Spacelab-J/STS-47
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Mission Overview
The STS-47 mission was launched on the Space Shuttle Endeavour on September 12, 1992, and landed eight days later, on September 20. The seven-member crew included the first Japanese astronaut, the first African American woman to fly in space, and the first married couple to fly on the same space mission.
The mission's primary objective was to fly the Spacelab-J (SL-J) payload. Several secondary objectives were also accomplished. The SL-J payload included 34 Japanese experiments and nine American experiments in the areas of materials science and the life sciences. Two of the 16 SL-J life sciences experiments were sponsored by Ames Research Center. The first, the Autogenic Feedback Training Experiment, was conducted on the astronaut crew. The second was the Frog Embryology Experiment. Kennedy Space Center sponsored the Plant Culture Research Experiment.
Life Sciences Research Objectives
The objective of the SL-J life sciences experiments was to conduct research that would help prepare humans for long-term space ventures. One of the difficulties crew members experience during space flight is Space Adaptation Syndrome, the symptoms of which are similar to those of motion sickness. Microgravity drastically alters the perceptions astronauts have of themselves and objects in space, and about half of all astronauts experience motion sickness shortly after the transition from 1 G. This syndrome interferes with the tightly scheduled work routines on space missions and can be life threatening if experienced while wearing a spacesuit. The Autogenic Feedback Training Experiment (AFTE) was designed to evaluate the effectiveness of autogenic feedback training in reducing space motion sickness. The training combined two self-regulation techniques, autogenic therapy and biofeedback, to enable crew members to control their physiological responses. Autogenic feedback training has many potential uses in alleviating disease symptoms on Earth, such as hypertension, low blood pressure, and nausea associated with chemotherapy. It also has potential nonmedical uses. Aircraft pilots can use autogenic feedback training to reduce the risk of accidents by training themselves to control the abnormal physiological responses associated with emergencies encountered during flying. The training could be used to reduce jet lag, fatigue, insomnia, and the high stress of certain work environments. The first AFTE study, conducted on the Spacelab 3 payload on STS-51B in 1985, verified the concept of autogenic feedback training. The experiment on SL-J continued the evaluation of the training with a redesigned Autogenic Feedback System to allow better data collection and increase crew participant comfort.
Scientists want to determine if reproduction and development occur normally in microgravity. The Frog Embryology Experiment was designed to examine the role of gravity in the fertilization and early development of an organism (Fig. 8). Previous experiments on amphibian development in space have produced inconclusive results, partly because egg fertilization was always carried out in Earth gravity rather than in space. It is likely that the developmental stages most susceptible to alterations in gravity levels occur just after fertilization. When a frog egg is fertilized, its contents assume a specific orientation with respect to gravity. The symmetry of the frog's body is established at this point in development. The absence of gravity, and therefore the ability of the egg to orient in a particular way, might disrupt the establishment of proper symmetry in the body. In the SL-J frog experiment, scientists attempted to test this hypothesis by fertilizing eggs in microgravity.
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Figure 8. Fertilization of a Xenopus egg is followed by cleavage (a succession of cell divisions that partition the large fertilized egg cell in smaller cells), differentiation and organogenesis. After hatching from the egg, the tadpole will exist in an aquatic stage with gills and a tail, until complex hormonal changes transform it into an adult frog.
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The plant experiment was designed to study the critical stages in plant embryogenesis using cultured cells and to study whether mitosis and chromosome behavior are modified by the space environment. Plants may be critical for long-term space flight missions to purify air and provide replenishable food supplies. They are also likely to make the small, enclosed chambers on spacecraft more conducive to human habitation on long-duration flights.
Life Sciences Payload
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Organisms
Two crew members participated in the AFTE. One was trained to self-regulate her physiological responses during the flight; and the other, who was not similarly trained, served as a control.
Four adult female South African clawed frogs, belonging to the species Xenopus laevis, were studied in the Frog Embryology Experiment. This species was selected for several reasons. There is a large quantity of information already gathered on the South African clawed frog, from which investigators could readily draw. Because fertilization and embryonic development in this frog is external, scientists can initiate timed fertilization by covering the eggs with sperm at specific times. Large egg size makes observation easy, and egg morphology allows identification of fertilized eggs. Care of the frog in a laboratory setting is straightforward, requiring only an aquatic environment and fish food. Because a single female lays hundreds of eggs, a large population of genetically related sibling tadpoles can be obtained for study. Furthermore, females can be conveniently induced to lay eggs by injecting them with the hormone human chorionic gonadotropin (HCG).
The Plant Culture Research Experiment used cultured cells of two plant species: carrot (Daucus carota) and daylily (Hemerocallis cv. Autumn Blaze).
For the AFTE, the participating crew member wore the Autogenic Feedback System-2 (AFS-2). The AFS-2 is a portable, belt-worn monitoring device that can continuously record up to eight physiological responses. It is powered by a battery pack and includes a garment, a headband, transducers, biomedical amplifiers, a digital wrist-worn feedback display, and a cassette tape recorder. The parameters recorded and displayed by the AFS-2 are electrocardiogram, heart rate, respiration waveform and rate, skin conductance, finger temperature, finger pulse volume, and triaxial accelerations of the head.
Frogs were kept in the Frog Environmental Unit (FEU), which provides a ventilated, temperature-controlled, moist habitat for four female adult frogs as well as a group of developing embryos. The maintenance of a stable temperature is critical for successful frog ovulation and embryo development. Within the FEU, the removable Adult Frog Box housed the frogs. The box is lined with a soft, water-absorbent material to prevent skin abrasion and contains Ringer's solution to keep the frogs moist. The FEU also accommodates two sets of Egg Chamber Units (ECUs). One set of 28 ECUs is kept in microgravity, while the other set of 28 ECUs is kept in a centrifuge inside the FEU, providing a simulated 1-G environment. Each ECU is equipped with a window that allows viewing of the embryo with use of a dissecting microscope and video equipment. The chambers are filled with Ringer's solution and can accommodate injections of fixatives or other materials.
HCG/Sperm Kits and a sperm suspension were stored in the Refrigerator/Incubator Module (R/IM). The R/IM is a temperature-controlled holding unit flown in the Shuttle middeck that maintains a cooled or heated environment.
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Embryos and tadpoles were viewed through the Dissecting Microscope, which supports general life sciences experiments requiring capabilities such as examination, dissection, and image recording of tissues and other specimens. Adjustable magnification permits, for example, viewing of a single embryo or entire tadpole flask. The Dissecting Microscope features a video camera and video interface unit that allow recording and downlink of images to the ground.
Crew members performed flight operations for the experiment using the General Purpose Work Station (GPWS). The GPWS can support biological experiments, biosampling, and microbiological experiments, and it can serve as a closed environment for containment while routine equipment repair or other inflight operations are performed. The GPWS cabinet provides workbench accommodations and allows two crew members to simultaneously perform tasks within.
Two Ambient Temperature Recorders (ATR-4) were used to record the temperature of the experiment system so that the researchers would be aware of any temperature anomalies that may have occurred during flight. One was mounted in the Adult Frog Box and the other in the HCG/Sperm Kit. The ATR-4 is a self-contained, battery-powered package that can record up to four channels of temperature data.
Plant cells were contained in Cell Culture Chambers provided by NASDA. These chambers are aluminum petri dish-like compartments. A honeycomb matrix inserted into the base of the chamber provides structural support for the solid agar medium containing the cultured cells. The cells are capable of gas exchange through a gas-permeable membrane at the top of the chamber.
Operations
Preflight
During the months before the mission, a crew member was given autogenic feedback training (AFT). During the training sessions, she was presented with augmented sensory feedback of her own physiological activity levels. While monitoring the feedback, she was instructed to perform specific exercises in order to learn to modify her autonomic responses. Several baseline physiological measurements were taken of all crew members, both trained and untrained. Motion sickness was induced during training by use of a rotating chair, a vertical acceleration device, and flights in the KC-135 aircraft. The rotating chair provides a clockwise Coriolis acceleration force. The vertical acceleration device can be displaced 2.5 feet upwards or downwards at programmable frequencies and gravity loads. The KC-135 is a pressurized Boeing 707 aircraft that can provide short periods of simulated microgravity during parabolic flights.
The sperm solution for inflight fertilization of frogs was prepared, sealed, and refrigerated. The whole testis was macerated and the solution was diluted to activate the sperm before use. Four frogs were loaded into the Adult Frog Box about 30 hours before the launch of the Shuttle. The box was placed in the FEU in the Spacelab.
About one week before flight, plant cell cultures were prepared at the investigator's laboratory. Cultured cells were transferred to two Plant Culture Chambers and allowed to solidify in nutrient medium containing an agar-like agent. The chambers were then hand-carried by commercial airliner to KSC. The chambers were kept in an unlit incubator at 22±2 °C until 17 hours before launch, when they were loaded into the Shuttle middeck. Simultaneous ground controls were maintained at the investigator's laboratory.
Inflight
For the AFTE, a crew member wore the AFS-2 for the first three days of the mission. She also used an 11-item symptom logbook to record the type and severity of symptoms at specially designated times during the mission and at any time that she experienced symptoms. She was required to perform daily 15-minute sessions during which she practiced controlling specific physiological responses with the help of the wrist-worn display unit. If she experienced symptoms during the flight she was required to apply the AFT methods to control them.
On the first day of flight, the crew injected the four frogs with human chorionic gonadotropin (HCG), inside the GPWS (Fig. 9). Approximately one day later, eggs were obtained from each flight frog and fertilized using the Sperm Kit. The percentage of fertilized eggs from each individual frog was noted to be relatively high. Eggs from the two best frogs were loaded into 22 egg chambers and placed in the FEU. Ten chambers were incubated in the centrifuge and 12 chambers were incubated in microgravity. Some eggs from both control and experiment groups were fixed with formaldehyde at 2.5 hours, 14 hours, and 22 hours after fertilization. Eggs arrested in these developmental stages were stored for postmission analysis. Some eggs from both groups were allowed to hatch undisturbed into tadpoles. The swimming behavior of the tadpoles was filmed and also downlinked directly to a ground station. Tadpoles were stored in the R/IM for reentry.
 Figure 9. Inflight activities for the development study using the Frog Environmental Unit. (Click to enlarge)
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For the Plant Cell Culture Experiment, ambient temperatures were recorded in the vicinity of the experiment package.
Postflight
Shortly after landing, the AFTE investigators interviewed the subject crew member about her experience of participating in the AFTE. Flight hardware, data tapes, and log books were returned to the investigator's laboratory within 24 hours of landing. The results of the AFTE from Spacelab-J were compared with the results from five other trials of the AFTE performed on other flights.
Preserved frog embryos and some of the live tadpoles brought back to Earth were microscopically examined to determine if microgravity affected their anatomy. Extensive behavioral tests of the tadpoles were conducted during the nine days following landing. Other tadpoles were raised to sexual maturity and mated to determine if microgravity affects multigenerational development.
The plant cell culture chambers were removed from the orbiter about three hours after landing and transported to the investigator's laboratory.
Results
Results were collected across multiple missions; however, flight data were collected for only six subjects (three treatment and three controls). The flight results showed that two AFTE subjects were symptom free, while the third had moderate symptoms on the first mission day. Two control subjects experienced vomiting episodes on the first three mission days, despite having taken medication. The third experienced mild symptoms. It was concluded that AFT is effective in controlling space motion sickness in some subjects, and that effectiveness is related to preflight learning ability.
Frog Study
Despite a few early developmental differences between the microgravity experiment group and the 1-G flight control groups, development to the neurula stage, in which the embryo first begins to develop the nervous system, was largely unimpaired in microgravity. All fixed neurula and tadpoles seemed normal. However, tadpoles that developed in microgravity failed to find an air/water interface and inflate their lungs. Within a few hours postflight, the tadpoles were observed to gulp air through inflating their lungs. Failure to inflate their lungs would have had serious effects on the frogs at metamorphosis had they been kept at microgravity for multigenerational studies. The flight tadpoles showed stronger optomotor behavioral responses than the control tadpoles, perhaps indicating additional reliance on visual information to compensate for the lack of gravitational cues. This difference disappeared by nine days postflight.
Plant Cell Study
Numbers of developed embryos and cells in division at time of recovery were significantly fewer in space-flown samples than in the ground controls. Significant aberrations in chromosome structure were found in the space-flown samples but not in the ground controls.
Additional Reading
Black, S., K. Larkin, N. Jacqmotte, R. Wassersug, S. Pronych, and K. Souza. Regulative Development of Xenopus laevis in Microgravity. Advances in Space Research, vol. 17(6/7), 1996, pp. 209–217.
Cowings, Patricia S. and William B. Toscano. Autogenic Feedback Training As a Preventive Method for Space Motion Sickness: Background and Experimental Design. NASA TM-108780, August 1993.
NASA. STS-47 Press Kit, September 1992. Contained in NASA Space Shuttle Launches Web site: http://www.ksc.nasa.gov/shuttle/missions/missions.html.
Interview with Joan Vernikos