Space Medicine in 1961-62

THE SUBORBITAL FLIGHT OF ALAN SHEPARD on May 5, 1961, was, in one sense of the word, anticlimactic. Gagarin had already orbited the earth on April 12. In another sense, however, the Shepard flight was even more dramatic than the Gagarin flight. For here, the entire world witnessed and shared the delays, the tension, and the success of the first U.S. astronaut to travel in space. His ballistic flight path reached a peak of 116 statute miles for a downrange distance of 302 statute miles.[1]

The details of this event, as well as those of the later manned space flights of Project Mercury, have been recorded in the annals of history. The present account will therefore concentrate upon the medical implications, both in terms of operations and lessons learned and in terms of long-range high-level planning for medical support of manned space flight, rather than upon recounting of each individual mission.

On July 21, 1961, the second suborbital flight was made with Astronaut Virgil Grissom aboard. (See pictures of flights).He traveled to an altitude of 118 statute miles, and 303 miles downrange.[2] With this flight and the subsequent orbital flight of the chimpanzee Enos, the Space Task Group could look forward to placing a man in orbit. As the summer of 1961 drew to a close, the rate of progress was unprecedented.

CHIMPANZEE ENOS AND THE NEAR-CRISIS

On November 29, 1961 the Mercury-Atlas 5 launch at Cape Canaveral carried chimpanzee Enos into orbit for a scheduled three-orbit mission. Because the attitude-control system malfunctioned, retrororockets were fired on the second orbit. The Mercury spacecraft was recovered 1 hour 25 minutes after the water landing, and Enos was recovered in seemingly excellent condition except that the extreme heat had obviously plagued him.[3]

During the postflight medical examination of Enos, there was to be considerable concern over the variations in cardiac rhythm which had been recorded by the instruments developed for this flight. (See Enos picture) The critical question posed was whether plans should proceed for the first manned orbital flight. Yet on the date of Enos’ flight, President Kennedy had announced that Lt. Col. John Glenn would be the prime astronaut for the first manned orbital mission to take place shortly, with Lt. M. Scott Carpenter as backup. Capt. Donald Slayton would be the prime astronaut for the second manned orbital mission with Lt. Comdr. Walter Shirra as backup.[4]

During the following days, however, it appeared that this announcement might have been premature in the light of medical findings of the Enos flight. The tension of those days has been described unofficially to the author. It must have been a period of uncertainty as to the proper course of action to take, for the first manned orbital flight was scheduled for December 1961.

Fortunately this potential medical crisis did not become full blown. Eminent cardiologists were asked to review the records and biological data obtained during the orbital flight of Enos, to determine the reason for the arrhythmia, if possible, and to separate it from the influences exerted by weightlessness in space flight. It was found that the difficulty lay with the instrumentation, and that the data were therefore invalid. Accordingly, it was recommended that the manned orbital flight proceed as scheduled.[5]

MEDICAL IMPLICATIONS OF THE CHIMPANZEE FLIGHTS

The two chimpanzee flights in Project Mercury were to reveal significant medical data. The suborbital flight of Ham was without complications, but it was considerably less complex than Enos’ orbital flight.

In the Mercury-Atlas 5 (MA-5) orbital flight, Enos performed a complex multiple operant task as he twice orbited the earth. The 42-pound subject, whose age was estimated to be 63 months, had been exposed to simulated launch accelerations on the centrifuge at the University of California. He had also served as a subject for a laboratory model of a 14-day flight. Over a 16-month period he had received a total of approximately 1,263 hours of training, of which 343 hours were accomplished under restraint conditions in a model of the actual couch used in flight.[6]

According to Henry, the results of the two animal flights (Ham and Enos) showed that:

On the basis of the flight, Henry and his group drew the following conclusions:

The experience gained from the two animal flights (MR-2 and MA-5) was, however, not the only source of information available on space flight.

MEDICAL IMPLICATIONS OF THE COSMONAUT FLIGHTS

On April 26, 1961, 2 weeks after the orbital flight of Gagarin, the Embassy of the Union of Soviet Socialist Republics in Washington, D.C., issued certain medical data about the mission.[8] The release read in part:

The time has come for the practical creation of extraterrestrial scientific stations . . . .They will be followed by manned flights to the moon and other planets of the solar system, the creation of manned interplanetary stations and the gradual conditioning of men to space flight.[9]

According to the release, Gagarin felt "perfectly well" throughout the orbiting phase and also during the period of weightlessness. It was noted that measures had been taken to protect the spacecraft from the hazards of space radiation.

To provide answers to the medicobiological problems posed by space flight, it was reported, Soviet scientists since 1951 had carried out experiments with flights of animals in rockets to altitudes up to 450 kilometers (approximately 280 miles). Later, artificial earth satellites were used for making biological experiments—for example, it was considered important to study with maximum accuracy the biological effects of cosmic radiation. As a result of experimentation, orbital flight below the radiation belts was found to be safe for organized representatives of the animal world. It was therefore concluded that manned flight could be undertaken without harm to the cosmonaut’s health.

The cosmonauts’ training had included, among other subjects, orientation in space medicine. Also included were special training and tests in aircraft flights under conditions of weightlessness, training in a simulated spacecraft cabin and on a special training machine, prolonged stay in a specially equipped soundproof chamber, centrifuge tests, and parachute jumps from air craft. Cosmonauts had to be able to stand the state of weightlessness for as long as 40 seconds and to partake normally of liquid, semi-liquid, and solid food during that time. They also had to be able to discharge such functions as writing, radio communication, and reading, and to maintain visual orientation in space. Physiological studies and special psychophysiological methods "permitted the selection of people best fitted to discharge the missions accurately and who had the most stable nerves—emotional health," according to the Soviet report of April 26, 1961. The future cosmonauts "systematically did physical exercises to raise the organisms’ resistance to acceleration forces as well as other factors of the new medium," it was reported. From the group of cosmonauts thus trained, Gagarin had been chosen to make the first orbital flight.

From the foregoing description, it is apparent that the U.S.S.R. and the U.S.A. had approached the problem of selection and training of the astronauts in much the same manner, following the traditional methods of selection and training of pilots. The main difference in the biological-medical procedures had been that the U.S.S.R. had carried out more extensive animal experimentation than had the United States.

A major difference in the approach, however, had been in the development of the life-support systems of the spacecraft. For Gagarin’s flight the air-conditioning system maintained normal pressure and normal oxygen concentration in the pilot’s cabin. The concentration of carbon dioxide did not exceed 1 percent. The temperature ranged from 15 degree to 22 degree C and the relative humidity from 30 to 70 percent. The air was regenerated chemically, and the heat in the pilot’s cabin was absorbed by a liquid cooling agent. Gagarin wore a protective space suit.

The journal Meditsinskiy Rabotnik (Medical Worker) reported that Gagarin ate solid, pastelike, and liquid food during the flight. His menu was designed to avoid both overcharging the digestive system and accumulating excessive cellular tissue. He had no difficulty eating in the condition of weightlessness. Prior to flight he had tested foods prepared for consumption in flight and had chosen his favorites. "It is important," wrote G. F. Arutyunov (Master of Science in Medicine), "to have all the constituents of the food ration assimilated by the organism to the utmost."[10]

The major problem with which the Russians had wrestled prior to manned orbital flight was that of reentry. In August 1958 they had sent two dogs on a ballistic flight to an altitude of 280 miles with successful recovery by ejection of the dog containers during the descent. Subsequent development and testing led to the system used by Gagarin, which included a descent phase lasting approximately 30 minutes. In case the braking engine failed, the ship was designed to take advantage of atmospheric drag. The cosmonaut would make a landing on dry land, as contrasted with the Mercury landings on water.[11]

On August 6, 1961, after Grissom’s suborbital flight in July, the U.S.S.R. launched Cosmonaut Gherman S. Titov into orbit in a spacecraft (Vostok II) weighing 13 pounds more than Vostok I, launched the previous April. (On the same date the report of the Space Science Board of the National Academy of Sciences was released; it recommended exploration of the moon and planets as the official goal of the U.S. space program.) The following day, August 7, it was reported from Moscow that Major Titov had successfully landed in Vostok II after 17 orbits in 25 hours 18 minutes. This was the first manned flight of more than one orbit, and the first test of man’s reaction to prolonged weightlessness.[12]

Other medical information would be forthcoming shortly.

TOWARD GEMINI AND APOLLO

Concurrent plans and objectives for space exploration brought the life sciences into an increasingly important role as the Mercury Space Task Group prepared for the next operational step. The long-range obligations of space exploration enunciated by the President meant that not only must Mercury be successfully completed but Gemini and Apollo now must be planned for.

All was not well, however, in the minds of the Nation’s life scientists, despite the obvious success of the two U.S. suborbital flights and the U.S.S.R. orbital flight. The international scientific community had become increasingly concerned about reports—unverified at first, and then confirmed—that Titov had suffered motion sickness while in orbit. Did this mean that there were hazards of weightlessness or of combined stresses that should be investigated before further plans were made to orbit a U.S. man in space? The matter was of grave concern to the U.S. life scientists, aware that their first projected orbital flight was but a few months away.

Also still unresolved was the total complex of problems that had bothered the life scientists since 1958 when Project Mercury was eablished. As Dr. White had reported, early work had been undertaken to extend man’s tolerance to the biomedical rigors calculated to be inherent in the early flights.[13] Although technology would sustain life-support systems, there still remained serious problems about man’s ability to meet the individual stresses which could not be reproduced on the ground (weightlessness and radiation) and the effect of the stresses on the body systems. The latter was complicated by the lack of knowledge of the impact of increasing time exposure. According to White:

... proposed as a serious area for study was the composite effect of: the psychological effects of flight; the accelerations and vibrations of powered flight; the abrupt shift to the weightless environment with its inherent requirement for the adjustment of the physiological systems to the new baseline, later a reversal of these orbital patterns back to an entry program of acceleration, vibration, oscillation, and heating; and the landing impacts. This composite effect was a highly suspect one which would challenge man’s survivability in space flight.[14]

Now, on the eve of the first U.S. manned orbital flight, these questions of man’s survivability in the light of these combined stresses were still unanswered.

NOTES TO CHAPTER 9

[1] Proceedings of a Conference on Results of the First U.S. Manned Suborbital Space Flight, NASA, June 6, 1961.

[2] For complete details, see Results of the Second U.S. Manned Suborbital Space Flight, July 21, 1961, Manned Spacecraft Center, NASA.

[3] L. E. Stringly, "Countdown and Procedures for Project Mercury. Atlas-5 Flight (Chimpanzee Subject); Final Technical Documentary Report." Aeromedical Res. Lab. Tech. Documentary Rep. 62-17, Holloman AFB, 1962.

[4] Aeronautical and Astronautical Events of 1961, Report of the National Aeronautics and Space Administration to the Committee on Science and Astronautics, U.S. House of Representatives, 87^th Congress, 2d sess., June 7, 1962, p. 68.

[5] Based on classified documents and off-the-record discussions by the author.

[6] Frederick H. Rohles, Jr., Marvin E. Grunzke, and Herbert H. Reynolds, "Performance Aspects of the MA-5 Flight," ch. 9 in Results of the Project Mercury Ballistic and Orbital Chimpanzee Flights, NASA SP-39, 1963.

[7] James P. Henry, "Synopsis of the Results of the MR-2 and MA-5 Flights," ch. 1 in Results of the Project Mercury Ballistic and Orbital Chimpanzee Flights, NASA SP-39, 1963.

[8] Press Release No. 109, Embassy of the Union of Soviet Socialist Republics, Apr. 26, 1961.

[9] Ibid.

[10] As cited, ibid.

[11] Ibid. See also D. I. Fryer, "The Medical Sciences and Space Flight," R.A.E. News, Feb. 1964.

[12] Aeronautical and Astronautical Events of 1961, op.cit.,p.38.

[13] See ch VIII, note 3.

[14] Ibid.

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