Toxicology and Environmental Chemistry – NASA
Achieving safe exploration of space in vehicles that rely on closed environmental systems to recycle air and water to sustain life and that are operated in extremely remote locations poses a major challenge. The Toxicology and Environmental Chemistry (TEC) group at Johnson Space Center (JSC) is made up of 2 interdependent groups: Toxicology support and the Environmental Chemistry Laboratory. Scientists from both groups play an important role in ensuring that the ISS crew breathes clean air and drinks clean water. TEC staff establish safe environmental limits for spacecraft, monitor air and water quality aboard current spacecraft (ISS and commercial crew and cargo vehicles), and support technological advancements. The TEC uses in-flight monitoring capabilities as well as post-flight sample analysis techniques to monitor air and water quality during spaceflight.
The JSC Toxicology Group serves as a NASA-wide resource for aspects of space toxicology and is responsible for several different tasks focused on protecting crew members and spacecraft systems from toxic exposures during spaceflight. These include assessing chemical risks for flight, establishing limits for contaminants in spacecraft air and water, evaluating environmental data from spacecraft in flight, and assessing the potential for off-gassing from new vehicles or modules. These assessments are documented in:
The JSC Environmental Chemistry Laboratory occupies approximately 6,000 square feet of laboratory space in one of the newer buildings on site. It is a fully equipped environmental and analytical laboratory with analysts who have supported several human spaceflight programs and provided central support for gas and liquid analysis. Work in the laboratories is carried out according to an ISO 9001/AS9100 certified quality plan with dedicated and independent quality staff.
The Environmental Chemistry Laboratory monitors contaminants in spacecraft air using in-flight and post-flight methods. Aboard the International Space Station (ISS), 2 air quality monitors (AQMs) use gas chromatography/differential mobility spectrometry to detect and quantify 23 target volatile organic compounds to provide a near real-time overview of the state of the ISS atmosphere. Other real-time monitors supported by the Environmental Chemistry Laboratory include the Compound-Specific Combustion Products Analyzer (CSA-CP), which uses electrochemical sensors to scan the atmosphere for the presence of fire-produced compounds, and the CO2 Monitor, which uses non-dispersive infrared reflectance to monitor the presence of a high concentration of CO2. For detailed post-flight analysis at the Environmental Chemistry Laboratory, astronauts use grab sample containers to collect in-flight samples, which are then returned to the JSC for detailed environmental analysis. Similarly, formaldehyde monitoring kits contain badges used to collect formaldehyde. These are also returned to the ground for spectroscopic analysis.
The Environmental Chemistry Laboratory also analyzes archival samples returned from the ISS. The majority of water consumed by ISS crew members is recycled from a combination of condensed atmospheric moisture and urine. This wastewater is then treated by the US Water Treatment Plant (WPA) to produce potable water, which is analyzed to ensure the water meets US potability requirements. Moisture condensate and condensate/urine distillate samples are also returned for analysis to provide insight into the operation of the WPA and the overall water reclamation system in the United States. The TEC leverages the in-flight analysis capability provided by the ISS Total Organic Carbon Analyzer (TOCA) to determine real-time total organic carbon concentrations, which are used to protect the health of the ISS crew as well as to manage consumables in the U.S. water system. Similarly, the Colorimetric Water Quality Monitoring Kit (CWQMK) is used to provide insight into the concentration of biocides in U.S. water.
Water samples are also collected in flight and stored for return to Johnson Space Center. The following ground equipment is used to analyze archival samples to ensure appropriate air and water quality:
- Liquid Chromatography/Refractive Index Detection (LC/RI)
- Gas Chromatography/Flame Ionization Detector (GC/FID)
- Gas chromatography/thermal conductivity detector (GC/TCD)
- Trace gas analyzer
- Gas chromatography/mass spectrometry (GC/MS)
- Liquid chromatography/mass spectrometry (LC/MS)
- Inductively coupled plasma/mass spectrometry (ICP/MS)
- Ion Chromatography (IC)
- UV/VIS spectrophotometry
- Fourier Transform Infrared Reflectance (FTIR)
- Total Organic Carbon Analyzer (TOCA)
In addition to analyzing flight samples and real-time data, the Environmental Chemistry Laboratory team plays an important role in the development of new environmental control and life support system hardware by providing analytical support during ground testing. Likewise, TEC scientists pursue and support technology demonstrations aimed at developing new methods of real-time data collection. Recent examples of this support include the Multi-Gas Monitor (MGM) and Personal CO2 monitor. TEC scientists are making critical contributions to consolidating environmental monitoring hardware to reduce mass and volume requirements, both important factors as NASA moves toward longer-term missions in smaller vehicles.
Environmental Toxicology and Chemistry (TEC) monitors airborne contaminants in spacecraft air and water. In-flight monitors are used to provide real-time insight into environmental conditions aboard the ISS. Archival samples are collected and returned to Earth for comprehensive characterization of the ISS air and water.
Paul Mudgett, Ph.D.
Valérie Ryder, PhD DABT
Spencer Williams, PhD DABT
William T. Wallace, PhD
