Browsing by Author "Limero, Thomas"
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Item Assessment of Ethanol Trend on ISS(46th International Conference on Environmental Systems, 2016-07-10) Gazda, Daniel; McCoy, Torin; Limero, Thomas; Perry, Jay; Carter, Donald; Kayatin, MatthewThe International Space Station (ISS) Environmental Control and Life Support System (ECLSS) provides a working environment for 6 crew through atmosphere revitalization and water recovery systems. In the last year, elevated ethanol levels have presented a unique challenge for the ISS ECLSS. Ethanol is monitored on the ISS by the Air Quality Monitor (AQM). The source of this increase is not currently known though it does appear to correlate with vehicle docking. This paper documents the credible sources for the increased ethanol concentration, the monitoring provided by the AQM, and the impact on the atmosphere revitalization and water recovery systems.Item Effects of Ambient Alcohol Levels on the Real-time Monitoring of the Atmosphere of the International Space Station(51st International Conference on Environmental Systems, 7/10/2022) Wallace, William; Limero, Thomas; Clark, Kenneth; Gazda, Daniel; Hudson, EdgarMonitoring of the spacecraft environment is required to ensure the health of the crew and the vehicle systems. For the ISS atmosphere, routine volatile organic compound (VOC) monitoring has been performed for almost a decade by Air Quality Monitors (AQMs). The target compounds measured by the AQMs include three types of chemicals: 1) those compounds that would be harmful to crew, 2) those compounds that have been detected regularly in archival samples, and 3) compounds that, while not necessarily harmful to crew health, could present problems for Environmental Control and Life Support Systems (ECLSS). Following the docking of SpaceX-Demo1 (SpX-DM1), the AQMs began to report high levels of isopropanol (IPA). While elevated IPA is routinely observed with visiting vehicles, the level measured by the AQM, and its continued presence following multiple days of scrubbing, caused concerns regarding the U.S. Water Recovery System. Following the departure of SpX-DM1, the IPA levels decreased to nominal levels, allowing the team to investigate the cause of the elevated measurements. Based on the changes in the shape of the gas chromatograph (GC) traces in the IPA region during docked operations, it appeared that an unknown coeluting species was causing problems with quantification. However, with the docking of Northrup-Grumman-11 (NG-11), the elevated IPA returned, as well as the changes in GC traces. In contrast to the SpX-DM1 results, the AQM IPA results did not return to nominal levels following the departure of NG-11, suggesting that the changes could not be tied directly to the visiting vehicle. In this paper, we will discuss a number of potential causes for both the genuine (measured in archival samples) increases in IPA as well as the much higher levels measured by the AQM. Additionally, we will discuss methods being explored to decrease the potential for a reoccurrence in the future.Item Effects of Ambient CO2 on Monitoring of the International Space Station Atmosphere with the Air Quality Monitor(48th International Conference on Environmental Systems, 2018-07-08) Wallace, William; Limero, Thomas; Gillispie, Robert; Gazda, DanielSince 2009, gas chromatography-differential mobility spectrometry (GC/DMS) has been used on-board the International Space Station (ISS) to monitor the atmosphere for volatile organic compounds. The technology was originally tested as part of a Station Detailed Test Objective (SDTO) and then transitioned to operational hardware. The operational version of this hardware, the Air Quality Monitor (AQM), currently monitors 22 compounds, though the target list is flexible and can be adjusted depending on changes in materials or the spacecraft environmental control systems. After separation on the GC column, target compounds are ionized via charge transfer from a Reactant Ion (RI). In the positive mode, H+(H2O)n is the RI while O2-(H2O)n acts as the RI in the negative mode. In the early stages of the SDTO, it was discovered that the position of the RI Peak (RIP) in the negative mode was shifting with time on orbit and the instrument was losing sensitivity to certain compounds. This shift of the RIP appeared to be correlated with increasing concentrations of CO2 in the recirculation system of the instrument. The operational version of the AQM uses larger, replaceable sieve packs to clean the recirculated carrier gas. It was hypothesized that incorporation of the large sieve packs would minimize the effect of CO2 on the position of the RIP. Unfortunately, this phenomenon has also been observed on the first two sets of AQMs that were operated on the ISS. In this paper, we will discuss the mechanisms behind the shifting RIP as well as the effects on the ionization of selected target compounds. Additionally, we will discuss potential approaches to mitigate the impact of the RIP shift and extend the current 6-month life of sieve packs on-orbit.Item Enhanced AQM: Development of an Exploration Compatible Air Quality Monitor(49th International Conference on Environmental Systems, 2019-07-07) Wallace, William; Limero, Thomas; Clark, Kenneth; Macatangay, Ariel; Mudgett, Paul; Gazda, DanielReal-time monitoring of volatile organic compounds (VOCs) on the International Space Station (ISS) is currently performed using a pair of Air Quality Monitors (AQMs), instruments that combine gas chromatography (GC) separation with differential mobility spectrometry (DMS) detection. Each AQM occupies a volume of approximately 4900 cm3 and has a mass of 3.7 kg. Each AQM also requires a power supply that is roughly the same size and mass. While these parameters do not present a concern on the ISS, they are too large for future exploration missions. The most obvious avenue for decreasing the size and mass of the AQMs lies in the reduction from two instruments and power supplies to a single unit and power supply. As currently configured, the required target VOCs cannot be successfully monitored on a single GC column, as the column cannot be cooled sufficiently to allow separation of early-eluting compounds. Here, we will show how limited method changes and additional cooling of the GC column can minimize the effects of compound coelution and allow all analytes to be monitored on a single AQM. We will also discuss other potential improvements that could increase the sensitivity and further reduce the size of an exploration-ready AQM.Item Operational Validation of the Air Quality Monitor on the International Space Station(44th International Conference on Environmental Systems, 2014-07-13) Limero, Thomas; Wallace, William; James, John T.Two air quality monitors (AQMs) were launched to the International Space Station (ISS) in March 2013. The AQM units, with different gas chromatographic columns, operate simultaneously on the ISS to accurately measure target compounds important to the assessment of the onboard air quality. The AQMs had to be validated, which meant they had to demonstrate their ability to accurately analyze target compounds in the ISS atmosphere, before they could be proclaimed ready for operational use. As the name implies, operational hardware can and will be used to make real-time decisions; therefore validation is necessary to have confidence in generated data. The AQMs were deployed in late March 2013 and validation was begun in May 2013. During the in-flight validation phase, a minimum of 6 mini-grab sample containers (mini-GSCs) were acquired nearly simultaneously with the AQM sample analysis. Six months was needed to acquire the necessary mini-GSC-AQM pairings to complete validation. The validation criteria, established prior to launching the AQMs, were applied to each compound and not to the AQM units. Furthermore, the validation included the checkout of the AQM battery operations in a remote location. The AQMs operate autonomously using a scripted analysis scheme and frequency. A remote desktop feature of the AQMs permits the scripts to be interrupted, without use of crew time, so that the AQM runs could be coordinated with the mini-GSC sample acquisition. This paper will briefly describe the AQM technology, describe the validation requirements, and present the results from the AQM validation.Item Preparation of the NASA Air Quality Monitor For A U.S. Navy Submarine Sea Trial(47th International Conference on Environmental Systems, 2017-07-16) Limero, Thomas; Wallace, William; Manney, Joshua; Smith, Matthew; O'Connor, Sara Jane; Mudgett, PaulFor the past 4 years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. Onboard ISS there are 2 AQMs, with different GC columns that detect and quantify 22 compounds. The AQM data contribute valuable information to the assessment of air quality aboard ISS for each crew increment. The U.S. Navy is looking to update its submarine air monitoring suite of instruments and the success of the AQM on ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which measures major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial results. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only 1 AQM will be deployed during the sea trial, but it is sufficient to detect the compounds of interest to the Navy for the purposes of this trial. The data from the sea trial will be compared to archival samples collected before and during the trial period. This paper will give a brief overview of the AQM technology and protocols for the submarine trial. After a quick review of the AQM preparation, the main focus of the paper will be on the results of the submarine trial. Of particular interest will be the comparison of the contaminants found in the ISS and submarine atmospheres, as both represent closed environments. In U.K. submarine trials in the early 2000s, the submarine and ISS atmospheres were found to be remarkably similar.Item Results from the U.S. Navy Submarine Sea Trial of the NASA Air Quality Monitor(48th International Conference on Environmental Systems, 2018-07-08) Limero, Thomas; Wallace, William; Manney, Joshua; Smith, Matthew; O'Connor, Sara Jane; Mudgett, PaulFor the past 4 years, the Air Quality Monitor (AQM) has been the operational instrument for measuring trace volatile organic compounds on the International Space Station (ISS). The key components of the AQM are the inlet preconcentrator, the gas chromatograph (GC), and the differential mobility spectrometer. On board the ISS are two AQMs with different GC columns that detect and quantify 22 compounds. The AQM data contributes valuable information to the assessment of air quality aboard the ISS for crew health. The U.S. Navy is looking to update its suite of instruments for air monitoring aboard submarines, and the success of the AQM on the ISS has led to a jointly planned submarine sea trial of a NASA AQM. In addition to the AQM, the Navy is also interested in the Multi-Gas Monitor (MGM), which measures major constituent gases (oxygen, carbon dioxide, water vapor, and ammonia). A separate paper will present the MGM sea trial preparation and the analysis of the most recent ISS data. A prototype AQM, which is virtually identical to the operational AQM, has been readied for the sea trial. Only 1 AQM will be deployed during the sea trial, but this is sufficient for NASA purposes and to detect the compounds of interest to the U.S. Navy for this trial. The data from the sea trial will be compared to data from archival samples collected before, during, and after the trial period. A brief overview of the AQM technology and preparation for the submarine trial will be presented. The majority of the presentation will focus on the AQM performance during the trial with comparison of AQM and archival data before, during, and after the submarine trial.Item Seeking the Tricorder: Evolution of the NASA Anomaly Gas Analyzer(49th International Conference on Environmental Systems, 2019-07-07) Mudgett, Paul; Skow, Mary Coan; Limero, Thomas; Beck, Steven; Pilgrim, JeffreyNASA requires a gas sensor for monitoring a wide variety of species onboard spacecraft. As a major constituents analyzer the device should measure oxygen, carbon dioxide and water vapor with high precision. As a post-event combustion monitor the device should measure carbon monoxide, hydrogen cyanide, hydrogen chloride and hydrogen fluoride with high sensitivity. As a leak detector the device should measure ammonia and chemical hydrazine with high specificity. The device should be portable, handheld, operate under its own power in a widely variable temperature-pressure-gravity-vibration-radiation environment while reliably reporting gas concentrations as quickly and unambiguously as possible. Alas, the tricorder! A two-year technology demonstration of the tunable diode laser based Multi-Gas Monitor (MGM) on the International Space Station (ISS) for major constituents plus ammonia, combined with extensive ground test of detecting combustion evolved gases led NASA to commission Vista Photonics to develop a device to measure all those species plus chemical hydrazine. Known as the Anomaly Gas Analyzer (AGA) project, the end product will be critical flight hardware for both Orion and the International Space Station. Three AGA engineering development units were delivered to NASA Johnson Space Center and are being subjected to a variety of tests at present. A device similar to the MGM was recently tested by the US Navy on a submarine. A sea trial of a more capable AGA-like device is in the planning stages. The Navy’s interest in testing NASA equipment is in a planned update to submarine environmental monitoring equipment. Vista Photonics is developing a scalable AGA-based architecture for the Navy that expands the target gases to include formaldehyde, ethylene, nitrous oxide, nitrogen dioxide, R12/R134a Freon, and acrolein. The core technology was developed by Vista Photonics through the Small Business Innovation Research (SBIR) program and expanded using NASA program funding.