Space Exploration Act of 2003

Space Exploration Act of 2003 - Requires the Administrator of the National Aeronautics and Space Administration (NASA) to set forth as goals for the future activities of NASA's human space flight program, the development and flight demonstration, within 8, 10, 15, and 20 years, respectively, of a reusable space vehicle capable of carrying humans between: (1) low Earth orbit and Earth-Sun and Earth-Moon libration points; (2) low Earth orbit and an Earth-orbit crossing asteroid; (3) lunar orbit and the surface of the moon, as well as deployment of a human-tended facility on the lunar surface; and (4) low Earth orbit and Martian orbit and between Martian orbit and the surface of Mars, as well as deployment of a human-tended facility on the surface of a Martian moon.

Requires the Administrator to establish: (1) an Office of Exploration to be responsible for planning, budgeting, and managing activities undertaken by NASA to accomplish these goals; (2) a process for conducting competitions for innovative, cost-effective mission concepts to accomplish the goals; and (3) an independent panel to conduct a merit-based competitive review of the proposals submitted under each competition and to submit a rank-ordered evaluation of such proposals to the Administrator.

Requires the Administrator to provide to the Committee on Science of the House of Representatives and to the Committee on Commerce, Science, and Transportation of the Senate for each competitively selected proposal its implementation plan and the results of an independent external review of the initial proposal and of each annually updated implementation plan.