So what's next for NASA with the retirement of the space shuttles? The recently released Global Exploration Roadmap (pdf) outlines a path for manned exploration to Mars. Along the way, NASA will build the necessary technologies by testing manned exploration to an NEA (Near Earth Asteroid) or by returning to the moon. The roadmap is a continuation of the Global Exploration Strategy previously released in 2007 representing NASA's continued recognition of international participation and growing commercial technology as critical components to success.

"International coordination and cooperation expands the breadth of human space exploration beyond what any one nation may accomplish on its own and increases the probability of success of human and robotic space exploration initiatives. More importantly, it will enable the complex and challenging missions to the Moon, asteroids, and Mars. Achieving the vision of sustainable human space exploration, including human missions to Mars, requires political support and resources over an extended period of time."