On September 9, 1959, NASA launched the "Big Joe" unmanned Mercury spacecraft from Cape Canaveral, Florida, on a suborbital flight that lasted 13 minutes. Its launch was the second in the Mercury program and the first using an Atlas booster. The flight helped NASA evaluate the booster, the new ablative heat shield, the capsule's flight dynamics and aerodynamic shape, and spacecraft recovery systems and procedures.

The heavily instrumented "Big Joe" was the most massive American spacecraft launched up to that time. It weighed about as much as a manned version would, and its success paved the way for the beginning of manned Mercury launches in 1961. This nitrogen bottle, skin section and bolts came with the spacecraft when NASA transferred it to the Smithsonian in 1967.