USS Valley Forge was one of 24 Essex-class aircraft carriers built during and shortly after World War II for the United States Navy. The ship was the first US Navy ship to bear the name, and was named after Valley Forge, the 1777–1778 winter encampment of General George Washington's Continental Army. Valley Forge was commissioned in November 1946, too late to serve in World War II, but saw extensive service in the Korean War and the Vietnam War. She was reclassified in the early 1950s as an attack carrier (CVA), then to an antisubmarine carrier (CVS), and finally to an amphibious assault ship (LPH), carrying helicopters and Marines. As a CVS she served in the Atlantic and Caribbean. She was the prime recovery vessel for an early uncrewed Mercury space mission. After conversion to an LPH she served extensively in the Vietnam War. Valley Forge was awarded eight battle stars for Korean War service and nine for Vietnam War service, as well as three Navy Unit Commendations.

Mercury-Redstone 1A (MR-1A) was launched on December 19, 1960 from LC-5 at Cape Canaveral, Florida. The mission objectives of this uncrewed suborbital flight were to qualify the spacecraft for space flight and qualify the system for an upcoming primate suborbital flight. The spacecraft tested its instrumentation, posigrade rockets, retrorockets and recovery system. The mission was completely successful. The Mercury capsule reached an altitude of 130 miles (210 km) and a range of 235 miles (378 km). The launch vehicle reached a slightly higher velocity than expected - 4,909 miles per hour (7,900 km/h). The Mercury spacecraft was recovered from the Atlantic Ocean by recovery helicopters about 15 minutes after landing. Serial numbers: Mercury Spacecraft #2 was reflown on MR-1A, together with the escape tower from Capsule #8 and the antenna fairing from Capsule #10. Redstone MRLV-3 was used. The flight time was 15 minutes and 45 seconds.