The Cosmos 782 mission marked the first time that the U.S. participated in the Soviet Cosmos program. Launched from Plesetsk on November 25, 1975, the Cosmos 782 biosatellite was recovered in Siberia on December 15. Various physics and biology experiments were flown on the 20 day mission. Scientists from France, Czechoslovakia, Hungary, Poland, Romania, the U.S., and the U.S.S.R. participated in these investigations.
More than 20 different species were flown on the mission. U.S. investigators conducted experiments on a subset that included rats, fruit flies, carrot tissue and cells, and fish eggs. A U.S. radiation dosimeter experiment was also carried out without using biological materials.
A centrifuge on the spacecraft created an artificial 1 g environment for some of the biological subjects. Specimens rotated on the centrifuge were compared with specimens maintained in microgravity conditions.
The general objective of the U.S. life sciences experiments was to compare the effects of microgravity and artificial gravity on the genetics, growth, development, and aging of biological systems. Aging processes were studied using fruit flies as experimental subjects. The effects of microgravity, artificial gravity, and the randomized gravity vector of a ground-based clinostat were studied on carrot tumor growth. Another experiment using cultured carrot cells studied the development process in higher plants. A follow-up to an Apollo-Soyuz experiment was conducted to explore the harmful effects of microgravity on growth and development in fish eggs. This experiment was the only joint U.S./U.S.S.R. study flown on the Cosmos series of biosatellites that was developed by JSC; all others were developed and managed by ARC. Rat experiments were designed to assess microgravity effects on gastrointestinal, endocrine and lymphoid systems and on blood, muscle, bone, and eye tissue. A radiation dosimetry experiment measured the high-linear-energy-transfer (LET) particle radiation aboard the biosatellite.
Twenty-five unrestrained male Wistar rats (Rattus norvegicus) were flown aboard the spacecraft in individual cages. Body temperature telemetry transmitters were implanted in five of the rats. Two control groups of rats were studied on the ground—the synchronous control group and the vivarium control group, discussed in detail below.
Studies on growth and development provided by U.S. specialists were conducted on 1000 embryos of Fundulus heteroclitus, a small shallow water minnow (Walbaum) of the Beaufort, North Carolina, strain. Embryos of five different age groups were used in the experiments. One hundred flight embryos from each age group were subjected to artificial gravity, and an identical flight group exposed to weightlessness. Four different control studies were conducted on the ground to support this experiment.
Experimental materials were arranged in three tiers inside the spacecraft (Fig. 4-33). The upper platform was a centrifuge which was set to rotate at a constant speed of 52 rpm. Containers with fruit flies, Fundulus embryos, carrot tissue, and cultured carrot cells were placed on this platform. They received a 1.0 g or 0.6 g force, depending on their position on the centrifuge. A stationary lower platform held materials identical to those on the upper platform. Twenty-five rats in individual cages occupied the space below the lower platform.
Each cage consisted of two intercommunicating cylinders (Fig. 4-34). Each had a diameter of about 9.5 cm and was about 20.8 cm long. The upper cylinder housed the rat, while the lower one served as a waste collection trap. Cabin air circulated through the cages and was returned, via the lower cylinder, to the cabin after being passed through an activated charcoal filter. The upper animal chamber was furnished with light on a 12:12 light and dark cycle. An automatic watering system provided water freely to the animal. A feeder cup dispensed 10 grams of paste food every 6 hours. A circular coil surrounding the cage monitored physical activity. Cages were arranged in groups of five and a common food and water reservoir used for each group.
Fish embryos were housed inside a two-chambered aluminum case. Each chamber contained five flattened polyethylene bags separated by thin perforated foam. Embryos were suspended in artificial sea water inside the polyethylene bags.
Fruit flies were maintained in standard cotton-stoppered vials placed in sheet metal flight containers. Standard food medium was provided.
Carrot tissue for the tumor growth experiment was contained in cylindrical acrylic canisters, each about 8.5 cm in diameter and about 10.5 cm in height. There was a stack of three dishes in each canister. The dishes were held together by a metal rod which passed through a hole in the center of each dish. Carrot slices were placed in four holes surrounding the central hole of each dish. The canisters were sealed with anodized aluminum caps which included filters and holes for the passage of air.
The carrot development experiment was also housed in acrylic canisters. Each canister consisted of a tube with two end caps and two filters for air, a thermometer, a foam pad, nine petri dishes and a four-legged standoff cushion. Each of the petri dishes contained clones of carrot cells in shallow agar medium.
Radiation detectors were made of cellulose nitrate and Lexan polycarbonate photographic films. High-LET particle flux and integral LET spectrum were measured by thin detector packages, each consisting of seven thin plastic films held together with tape. Aluminized mylar wrapping protected the films from exposure to ultra-violet irradiation. Thick detector packages, each consisting of 75 plastic films, measured charge spectrum.
Two kinds of ground control experiments aided in interpreting in-flight data. The synchronous ground control experiment was initiated 5 days after launch. Experiments identical to the flight experiments were carried out in a spacecraft mock-up. The environmental conditions of the spacecraft were also duplicated. The centrifuge used as a control for the in-flight centrifuge rotated at the same speed as during flight, but gravitational forces on the ground resulted in a greater centrifugal force. Launch stresses were also simulated during the synchronous control study. The vivarium control experiment, begun at the time of launch, provided data on minimally stressed specimens. Environmental conditions for this experiment were like those in a standard laboratory.
The U.S.S.R. supplied rats and fruit flies. The U.S. investigators provided specimens for other U.S. experiments. Several treatments had to be performed on the three experimental groups before the experiments began. In the case of the rat experiments, injections, changes in diet, and cage training needed to be carried out.
Onboard sensors gathered housekeeping data during the flight. Information on rat body temperature and motor activity was telemetered to the ground.
Biological materials needed to be retrieved within six hours after the biosatellite landed. Equipment and a team of engineers and scientists were airlifted to the recovery site to conduct the necessary procedures. A field laboratory was set up in insulated tents (Fig. 4-35). Electrical power was supplied by two portable generators. A temperature of 18-22°C was maintained within the laboratory, an extraordinary accomplishment in a Siberian winter.
Within 11 hours of recovery, 12 of the 25 flown rats underwent autopsies at the landing site. Readaptation studies were conducted in Moscow on the remaining flight rats for 25 days after the mission to assess their ability to readjust to Earth gravity. Autopsies were then performed on these rats and on rats in the ground control groups.
The onboard centrifuge demonstrated that the organisms flown experienced stress due to prolonged weightlessness, and not to other flight factors.
Flight rats had lowered body temperature, on average. Airflow, isolation, and confinement were thought to have contributed to this effect together with the altered muscular activity in microgravity. On recovery, rats appeared healthy and autopsies revealed no pathological disturbances attributable to space flight. Weight gain was lower in flight rats than in control animals. An increase in adrenal weight, reduced weight of thymus, spleen and some hind limb muscles, and a tendency toward reduced weight of lymph nodes were noted.
Flight rats showed an increased immune response, contradicting the hypothesis that space flight has a detrimental effect on cell mediated immunity. However, results also indicated an increased destruction of lymphoid cells. Survival of red blood cells was shown to be reduced in the flight animals, and hemolysis was significantly greater. In addition, some perturbations in endocrine function were also found.
Results of bone studies showed a decreased rate of bone formation rather than accelerated bone resorption in flight animals. A significant increase in bone formation was seen after the postflight recovery period.
Some abnormalities were noted in the eye tissue of flight rats. However, the tissue was normal for the most part, indicating that space flight of this duration would be safe for humans.
During postflight readaptation studies, the flight rats displayed disturbances in vestibulo-motor function. These effects disappeared by the tenth postflight day.
The only detrimental effect of space flight appeared to be a decrease in negative geotaxis and mating.
A high incidence of anomalous development was noted, but this effect was found to be due to the toxicity of new labeling tape on the plastic bags. The original labeling tape had been replaced with the new tape just prior to the flight. No major microgravity-related changes occurred in fish that developed in flight. Possible exceptions may be in those aspects of development that require gravity as a cue or a reference stimulus.
The development of viable embryos from carrot cells appeared to be unimpaired during space flight. A change in carbohydrate content was observed in carrot flown onboard; however, this effect was probably attributable to factors other than weightlessness. Tumors were found to be smaller in carrot disks exposed to weightlessness, a result that conflicts with ground-based studies using simulated microgravity. Differences were also noted in enzyme activity in carrot tissue exposed to weightlessness.
The high-LET particle radiation in the biosatellite was measured.
Interview with Lyuba Serova
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Rosenszweig, S.N. and K.A. Souza. U.S. Experiments Flown on the Soviet Satellite Cosmos 782. Final Reports. NASA TM-78525, September 1978.
Souza, K.A. The Joint U.S.-U.S.S.R. Biological Satellite Program. Bioscience, vol. 29, no. 3, 1979 pp. 160-167.