Early evaluation of the internal environment from air, water and surface samples of International Space Station (ISS) provided a baseline of the contaminant characterization onboard the ISS. The data obtained from Environmental Monitoring provides insight into the environmental contamination during the stages of construction and habitation of ISS.Principal Investigator(s)
Kennedy Space Center, , FL, United States
National Aeronautics and Space Administration (NASA)Sponsoring Organization
Human Exploration and Operations Mission Directorate (HEOMD)ISS Expedition Duration:
November 2000 - March 2010
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19/20,21/22Previous ISS Missions
Environmental monitoring investigations have been conducted since the beginning of the space program.
To successfully live and work in the environment of space the ISS environment must be monitored to ensure the health of the crew living and working there. Astronauts can be more sensitive to air pollutants because of the closed environment. Pollutants in this environment are magnified in ISS because the exposure is continuous.
Sources of physical, chemical, and microbiological contaminants include humans and other organisms, food, cabin surface materials and experiment devices. One hazard is the off-gassing of vapors from plastics and other items on ISS; although this is a small hazard, the accumulation of these contaminants in the air can prove dangerous to crew health. The air sampling systems on ISS periodically checks the air for potential hazards. Advanced high efficiency particulate air (HEPA) filters and periodic filter cleanings have been successful in keeping harmful vapors out of the air. Other significant contaminants that pose hazards to the crew are microbial growth, both bacterial and fungal; air, water and surface sampling by the crew in conjunction with periodic cleaning keep the microbial levels on ISS in check.
The volatile organic analyzer (VOA) is an atmospheric analysis device on ISS that uses a gas chromatograph and ion mobility spectrometer to detect, identify, and quantify a selected list of volatile organic compounds (i.e., ethanol, methanol and 2-propanol) that are harmful to humans at high levels in a closed environment, such as ISS.
To monitor microbial levels on ISS crew members use devices called grab sample containers, dual absorbent tubes and swabs to collect station air, water and surface samples and send them to Earth for detailed analysis and identification every 6 months. This data provides controllers on Earth detailed information about the type of microbial contaminants on board ISS. The controllers can then give direction to the crew on sanitation if increased microbial growth is identified. The crew keeps microbes under control on ISS through periodic scheduled sanitation of the ISS.
Missions to the Moon and Mars will increase the length of time that astronauts live and work in closed environments. To complete future long duration missions the crews must remain healthy in closed environments, hence future spacecraft must provide sensors to monitor environmental health and accurately determine and control the physical, chemical and biological environment of the crew living areas and their environmental control systems.
Environmental Monitoring is vital to ensuring crew and spacecraft health during space flight. The results are being used to identify specific effects of a closed space environment on astronauts. This knowledge will allow scientists to develop systems to enable the crew to remain health on future long duration missions to the Moon and Mars.Earth Applications
Increased understanding of the affects of a closed space environment on humans will increase the knowledge of living in extreme conditions such as submarines or the artic.
Numerous air, water and surface samples are collected by ISS crews on a regular basis. Many of these samples are cultured on board ISS while others are preserved and returned to Earth for later analysis. These samples are analyzed using the following methods on board ISS:
The crew utilizes handheld equipment to monitor the air, water and surfaces of ISS on a daily, weekly and monthly basis. The samples can be returned to Earth for analysis by scientists. Other automated equipment, including the Compound Specific Combustion Product Analyzer, VOA and Major Constituent Analyzer monitors the atmosphere of ISS daily for potential harmful contaminants. The crew also performs weekly housekeeping duties on board ISS, which includes disinfecting surfaces and cleaning air filters which contributes to environmental monitoring.
During one study of the ISS atmosphere, 12 bacterial strains were isolated and fingerprinted from the ISS water system. These bacteria consisted of common strains and were encountered at levels below 10,000 colony-forming units/10 cm2, which is well below the minimum of bacteria needed to cause illness. These data represent the beginning of ISS habitation and indicate that the lessons learned from previous Mir and Skylab missions were implemented and have been effective in keeping station a safe place in which to live and work (Castro et al. 2004).
Other studies performed an in-depth microbial examination of the drinking water in various stages (from the NASA Kennedy Space Center, Cape Canaveral, FL to the ISS ports). These studies have revealed that NASA policy for biocide treatment has effectively removed pathogenic microbes traveling to space (La Duc et al. 2004; Plumlee et al. 2002; Plumlee et al. 2003). Studies on station air quality found that the active (volatile organics analyzer) and passive (HEPA filters) controls in place on ISS are effective in controlling trace contaminants of volatile organic compounds on space station (James 2003; Perry 2003). (Evans et al. 2009)
James JT, Limero TF, Beck S, Martin M, Covington P, Boyd J, Peters R. Toxicological Assessment of the International Space Station Atmosphere with Emphasis on Metox Canister Regeneration. 33rd International Conference on Environmental Systems SAE; 2003; Vancouver, Canada.
La Duc MT, Summer R, Venkateswaren KJ, Pierson DL, Venkat P. Evidence of pathogenic microbes in the International Space Station drinking water: reason for concern?. Habitation. 2004; 10: 39-48.
Perry JL, Peterson BV. Cabin air quality Dynamics on Board the International Space Station. 33rd International Conference on Environmental Systems; 2003; Vancouver, Canada.
Plumlee DK, Mudgett PD, Schultz JR. ISS Potable Water Sampling and Chemical Analysis: Expeditions 4 & 5. 33rd International Conference on Environmental Systems; 2003; Vancouver, Canada.
Plumlee DK, Mudgett PD, Schultz JR. Chemical Sampling and Analysis of ISS Potable Water: Expeditions 1-3. 32nd International Conference on Environmental Systems; 2002 July 15; San Antonio, TX.
Castro VA, Thrasher AN, Ott CMark, Healy M, Pierson DL. Microbial Charcterization during the Early Habitation of the International Space Station. Microbial Ecology. 2004; 47: 119-126. DOI: 10.1007/s00248-003-1030-y.