4 Laboratory (Flight Backup Subjects)

Primate Life Support System; Primate Physiological Sensors

This portion of the primate mission was to determine the physiological effects of Earth orbit on a nonhuman primate, so as to provide insights into the possible hazards associated with long-term space flight, and to acquire information on basic physiological adjustments to extended weightlessness, particularly concern- ing the cardiovascular system. The basic premise was that in weightlessness, as a consequence of reduction of the gravitational effect on the long columns of blood in the body, pooling of blood in the large vessels would occur, and that a compen- satory mechanism would act to decrease this high blood volume. One indicator of this reflex is the pressure in the large vessels near the heart.

Inflight vascular pressures were obtained by catheterization techniques. A low power pulsate infusion system maintained catheter patency, and amplification was incorporated to obtain signals compatible with Biosatellite III telemetry. Four indwelling catheters, two venous and two arterial, yielded redundant pressure measurements; additional redundance was obtained by connected tow transducers to each arterial catheter. One pair of electrodes provided electrocardiographic and respiratory information. Heparin pumps were used to keep the catheters clear. Inflight results were compared to the four ground control monkeys, plus the preflight baseline data from the flight monkey.

There was a shift of blood volume to the heart; the flight subject experienced an immediate sustained increase in central venous pressure resulting from a central pooling of blood volume. The observed increase in atrial pressure of 2-3 cm water was large enough to provide a stimulus whereby urine level was initially main- tained at a high level, which coupled with a high evaporative fluid loss, produced an early dehydration, probably associated with electrolyte imbalance. Weightless- ness and hypothermia acted to shift blood volume centrally, which provided a strong drive for the reduction of blood volume. Restraint, unusual vestibular sensations, and the continuing polydipsia all acted to disturb the central mecha- nisms which might have acted to restore normal control and regulation of salt and water metabolism. Venous pressure started to fall on flight day five, while arterial pressure and heart rate were within physiologic limits until day eight, i.e. near the termination of the flight.

Adey, W.R. and P.M. Hahn: Introduction: Biosatellite III Results. Aerospace Medicine, vol. 42, 1971, pp. 273-280.

Adey, W.R. et al.: Biosatellite III: Preliminary Findings. Science, vol. 166, no. 904, 1969, pp. 492-493.

Adey, W.R. et al.: Central Nervous, Cardiovascular, and Metabolic Data of a Macaca nemestrina During a 30-Day Experiment. Circadian Rhythms in Non-Human Primates: 2nd Symposium International Congress of Primatology, Atlanta, Ga., July 2, 1968, Emory University, 1969, pp. 8-38.

Adey, W.R. et al.: Central Nervous, Cardiovascular, and Metabolic Data of a Macaca nemestrina During a 30-Day Experiment. Bibliotheca Primatologica, no. 9, 1968, pp. 8-38.¥

Adey, W.R.: Studies on Weightlessness in a Primate in the Biosatellite III Experiment. Life Sciences and Space Research: Proceedings of the 14th Plenary Meeting of COSPAR, Seattle, Wash., June 21-July 2, 1971, Akademie-Verlag, 1972, pp. 67-85.

Meehan, J.P. and R.D. Rader: Cardiovascular Observations in the Macaca nemestrina Monkey in Biosatellite III. Physiologist, vol. 16, 1973, pp. 184-193

Meehan, J.P. and R.D. Rader: Cardiovascular Observations in the Macaca nemestrina Monkey in Biosatellite III. Aerospace Medicine, vol. 42, 1971, pp. 322-336

Meehan, J.P. and R.D. Rader: Cardiovascular Observations of the Macaca nemestrina Monkey in Biosatellite III. BIOSPEX: Biological Space Experiments, NASA TM #58217, 1979, pp. 125.

Meehan, J.P. and R.D. Rader: Monitoring Cardiovascular Function in the Primate Under Prolonged Weightlessness: Final Report. NASA CR-73498, 1970.

Meehan, J.P.: Biosatellite III: A Physiological Interpretation. Life Sciences and Space Research: Proceedings of the 13th Plenary Meeting of COSPAR, Leningrad, USSR, May 20Ð29, 1970, Akademie-Verlag, 1971, pp. 83-98.

Meehan, J.P.: Cardiovascular Adjustments Observed in the Biosatellite III Experiment. Proceedings of the Orbital International Laboratory, Cloudcroft, N.M., September 28-October 2, 1969, Space Conference, 1970, pp. 318-323

Meehan, J.P.: Cardiovascular Adjustments Observed in the Biosatellite III Experiment. International Academy of Astronautics, Orbital International Space Conference, New Mexico, October, 1969, pp. 318-323.

Walter, D.O.: Biosatellite Program: Cerebral, Cardiovascular, and Behavioral Performance of Monkey in Space. Washington Symposium on the Analysis of Central Nervous System and Cardiovascular Data Using Computer Methods, NASA, 1965, pp. 385-395.

¥ = publication of related ground-based study