The perceived national security threat posed by early Soviet leads in spaceflight drove NASA’s budget to its peak, both in real inflation-adjusted dollars and in a percentage of the total federal budget (4. 41% in 1966). But the U. S. victory in the Space Race — landing men on the Moon — erased the perceived threat, and NASA was unable to sustain political support for its vision of an even more ambitious Space Transportation System entailing reusable Earth-to-orbit shuttles, a permanent space station, lunar bases, and a manned mission to Mars. Only a scaled-back Space Shuttle was approved, and NASA’s funding leveled off at just under 1% in 1976, then declined to 0. 75% in 1986. After a brief increase to 1. 01% in 1992, it declined to about 0. 49% in 2013.