Engineering topics
Publications and source records attributed to Meyers, Valerie.
Based on these limited data, air quality was nominal on ISS for this period, and potable water remains acceptable for crew consumption.
The Moon's surface is covered by a layer of fine, potential reactive dust. Lunar dust contain about 1‐2% of very fine respirable dust (less than 3 micrometers). The habitable area of any lunar landing vehicle and outpost would inevitably be contaminated with lunar dust that could pose a health risk. The purpose of the study is to evaluate the toxicity of Apollo moon dust in rodents to assess the health risk of dust exposures to humans. One of the particular interests in the study is to evaluate dust‐induced changes of the expression of fibrosis‐related genes, and to identify specific signaling pathways involved in lunar dustinduced toxicity. F344 rats were exposed for 4 weeks (6h/d; 5d/wk) in nose‐only inhalation chambers to concentrations of 0 (control air), 2.1, 6.8, 21, and 61 milligrams per cubic meters of lunar dust. Five rats per group were euthanized at 1 day, 1 week, 1 month, and 3 months after the last inhalation exposure. The bronchoalveolar lavage fluid (BALF) was collected by lavaging with phosphate‐buffered saline (PBS). A zymosan‐induced luminolbased chemiluminescence assay was used to assess the activity of BAL cells. The lavaged lung tissue was snap frozen in LN2 and total RNA was isolated using the Qigen RNeasy kit. The expression of 84 fibrosisrelated genes were analyzed using the RT2 Profiler PCR Array technique. The expression of 18 genes of interest were further measured using real‐time PCR technique in all the samples. 10 out of 18 genes of interest showed persistently significant expression changes in the local lung tissue exposed to lunar dust, indicating a prolonged proinflammatory response. The expressions of several of these genes were dose‐ and time‐dependent and were significantly correlated with other pathological parameters. The potential signaling pathways and upstream regulators were further analyzed using IPA pathway analysis tool based on the gene expression data. The data presented in this study, for the first time, explore the molecular mechanisms of lunar dust induced toxicity, contributing not only the risk assessment for future space exploration, but also understandings of the dust‐induced toxicity in humans on earth.
Based on these limited data, air quality was nomial on ISS for this period, and potable water remains acceptable for crew consumption.
NASA has accumulated considerable experience in offgas testing of whole modules prior to their docking with the International Space Station (ISS). Since 1998, the Space Toxicology Office has performed offgas testing of the Lab module, both MPLM modules, US Airlock, Node 1, Node 2, Node 3, ATV1, HTV1, and three commercial vehicles. The goal of these tests is twofold: first, to protect the crew from adverse health effects of accumulated volatile pollutants when they first enter the module on orbit, and secondly, to determine the additional pollutant load that the ISS air revitalization systems must handle. In order to predict the amount of accumulated pollutants, the module is sealed for at least 1/5th the worst‐case time interval that could occur between the last clean air purge and final hatch closure on the ground and the crew's first entry on orbit. This time can range from a few days to a few months. Typically, triplicate samples are taken at pre‐planned times throughout the test. Samples are then analyzed by gas chromatography and mass spectrometry, and the rate of accumulation of pollutants is then extrapolated over time. The analytical values are indexed against 7‐day spacecraft maximum allowable concentrations (SMACs) to provide a prediction of the total toxicity value (T‐value) at the time of first entry. This T‐value and the toxicological effects of specific pollutants that contribute most to the overall toxicity are then used to guide first entry operations. Finally, results are compared to first entry samples collected on orbit to determine the predictive ability of the ground‐based offgas test.
Based on these limited data, air quality was nominal on ISS for this period, and potable water remains acceptable for crew consumption.
Fourteen mini grab sample containers (msGSCs) were collected on ISS between June and September 2013 and were returned on 34S; however, the ATV-4 first ingress mGSC did not contain sufficient sample to report results (initial sample pressure = 1.2 psia). Of the remaining 13 mGSCs, 12 were collected as routine monthly samples in the Russian Service Module (SM), US Laboratory (Lab), and either the Japanese Pressurized Module (JPM) or the Columbus module (Col), and 1 was collected during HTV-4 first ingress. A summary of the analytical results from the 13 valid mGSCs is shown.
One mini-grab sample container (M-GSC) was collected by crew members onboard ISS during first ingress into SpaceX-2 on March 3, 2013, three days after late cargo loading and a pre-launch clean air purge. Recoveries of the three surrogate standards from the m-GSC were: 13C-acetone, 97%; fluorobenzene, 95%; and chlorobenzene, 68%.
Two grab sample containers (GSCs) were collected by crew members onboard ISS in response to a vinegar-like odor in the US Lab. On February 5, the first sample was collected approximately 1 hour after the odor was noted by the crew in the forward portion of the Lab. The second sample was collected on February 22 when a similar odor was noted and localized to the end ports of the microgravity science glovebox (MSG). The crewmember removed a glove from the MSG and collected the GSC inside the glovebox volume. Both samples were returned on SpaceX-2 for ground analysis.
A summary of the analytical results from 4 mini-grab sample (mGSCs) collected on ISS and returned aboard 33S is shown in Table 1. Due to the launch delay of the ATV4 resupply mission, monthly samples were reduced in April and May by omitting sampling of the Service Module in order to ensure contingency samplers were available if needed. Complete data tables of all measured concentrations and corresponding T-values based on 180-day SMACs are enclosed. detection limit for all target compounds, except m/p-xylenes and hexachloro-1, 3-butadiene was 0.025 mg/cu m. The detection limit for m/p-xylenes and hexachloro-1, 3-butadiene and all non-target compounds was 0.05 mg/cu m. The average recoveries of the 3 surrogate standards from the mGSCs were as follows: C-13-acetone, 116 +/- 12%; D-5-fluorobenzene, 117 +/- 7%; and D-5-chlorobenzene, 111 +/- 15%. Initial measured sample pressures were between 13.9 and 14.1 psia for all samples, indicating nominal sample collection. A summary of the analytical results from 3 pairs of passive-diffusion formaldehyde badges collected on ISS and returned aboard 33S is also provided in Table 1. In an effort to conserve samples due to the delay of the ATV4 resupply mission, FMK sampling was only conducted in the US Lab in May. Positive control recoveries (1 trip and 2 lab controls) were 79%, 87%, and 116% respectively.
A summary of the analytical results from 12 grab sample containers (GSCs) collected on ISS and returned aboard 30S is shown in Table 1. The average recoveries of the 3 surrogate standards from the GSCs were as follows: 12C-acetone, 115 +/-- 11%; fluorobenzene, 108 +/- 8%; and chlorobenzene, 102 +/- 16%. Shaded rows indicate data that re limited due to low sample pressures. For completeness, previously reported data from the US Lab collected in May 2012 are included here as well. The revised report provides results from one returned sample that was unlabeled and originally assumed to be unused. The sample was prepared and analyzed for the purpose of measuring the surrogate compounds. It was later determined, based on serial number, that this was the HTB3 first ingress sample.
This slide presentation describes the career path and projects that the author worked on during her internship at NASA. As a Graduate Student Research Program (GSRP) participant the assignments that were given include: Human Mesenchymal Stem Cell Research, Spaceflight toxicology, Lunar Airborne Dust Toxicity Advisory Group (LADTAG) and a special study at Devon Island.
Many lamps used in various spacecraft contain elemental mercury, which is efficiently absorbed through the lungs as a vapor. The liquid metal vaporizes slowly at room temperature, but may be completely vaporized when lamps are operating. Because current spacecraft environmental control systems are unable to remove mercury vapors, we considered short-term and long-term exposures. Using an existing study, we estimated mercury vapor releases from lamps that are not in operation during missions lasting less than or equal to 30 days; whereas we conservatively assumed complete vaporization from lamps that are operating or being used during missions lasing more than 30 days. Based on mercury toxicity, the Johnson Space Center's Toxicology Group recommends stringent safety controls and verifications for any hardware containing elemental mercury that could yield airborne mercury vapor concentrations greater than 0.1 mg/m3 in the total spacecraft atmosphere for exposures lasting less than or equal to 30 days, or concentrations greater than 0.01 mg/m3 for exposures lasting more than 30 days.
This viewgraph presentation provides a review of NASA Johnson Space Center's Toxicology program. The mission of this program is to protect crews from toxic exposures during spaceflight. The presentation reviews some of the health hazards. A toxicological hazard level chart is presented that reviews the rating of hazard level, irritancy, systemic effects and containability. The program also participates in the Lunar Airborne Dust Toxicity Advisory Group.