3/7/61 - Spacecraft delivered to Hanger S CCAFS Payload:Spacecraft # 11, Launch Vehicle S/N MR-8Mission Objective: Mercury-Redstone 4 was the fourth mission in the Mercury-Redstone series of flight tests and the second U.S. manned suborbital spaceflight.It was the next step in the progressive research, development and training program leading to the study of man's capabilities in a space environment during manned orbital flight.Launch Date: July 21, 1961. 7:20 a.m. EST.Crew: Crew: Virgil I "Gus" Grissom Backup Crew: John H. Glenn, Jr.Launch Vehicle: Liberty Bell 7