On December 18, 1958, the Air Force launched the Atlas prototype 10B from Launch Pad 11 at the Cape. Following the secret flight plan, the missile’s internal guidance system pitched the Atlas over parallel to the Atlantic at an altitude of 110 miles and the sustainer engine burned up the remaining tons of propellant. Five minutes later the entire 60-foot, four-ton aluminum shell was in orbit. The Defense Department proudly announced the success of Project SCORE (Signal Communications by Orbiting Relay Equipment). A tiny transmitter inside the empty Atlas shell broadcast tape-recorded Christmas greetings from President Eisenhower to the world below. It was international showmanship worthy of Nikita Khrushchev.
The Space Task Group’s first priority was to design an orbital vehicle that would protect a human passenger through all phases of a spaceflight “envelope”: launch acceleration, weightlessness above the atmosphere, reentry deceleration with its furnacelike heat, and descent to parachute deployment at about 10,000 feet. NASA designers had two basic choices: the first was a winged spaceplane like the rocket-powered X-15 and the futuristic Dyna-Soar space glider the Air Force wanted; the second was a wingless high-drag, blunt-body capsule. A capsule was the only design that met the weight limits imposed by the Atlas missile (the sole American booster capable of orbiting a manned spacecraft): approximately 3,000 pounds.
Max Faget, Langley’s ablest designer, and his team proposed a variation of the existing conical missile warhead that looked like an upside-down badminton shuttlecock. The blunt bottom was a convex fiberglass heat shield that would point forward and disperse the reentry deceleration heat through a fiery meteor trail – a process known as “ablation.” A cluster of small solid retrorockets in the center of the heat shield would brake the capsule from its orbital speed and return it to Earth. The tiny cabin was a lopped-off cone topped by a squat cylinder that held radio antennas and the parachutes. On top of this cylinder was a girdered escape tower powered by solid rockets that would pull the capsule away from a stricken booster (no one really trusted the Atlas), lifting it to a safe altitude for parachute deployment. The whole thing was a far cry from the sleek, winged spacecraft that many popular scientific magazines had imagined.