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 human 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 0.5% in 2013.