The first U.S.S.R. orbital flight of a nonhuman primate was accomplished on the Cosmos 1514 mission. Launch occurred on December 14, 1983. The biosatellite was recovered five days later.
On the mission, 2 monkeys flew as human surrogates, together with 10 pregnant rats. More than 60 experiments were performed by investigators from Bulgaria, Hungary, the German Democratic Republic, Poland, Romania, Czechoslovakia, France, the U.S.S.R., and the U.S. Three experiments on primates and another on the rat subjects were conducted by U.S. scientists.
The mission differed markedly from earlier Cosmos flights, both in terms of Soviet scientific goals and in the degree of cooperation required between the U.S. and the U.S.S.R. The two countries had to interact at a high level because much of the U.S. experiment hardware had to be integrated with the Soviet spacecraft and instrumentation systems.
Experiments focused on the effect of weightlessness on various physiological parameters. A study of circadian rhythms was concerned with the synchronization of primate motor activity, body temperature, and skin temperature rhythms to a fixed light and dark cycle and to each other. Blood pressure and flow were monitored, to evaluate short- and long-term changes in these parameters. Changes in calcium metabolism were studied to determine the effect of weightlessness on the skeleton. A neuro-ontogeny experiment was conducted to investigate space flight effects on the sensory development of rats that spent part of their prenatal gestation period in space.
Two rhesus monkeys (Macaca mulatta) named Bion and Abrek were flown onboard. Both were about three years of age and each weighed approximately 4 kg. Height was a constraint in selecting animals for flight because there was limited vertical clearance in the animal capsules. The monkeys were conditioned to sit in the restraint couches and perform tasks for food rewards. Tasks included pressing a lever with their feet and tracking a moving light with their eyes. Monkeys were also trained to eat and drink from food and juice dispensers. All experimental subjects in the flight candidate pool were tested for their tolerance of launch and re-entry accelerations and of a several-hour stay in the right-lateral supine position, which would be experienced during prelaunch rocket maneuvers. Monkeys in the flight and control groups were implanted with sensors to measure several physiological parameters. Bion and several control monkeys also had implanted blood pressure and flow cuffs.
Ten pregnant female Wistar rats (Rattus norvegicus) were flown. Ground control groups contained the same number of rats. At the start of the flight or control experiments, the rats were at gestation day 13 of their 21-day cycle.
The spacecraft contained two monkey biological satellite (BIOS) capsules, which provided life support and experiment hardware (Fig. 4-32). The orientation of the two capsules within the spacecraft allowed the monkeys to view each other. The monkeys were placed within restraint couches in each capsule (Fig. 4-42). A remotely controlled chest restraint pad, a lap restraint plate with a leg divider, and upper and lower arm restraint straps were used to maintain each monkey in an appropriate, comfortable posture and to provide adequate support upon ground impact. The degree of thoracic restraint could be modified by ground command. Unidirectional airflow moved excreta toward a centrifugal collector underneath the restraint couch. The monkey could activate the paste diet and juice dispensers located in each capsule by operating bite switches. The monkey's access to these dispensers could also be controlled remotely from the ground. A video camera mounted within each capsule monitored in-flight animal behavior. A 16:8 light and dark cycle was provided in the monkey compartments during the flight.
A psychomotor system within each capsule was used to test the responses of the monkey subjects to various stimuli. The monkeys were trained to press a lever whenever a light signal was presented. The strength required to press the lever could be determined from the electromyogram (EMG) signals recorded from limb muscles. Vestibular tests conducted in flight included monitoring the eye-tracking response of the monkeys to a semicircular array of programmed lights located in front of each monkey. A sensor attached to the skull cap of the monkey registered that a correct response had been made when the sensor was pointed directly at the light on the panel. Juice rewards were presented for correct responses.
Rats were group housed in a single compartment called the rodent BIOS. The BIOS was formed by removing the partition that separated males and females in the Cosmos 1129 rodent mating chamber. It was equipped with ten nozzles for delivering paste food and 10 nozzles for dispensing water. Food was provided at regular intervals; water was available ad lib to the animals. Unidirectional airflow moved waste and debris into a waste collector located at the bottom of the cage. The light and dark cycle was regulated to 12:12.
Ground support equipment for the rat neuro-ontogeny experiment included maternity cages with video monitors, rotation and tilt devices for vestibular tests, and an olfactory, respiration, auditory, and visual testing system.
All hardware required for conducting the cardiovascular experiment was developed by the U.S. Flight hardware included blood pressure and velocity transducers, signal conditioners, and control circuitry. The signal conditioners were powered by a lithium battery pack to minimize electrical noise. A cuff made of injection-molded plastic contained the pressure and flow transducers in its upper half. The lower part of the cuff consisted of several interchangeable shells that could fit around blood vessels of varying diameters. The cuff was surgically placed around the carotid artery of one of the flight monkeys and two control animals. Upon entry into orbit, the cardiovascular signal processor was activated by a signal from the biosatellite and data recorded on a Soviet tape recorder.
Test and calibration equipment to support flight hardware was also developed by the U.S. This equipment included custom-made biological signal simulators (which were used for system integration purposes when no animals were present), oscilloscopes, signal generators, impedance meters, and receivers.
The U.S. developed custom solid-state recorders and a data readout and control unit to record skin and body temperature, ambient temperature, and motor activity for the circadian rhythm experiment during flight. A sensor and signal conditioner were used to measure activity, and a surface thermistor measured skin temperature. A Soviet-developed sensor was implanted subcutaneously for measuring body temperature.
Skeletal radiographs of the monkey during the preflight and postflight periods were obtained with a portable x-ray machine.
As in all Cosmos missions, control experiments were conducted on the ground to help interpret flight data. A synchronous control experiment was designed to simulate the flight experiment in all aspects except the condition of weightlessness. This was conducted several days postflight in the same spacecraft used for flight, with animals that were not flown on the mission. Postflight data was collected during a 21-day period following the completion of the synchronous control experiment. Data on animals housed in normal laboratory conditions were obtained in a vivarium control experiment. This experiment was meant to control all factors that were unique to the internal spacecraft environment such as lighting, humidity, and temperature. The protocol of the vivarium control for the monkey subjects varied according to the needs of the specific investigator.
Because many aspects of the U.S. experiments had to be carried out by Soviet specialists, adequate training was an important preflight activity. Soviet specialists implanted blood pressure and flow cuffs, assembled and installed experiment hardware within the BIOS capsules, and attached sensors to the monkeys. Their postflight role was equally significant; they were responsible for collecting, preparing, and coordinating transport of biosamples to the U.S. for analysis.
Training of flight and control monkey subjects began more than a year prior to launch. Physiological sensors were surgically implanted in the subjects during the three months preceding the start of the experiments. For the Soviet experiments, brain electrodes were implanted and skull caps attached to the subjects. These experiments also required implanting 15 subcutaneous electrodes in each monkey, including an ECG, EMG, rheoplethysmogram, and an axillary temperature transmitter. For the U.S. experiments, carotid pressure and flow cuffs were implanted in some monkeys.
Preflight control data were gathered from several flight candidate monkeys during a 10-day period about 2 weeks prior to launch. Flight and synchronous control subjects were selected after this period ended.
A remote signal from a U.S.S.R. controller activated the cardiovascular signal conditioners onboard the spacecraft shortly after it went into orbit. The signal conditioners were reactivated every two hours during the flight for five-minute periods of data acquisition. A remote signal was also given after orbital insertion to loosen the chest restraint straps securing the animals to their couches, so that the monkeys could move more freely during the flight period. The straps were tightened before re-entry to provide maximum support for the animals during ground impact. During the five days spent in orbit, the monkeys followed the activities described in Figure 4-43. Video cameras located inside the capsules enabled ground personnel to monitor in-flight monkey behavior.
No special activities were conducted within the rat chamber during the flight.
Soon after the biosatellite was recovered, it was enclosed within a temperature-controlled portable field laboratory. Animals were removed, examined, and flown to Moscow.
Bion began to exhibit signs of ill-health on the second day after landing and died during postflight day three. Postmortem analyses revealed that the cause of death was a strangulated bowel. The problem may have been congenital in nature and appeared to bear no relation to either the implanted instrumentation or the space flight. Postflight studies continued with the second monkey, Abrek. Because of the significant weight loss that occurred during the flight period, the Soviets decided to supplement the paste diet postflight with fresh food.
Cardiovascular data was transferred from the Soviet flight tape recorder to a U.S. ground-based recorder after the flight. Circadian rhythm data was also transferred from solid-state memory to permanent copy at this time.
Five of the rats were euthanized at the recovery site and biospecimens were stored for transport to Moscow. The remaining five females were flown to Moscow, where they delivered their litters approximately five days after landing. Four of the females gave birth to at least 12 pups, while the fifth delivered stillborn pups after undergoing a prolonged labor. Pups and mothers were transferred to special cages for behavior studies.
Patterns of food and juice consumption indicated that Abrek adapted to the flight conditions faster than Bion. Bion was less active and began to drink juice only on the third day of flight and to consume food on the fourth. Both monkeys lost weight during the flight. Body dehydration was noted at recovery. Circulating blood and plasma volume and extracellular and interstitial fulid had decreased, while venous hematocrit had increased.
Noticeable changes were evident in Bion's cardiovascular system early in the flight. Signs of adaptation were noted from the third to the fifth day of flight.
Circadian rhythms of activity and temperature were shown to persist in the space environment although entrainment to the light and dark cycle appeared to be weaker than on Earth. Changes were also seen in the levels of circulating calcium.
Pregnant females gained less weight during flight than during the synchronous control experiment. Decreases in muscle and liver mass, hemoglobin, and amniotic fluid were also apparent in flight rats.
Offspring of flight dams appeared to have impaired auditory detection capability and possibly vestibular supersensitivity. Other perturbations in development caused by the space environment may have been compensated during the five days between biosatellite recovery and birth.
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Gazenko, O.G., ed. Ontogenesis of Mammals in Microgravity. NASA TM- 103978, April 1993. [A translation of Ontogenez Mlekopitayuschikh vNevesomosti, Nauka Publishers, Moscow, 1988.]
Mains, R.C. and E.W. Gomersall. U.S. Monkey and Rat Experiments Flown on the Soviet Satellite Cosmos 1514. Final Reports. NASA TM-88223, May 1986.