Revolutionary Space Transportation Needed

摘要

The fundamental goal of U.S. space exploration policy is to advance U.S. scientific, security and economic interests through a robust space exploration program. The pursuit of this goal with evolved transportation systems would be extremely difficult, for example, for human missions to Mars, for responsive, flexible and resilient Earth-to-orbit transportation, and for space tourism. Instead, it will take a combination of evolutionary and revolutionary space transportation systems to achieve this goal.