A discussion of the Apollo Spacecraft Program must include reference to the Mercury and Gemini Programs, not because they are manned space programs but because of the interrelationship between the programs in time, in people, and in organizations, and the differences and similarities in the requirements of the programs. The Mercury Program had a very specific objective, namely to place a man in orbit and return him to earth. The Gemini Program was somewhat different. It was operating in the same earth orbital environment as Mercury but had as its goal a number of objectives which were intended to explore and develop our capabilities to work in this environment. In doing this, the Gemini Program had more resources than Mercury, in terms of increased payload weight in orbit. Apollo is more like Mercury. It has a well-defined objective that involves moving into a new environment deep space - and resources that offer little if any payload capability beyond that required to achieve the objective. Perhaps the Apollo Applications Program will be to Apollo what Gemini has been to Mercury, establishing an operational capability in an environment which has been first explored in a prior program.
The Mercury project was formally initiated in October 1958 and at that time the Space Task Group was formed to manage the project. This group and others had been studying the specifics of the program for over a year at Langley and other NACA Centers. During 1959, the requirements of the Mercury Program left no time for advanced program study by the Space Task Group. In 1960, the first organized activity related to advanced mission study began. Committee studies, such as that carried out by the Goett Committee, had indicated that the lunar mission should be the next major manned objective. With this in mind, a series of technical guidelines was developed to guide the spacecraft studies. These guidelines were based on assumptions that launch vehicles then planned were capable only of circumlunar flight rather than lunar landing and that there were enough unknowns related to the lunar mission that the hardware should be equally capable of advanced earth orbital missions as an alternative.
Based on the technical guidelines, three efforts were undertaken. A formal liaison activity was set up with other NASA Centers to stimulate and encourage their research and studies toward the lunar mission, using the guidelines as a general reference. Three system study contracts were let to industry and a preliminary design study was conducted by Space Task Group personnel. This total effort took approximately one year and culminated in a conference held in Washington in June 1961. These studies were primarily based on a circumlunar mission with the intent that the hardware elements developed would have application to a later lunar mission.
Concurrent with the completion of this year of study effort in the Spring of 1961, two events of utmost significance to the program took place. The first U.S. manned suborbital flight, of Lt. Cdr. Alan B. Shepard, Jr., was successful. Shortly thereafter, President John F. Kennedy announced the national objective of a manned lunar landing mission within the decade.
As a follow-on to the study effort of the previous year, specifications were being prepared for the command and service modules so a contract could be let to industry. These specifications were changed to acknowledge the requirement for a lunar landing rather than a circumlunar mission. Since the lunar-mission launch vehicle had not been determined, it was assumed that a single launch vehicle would insert a spacecraft into the lunar trajectory and that the command and service modules would land on the lunar surface with the aid of a third module which would decelerate the total spacecraft as it approached the surface. The launch vehicle required for this approach was never fully defined but was of the class referred to as the Nova.
During the Spring and Summer of 1961, work statements and specifications were completed and issued to industry for the command and service modules. During the Fall, proposals were evaluated and a contractor was selected in November 1961. Throughout this period, practically all Space Task Group activity had been directed toward the command and service modules; launch vehicle studies by Marshall Space Flight Center and others had led to a selection of the Saturn C-5 as the lunar launch vehicle in the Fall of 1961.
This decision eliminated the lunar mission approach previously described, involving the Nova class vehicle, and offered two alternatives. The first involved the use of two Saturn C-5's and an earth orbit rendezvous to mate the spacecraft module, plus an earth-to-moon rocket stage. This would allow a landing of the entire spacecraft, employing a third module to decelerate the command and service modules to the lunar surface; then a launch from the lunar surface would use the servicemodule propulsion. The other alternative was to use a single Saturn C-5 launch vehicle carrying the entire spacecraft, consisting of three modules. The third module, instead of being an unmanned module whose purpose was to decelerate the other two modules to the lunar surface, would be a manned module which would go to the lunar surface from lunar orbit and return, while the command and service modules waited in lunar orbit to rendezvous with the third module.
This latter approach had been studied by the Langley Research Center and others during 1960 and 1961. At first it was not received enthusiastically by the Space Task Group in comparison with the Nova direct approach previously described.
In late 1961, the Space Task Group (redesignated Manned Spacecraft Center, November 1, 1961) personnel moved to Houston and initiated studies of the two remaining approaches offered by the C-5 vehicle. Studies were also being conducted by Marshall, Headquarters, and other groups. The Manned Spacecraft Center study concentrated on the feasibility of the lunar orbit rendezvous method and the definition of the lunar module, then known as the LEM (Lunar Excursion Module). In the Spring of 1962, the Manned Spacecraft Center studies indicated the desirability of the lunar orbit rendezvous approach as opposed to the earth orbit rendezvous approach. Discussions were held with Headquarters and Marshall. It was decided to complete preparation of the work statement and specifications for the LEM and to issue them to industry. This was done in the Summer and contractors' proposals were evaluated. In early November, the final decision was made to go the lunar orbit rendezvous approach. A contractor was selected and negotiations were completed by the end of 1962.
Parallel to the effort related to mission selection, specifications preparation, and contractor selection for the major modules, additional work was being done on the navigation and guidance system. During this 1960 study phase previously described, Massachusetts Institute of Technology (MIT) was conducting a study of concepts for the Apollo system. It was subsequently decided that MIT would be given the navigation and guidance system task, with support from appropriate industrial contractors. The contract with MIT was signed in August 1961, the support contractor work statements and specifications were prepared and issued in early 1962, and three contractors were selected in the Spring of that year.
In summary, the period through 1962 was one of mission definition and major contractor selection. With the selection of the lunar orbit rendezvous mission mode and the LEM contractor, the program was in a position to move into specific design efforts.
Robert O. Piland
Science and Applications Directorate
Manned Spacecraft Center