John Bruce Medaris (May 12, 1902 – July 11, 1990) was a U.S Army officer who was commander of the Army Ballistic Missile Agency during the 1950s. During this period, the agency developed the Redstone, Jupiter-C, and Saturn I boosters.
During World War II, Medaris was a Colonel within the Ordnance Corps and helped organize the modification of tanks for the fighting in Normandy. These modified tanks, known as Rhino tanks and based on a device created by Curtis G. Culin, were able to breach the bocage countryside of Normandy.
Post-war, now Major General, Medaris became Wernher von Braun's patron when he took over command of the ABMA during the International Geophysical Year (IGY). Although the Navy's Vanguard was the official satellite program, Medaris encouraged von Braun to continue development in case Vanguard failed. When news of Sputnik I's launch was broadcast, von Braun said to the Defense Secretary, Neil McElroy, 'For God’s sake, let us do something. We can put up a satellite in sixty days.'
Medaris, knowing the Jet Propulsion Laboratory would need more time to prepare what became Explorer I, admonished Von Braun, "No, Wernher. Ninety days."
Rocket Girl, a stage play by George D. Morgan, deals with the invention of hydyne, a special fuel designed to boost Explorer I, America's first satellite, into orbit utilizing the Redstone/Jupiter C. The character of General Medaris appears throughout the first scene of the play.