A tale of two hatches

On 7 December 1961 Robert Gilruth, director of the Manned Spacecraft Center in Houston, announced plans for a spacecraft that would be piloted by two astronauts and would advance the United States to the next level of manned space flight. This new program would help to develop manned space flight rendezvous techniques in a more spacious craft capable of docking with other vehicles while in Earth orbit. This “Advanced Mercury” concept would also serve as a bridge between the Mercury and Apollo lunar landing programs. Since no project title had been officially assigned to the new program, it was simply referred to as Mercury Mark II.

A NASA bulletin reported that the agency would negotiate with the McDonnell Aircraft Corp. of St. Louis as prime contractor for the new spacecraft. Weighing about two tons – twice that of the Mercury capsule – the spacecraft was intended to be launched atop a new booster, the Air Force Titan II, constructed by the Martin-Marietta Company. The rendezvous target to be used during the program was to be an Agena stage produced by the Lockheed Aircraft Corporation, and this would be launched by an Atlas rocket. Preliminary cost estimates for the program, including about a dozen spacecraft, Atlas-Agena and Titan II vehicles, was in the vicinity of $500 million. As the NASA bulletin suggested:

Two-man flights should begin in 1963-64, starting with several unmanned ballistic flights from Cape Canaveral for tests of overall booster-spacecraft compatibility and systems engineering. Several manned orbital flights will follow. Rendezvous flybys and actual docking missions will be attempted in final phases of the program.

This program provides the earliest means of experimenting with manned rendez­vous techniques. At the same time, the two-man craft will be capable of Earth­orbiting flights of a week or more, thereby providing pilot training for future, long-duration circular and lunar landing flights.

NASA’s current seven astronauts will serve as pilots for this program. Additional crew members may be phased in during later stages.1