The health of Apollo crewmembers was a matter of genuine concern. An inflight illness, particularly should it occur during a critical mission phase, could have had serious consequences. To minimize the chance of illness, an extensive health maintenance program was conducted to ensure the highest of health standards. This section describes the clinical practices which were followed and certain special projects conducted to obtain information bearing on the health of astronauts.

W. Royce Hawkins, M.D.

John F. Zieglschmid, M.D.

Lyndon B. Johnson Space Center

[43] While the primary goal of the Apollo Program was to land men on the moon and return them safely to Earth, there were other very important medical objectives. The earlier Mercury and Gemini programs had raised some concerns about the health and safety of future crews. For example, the high metabolic energy expenditure of extravehicular activity during the Gemini missions was unexpected. Before Apollo astronauts could safely explore the lunar surface, reliable predictors of energy cost and real-time monitoring techniques had to be developed. Physiological changes were noted in individual crewmen, some more consistently than others. The most important of these changes was in cardiopulmonary status demonstrated by decreased exercise capacity, loss of red blood cell mass, and cardiovascular deconditioning demonstrated by a decrease in the effectiveness of antigravity cardiovascular responses during posflight stress testing.

At the end of the Gemini program, with 2000 man-hours logged in space, it was clear that man could engage in relatively long space flight without any serious threat to health. However, clarification was still required in many areas. First of all, because of the small number of individuals who flew in space and because of the variability of their responses, it was impossible to distinguish between space-related physiological changes and individual physiological variations. Secondly, for those changes which were directly related to space flight, the relatively short mission durations precluded the identification of trends.

In view of the foregoing considerations, four medical objectives were specified for the Apollo Program:

1 Ensuring crew safety from a medical standpoint. This objective required that every effort be made to identify, eliminate, or minimize anything which posed a potential health hazard to the crew.

 

[44] 2. Improving the probability of mission success by ensuring that sufficient medical information was available for management decisions.

 

3. Preventing back-contamination from the lunar surface.

 

4. Continuing to further the understanding of the biomedical changes incident to space flight. This objective was formulated to detect, document, and understand changes occurring during space flight.

The program to ensure crew safety commenced long before the Apollo Program itself with the development and implementation of the medical selection and screening program for astronauts. Apollo astronauts were drawn from a pool of individuals who were thoroughly screened to preclude any physical or physiological problems which would jeopardize either the mission or the astronaut candidate. Later, special measures were taken to further protect the health and enhance the safety of those astronauts chosen for specific Apollo missions. These included preflight medical examinations, a health stabilization program, drug sensitivity testing of astronauts for all medications aboard the spacecraft, and other measures.

The preflight medical program was designed to preclude, as far as possible, the development of any clinical medical problems during space flight. Since no preventive medicine program, however carefully conceived, can ever guarantee the absence of illness or disease, medications were carried onboard the Apollo spacecraft. The contents of the medical kit were revised as need indicated throughout the Apollo Program. Onboard bioinstrumentation was provided to monitor vital signs for rapid diagnosis of any physiological difficulty in a crewmember and to provide medical information required for mission management. Additional information was transmitted via voice communication between the crew and the ground-based flight surgeons. During extravehicular activity, methods were added to provide metabolic rate assessment. In addition to heart rate, oxygen consumption was monitored along with inlet/outlet temperature of the liquid cooled garment worn by the crewmen.

Opportunities for inflight medical investigations were severely restricted on the Apollo missions because of conflict with the principal operational objectives. Furtherance of the understanding of the effects of space flight on human physiological functioning had to rely almost exclusively on comparison of preflight and postflight observations. These were carefully selected to focus attention on the areas which appeared most likely to be affected, for example, cardiovascular function. Other areas were also investigated for unforeseen changes and corroborative information.

The sections which follow describe medical procedures and findings for Apollo astronauts in the preflight, inflight, and postflight phases of the Apollo missions.

The procedures implemented in the preflight period for Apollo missions had five major objectives. These were:

1. The discovery of latent illnesses during the process of selection of astronauts and preparation for missions.

 

[45] 2. The implementation of the health stabilization program and other preventive measures.

 

3. Determination of individual drug sensitivity to the contents of the Apollo medical kits

 

4 Providing baseline data against which to compare postflight data for determination of space flight effects.

 

5. Prevention of any situations which might delay or otherwise interfere with operational aspects of the missions.

The procedures performed in the preflight period ensured improved performance of flight tasks and, with rare exceptions, prevented the outbreak of illness inflight. This outcome was, in part, the result of medical screening and selection programs designed to provide physically competent crews. Observation and semi-isolation programs also helped to detect latent ailments which might have produced frank symptoms during flight. Finally, a training course was presented to astronauts to acquaint them with stresses of space flight and their effects upon the human organism.

Medical Screening/Examinations

Preventive health care in a population which has been chosen for a particular job begins with the medical selection of that population. Rigorous astronaut selection standards were established to identify:

1. Individuals who were physically capable of performing astronaut duties; specifically those possessing the necessary physical and psychomotor capabilities and not subject to incapacitating physiological disturbances when exposed to the various stresses of space flight.

 

2. Individuals who were free of underlying physical defects or disease processes which could shorten their useful flight careers.

Apollo astronauts were initially medically screened by techniques which varied only in minor degree from those applied to the first seven Mercury astronauts. The standards used closely approximated U. S. Air Force Flying Class I Standards, except in the selection of scientist-astronauts where visual standards were relaxed to qualify a sufficient number of candidates. These examinations were performed at the U. S. Air Force School of Aerospace Medicine, with final review and medical acceptance of candidates by the NASA Lyndon B. Johnson Space Center medical staff. Listed below are the components of the examination used for medical selection.

1. Medical history and review of systems.

 

2. Physical examination.

 

3. Electrocardiographic examinations, including routine electrocardiographic studies at rest, during hyperventilation, carotid massage, and breath holding, a double Master exercise tolerance test, a cold pressor test, and a precordial map.

 

[46] 4. Treadmill exercise tolerance test.

 

5. Vectorcardiographic study.

 

6. Phonocardiographic study.

 

7. Tilt table studies.

 

8. Pulmonary function studies.

 

9. Radiographic studies, including cholecystograms, upper Gl series, lumbosacral spine, chest, cervical spine, and skull films.

 

10. Body composition study, using tritium dilution.

 

11. Laboratory examinations, including complete hematology workup, urinalysis, serologic test, glucose tolerance test, acid alkaline phosphatase, BUN, sodium, potassium, bicarbonate, chloride, calcium, phosphorus, magnesium, uric acid, bilirubin (direct and indirect), thymol turbidity, cephalin flocculation, SGOT, SGPT, total protein with albumin and globulin, separate determinations of Alpha 1 and Alpha 2, Beta and Gamma globulins, protein bound iodine, creatinine, cholesterol, total lipids and phospholipids, hydroxyproline, and RBC intracellular sodium and potassium. Stool specimens were examined for occult blood, and microscopically for ova and parasites. A urine culture for bacterial growth was done, and a 24-hour specimen analyzed for 17-ketosteroids and 17-hydroxycorticosteroids.

 

12. Detailed examination of the sinuses, larynx, and Eustachian tubes.

 

13. Vestibular studies.

 

14. Diagnostic hearing tests.

 

15. Visual fields and special eye examinations.

 

16. General surgical evaluation.

 

17. Procto-sigmoidoscopy.

 

18. Dental examination.

 

19. Neurological examination.

 

20. Psychologic summary, including Wechsler Adult Intelligence Test, Bender Visual-Motor Gestalt Test, Rorschach Test, Thematic Apperception Test, Draw-A-Person Test, Gordon Personal Profile, Edwards' Personal Preference Schedule, Miller Analogies Test, and Performance Testing.

 

22. Electroencephalographic studies.

 

23. Centrifuge testing.

The preflight medical examinations for Apollo crewmembers included detailed physical examinations and special studies. The physical examinations commenced 30 days prior to launch and ended on the day of lift-off. The special studies involved collection of baseline data for comparison with postflight findings. The areas of particular interest were microbiology, immuno-hematology, clinical chemistry, and cardiopulmonary function. Baseline data collection in each of these areas, of course, had bearing on crew health, but was additionally obtained in order to answer the following critical questions:

1. Did a change take place in a particular dependent variable?

 

[47] 2. Was the change significantly different from that occurring in a control group?

 

3. What was the extent of the change?

 

4. What was the time course of the observed change?

 

5. Was it possible to provide causal interpretations?

The following sections provide details concerning the preflight physical examinations and special baseline studies.

Physical Examinations. The physical examinations of Apollo crewmembers were intended to document the crewmembers' physical qualifications for the mission, to detect any medical problems which might require remedial or preventive intervention, and to provide baseline data for postflight comparison. Physical examinations were conducted in the following manner:

1. Preliminary examination at F-30 days. At this time, interval history, vital signs and a general physical examination were conducted.

 

2. Interim examination at F-15 days. General physical examination, dental examination, and monitoring of vital signs were accomplished.

The preliminary and interim examinations included the following procedures:

• An interval history and detailed review of systems, vital signs-to include oral temperature, blood pressure, and pulse rate.
• ENT examination to include visual inspection of the external ears, auditory canals, and tympanic membranes, the nose and nasal passages, transillumination of the frontal and maxillary sinuses, and visual inspection of the anterior and posterior middle pharynx.
• Examination of the eyes to include visual inspection and palpation of the lids and lacrimal apparatus, visual inspection of the conjunctiva, sclera, and cornea, and ophthalmoscopic examination of the lens, media, and fundus.
• Examination of the heart to include palpation, percussion, and auscultation.
• Examination of the lungs to include palpation, percussion, and auscultation.
• Examination of the abdomen to include palpation, percussion, and auscultation.
• Examination of the genitalia and anal regions.
• Examination of the extremities for recent trauma or limitation of function.
• Neurological examination to include a brief examination of the cranial nerves and motor, sensory and proprioceptive modalities.
• Skin, visual inspection.
• Lymph nodes, by palpation.
• Dental examination (interim examination only).

3. Comprehensive examination at F-5 days. The comprehensive examination consisted of the procedures on the following page.

• [48] Interval history, vital signs, including height, weight, oral temperature, pulse rate, and blood pressure.
• ENT Examination:
  • a. Ears: Visual inspection of external ears, auditory canals and tympanic membranes, screening Rudmose audiometry.
  • b. Nose: Visual inspection, sinus transillumination, if indicated by recent history.
  • c. Throat: Direct examination of middle pharynx.
  • d. Eyes: Same as for preliminary examination, plus distant and near visual acuity, near-point of accommodation, phorias, and visual fields.
• Heart: Palpation, percussion, and auscultation, plus standard twelve-lead EKG.
• Lungs: Palpation, percussion, and auscultation, plus PA chest film.
• Abdomen: Palpation, percussion, and auscultation, plus abdominal scout film.
• Genitalia and anus: inspection, plus digital rectal examination.
• Extremities: Examination for recent trauma, range of function.
• Neurological examination: Detailed examination of cranial nerves, motor, sensory, and proprioceptive modalities.
• Skin: Visual inspection, plus photographs of any areas of significant interest.

4. Cursory examination - F-4 to F-O days. Brief physical examinations and histories were conducted in the last four days before flight. These included recording of vital signs, oral temperature, pulse, blood pressure, weight, plus a brief examination of the ears, nose, throat, heart, and lungs. Other signs and systems were examined as indicated by the medical history.

The scheduled physical examinations varied slightly with mission requirements. However, these had to commence not earlier than 30 and not later than 21 days prior to lift-off in order to provide sufficient time to diagnose and treat any illnesses of recent onset. Some of the significant medical findings that occurred during the 30-day preflight period are listed in table I. The comprehensive examination performed five days prior to launch was intended to accurately document the physical status of each crewmember at the outset of the mission. The final examination prior to flight involved last minute recordings of critical parameters to provide the most reliable basis that could be obtained for postflight comparisons.

The following paragraphs provide some detail on various aspects of the physical examination.

Dental Examinations. Dental care was provided as a regular part of the ongoing health care program of astronauts. However, special measures were taken prior to missions to preclude, wherever possible, dental problems during flight. All crewmen were evaluated at or about F-15. Because of the relatively short duration of the Apollo flights, emphasis was placed on general observation rather than definitive quantitative research.

[50] Again, because mission duration was short, no special inflight dental treatment capability was provided for Apollo. It was felt that the risk of a problem occurring was slight and, when weighed against limitations of weight, space, and training time, providing an inflight treatment capability was not indicated. Analgesic and antibiotic drugs were provided for symptomatic treatment of any dental problems. As a further precaution, restorative dental treatment was avoided in the three-month period prior to launch. The object of this measure was to minimize the possibility of barodontalgia, a sudden, severe toothache which can occur when barometric pressure is reduced as a result of expansion of air entrapped in a dental restoration. When a dental problem arose in the three-month period prior to flight and a restoration became necessary, the astronaut in question was subjected to reduced barometric pressure to ascertain the condition of the tooth.

Dental problems that occurred among crewmembers during the Apollo Program resulted in no appreciable mission impact. During the 90-day preflight period, five of the thirty-three Apollo crewmen had dental problems requiring treatment. One preflight and one postflight occurrence of pulpitis could have caused significant crewmember impairment if the pulpitis had occurred during a flight. Pulpitis, an inflammation of the dental pulp, causes severe pain that usually can be stopped only by root-canal therapy, performed by a skilled dentist in a fully equipped dental suite, or by extraction. Prediction of such occurrences is virtually impossible, although the preventive treatment of known causative factors can lower the risk of occurrence. The only other preflight problems were minor fractures of previously placed restorations or minor fractures of part of a crown of a tooth. Inflight, no problems were experienced. No case of barodontalgia ever occurred, although some astronauts bad experienced this discomfort during their flying careers.

Experience with Apollo astronauts in an intensive preventive dentistry program led to the conclusion that the probability of a disabling dental emergency in the astronaut population is one occurrence in 9000 man days. The probability of dental problems of lesser severity, but associated with significant discomfort, is one in 1500 man-days. These figures are comparable to those recorded for Navy personnel on long submarine patrols. From these estimations, it is obvious that a provision for emergency inflight dental care must be made only for very long-duration missions.

Visual Function Testing. Visual function testing was a part of the pre and postflight physical examination of Apollo astronauts. Ten visual parameters were tested during the Apollo Program:

• Unaided visual acuity, 7 m (20 ft)
• Amplitude of accommodation
• Near point of convergence
• Fusional amplitudes, base-in and base-out
• Horizontal phorias, 7 m and 33 cm (20 ft and 13 in.)
• Refraction
• Intraocular tension
• Color perception
• Depth perception
• Visual fields

[51] One of the major considerations in flight was the amount of harmful ultraviolet (UV) radiation to which the crewmen would be subjected during extravehicular activity. Prior to Apollo missions, the UV threshold of the eye was unknown. Over a three-year period, NASA-sponsored research determined these levels. The problem was, however, subsequently resolved with the development and use of Lexan in the extravehicular visor assembly. since Lexan was opaque to UV radiation. A minimum of 2000 hours of exposure would be required to produce a corneal "burn" through this plastic.

Table 2 gives the data ascertained for ocular thresholds to UV radiation.

Total ultraviolet effective flux :13.6483 X 10^-4J/cm²/sec

Ocular burn threshold for ultraviolet: 40 X 10^-4W/cm²

Ultraviolet band threshold time : 2.93 seconds

The harmful effects of UV radiation extend over an area slightly greater than the 215 to 315 nanometer range noted above; however, the relative effectivity outside these extremes is very low. Summating these slight effects into the flux listed above could possibly lower the total UV band threshold time to about two and one-half seconds in a Zero Air Mass environment.

Special Studies. A number of special preflight examinations were conducted and measurements made to provide a baseline against which to compare postflight findings in the areas of microbiology, immuno-hematology and clinical chemistry, and cardiopulmonary function. Details of each of these studies are provided in the related chapters in Section III of this book. The preflight examination procedures required for each are discussed only briefly here.

In order to study any microflora alterations which could have occurred in space flight, preflight samples were taken to catalog the microorganisms found on the crewmembers and their clothing, and on spacecraft surfaces. Samples collected for culture [52] included swabs of various parts of the body, throat gargle, and urine and fecal samples. These were collected on four occasions in the month prior to flight. Blood samples were also collected on three occasions in this same time frame.

Baseline data were obtained on the cellular elements of the blood, the chemical constituents of the blood and urine, and the humoral and cellular factors involved in immunity. The hematological and chemical measurements of various blood constituents were one portion of comprehensive examinations designed to disclose the state of well-being or the presence of occult disease in the crews. Blood analyses furnished data which, when integrated with facts obtained from histories and physical examinations, permitted an objective assessment of the physical status of the astronauts and allowed for remedial action if required. However, no values outside of the normal range were observed.

Biochemical and hematological baseline information was obtained, in part to quantitate the effect of the stresses inherent in space flight, and in part to aid medical personnel in medical management of crews in the postflight period.

Cardiopulmonary evaluations and findings are discussed at length in Section III, Chapter 4 Apollo Flight Crew, Cardiovascular Evaluations, and Chapter 5, Exercise Response. Preflight orthostatic tolerance tests and exercise response tests were performed to provide baseline information to facilitate assessment of space flight effects.

Cardiopulmonary data were obtained to develop heart rate versus metabolic rate calibration curves that would be used for estimating real-time work output during extravehicular activity. Utilization of Douglas bags, a Tissot spirometer, and an oxygen consumption computer or metabolic rate meter also made determination of cardiopulmonary efficiency possible. Evaluation of cardiopulmonary data was accomplished by observing how the dependent variables - workload, oxygen consumption, blood pressure response, respiratory response, and EKG-changed in response to the independent variable, heart rate.

The extent of cardiovascular system "deconditioning" was assessed also by comparison with preflight baseline responses to the application of negative pressure to the lower half of the body by means of the lower body negative pressure (LBNP) device. Preflight evaluations were made at least three times in the month preceding flight. The test procedures involved five minutes with the subject at supine rest in the LBNP device, a total of fifteen minutes at negative pressures ranging from -40 x 10²N/m² to -67 x 10²N/m² (-30 to -50mm Hg), and five minutes of recovery. Because missions involving postflight quarantine could not accommodate the size of the LBNP device in the Mobile Quarantine Facility, a static stand-type of orthostatic tolerance testing was substituted. This involved obtaining five minutes of electrocardiographic data while the crewman was standing still with his back to the wall and his feet apart. Test conditions were controlled and standardized to exclude unnecessary variables such as environmental temperature, time of day, food intake, physical exertion, or venipuncture.

Health Stabilization

The problem of communicable disease exposure prior to flight, with subsequent development of symptoms in flight, was recognized as a potential hazard from the beginning of the United States space program. Total isolation of flight crews for a period [53] of time prior to launch offered indisputable advantages but was initially thought to be infeasible because of the operational difficulties involved. Flight crews were required to be in contact with large numbers of people and to move from place to place during the last few weeks of their training in preparation for a space flight.

When clinical illnesses impacted preflight mission operations during Apollo 9 and 13, it became apparent that some type of preflight health stabilization program was imperative Prior to Apollo 14, 57 percent of the Apollo crewmembers experienced some illness of varying degrees of severity at some time during the 21 days before launch. Based on observations of the first several flights and on the observation of crewmember activities during earlier manned Mercury and Gemini missions, the Flight Crew Health Stabilization Program was developed and implemented for the Apollo 14 mission and subsequent missions. Such a program, rigorously enforced, can result in a significant reduction of infectious disease hazard, although the hazard cannot be eliminated completely.

Table 3 lists the illness events in Apollo crewmen and shows the dramatic reduction in illness following the implementation of the health stabilization program.

Drug Sensitivity Testing

Drug sensitivity testing was performed to determine the response of flight crewmembers to each item in the medical kit to preclude allergic reactions and other able side effects in flight. Each Apollo crewmember was tested under controlled [54] conditions to determine his response to medical kit items carried onboard the spacecraft. (The medical kit is described later in this chapter in the section concerning inflight Procedures and Findings.) After a medical history was obtained by a physician regarding the experience of each crewmember with each medication under test, and it had been determined that (1) no adverse reaction had been experienced, and (2) there was no evidence of impaired health at the time of testing, the medication was administered to the astronaut. The crewmember was observed by the physician for an appropriate period of time following administration of the medication and was queried about subjective responses. If positive subjective findings were reported, the test was either repeated with a double-blind placebo method, or an appropriate drug was substituted for which no undesirable side effects had been reported. Individuals were additionally tested for any allergic reaction to the electrode paste.

Table 4 indicates the drug administration and observation constraints applied. All medications used were treated in a similar fashion.

Medical Training

To perform their inflight tasks optimally, Apollo crewmen required an understanding of the interaction of space flight stresses and their effects on the human organism, including the manner in which the body adapts to space flight factors. Further, these crewmen had to recognize any abnormalities in their health status and understand the therapeutic measures which might have been prescribed for inflight problems. Medical training began shortly after astronaut selection with a series of lectures concerned with space flight physiology and therapeutics. The curriculum encompassed about 16 hours of didactic instruction provided by experts in each area. The principal elements were as follows:

Cardiovascular System. Brief outline of anatomy and physiology, methods of observing and monitoring cardiac activity, system response to acceleration, weightlessness, work and other stresses, functional testing, such as tilt table, lower body negative pressure, bicycle and treadmill systems.

Pulmonary System. Brief outline of anatomy and physiology, pulmonary function, gas exchange, problems related to hypo- and hyperbaric environments, physiologic limits of spacecraft atmospheres, contemplated atmospheres for future vehicles, respiratory response to acceleration, weightlessness and work, physical conditioning and testing, respiratory capacity.

Hematology and Laboratory Medicine. Review of Mercury and Gemini findings involving blood elements and chemistries, review of programs scheduled for Apollo and Skylab Programs, illustration of the need to establish good baseline data, controls, and possible expansion of the present program.

The Role of Psychiatry in Crew Selection. Crew and dependents support, personal considerations of long term confinement, group dynamics, and responses to various stresses encountered in flight and on the ground.

Description of vestibular System. Its function and equilibrium, and testing thereof, response of the vestibular system to acceleration, weightlessness, flight experiments in Gemini, and planning for Apollo and Skylab Programs.

Visual System. Brief description of anatomy and physiology, relationships to other sensory organs, effects of acceleration and weightlessness on eye and visual system, problems in space, such as light, ultraviolet trauma, high closing speeds, and depth perception without reference points.

Refresher courses were required of each astronaut every three years in the technical and practical aspects of altitude physiology and the medical aspects of survival.

Before each mission, a detailed medical briefing was provided by staff members of the Johnson Space Center approximately one month before launch. The purpose of the briefing was as follows:

[57] 1. To acquaint the crewmembers with the pre- and postflight medical procedures planned for their mission

 

2. To discuss with the crew preventive medicine measures (related to diet, potential sources of infection, and physical conditioning) recommended for their health and comfort.

 

3. To acquaint the crew with the Apollo medical kit and its uses.

 

4. To review with the crew the flight food and hygienic supplies selected for their flight.

 

5. To demonstrate the configuration and operation of the biomedical harness.

 

6. To achieve final coordination of procedures for logging or communicating medical data during flight.

 

7. To familiarize the crew with toxicological considerations.

The Astronaut Health Care Program

Once selected, retention of space crewmen on flying status assumes great importance for a number of reasons, not the least of which is the cost of training such individuals. Consequently, comprehensive health care is provided all astronauts and their families through a preventive, diagnostic, and therapeutic program managed by the National Aeronautics and Space Administration, with aid from many civilian and military consultants. Care of families by the same physicians rendering care to the astronauts provides an understanding of the total milieu in which the astronaut lives and functions.

Astronauts must report any and all illnesses and injuries for evaluation and treatment. Once yearly, during the month of their birth, a thorough physical examination is performed, whether or not an astronaut remains on active duty status. Preventive dental care is also rendered. All patients are seen by a dentist at least once every six months and their conditions evaluated at that time. Emphasis is placed on a home care program. During these periodic examinations, care is taken to minimize ionizing radiation exposure during the use of diagnostic X-rays. Astronauts represent a unique population. They have been exposed to some environmental factors never before experienced by man and to others to which men have been exposed, but not in the same combination or sequence. As such, the astronaut population represents the opportunity for a unique longitudinal study which should yield invaluable information for selection of future space flight crews.

Listed in tables 5 through 11 are examples of significant medical problems detected during the annual physical examination. These tables serve to highlight the types of medical findings contained in the past histories of the astronaut crews. The findings are invaluable to the mission flight surgeon as background information in the real-time assessment of inflight medical problems and in pinpointing potential problems that may arise. It is vital that all inflight signs and symptoms be evaluated in the context of past medical findings such as are enumerated in these tables.

During the inflight phase of Apollo missions, medical care was limited to long-distance biotelemetry monitoring, diagnosis, and treatment with the appropriate onboard drugs This treatment was carried out by the space crewmen themselves under [58] the direction of ground-based flight surgeons. The weightless flight phase of Apollo missions was characterized by certain transient adaptational difficulties, by a few clinical illnesses, and by a limited number of physiological phenomena apparently related largely to space flight factors. The following sections describe the clinical and medical aspects of the inflight portion of Apollo missions.

[61] Monitoring

When the United States space program first began, the concept of obtaining continuous physiological data by instrumenting the human operator was a new one. No sufficiently reliable off-the-shelf hardware was available. Since that time, sophisticated and highly reliable biotelemetry devices have been developed.

Each Apollo crewman wore a biosensor harness which provided a means of transmitting critical physiological data to the ground. Through this system, medical personnel were able to evaluate physiological status during such critical phases as launch and docking, extravehicular activity, and lunar explorations. This real-time telemetry of vital biomedical information was also available for monitoring Apollo crewmen in the event of inflight illness.

The operational bioinstrumentation system was designed as an individually adjustable unit worn under the flight clothing. The biobelt assembly was an electronic system that included sensors, signal conditioners, and telemetry interfaces. The system returned electrocardiogram, heart rate, and respiratory pattern and rate data. A two-lead EKG with synchronous phonocardiography provided an index of cardiac activity. Cardiotachometer equipment made monitoring of instantaneous and average heart rate information possible. Voice communications and real-time television observations, coupled with monitoring of the vital signs, provided the medical basis for an inflight clinical profile of the Apollo astronauts.

Data from the biotelemetry of the spacecraft were displayed at consoles at the launch and mission control centers. The consoles were manned continuously by medical personnel during the course of each mission. Heart and respiration rates were displayed in digital form; electrocardiogram and impedance pneumogram data were presented on a cathode ray oscilloscope.

In general, the equipment worked well, although some minor losses of data were experienced throughout the program. Problems with breakage of bioharness leads and pin connectors encountered on the Apollo 7 mission were corrected for subsequent flights. Some degradation of physiological data was caused by loose biosensors, but restoration of good data was usually obtained by reapplication of the sensors. Sponge pellet electrodes were used in the biosensor harness for the first time on the Apollo 15 mission. This modification reduced skin irritation that had earlier resulted from continuous wearing of the electrodes.

The quality of the data obtained with the new electrodes was excellent. Some data loss resulted because air became trapped under the electrodes during the Apollo 15 mission, but this was easily corrected by modifying the electrodes with small vents.

Additional data were telemetered during lunar surface extravehicular activity to permit assessment of the portable life support system and, additionally, the determination of the metabolic activity during lunar excursions. Metabolic rate was approximated by monitoring the inlet and the outlet temperatures of the liquid cooled garment. Heart rate and oxygen usage were also monitored as metabolic rate indices. Of the three methods, the thermal data and oxygen use methods proved to be reasonably accurate and significantly more reliable as a means for determining metabolic rate than did heart rate data.

Further documentation of the Apollo bioinstrumentation system is reported in Section Vl, Chapter 3, Bioinstrumentation. Additional information concerning [62] monitoring during extravehicular activity is contained in Section II, Chapter 4, Metabolism end Heat Dissipation During Apollo Extravehicular Activity Periods.

Inflight Medications

The initial philosophy regarding use of medication precluded usage except in a medical emergency. Additional experience and the confidence gained thereby permitted some alteration of this philosophy to the extent that certain drugs were prescribed during Apollo missions when indicated. For example, hypnotics were prescribed when adequate rest could not be obtained, particularly when sound sleep was important prior to critical mission phases.

Medical Kit. The contents of the Apollo medical kit (figure 1) were selected based on experience gained during earlier missions. The drugs were intended to treat the contingency situations most likely to arise. As noted previously, crewmembers were tested for sensitivity to all drugs in the medical kit and substitutions were made when necessary.

---

Table 12 lists drugs and drug stowage and usage aboard the Apollo Command Module. The contents of the medical kits were changed as more effective medications were identified. For example, the combination scopolamine/Dexedrine was substituted after Apollo 11 for the previously stowed Marezine after ground-based tests indicated it was more effective for the treatment of motion sickness. Likewise, a short-acting barbiturate, Seconal, was added after reports of sleep difficulties by the Apollo 7 crew. The cardiac arrhythmias experienced during the Apollo 15 mission dictated the addition of Pronestyl, Lidocaine, atropine, and Demerol in missions subsequent to Apollo 15. Each Apollo vehicle also carried a medical accessory kit in a compartment behind the Lunar Module Pilot's couch. Its contents are listed in table 13. An abbreviated version of the Command....