Russian and American scientists and engineers worked together more closely on Cosmos 2229 than on any previous space mission. NASA developed several flight hardware units for the mission, trained Russian engineers and technicians to operate the hardware, and in collaboration with its Russian counterparts, developed postflight procedures. The Russians provided the spacecraft environmental control systems and animal life support equipment for the experiments and were responsible for mission management, preflight training and instrumentation of animal subjects, primary support of postflight controls, and data management and distribution.
Cosmos 2229 was an international venture, accommodating experiments conducted by scientists from Russia, the U.S., Germany, France, Canada, China, the Netherlands, Lithuania, Ukraine, Uzbekistan, and the European Space Agency (ESA). One of the objectives of the mission was to conduct experiments within ESA's Biobox facility, a fully automated, programmable incubator for research in gravitational biology. Several experiments were also conducted outside the Biobox facility. The biosatellite carried a variety of organisms, including two rhesus monkeys, Spanish newts, fruit flies, desert darkling beetles, silkworm larvae, clawed frog eggs, and animal and plant cell cultures. Scientists sponsored by Ames Research Center (ARC) conducted 13 life sciences experiments during the mission, using the two rhesus monkeys as experiment subjects.
Life Sciences Research Objectives
The NASA experiments were designed to study various biological systems likely to be affected by the space environment. Bone and muscle are used by many terrestrial organisms to maintain their body positions relative to gravity. Microgravity has been found to cause significant changes in these body components in both monkeys and humans. To gather further data in this area, Cosmos 2229 experiments studied bone strength, density, and structure, bone biochemistry, calcium metabolism, and neuromuscular function. Experiments on previous Cosmos and several Spacelab missions have indicated that the neurovestibular system is affected by microgravity. Since the ability to perform coordinated movements is of crucial importance for astronauts, neurovestibular studies are a high priority. Three of the investigations on Cosmos 2229 addressed this area. Immune and metabolic changes, as well as the way that circadian rhythms of brain, skin, and body temperatures change during space flight, were also studied.
Rhesus Monkey (Macaca mulatta)
U.S. Life Sciences Payload
Two rhesus monkeys (Macaca mulatta
) were used as experimental subjects on the mission, as on four previous Cosmos missions. The subjects, named Ivasha and Krosh, were approximately three years old at launch.
Hardware used for the NASA experiments was similar to that used on Cosmos 1514, Cosmos 1667, Cosmos 1887, and Cosmos 2044, although modifications and upgrades were made for this mission. The life support equipment and some of the experiment hardware were supplied by Russian companies, primarily SKTB Biophyspribor. ARC developed and provided several hardware elements, including sensors and a signal processor/data collection system for the circadian rhythm and temperature regulation studies, tendon force and EMG sensors for the muscle studies, and head motion velocity sensors, amplifiers, and preamplifiers for the neurovestibular studies.
The flight monkeys were housed in two Primate-Bios capsules within the Cosmos spacecraft landing module. The capsules, each containing life support and experiment equipment, are oriented within the spacecraft so that the monkeys can view each other. Couches inside the capsules support and confine the monkeys and provide adequate cushioning when the capsule impacts the ground at landing. A light-weight bib prevents the monkeys from disengaging leads emerging from the implanted sensors. Unidirectional air flow moves excreta toward a centrifugal collector beneath each couch. Monkeys can obtain juice and food, in paste form, from dispensers located in each capsule by biting on switches in the delivery tubes. Primate access to the dispensers can be controlled remotely from the ground. A video camera in each capsule monitors animal behavior during flight.
A Psychomotor Test System (PTS) installed in each capsule measures behavioral and vestibular parameters and provides environmental enrichment for the monkeys. The display screen presents task stimuli to which the monkeys are trained to respond. The system also includes a hand lever, foot lever, and touch screen for monkeys to give a correct response, depending on the type of stimulus.
Improvements made to the hardware for this mission were designed to increase the quality of life support data collected. The inflight data recording system was updated so that high-quality brain and neuromuscular recordings could be obtained. The monkey feeder system was improved, and a backup feeder was added to reduce the risk of losing science data in case of feeder malfunctions. Modifications in the monkey restraint system permitted increased arm movement. The neurovestibular data acquisition system was significantly modified through a joint U.S.Russian development effort, allowing a greater number of parameters to be recorded inflight.
Several pieces of ground-based hardware were used for extensive pre- and postflight testing. One vestibular experiment measured changes in ocular counter-rolling and the vestibulo-ocular reflex using a four-axis vestibular and optokinetic rotator. The rotator is surrounded by an optokinetic sphere with vertical black and white stripes on its inner surface. The primate couch, attached to the rotational axis of a C gimbal (a device that allows an object to incline in any direction) can be fixed in positions about the subject's x, y, and z axes. This arrangement allows the rotator to tilt in any position while the subject is pitched or rolled and stimulated visually by the optokinetic sphere.
Another vestibular experiment used a multi-axis rotator, which can rotate a monkey along three different axes. The rotator allows measurement of eye position, vestibular nuclei response, and vestibular primary afferent responses.
The remaining vestibular experiment used a Portable Linear Sled (PLS) to take vestibular measurements made during horizontal and vertical oscillations of specified frequency and sinusoidal acceleration (Fig. 20). The test subject is placed into a light-tight Specimen Test Container (STC) that travels on air bearings along ceramic rails of the sled and provides vibration-free motion. The STC is gimballed to allow yaw, pitch, or roll stimulation of each monkey.
Figure 20. The Portable Linear Sled is designed to provide neurovestibular stimulation thorough vibration-free oscillations, horizontally and vertically.
The bone experiments took pre- and postflight measurements of tibial bone strength using the Mechanical Response Tissue Analyzer (MRTA). A NASA-modified version of a commercial system, the MRTA uses a low-frequency vibratory stimulus to assess bone strength noninvasively.
The metabolism study used a Doubly Labeled Water Kit, containing 2
O, to measure energy expenditure. No flight hardware or inflight monitoring was required for this experiment.
Training and selection of monkeys for the mission began a year and a half prior to flight. Candidate monkeys were initially selected after extensive health evaluations. Monkeys in the flight candidate pool were acclimated to couch confinement and enclosure within the Primate-Bios capsule. They were also trained to obtain food and juice from automatic dispensers and to carry out a series of performance tasks using the PTS.
About four and a half months before flight, 14 monkeys were each implanted with sensors and electrodes for circadian rhythm and temperature, neuromuscular, and neurovestibular data measurements. Preflight measurements were made using the PLS, the two rotators, the MRTA, and a commercial densitometer system, which uses dual-energy X-ray absorptiometry to measure bone mass and overall body composition.
Doubly labeled water was administered after collection of baseline urine samples. Baseline muscle biopsies were performed, and blood and bone marrow samples were taken.
Final selection of flight monkeys was based on health status, level of adaptation to flight hardware, level of training, ability to tolerate the acceleration force encountered during launch, and adequate functioning of implanted sensors. Seven fully trained monkeys with surgically implanted sensors were brought to Plesetsk three weeks before launch. Of the seven monkeys, two were finally selected as flight animals.
A telemetric link between ground monitoring stations and the biosatellite permitted monitoring of spacecraft systems, the capsule environment, and some primate physiological parameters.
The monkeys were exposed to a light/dark cycle of 16 hours of light, alternating with eight hours of darkness. Vestibular tests conducted inflight included the Psychomotor Test, which monitored the monkeys' eye-tracking response to a semicircular array of programmed lights. A sensor attached to the skull cap of each 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. Incorrect responses resulted in a delay before the presentation of the next task.
During the flight, all equipment functioned normally. Relative humidity remained between 30 and 70 percent throughout, and barometric pressure was between 720 and 760 mm of mercury. Temperature within the capsule ranged from 20 to 26 °C on the first 9.5 days of flight. On the tenth day, the capsule became continuously exposed to the sun as a result of the flight orbit of the biosatellite. Solar heating combined with heat from the payload resulted in an increase in capsule temperature to 30 to 31.3 °C. One of the payload components, the ESA-developed Biobox, was shut off to ameliorate the problem. This situation negatively impacted ESA's science results. The temperature then returned to 27.7 °C within 12 hours.
Both monkeys remained in good health during flight. However, Ivasha developed space motion sickness during the first few days of flight, consuming smaller quantities of food and juice than necessary. To prevent Ivasha from becoming dehydrated, extra juice was made available by means of a ground command.
The recovery team reached the capsule within 40 minutes of touchdown. The monkeys were recovered in good condition. Both were active and responsive to environmental stimuli. Ivasha had lost 13 percent of body weight during the flight, while Krosh had lost 5 percent. After preliminary examinations were completed, the monkeys were flown to Moscow to undergo further testing.
As in preflight operations, the Portable Linear Sled, the two rotators, the MRTA, and the densitometer were used to obtain postflight measurements. Muscle biopsies were performed, and blood, bone marrow, and urine samples were taken.
A flight simulation control study was conducted 45 days after recovery of the capsule, using the two flight animals and four additional monkeys (Table 14). For this simulation, the animals were maintained for 11.5 days in conditions similar to those that they had experienced during the mission.
Table 14. Flight and Control Groups for Cosmos 2229 Primates.
The results of the experiments indicated that the monkeys were affected in various ways by confinement as well as the space flight environment. An increase in serum calcium levels was noted immediately postflight. Changes observed in bone and muscle were compatible with those observed in bed rest studies and space flight experiments on human subjects. Bone loss was not significant during this short-duration flight. Bone formation, however, appeared to be increased during the period after flight, when the monkeys were able to walk. Some lean tissue loss was observed during the flight. This loss was reversed rapidly during the postflight period. Other effects noted in the monkeys included vestibular and muscular changes and alterations in temperature regulation, metabolism, and circadian timing. Immunological function was also found to be decreased after the flight.
Connolly, James P., Michael G. Skidmore, and Denice A. Helwig. Final Reports of the U.S. Experiments Flown on the Russian Biosatellite Cosmos 2229.
NASA TM-110439, April 1997.
European Space Agency. The Euro/Russian Bion 10 Mission Completed. ESA Press Release Nr. 03.93, Paris, January 19, 1993. Contained in the European Space Agency Web site. http://subs.esa. int: 8330/frame/press.html.