U.S. President George Bush on Wednesday will unveil a bold new plan for the future of NASA that will give the agency the green light to start developing the hardware required to return to the Moon and eventually journey on to Mars, government officials told SPACE.com Friday.This ambitious new plan will require Congress to approve billions of dollars in new spending and the elimination of other NASA programs, they said. Bush will ask Congress for an additional $800 million for NASA in the 2005 budget request he will submit this month, they said. The plan also calls for 5 percent annual increases in NASA’s budget beyond 2005.This new direction for the space agency’s human spaceflight program will lead to major changes in NASA’s current priorities, the officials confirmed.Those changes include retiring the shuttle fleet at the end of the decade and replacing it with a new vehicle, which is now called the Orbital Space Plane (OSP). The OSP soon will be renamed the Crew Exploration Vehicle -- the building block of the spacecraft that will be needed to transport crews to and from the moon early in the next decade.The Crew Exploration Vehicle would be launched aboard existing expendable rockets such as the Boeing Delta 4 or Lockheed Martin Atlas 5. Another existing NASA program, Project Prometheus, would continue to be focused on developing nuclear propulsion for interplanetary spacecraft and new long-lasting power sources for future bases.