target launch date of June 28. The mission would be the 135th and final space shuttle flight.
Prepping for the next shuttle mission, STS-133, continues in the Vehicle Assembly Building at NASA's Kennedy Space Center in Florida where technicians are making good progress in their work to modify the stringers on Discovery's external fuel tank.
Discovery and its six astronauts are targeted to launch on the STS-133 mission to the International Space Station on Feb. 24.
Having been joined by their newest crew member, Steve Bowen, Discovery's astronauts will review robotics procedures and review spacewalk timelines at NASA's Johnson Space Center in Houston. Bowen, who flew into space on STS-132 in May 2010, will be the first astronaut to fly on consecutive missions.