Objectives
Microorganisms are ubiquitous in spacecraft environments, as they are on Earth. Microbes pose several risks to humans in space including infectious diseases, allergies, degradation of air quality (e.g. release of volatiles), release of toxins, degradation of critical materials, and systems failure (e.g. water reclamation system). Maintaining the health and performance of humans in closed environments in microgravity while reusing reclaimed water is a daunting task. Determining medical and technological risks which are dependent on microbiological factors during long-term space flight is a vital problem in theory, as well as in practice. In such a closed environment, the humans will be a major source of microbes released into the spacecraft. Some microbial species will thrive and some will disappear, resulting in a unique microbiota in the spacecraft. Animals and plants, when present, will also be significant contributors to the overall bioburden, and suitable containment and purification technologies are essential. The success of long-duration space missions will depend on our ability to mitigate the adverse effects of microorganisms. This will require a much better understanding of the microbiology of closed environments and the human-microbe-environment interactions. The Mir Space Station provides an opportunity for a relatively comprehensive study of the crewmembers and environment on an 11-year-old space station.
The objectives of this experiment were to characterize the microbiota of crewmembers, air, surface, and water microbes before, during, and after a long-duration mission aboard the Mir Space Station; to determine the exchange and distribution of microbes throughout the Mir Space Station; and to have operationally-ready hardware systems ready for the International Space Station (ISS).
Shuttle-Mir Missions Approach
Air Microbiology: Air samples were collected from each Shuttle before and after launch using the Microbial Air Sampler. This device was an impaction air sampler, in which a small fan unit draws a known volume of air through a sampler and airborne particles are impacted onto growth media. Inflight air samples were collected from the Shuttle and Mir with the Microbial Air Sampler Kit, which collected samples in the same manner described above. Samples were collected from the middeck and flight deck areas of the Shuttle, once before docking with the Mir and once during the docked phase. Samples were also collected from four locations in the Mir, including the area of the Commander's seat, dining table area, in the Commander's cabin and in the Kristall Module hatch.
Water Microbiology: Water samples were also collected from each Shuttle before and after launch; tank A was sampled before launch, and tank A and B were sampled after landing. Inflight water samples from the Mir were collected and processed with the Water Experiment Kit. Mir sampling locations included the galley-hot and cold water ports and the ground supplied water tank (SVO-ZV). Samples were collected into bags, then processed through a microbial capture device (MCD). MCDs were then incubated for five days and examined for microbial growth on the second and fifth days. After incubation was complete, all microbial samples were stowed for further analysis on Earth. Archived water samples were also returned to Earth for ground-based analysis.
Surface Microbiology: Surface samples were collected from three locations in the Shuttle before and after each mission, including the vent above the waste control system in the middeck, the left most air-return in the port side crawl-through, and the air vent for the Commander's chair in the flight deck. Inflight surface samples were collected using the Surface Sampler Kit from the same three locations in the Shuttle and five locations in the Mir, including the Commander's seat, the dining table, Commander's cabin, the treadmill handle, and the wall above the Kristall Module hatch. Samples were then incubated for five days and examined for microbial growth on the second and fifth days.
Results
The Mir environment was found to be microbiologically similar to that of the Shuttle. Microbial levels in air and on surfaces were generally within acceptability limits set for the International Space Station (ISS); fungal levels tended to be higher on Mir than found on Shuttle. Levels of microbes in hot water were also within ISS acceptability limits; levels in ambient and ground-supplied water sources frequently exceeded U.S. limits, but were within Russian limits. Analysis of surface condensation was important for environmental assessment (this investigation demonstrated the first inflight recovery of protozoa and dust mites).
This investigation also allowed the development of a surface sampling kit for culturing microbes on a variety of spacecraft surfaces for inflight analysis, conducted microbial air sampling using a Burkard air sampler, developed a water microbiology kit for the inflight analysis of spacecraft water, and conducted the first inflight microbial analysis of a spacecraft water supply.
Earth Benefits Publications
Koenig, D. W., Novikova, N. D., Mishra, S. K., Viktorov, A. N., Skuratov, V., Lizko, N. N., and Pierson, D. L. 1996. Microbiology investigations of the Mir Space Station and flight crew. American Society for Microbiology, New Orleans, LA
Pierson, D. L. and Konstantinova, I. V. 1996. Reactivation of latent virus infections in the Mir crew. American Society for Microbiology, New Orleans, LA
Sauer, R. L., Pierson, D. L., Limardo, J. G., Sinyak, Y. E., Schultz, J. R., Straub, J. E., Pierre, L. M., and Koenig, D. W. 1996. Assessment of the potable water supply on the Russian Mir Space Station. American Institute of Aeronautics and Astronautics. Life Sciences and Space Medicine Conference, Houston, TX
Koenig, D. W., Bruce, J. L., Bell-Robinson, D. M., Ecret, L. D., Zakaria, Z., and Pierson, D. L. 1997. Analysis of bacteria isolated from water transferred from the Space Shuttle to the Mir Space Station. American Society for Microbiology, Miami, FL
Pierson, D. L. and Viktorov, A. N. 1997. Microbiology of the Russian Space Station Mir. Society for Industrial Microbiology, Reno, NV
Pierson, D. L., Viktorov, A. N., Lizko, N. N., Novikova, N. D., Skuratov, V., Groves, T. O., Bruce, R. J., Mishra, S. K., and Koenig, D. W. 1997. Microbiology of the Mir Space Station and flight crew during the Mir 19 mission. American Society for Microbiology, Miami, FL
Mehta, S. K., Lugg, D. J., Payne, D. A., Tyring, S. K., and Pierson, D. L. 1998. Epstein-Barr Virus reactivation in spacecraft and ground-based analogs. American Society of Gravitational Biology, Houston, TX.
Principal Investigators
Aleksandr N. Viktorov, Ph.D. Co-Investigators
Mir-22, NASA-3, NASA-4, NASA-5, Mir-24, NASA-6, Mir-25, NASA-7
Crew Microbiology: Before and after flight, microbial samples from the throat, nose, ear, hand, scapula, axilla, groin and urine were collected from the crewmembers and examined for bacteria and fungi; feces were also collected and examined for bacteria, fungi, ova and parasites. Inflight samples were collected from the throat, nose, ear, hand, scapula, axilla, groin using the Crew Microbiology Kit, which held swabs and tubes containing growth media for sampling.
The aerobic microbial flora of crewmembers were characteristic of healthy individuals. Fecal anaerobic microbiota data indicated that a shift in intestinal microorganism ratios occurred in some crewmembers. The transfer of microorganisms between crewmembers was demonstrated by DNA fingerprinting.
Microbes' colonization of inanimate surfaces and hardware of the spacecraft can also lead to biodeteriortion of critical life support instrumentation and equipment, as well as the release of toxic volatiles. All of these are conditions associated with an Earth problem commonly called "sick building syndrome" (SBS) or "building-related illness" (BRS). Reducing risk to SBS requires monitoring both the habitation environment and the occupants, such that the levels and types of microbes do not reach critical levels. A thorough understanding of the microbial population dynamics onboard spacecraft will allow for development of predictive measures that can be used on Earth. The information gained from this study will be helpful in the design of future spacecraft, as well as environmentally conscience buildings, and development of monitoring requirements to minimize microbial cross-contamination.
Isenberg, H.D., Pierson, D. L., Mishra, S. K., Viktorov, A. N., Novikova, N. D., and Lizko, N. N. 1996. Microbiological findings from the Mir-18 crew. Aerospace Medical Association, Atlanta, GA
Duane L. Pierson, Ph.D.
NASA/Johnson Space Center
Institute of Biomedical Problems
Theron Groves
Rebekah Bruce
Natalia Novikova, Ph.D.
Vladimir Skuratov, Ph.D.
Nadezda Lizko, Ph.D.
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Curator:
Julie Oliveaux
Responsible NASA Official: John Uri |
Page last updated: 07/16/1999
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