From its inception, the United States space program has been dedicated to the concept of manned space flight. We have always viewed man as a vital element in the system. Man's adaptive intelligence proved to be indispensable during many critical operations. In 1961, when we became committed to a national objective to place an American on the moon within nine years, virtually nothing was known about man in space, beyond the fact that he could survive. Yet, NASA was charged with the responsibility to send men on a mission that would take them beyond the Earth's gravitational field, into orbit around the moon, and safely back to Earth after a stay on the lunar surface. Such a mission could not be accomplished in less than eight days of exposure to stresses whose effects were still a mystery.
People who were concerned with the future of man in space quickly became aligned with one of two points of view. On the one side, there were the more cautious and conservative members of the medical and scientific community who genuinely believed man could never survive the rigors of the experience proposed for him. The spirit in the other camp ranged from sanguine to certain. Some physicians, particularly those with experience in aeronautical systems, were optimistic. But by far the most enthusiastic proponents were the very individuals who would themselves make the historic journey to the moon. The population from which the astronaut corps was formed had considerable test pilot experience. Pilots, and the engineers who develop the aircraft they fly, characteristically view man as an element of the operational system that is every bit as strong and reliable as any other component of that system. It became the task of the medical team to work toward bringing these divergent views toward a safe middle ground  where unfounded fears did not impede the forward progress of the space program, and unbounded optimism did not cause us to proceed at a pace that might compromise the health or safety of the individuals who ventured into space.
At the start of the space program in this country, many scientists had qualms about man's ability to survive in space. Since there were so many unknowns about the environment and it was presumed to be hostile, some focused on the known limitations of the delicately balanced human physiological system. In order to survive, the human body requires food, mental stimulation, waste disposal, a relatively narrow temperature range, and oxygen at a particular pressure for absorption into the blood stream. Those who were discouraged or pessimistic about the fate of astronauts envisioned dire consequences; for they felt the space flight environment would not allow these requirements to be met. Before Cosmonaut Gagarin flew, some scientists predicted that an astronaut would never survive launch because launch acceleration would cause heart rate to soar, creating severe pathologic disorders or terminal fibrillation. Some believed the phenomenon of weightlessness would result in a plethora of difficulties for an erect animal like man. Man had evolved through millions of years with organs that had been genetically designed to pump blood against the pull of gravity and to maintain an internal fluid balance based on a gravity system. Some thought man would not be able to urinate, swallow, or perform any physiological function that seemed to be gravity-dependent. Others felt his vision might be impaired, and predicted empty field myopia would result from staring endlessly into the void of space. Among other physiological disruptions feared were cardiac arrhythmias, muscular atrophy, hallucinations, disorientation, and nausea.
Because of the rapid progress of the program and the fact that so few astronauts were actually flown, decisions concerning appropriate mission lengths had to be made conservatively. Far less medical information was available for decision making than would ideally have been the case. At the conclusion of the Mercury Program, the longest U.S. manned space flight was 34 hours. Mercury 9 was scheduled to be the last flight in the Mercury series, to be followed by the first Gemini mission, dated for seven days. However, the last two Mercury astronauts had shown significantly reduced cardiovascular tolerance upon reentering Earth's gravity, engendering reluctance to commit man to a week-long flight without additional medical data. One solution would have been to fly another Mercury mission to bridge the gap. From a medical standpoint, the question of man's safety in space was, at that point, still a serious one. Only electrocardiographic and blood pressure monitoring were available.
Budgetary and other considerations precluded a Mercury 10 mission. Moreover, an additional Mercury flight might have diluted the effort directed toward Gemini and interrupted its momentum. The solution was to schedule the first Gemini mission for four days rather than seven. If a four-day mission went well, a second mission of eight days could be safely recommended, which in turn, would provide a sound basis for proceeding with a fourteen-day mission. A fourteen-day mission was deemed necessary because it was projected that no Apollo mission would exceed two weeks. With two weeks worth of medical data, man could be committed safely, from a physiological standpoint, to a lunar landing mission.
 Conduct of medical investigations during the two-week Gemini mission was critical to planning for lunar landings. Because there was a paucity of information concerning man in the environment of space flight, every opportunity had to be exploited to collect data in a systematic way. However, some compromises had to be made for operational reasons. One of the astronauts selected for the fourteen-day Gemini mission exhibited a liver enzyme abnormality. Ideally, from a purely medical experimentation point of view, such an individual would not have been chosen because his condition could be expected to influence hematological findings. From an operational standpoint, however, he was the man for the job.
The medical experience of Gemini was extremely valuable, and plans had been made to continue medical experimentation in the early Apollo flights. When the Apollo 204 fire tragically supervened, a planned series of inflight medical experiments was deleted and all energies were directed toward engineering and other operational problems.
Amassing medical information was difficult for numerous technological reasons, and was further compounded by certain attitudinal issues. Some astronauts were reluctant to admit physiological difficulties for various reasons, some purely pragmatic. In military aviation, the field from which the vast majority of astronauts were selected, the flight surgeon is required to keep close watch over pilots and to disqualify them when they are unfit for flight. The psychological set of the astronauts may have caused them to fear exclusion from the program for medical reasons
With the enormous investment of time and training in the astronaut corps, the medical approach in the space program was quite different. Every effort was made to keep these highly select, highly trained individuals qualified for flight. One astronaut who had been scheduled for a mission was not permitted to participate because a bony bridge developed on a cervical vertebra and had to be removed surgically. After surgery, he was requalified and flew on a critical space mission. Another astronaut who suffered from Meniere's syndrome was also qualified after surgery corrected the situation with an endolymphatic shunt.
A final aspect of the philosophy which governed the manned space flight program in general and the Apollo Program in particular is worthy of note. Space flight created a unique problem for personnel charged with medical management. Many aspects of the entire space flight experience, during all phases - before flight, during flight, and after flight-have a potential for straining the privileged communication between doctor and patient. The entire issue of medical privacy is, and always has been, a very difficult one for physicians involved with persons of any notoriety. Astronauts, as such a group, lost many of their rights of privacy by virtue of their position. An individual who has volunteered as an astronaut in our nation's space program must pay a certain price and owes a certain debt for the privilege of his participation. As part of this debt, he must give up a certain amount of privacy and be willing to sacrifice an "image" where such a sacrifice bears on the success of his mission or future missions. A physician monitoring a space mission has to receive reports on such intimate issues as the number of bowel movements, the types of pains suffered, the amount of sleep obtained, and so forth. Reporting this information was particularly irksome to many astronauts, especially since this information had to be transmitted over open loop telemetry links and became public  knowledge. The small number of astronauts involved in any mission made it impossible to maintain anonymity for the individual. For example, if a crewman had vomited in the spacecraft during a mission, the press, as a whole, was unable or unwilling to accept a statement to the effect that a crewman had vomited. They demanded to know which crewman. The astronauts became, in a sense, public property. They belonged to the entire nation, and the press felt they had an obligation to report their status to the people.
Every effort was made, however, to safeguard the privacy of astronauts as individuals wherever possible. A distinction was drawn between information of medical importance related to the safety of a mission or to the safety of future missions, and medical information which was not of such import and could properly be maintained as privileged doctor-patient information. This point can clearly be illustrated in the case of information sought by Congressional committees concerning the crewmen who perished in the Apollo 204 incident. Congressional committees in both the House and Senate spent a substantial amount of time interviewing NASA staff members concerning the fire to attempt to determine any factors that could prevent such an incident in the future. This was their proper concern. At one point during the investigation, however, a fire occurred in an altitude chamber at the Brooks Air Force Base and an airman was killed. The House Armed Services Committee then became involved in a situation which was not totally dissimilar from that faced by the Senate and House Committees concerned with aeronautics and astronautics. The Armed Services Committee asked to have the medical records of the deceased Apollo crewmen made available to them. The medical records per se were privileged information and could not be surrendered. Instead, all pertinent facts related to the accident and causes of death that were relevant to the Committee's concern were presented.
Every hour crewmen spent in space and all their responses to that peculiar environment were important, not just to ensure their safety but to provide for the safety of crews who would fly for longer periods of time. Every data point assumed much greater importance because data points were few.
Many of the early biomedical preconceptions concerning man in space were answered during Mercury and Gemini flights. Project Mercury's indispensable. legacy was that man could survive in space and, moreover, that he could do useful tasks. The legacy of Gemini was in many respects an even richer one. The fourteen-day Gemini mission demonstrated that weightlessness does indeed cause changes in man. Cardiovascular and bone density changes were just two findings that signaled that the world of zero gravity profoundly affected the human. Gemini missions also provided a fund of knowledge concerning the measurement of physiological functioning at a distance. But, at the end of the 2000 man-hours of Gemini, we were confronted with difficult issues. Because the number of individuals involved was small, we could not tell whether genuine space-related phenomena were being observed or whether the changes reflected individual variations. If the changes seen were authentic responses to the space environment, we could not at that point say whether they represented the beginning of downward trends, whether they would level off in time, or whether, perhaps, they would be cyclic. The contribution of  confinement to physiological effects observed during and after space flight bad also to be assessed, along with numerous less well-defined factors. This was Gemini's legacy to Apollo, and it became the task of the Apollo Program to search for answers.
The Apollo Program provided an opportunity to gain biomedical information in a more orderly manner than was possible during the Gemini missions. More definitive data now could be obtained concerning man's performance during what was truly a space voyage. Biomedical information returned from the later Apollo missions has allowed us to progress significantly toward a detailed description of man's behavior in space and the physiological changes which occur.
Apollo 7 marked our first experience with inflight illness. It also represented our first experience in diagnosing and treating illness via telemetry across the void of space. This situation illustrated the difficulty of dealing with medical issues privately. Space flight procedures called for all consultations to be effected through the Capsule Communicator and not directly between the physician and patient, eliminating the possibility for privileged communication. The Apollo 7 crew suffered colds and upper respiratory symptoms. Colds on Earth are bothersome enough, but weightlessness exacerbates symptoms still further. In zero gravity, mucous clogs the nasal passages and does not drain. Even decongestants seem less effective; shrinking of the membranes gives no relief because there is no drainage from the sinuses. There was some concern on the part of the crew about the possibility of rupturing their eardrums if they wore helmets during reentry and were unable to perform a modified Valsalva maneuver to equalize pressure on either side of the tympanic membrane. The crew made the decision to reenter with helmets off despite opposition from the ground. As it turned out, the crewmen were able to ventilate the ears during reentry.
In Apollo 8, the first incident of vestibular illness was encountered during an American space flight. When the astronauts left their couches after the spacecraft bad entered orbit, all three developed vertigo. One crewman had a vestibular problem for about two and one-half days and suffered nausea; another vomited and had diarrhea. For the first time, astronauts were moving around rapidly in a spacecraft with a relatively large volume, and some of them were quite susceptible to motion sickness. The effects of Seconal, a sleeping medication, and viral gastroenteritis have been implicated, but vestibular disturbance may well have been a significant factor in the difficulties suffered by the crew.
Even more severe vestibular disturbances were experienced during the Apollo 9 mission, and a portion of the scheduled extravehicular activity bad to be cancelled as a result. There was grave concern over this incident because, for the first time, vestibular disturbances interfered with performance of mission-related tasks. This was a distressing discovery because it suggested, ominously, that missions could indeed be compromised by vestibular problems. In the extreme case, mission success and even crew lives could be threatened.
The mission of Apollo 9 underscored the problems that could be created by any illness in flight, and alerted us to the hazards of clinical illness. At that time, there was no preflight isolation program, and crews engaged in a rigorous preflight schedule of activities. After the flight, there were press conferences and tours to be taken, and the astronauts were not allowed sufficient time to readjust before they engaged in these  activities. In fact, the launch of Apollo 9 had to be delayed for three days because all three crewmembers developed upper respiratory symptoms. The problem of the lack of a preflight isolation program to prevent clinical illness was brought into sharp focus. This topic has been dealt with in detail in several chapters of this book, and will be discussed further later in this chapter from the point of view of medical program management
Apollo 10 was the first Apollo mission during which no inflight illness occurred. While there was still no highly structured preflight preventive medicine program, illness was kept in check.
Apollo 11, the first lunar landing mission, gave man the first opportunity to visit an extraterrestrial body and to experience an environment where the gravity was one-sixth what it is on Earth. There had been concern in many quarters about man's capability to operate effectively in this environment. Some felt man would be disoriented in lunar gravity, and, when he attempted to walk on the moon, would become motion sick and vertiginous and be unable to move in a given direction. This fear was resoundingly demonstrated to be baseless by Apollo 11.
Apollo 12 gave us further confidence about man's capabilities in a 1/6-g field. Projections concerning metabolic cost of work in this environment proved to be reasonably accurate. Metabolic cost of routine locomotion and nominal tasks was not excessive, nor was it detrimental to adequate lunar surface performance.
Apollo 13 was the most difficult, danger-ridden mission in the U.S. space program Even before the flight, the mission had been threatened by medical difficulties. The incident in point began just before the 21-day examination period. Astronaut Charles Duke, a backup crewmember, and his family spent a weekend with friends. Two of the children in the household had rubella (German measles), and Astronaut Duke contracted it. Detailed blood studies were conducted, and other viral illnesses were considered because rubella is easily misdiagnosed. When the illness was confirmed as rubella, an epidemiological investigation was initiated. A flight surgeon visited the family from whom the disease had been contracted, and blood samples and epidemiologically significant data were collected. Next, complete immunologic evaluations were made of the Duke family and of all prime and backup crewmen.
On the day before Astronaut Duke exhibited the rubella rash, a prime crewman had worked with him in the Command Module Trainer. The crewman, Thomas K. Mattingly, was the only individual in the prime crew who showed no protective antibodies against the disease. With the launch fast approaching and the crew already at Cape Kennedy making preparations, a complex epidemiological and medical situation was created. Daily flights were made between Houston and the Cape to study blood samples collected from the prime crew. Specialists from the National Institute of Allergy and Infectious Diseases were consulted on the problem, and assisted in evaluating the risks. By this time, the crewman's measles exposure was public knowledge. Agency officials were queried from many quarters, some requesting daily briefings concerning the status of the flight.
There was no question of the risk involved, and a decision had to be made to substitute a backup crewman. The decision to make the crew substitution was based on medical advice given by many respected individuals. In fact, Mattingly did not develop rubella, although he just as easily might have. He was subsequently immunized to the disease and participated in a later mission.
 The events surrounding the harrowing inflight experience of Apollo 13 are well known. The only medically significant occurrence during that mission was a urinary tract infection in one. crewmember resulting from reduced water intake and the cold environment of the Lunar Module "life boat." The afflicted individual had chills and fever associated with the illness, but be did not identify these as symptoms of clinical illness because all crewmembers were chilled by the cold.
Apollo 14 was unremarkable from a medical standpoint. This was the first mission for which a full-fledged Flight Crew Health Stabilization Program was in effect. This program, and the effectiveness with which it was executed, must be credited for its contribution to the reduction of inflight clinical problems on this flight and subsequent missions.
Apollo 15 will remain an anomaly in the Apollo Program. Preflight and inflight activities went well. The lunar surface operations were characterized by heavy work schedules and some sleep difficulties. The crewmen worked to a point of near exhaustion on some occasions, and the Commander pulled a shoulder muscle while operating the lunar surface drill. The pain from the muscle injury interfered with his sleep on the lunar surface and during the return flight to Earth, and persisted for several weeks. At the conclusion of Apollo 15's lunar surface activities, a very tired crew departed the moon to rendezvous with the Command Module.
The schedule of the labors after the link-up was also heavy, and the Command Module Pilot had to rely on his already fatigued companions to transfer equipment from the Lunar Module to the Command Module, a task he himself had been slated to perform. Once transfer operations were complete, difficulty was experienced in sealing the hatch between the two vehicles. This problem necessitated two additional lunar orbits and additional labors before the tunnel connecting the vehicles was successfully sealed and the LM could be jettisoned.
After Lunar Module jettison, the crew was engaged in a space suit integrity check when a bigeminal rhythm appeared on the console monitoring Astronaut Irwin's electrocardiogram. Paper copies of the trace were called for to establish that the irregularity was not artifactual. The bigeminal arrhythmia lasted for 10 to 20 beats, and was followed by a series of premature ventricular and atrial beats, interspersed with normal ones. One other crewman had exhibited some arrhythmias, but they were far less serious than those with which Astronaut Irwin was afflicted. The crew had transmitted no messages indicating a problem. In fact, Astronaut Irwin reported later that he had experienced a feeling of a brief loss of contact as though he had momentarily gone to sleep. In retrospect, this episode could have been a momentary loss of consciousness at the precise time the arrhythmia was noted. After the arrhythmias were noted, continuous electrocardiographic recordings were obtained for all three crewmen while they slept.
It took the Apollo 15 crew three to four weeks after the flight to return to preflight normal levels of exercise and cardiovascular orthostatic tolerance. This was the longest recovery period seen in our space program and was uncomfortably reminiscent of the findings of the eighteen-day Soviet Soyuz 9 mission. This Soviet mission had been marked by a prolonged recovery wherein cardiovascular, vestibular, and musculoskeletal difficulties were experienced by the crewmen. While it would have been, ideally, preferable to shield the two astronauts from public attention, it  was judged in the best interest of the space program to provide information about their conditions.
There is a reasonable basis for suspecting that the Apollo 15 crew was launched with a potassium deficit. They had engaged in very rigorous training for lunar surface tasks prior to this space mission in intense summer heat. The crew drank considerable amounts of an electrolyte solution during this training, which tended to leach potassium from the system. These factors, coupled with inflight diets that were not particularly high in potassium, are believed to have contributed to negative potassium balances.
Apollo 16 and 17 crewmen were free of any cardiac difficulties during their missions. This may have been in part due to the institution of a program involving dietary potassium supplements and revised work/rest schedules to preclude a negative potassium balance. Such a negative balance can contribute to cardiac irritability and can predispose to arrhythmias. The crews of both missions were also free of any clinical illness during flight. Again, the meticulously conducted Flight Crew Health Stabilization Program seemed to be effective. All crewmen took sleeping medications to ensure sufficient rest to complete busy lunar surface schedules. Both the Apollo 16 and 17 missions were unqualified successes from an operational and a medical standpoint.
The clinical illnesses which were encountered in the early Apollo missions clearly indicated the need for a health stabilization program during the preflight period. Uncertainty about the nature of potential lunar soil contaminants dictated in the minds of some individuals in the scientific community the necessity for a postflight quarantine program after the first several lunar surface missions. Details of these programs can be found in Section II, Chapters 1 and 6, and in Section V of this book. Some of the nuances surrounding the establishment and the conduct of the isolation and quarantine programs are presented here.
As mentioned earlier, the launch of Apollo 9 had to be delayed for three days because of the development of upper respiratory infections in the crew. That was the first instance of medical problems impacting the operational aspects of a space flight. Understandably, there were some objections to the sort of control medical management proposed to exercise during the preflight period. But the facts were immutable. Crewmen were becoming ill during flight, and an illness of any severity could seriously jeopardize the safety of a mission and crew. Some form of preflight isolation was mandatory.
A postflight quarantine period was to be required for the first lunar landing and for the missions of Apollo 12,13 (not conducted because the lunar landing was aborted), and Apollo 14. The Interagency Committee agreed to remove this requirement when exhaustive studies conducted by NASA indicated beyond a doubt that no life of any kind existed on the moon.
Every precaution was taken which feasibly could have been taken to safeguard the objectives of the quarantine program, When Lunar Receiving Laboratory technicians and other persons were accidentally exposed to lunar materials through breaks in the gloves which allowed manipulation of these materials, off they went into "exile" with the crew and quarantine support personnel until the official quarantine period had ended.
 Had there been an organism on the moon, the quarantine program would, in this writer's opinion, have had about a 90 percent chance of containing it. Preflight isolation simplified the matter of identifying the etiology of any illness that might have arisen postflight. Catalogs of crew microorganisms allowed for postflight identification of organisms as terrestrial versus lunar.
The problems associated with conducting the isolation periods preceding and following space flight were myriad. Emotions ran high when families had to be separated, and there were occasional tense moments.
Apollo 11 demonstrated that man could indeed fly the Lunar Module after having flown only a training device, which was, of course, not am exact duplicate. In fact, not only could he fly the vehicle near the lunar surface and effect a landing, but he could change the coordinates of that landing based upon terrain characteristics making such a change necessary. This was the case with the Apollo 11 lunar landing. Astronaut Armstrong did a masterful job conducting the landing and demonstrated man's capability to execute such control operations under adverse circumstances.
There had been much conjecture concerning man's response to the one-sixth gravity environment. Serious concern also existed about his ability to work effectively in 1/6 g in a pressure suit. Therefore, his capability to do so was measured by conducting lunar surface-type activities in simulated l/6-g conditions on the ground. Man's responses were also evaluated in underwater, neutral buoyancy simulations in order to determine the metabolic loads associated with various activities. The first true data obtained from the Apollo 11 crew's lunar experience indicated that the real metabolic cost of 1/6 g activities was an acceptable one.
At first, it was speculated that time spent in 1/6 g might have a salutary effect after zero-g exposure, and perhaps reduce the postflight "deconditioning" effect. However, it was not possible to show any salutary effect on deconditioning from the brief periods spent at 1/6 g, perhaps because these effects were obliterated by the additional two and one-half to five days spent in weightlessness on the return flight to Earth. However, in the case of one astronaut, 1/6 g did appear to counteract vestibular disturbances-stomach awareness and vertigo-experienced in zero g.
One of the questions most frequently asked about space flight is what psychological effect does it have on astronauts? Do they experience fear? What is their reaction during launch when seven and one-half million pounds of thrust catapults them from the surface of the Earth? How do they feel when they are approaching the moon? Are they compatible in the cramped quarters of a spacecraft?
It is perhaps remarkable that there was virtually no difficulty from a psychological and psychodynamic viewpoint among highly competitive, driving, and forceful individuals. Some of the success in the psychological sphere must be attributed to the original astronaut selection process. All Apollo astronauts were carefully screened psychologically and psychiatrically prior to entry into the program; and attempts were made to assess their ability to deal with stressful situations. The fact that most astronauts were veteran military pilots aided in the selective process since this served to indicate they  could keep emotional reactions under control and were capable of professional behavior during conditions of danger. This was buttressed by numerous observations made during medical and other types of training and monitoring activities in the preflight period.
Certainly there were times when tempers flared and differences of opinion led to arguments. But at no time were any psychological responses observed before, during, or after flight which could be considered in any way abnormal.
Careful psychological screening and selection excluded individuals with any psychopathology from the astronaut corps. The astronauts were intrinsically stable individuals. But several other important factors accounted for the high degree of psychic stability exhibited in some exceedingly stressful inflight situations. The first, and perhaps most important, was the level of motivation among these individuals. Astronauts are an exceedingly motivated group. Their training program is an extremely rigorous one. It involves countless hours of difficult training, some of which is unpleasant and some frankly dangerous. All astronauts must go through this training, even before they are designated to fly on a particular flight. Many never will participate in a space mission, and they know it. By the end of the Apollo Program, only 52 percent of the astronaut corps ever actually flew an operational mission. All of these factors are testimony to the inherent motivation of these people. This spirit allowed them to overcome many difficulties which would have been extremely bothersome to other individuals less determined to succeed.
Space flight operations clearly have aspects that would frighten any ordinary person. Nothing on Earth could have prepared these men for the stillness of the void of space or the experience of being weightless. And, a whole complex of emotions must have been produced by knowing one was totally alone and literally out of this world. Workload played an important part in helping the astronauts manage the anxiety-provoking parts of the space flight experience. Time lines were constantly active. This allowed little time for deep contemplation. In the author's opinion, had there been long periods of unprogrammed time, it is possible that some difficulty might have developed in the psychological sphere.
A voyage to the moon is unquestionably one of the most profound experiences encountered by man. It would have been shortsighted of us to have believed that such an experience would not impact our astronauts at some later time. It is perhaps surprising that more individuals did not react in some marked way to this experience.
Several astronauts had some rather well publicized difficulties in the psychological sphere after flight. Astronaut Aldrin was clinically depressed after his mission. By his own account, the largest factor contributing to this depression was difficulty in handling public exposure after Apollo 11. Further, he had expected that the landing of men on the moon would have a tremendous impact on the world. He was extremely distressed to find that the world did not change appreciably, and certainly not immediately, as a result of the achievement of Apollo 11.
Two other individuals radically changed their way of life after space flight. Astronaut Irwin became actively involved in evangelical religion, and Astronaut Mitchell in parapsychology. Neither of these developments was especially surprising in view of the interests each individual had prior to space flight in these respective areas. In this writer's opinion, neither one of these astronauts exhibited any behavior which could be described  as psychologically aberrant. Having gained new perspectives, they simply chose different life styles.
Space flight must be recognized as an experience which taxes the individual every bit as much psychologically as it does physiologically. This aspect of the experience must not be overlooked.
Before the Apollo program began, there were many questions regarding the physiological phenomena space flight produced. The Apollo missions answered many questions left unresolved by the Gemini Program, and, as is so often the case where phenomenological issues are involved, it raised as many new questions as it answered. The biomedical results of Apollo assured us that our planning and preparation had been of great value. Almost every observation in the physiological realm had been identified, at least in kind if not in degree, by the Gemini experience. Physiological changes did indeed occur, but these were all reversible shortly after flight. The single exception to this rule was the Apollo 15 crew. Apollo 15 stands out as an anomaly. It took this crew nearly a month to recover from the effects of space flight. The anomalous findings of Apollo 15 will perhaps never be totally understood, but they were probably due largely to a lack of adequate potassium intake. Cardiac arrhythmias suffered by two members of this crew had not been seen in other missions and were not seen following increased potassium intake in the two subsequent crews. It is, of course, difficult to be certain that potassium deficits were the cause or, for that matter, that potassium supplements were the cure.
We learned from Apollo that man can perform very nicely in a one-sixth gravity environment. One-sixth of the gravity to which he is accustomed proved to be sufficient to give man a feeling of near normalcy for performing functions with at least the same ease as he does on Earth and, in some cases, with greater ease. The astronauts adapted quickly to movement in the lunar gravity environment and traversed the surface of the moon rapidly using many gaits, some of them fanciful but all of them efficient. Apollo lunar surface activity also demonstrated that the metabolic costs of working in that environment were completely acceptable. On the basis of this experience, a lunar surface laboratory in the future is not only feasible but may be highly desirable. Perhaps an international laboratory will ultimately be established there for the study of our solar system and the universe.
The Apollo experience also emphasized the importance of preflight isolation of crewmen to guarantee, insofar as is medically possible, that no infectious illness will intervene in the inflight or the immediate preflight period. We learned the importance of closely following the immunologic status of crewmen and of immunizing them adequately against childhood diseases. Postflight quarantine was an interesting and valuable exercise which provided experience for future quarantine programs. We learned m the course of a carefully conducted program, however, that there are no organisms, live or dead, on the lunar surface.
Satisfying the medical objectives of the Apollo Program had a number of unanticipated benefits. Much of what we have come to call spinoff was produced by the program. Technology developed in support of Apollo missions has found useful and  widespread application in the public sector. A few of the many examples which can be cited have been selected for comment. A one-sixth gravity simulator originally designed to allow the astronaut to adapt to lunar surface gravity in advance of his mission has been used in rehabilitating the physically handicapped. The Apollo liquid cooling undergarment has found medical application in the symptomatic treatment of sustained, high febrile states and in persons working in high thermal environments, such as oil well fire fighting. A portable, noninvasive, continuous blood pressure monitoring and recording system has made possible biomedical monitoring of hypertensive patients during uninterrupted, normal daily activities. Laminar airflow clean room techniques, used in the Lunar Receiving Laboratory and the crew quarters at Cape Kennedy to reduce the spread of infectious agents, are used with enormous success in hospitals and surgical suites for identical reasons.
Probably the most impressive aspect of the Apollo medical program and its most important accomplishment was that man could be supported in the hostile operating environments of space and the lunar surface. This was done with minimal data and in the face of difficulty in obtaining some of the data. We monitored man's vital signs across the void of space and could offer him assurance of his safety during dangerous and difficult operations. The Apollo medical program supported man on his journey to the moon and back and provided a fund of information that will form the medical data core for allowing him to venture still further into the solar system and, perhaps, live and work in lunar laboratories of the future.
The Apollo Program triumphantly closed man's first decade in space. To reach for the moon in 1961 when man's total orbital flight time was less than two hours, and to declare that we would attain it before the decade was out, was an extremely ambitious goal. The vehicle for this achievement was the Apollo spacecraft, and it served its purpose well. The Apollo Program placed twelve men on the moon, leaving them there for a total of over four man-weeks, and returned them safely to Earth. It was an engineering and medical feat with few parallels in the history of mankind. The universe is man s destiny, and the Apollo Program was the first definitive step toward that destiny. The term space flight always connotes manned space flight in my view. No machine can observe space and celestial bodies with the resourcefulness and intuition that man can bring to the task.
* Formerly NASA Director for Life Sciences