Under the plan, Mr. Bush would withdraw the United States from the International Space Station by 2010. Construction of the station with the space shuttle is scheduled to be complete by that date, fulfilling the U.S. commitment to the 15 partner nations. After that, U.S. research on the orbiting laboratory would focus on the effects of long-term space flight on the human body. First proposed by Ronald Reagan in his 1984 State of the Union address, U.S. involvement in the ISS project costs about $1 billion annually. The program was put on hold since the Columbia space shuttle tragedy. In 2004, construction was about 60 percent completed. Click here for more on the ISS.