Robert Allan Ridley Parker is an American physicist and astronomer, former director of the NASA Management Office at the Jet Propulsion Laboratory, and a retired NASA astronaut. He was a mission specialist on two Space Shuttle missions, STS-9 and STS-35.

STS-9 was the ninth NASA Space Shuttle mission and the sixth mission of the Space Shuttle Columbia. Launched on 28 November 1983, the ten-day mission carried the first Spacelab laboratory module into orbit.