The Apollo Program has been acclaimed as one of the greatest feats of exploration and engineering development ever accomplished. Landing men on the moon and returning them safely to Earth was considered impossible only a few decades earlier. No doubt the vigor and determination which characterized the Apollo Program were largely attributable to the challenge of President John F. Kennedy in 1961 that it be accomplished "before this decade is out." It is also evident, however, that the events which culminated in sending men to the moon were not brought forth de novo, to implement President Kennedy's proclamation. These events were in large measure an extension of technology which made possible an achievement whose time had come.
There were three principal technology requirements imposed by the Apollo mission. First, because the United States was committed to manned lunar exploration, it became necessary to identify the means to ensure man's health and functional capability in a hostile environment. Here, the program drew on the tremendous developmental advances in full pressure suit and oxygen system technologies made during and immediately following World War II. Second, because habitable vehicles sufficiently large to accommodate several men and their necessities would be used, a very complex and powerful launch and transportation system was required. The technology of chemical rocket propulsion, begun earlier in this century by Tsiolkovsky, Goddard, Oberth, and others, with significant advances in World War ll, was available. Third, because man would participate, the mission would require the highest probability that the vehicle would reach the moon and return safely. This requirement drew on the substantial advances in rocket guidance and navigation technology begun in World War ll and extended during the Mercury and Gemini Programs.
Project Apollo, owing much to existing technology, repaid the debt many times with dramatic technological and scientific progress in many fields, including medicine. The contribution of Apollo to the biomedical sciences was twofold. First, there was opportunity to study man performing useful work in the space environment. In dealing with the health issues of a lunar exploration mission, the practice of space medicine  became a reality. Second, significant advances were made in life-support systems, biotelemetry techniques, and inflight monitoring methodology. The biomedical hardware necessary to support space flight developed appreciably in functional capability, in reliability, and in acceptability to the crewman.
The purpose of this book is to describe the biomedical program developed for Apollo, to list the findings of those investigations which were conducted to assess the effects of space flight on man's physiological and functional capacities, and to document significant medical events in Apollo.
There were three principal objectives of the Apollo biomedical program. These three distinct and rather separate goals, listed below, served in large measure as a basis for the functional organization of the biomedical effort.
1. Ensure the Safety and Health of Crewmembers. The Mercury flights showed that man could safely withstand the stresses of space flight for limited periods. In the Gemini 7 flight, the period of exposure was increased to 14 days with no major adverse findings. Therefore, it was well established prior to the first Apollo flight that man could be kept safe and healthy for the mission durations under consideration. However, there remained a number of health issues to be assessed. Principal among these was that of inflight illness. During the orbital flights of Mercury and Gemini, it was always possible to abort the mission and recover the astronaut within a reasonable time should an inflight medical emergency occur. This alternative was greatly reduced during Apollo. A serious illness occurring during circumlunar flight could not receive direct medical attention for at least several days. For this reason, it was necessary to develop a program which would keep the possibility of inflight illness at an absolute minimum and which would make provision for emergency treatment during the course of the mission.
2. Prevent Contamination of Earth by Extraterrestrial Organisms. Prior to the first lunar mission, there was great concern over possible contamination either of the moon by Earth-borne microorganisms or the Earth by unknown or strange microorganisms carried from the lunar surface by the crew or in lunar samples.
The prevention of the contamination of Earth by microorganisms returned from the moon was considered especially important since the nature of the microorganisms would be unknown. For these reasons, Apollo biomedical personnel were given the responsibility for developing techniques to minimize the contamination of the moon and to preclude the introduction of any lunar organisms into the Earth's ecology.
3. Study Specific Effects of Exposure to Space. The Gemini missions amply demonstrated that man could survive in space for as long as 14 days with minimal physiological changes. There were some findings, however, which caused concern as to their possible significance on much longer flights. For example, red blood cell mass losses in the order of 20 percent were noted after the eight-day Gemini flight. Obviously, a finding such as this meant that additional study was required both for verification and to assess the real meaning of the observed changes.
 A number of investigations were conducted during the Apollo Program to determine the effects of the space environment on specific body systems and functional performance. Subsequent chapters describe these investigations in detail.
Mercury and Gemini Background
The foundations of the Apollo biomedical program can be found in earlier Mercury and Gemini efforts. The basic organizational structure for medical support was developed during Mercury. Many of the Apollo personnel had worked through both the Mercury and Gemini flights.
The fist biomedical issue to be confronted in Project Mercury was the need to establish selection criteria for astronauts. This assignment was given to members of the newly-formed Space Task Group, a unit established at Langley Field, Virginia, in October 1958. This group, under the direction of Dr. Robert R. Gilruth, was responsible for establishing the nation's fist manned spacecraft project, later to be known as "Project Mercury."
General physical requirements for Mercury astronauts were established by the NASA Life Sciences Committee, an advisory group of prominent physicians and life scientists chaired by Dr.W. Randolph Lovelace. Aeromedical personnel and facilities of the Department of Defense were used to conduct psychological and stress testing of candidates. Final selection was based on a review of the medical findings and technical experience of the candidates. The basic and extensive screening and testing procedures defined for the selection of Mercury astronauts were used for the later selection of Gemini and Apollo astronauts.
The success of Project Mercury demonstrated that man could indeed exist in the space environment. While the Mercury missions, one of which lasted for 34 hours, were primarily demonstration flights, some quite meaningful medical information was obtained. The principal conclusions were:
The biomedical information obtained during the Mercury flights had a positive reinforcing effect in terms of expanding the manned space flight program. Plans for Project Gemini were pressed with increased confidence.
With the launch of the first manned Gemini flight in 1965, the United States space program entered a new phase. With Project Gemini, the broad objective was to gain operational proficiency in manned space flight. The three major goals of the program were (1) to accomplish rendezvous and docking of two space vehicles, a necessary step toward the lunar landing program; (2) to perform extravehicular activity and to validate personal life support systems and astronaut performance capabilities under those conditions; and (3) to develop a better understanding of how man adapts to extended  weightless flight, that is, whether stability was achieved for all physiological measures, or whether significant changes occurred.
As a result of the change of emphasis of Project Gemini, there was an improved opportunity to study the effects of space on man. There also was a requirement to develop systems which would maintain man in space over much longer periods than flown in Project Mercury. In the 14-day Gemini 7 flight, extensive observations were made of the physiological and psychological response of astronauts to the stresses of space.
At the conclusion of the Gemini Program, approximately 2000 man-hours of weightless experience had been logged by U.S. astronauts. The principal biomedical conclusions were:
The techniques used for the study of man in the Gemini Program, and the life support systems which were used, established the plan-of-action to be followed in Apollo.
Development of Apollo Biomedical Effort
The formal structuring of the Apollo Program bad its genesis in 1961. It actually began, however, several years earlier with the award of three study contracts to industry and with an in-house study program conducted by the Langley Space Task Group. The initial objective of these efforts was to develop specifications for circumlunar flight. Then, in 1961, President Kennedy changed the goal to one of lunar landing.
It was also m 1961 that the National Aeronautics and Space Administration announced it would build, on a site near Houston, Texas, a 60 million dollar research and command center for the Project Apollo Program of manned flight to the moon and for later space flight programs. This center, with Dr. Robert R. Gilruth as its Director, was to be used to train space flight crews; to design, develop, and test spacecraft; and to conduct manned space flight operations. The life scientists associated with the Langley Space Task Group soon moved to temporary quarters in Houston to await the completion of the Manned Spacecraft Center at Clear Lake.
New and unique requirements were placed on the Life Sciences Team by the Apollo Program. Medical personnel were required to develop requirements, to make projections of physiological functions and to conduct their daily activities as part of an engineering-oriented team effort. The space program also emphasized the study of healthy individuals and an understanding of normal physiological responses as opposed to  the conventional medical concerns of diagnosis and care of the ill. Life scientists concerned with manned space flight programs continually demonstrated an ability to adapt to a new working environment and, throughout the various flight programs, maintained a dedication to the health and safety of space flight crewmen.
And so, although the principal objectives of Apollo were manned lunar landing and subsequent lunar exploration, a considerable body of useful biomedical information was derived from the program, These findings are documented in this volume and, in part, served as a basis for asking more incisive, more penetrating biomedical questions of the forthcoming and very ambitious Skylab Program. This volume then may be regarded as "a prelude to Skylab."