Liberty Bell 7 Pre-Launch Activities Poster

This is MR-4 in the final minutes of the mission countdown on July 19. In the background is the rocket's service structure, which was moved to the edge of the pad at T-60. Shortly thereafter the "cherry picker" was stationed at the spacecraft's hatch to permit emergency egress of the pilot, if necessary. Mercury Redstone 4 (MR-4, also designated Liberty Bell 7) was the second flight of an American rocket with a human on board (Virgil I. "Gus" Grissom) and the last suborbital manned flight. The objectives of MR-4 were to: (1) familiarize man with a brief but complete space flight experience, including the lift-off, powered flight, weightless flight (approximately 5 minutes), re-entry, and landing phases of the flight; (2) evaluate man's ability to perform as a functional unit during space flight by demonstrating manual control of spacecraft attitude before, during, and after retrofire and by use of voice communications during flight; (3) study man's physiological reactions during space flight; and, (4) qualify the explosively-actuated side egress hatch.