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All sourcesNASA NTRSDOE OSTI
NASA NTRS2020

SAGE III/ISS Contamination Monitoring Package: Observations in Orbit

The Stratospheric Aerosol and Gas Experiment III (SAGE III) telescope and instrument assembly employ the methods of solar occultation and lunar occultation to retrieve near-global vertical profiles of atmospheric ozone, water vapor, nitrogen dioxide, aerosol extinctions, and other gaseous species and atmospheric state parameters. The SAGE III grating spectrometer measures light within the spectral range of 280 nm to 1037 nm at approximately 1 nm resolution, but retrievals in the Ultraviolet (UV) are particularly sensitive to contamination of the optical train. Therefore, a contamination door that contains a quartz optical window can be closed over the telescope aperture during periods of enhanced external contaminant flux. This optically transparent window permits continued science event acquisition at an acceptably diminished signal-to-noise ratio, which is expected to decline with ongoing accretion of contaminant material. To date, this impact has been short term, and science quality through the window returns to baseline performance after a contamination source is removed and spontaneous desorption removes material from the low-affinity quartz surface. Two Contamination Monitoring Packages (CMPs) consisting of eight Thermoelectric Quartz Crystal Microbalances (TQCMs) from QCM Research provide characterization and redundant monitoring of contaminant deposition from the 2pi steradian solid angle on the payload side of the Expedite the Processing of Experiments to the Space Station (ExPRESS) Payload Adapter. CMP data are closely examined by the SAGE III team to determine when the contamination door should remain closed during science events and in what direction the instrument assembly scan head should stow when not acquiring science measurements. Additionally, should the CMPs indicate an unacceptable accretion rate, the flight computer will close the contamination door as part of the automatic fault detection system. Along with spectrometer measurements of the quartz window's transmission, the payload CMPs enable auditing of the mission contamination budget. The process of Thermogravimetric Analysis (TGA) can be used to help identify chemical constituents accreted on the CMP sensors. To be presented here along with an explanation of the CMP systems are the first two and a half years of observations of the contaminant deposition environment around the payload in quiescence and during special events like docking vehicles.

Tyler T Dawson↗
DOE OSTI2024

Gaseous contaminant transfer in membrane-based air-to-air energy exchangers

Membrane-based air-to-air energy exchangers (M–AAEEs) transfer heat and moisture between building exhaust air and fresh ventilation air streams through a membrane, thereby reducing the energy required for conditioning the fresh ventilation air. Energy exchangers are typically used in buildings with relatively clean building exhaust air, such as office buildings and schools. Recently interest in using energy exchangers in a wider range of buildings has grown, to reduce the energy consumption associated with the heating, ventilating, and air-conditioning (HVAC) systems in these buildings. However, if the building exhaust air is not clean, as would be the case for laboratories or factories, new risks are encountered when using energy exchangers. It is possible that gaseous contaminants in the exhaust air may also transfer along with the moisture through the membranes, contaminating the incoming fresh ventilation air. Current test standards provide a test procedure to determine the contamination of the fresh ventilation air by measuring the transfer of an inert tracer gas in an energy exchanger. However, the tracer gas test may not represent the transfer of common indoor air contaminants due to differences in their transport properties. Therefore, in this study, an experimental facility is developed to determine the transfer of seven different contaminants through two membranes (porous and dense) at different flow rates. Contaminant transfer is quantified using a parameter called the exhaust contaminant transfer ratio (ECTR), which gives the fraction of the contaminants transferred from the exhaust air to the fresh ventilation air. A theoretical model based on the effectiveness-number of transfer units (ε-NTU) correlation and moisture transfer resistance of the membrane is presented to determine transfer through porous membranes and validated with experimental results. The major contribution of this paper is that it presents a simple method to predict the transfer of different contaminants through a porous membrane based on the moisture transfer resistance of the membrane at different operating conditions. It is found that as contaminant diffusivity decreases, ECTR generally also decreases, and as the flow rate increases, ECTR decreases, which is consistent with the predictions from the correlation.

42 ENGINEERING↗
DOE OSTI2024

Private, public, and bottled drinking water: Shared contaminant-mixture exposures and effects challenge

Background: Humans are primary drivers of environmental–contaminant exposures worldwide, including in drinking-water (DW). In the United States, point-of-use DW (POU–DW) is supplied via private tapwater (TW), public-supply TW, and bottled water (BW). Differences in management, monitoring, and messaging and lack of directly–intercomparable exposure data influence the actual and perceived quality and safety of different DW supplies and directly impact consumer decision–making. Objectives: The purpose of this paper is to provide a meta-analysis (quantitative synthesis) of POU–DW contaminant–mixture exposures and corresponding potential human–health effects of private-TW, public-TW, and BW by aggregating exposure results and harmonizing apical–health–benchmark–weighted and bioactivity–weighted effects predictions across previous studies by this research group. Discussion: Simultaneous exposures to multiple inorganic and organic contaminants of known or suspected human-health concern are common across all three DW supplies, with substantial variability observed in each and no systematic difference in predicted cumulative risk between supplies. Differences in contaminant or contaminant–class exposures, with important implications for DW–quality improvements, were observed and attributed to corresponding differences in regulation and compliance monitoring. Conclusion: The results indicate that human-health risks from contaminant exposures are common to and comparable in all three DW–supplies, including BW. Importantly, this study’s target analytical coverage, which exceeds that currently feasible for water purveyors or homeowners, nevertheless is a substantial underestimation of the breadth of contaminant mixtures in the environment and potentially present in DW. Thus, the results emphasize the need for improved understanding of the adverse human-health implications of long-term exposures to low–level inorganic–/organic–contaminant mixtures across all three distribution pipelines and do not support commercial messaging of BW as a systematically safer alternative to public-TW. Regardless of the supply, increased public engagement in source-water protection and drinking–water treatment is necessary to reduce risks associated with long-term DW–contaminant exposures, especially in vulnerable populations, and to reduce environmental waste and plastics contamination.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2018

External Contamination Integration of Visiting Vehicles on the International Space Station

The International Space Station (ISS) is an on-orbit platform for science utilization in low Earth orbit. The induced contamination environment can impact performance, mission success, and science utilization. Cargo and crew vehicles visiting the ISS represent significant sources of contamination. The Space Environments Team of the ISS Program Office has developed visiting vehicle requirements and methodologies to address the increasingly complex challenge of integrating multiple visiting vehicles while maintaining overall ISS contamination control requirements. The external contamination control requirements are summarized and the integration and verification process is described along with required data deliverables. Contamination characterization data deliverables address vacuum-exposed materials, thrusters, vacuum venting, and particulate releases. Visiting vehicle external contamination analyses are conducted by the ISS Space Environments Team to certify compliance with external contamination control requirements. Unpressurized cargo contamination analyses are also performed to characterize induced contamination to payloads while in transit to ISS. Efforts to confirm the visiting vehicle contamination modeling and analysis process based on on-orbit data are discussed.

outgassing↗
NASA NTRS2019

Searching for Life on Mars: The Contamination Paradox

As we search for life on Mars, we will be simultaneously contaminating Mars with life from Earth. The contamination from Earth could be mistaken for Martian life. How can this paradox be avoided? With the results of our research, the scientific community will be able to determine locations of future habitats that minimize the aerial extent subject to bio-contaminants, protect sites of astrobiological interest, and constrain landing site selection of life detection missions to reduce risk of false positives. We consider a putative human habitat on Mars. Biological contaminants will flow out of the habitat into the Martian atmosphere, and the atmosphere will move these contaminants around. How many biological particles per year will be released from the habitat into the Martian ambient environment? How far will the contamination travel? In what directions will it travel? How long will the contamination be in the atmosphere? We study these questions quantitatively by simulating the Martian atmosphere using the NASA Ames Mars Global Climate Model. Various combinations of human habitat locations and contaminant sizes are considered. The results from these simulations enable the creation of novel contamination heat maps showing the aerial distribution of contaminants from putative human habitats on Mars.

Contamination↗
NASA NTRS1971

Back contamination.

Discussion of the concept and implications of back contamination and of the ways and means for its prevention. Back contamination is defined as contamination of the terrestrial biosphere with organisms or materials returned from outer space that are capable of potentially harmful terrestrial activity. Since the question of whether or not life exists on other planets may, in reality, not be answered until many samples are returned to earth for detailed study, requirements for the prevention of back contamination are necessary. A review of methods of microbiologic contamination control is followed by a discussion of the nature of back contamination and its risk levels, contamination sources and locations, and possible defenses against back contamination. The U.S. lunar back contamination program is described and shown to provide a valuable basis for further refining the technology for the control of planetary back contamination.

Phillips, G. B.↗
NASA NTRS1996

Silicone Contamination Camera for Developed for Shuttle Payloads

On many shuttle missions, silicone contamination from unknown sources from within or external to the shuttle payload bay has been a chronic problem plaguing experiment payloads. There is currently a wide range of silicone usage on the shuttle. Silicones are used to coat the shuttle tiles to enhance their ability to shed rain, and over 100 kg of RTV 560 silicone is used to seal white tiles to the shuttle surfaces. Silicones are also used in electronic components, potting compounds, and thermal control blankets. Efforts to date to identify and eliminate the sources of silicone contamination have not been highly successful and have created much controversy. To identify the sources of silicone contamination on the space shuttle, the NASA Lewis Research Center developed a contamination camera. This specially designed pinhole camera utilizes low-Earth-orbit atomic oxygen to develop a picture that identifies sources of silicone contamination on shuttle-launched payloads. The volatile silicone species travel through the aperture of the pinhole camera, and since volatile silicone species lose their hydrocarbon functionalities under atomic oxygen attack, the silicone adheres to the substrate as SiO_x. This glassy deposit should be spatially arranged in the image of the sources of silicone contamination. To view the contamination image, one can use ultrasensitive thickness measurement techniques, such as scanning variable-angle ellipsometry, to map the surface topography of the camera's substrate. The demonstration of a functional contamination camera would resolve the controversial debate concerning the amount and location of contamination sources, would allow corrective actions to be taken, and would demonstrate a useful tool for contamination documentation on future shuttle payloads, with near negligible effect on cost and weight.

Source record↗
NASA NTRS2001

Atomic Oxygen Interactions With Silicone Contamination on Spacecraft in Low Earth Orbit Studied

Silicones have been widely used on spacecraft as potting compounds, adhesives, seals, gaskets, hydrophobic surfaces, and atomic oxygen protective coatings. Contamination of optical and thermal control surfaces on spacecraft in low Earth orbit (LEO) has been an ever-present problem as a result of the interaction of atomic oxygen with volatile species from silicones and hydrocarbons onboard spacecraft. These interactions can deposit a contaminant that is a risk to spacecraft performance because it can form an optically absorbing film on the surfaces of Sun sensors, star trackers, or optical components or can increase the solar absorptance of thermal control surfaces. The transmittance, absorptance, and reflectance of such contaminant films seem to vary widely from very transparent SiOx films to much more absorbing SiOx-based films that contain hydrocarbons. At the NASA Glenn Research Center, silicone contamination that was oxidized by atomic oxygen has been examined from LEO spacecraft (including the Long Duration Exposure Facility and the Mir space station solar arrays) and from ground laboratory LEO simulations. The findings resulted in the development of predictive models that may help explain the underlying issues and effects. Atomic oxygen interactions with silicone volatiles and mixtures of silicone and hydrocarbon volatiles produce glassy SiOx-based contaminant coatings. The addition of hydrocarbon volatiles in the presence of silicone volatiles appears to cause much more absorbing (and consequently less transmitting) contaminant films than when no hydrocarbon volatiles are present. On the basis of the LDEF and Mir results, conditions of high atomic oxygen flux relative to low contaminant flux appear to result in more transparent contaminant films than do conditions of low atomic oxygen flux with high contaminant flux. Modeling predictions indicate that the deposition of contaminant films early in a LEO flight should depend much more on atomic oxygen flux than it does later in a mission.

Banks, Bruce A.↗
NASA NTRS2008

Checking Contamination during Storage of Carbonaceous Chondrites for Micro FTIR Measurements

We examined organic contamination by Fourier transform infrared micro spectroscopic (micro FTIR) measurements of carbonaceous chondrite samples. Carbonaceous chondrites, Tagish Lake (C2), Murchison (CM2) and Moss (CO3), and some mineral powder samples pressed on aluminum plates were measured by micro FTIR before and after storage in several containers with silicone rubber mat. During storage, samples did not touch directly anything except the holding aluminum plates. The carbonaceous chondrites containing hydrous minerals (Tagish Lake and Murchison) pressed on aluminum plates and measured by transmission-reflection micro FTIR measurements were found to be contaminated during storage after only one day, as revealed by an increase of approximately 2965 /cm and approximately 1260 /cm peaks. The Moss meteorite which contains no hydrous minerals, did not show an increase of these peaks, indicating no organic contamination. This difference is probably related to the differing mineralogy and physical properties (including porosity and permeability) of these chondrites. Hydrous minerals such as antigorite, muscovite, montmorillonite and silica gel showed organic contamination by the same infrared measurements, while anhydrous materials such as SiO2 and KBr showed no contamination. These results indicate importance of surface OH groups for the organic contamination. Organic contamination was found on silica gel samples pressed on aluminum plates when they were stored within containers including silicone rubber, silicone grease or adhesive tape. Long path gas cell FTIR measurements for silicone rubber indicated methylsiloxane oligomers were released from the silicone rubber. In-situ heating infrared measurements on the contaminated antigorite and Tagish Lake showed decrease of the 1262 /cm (Si-CH3) and 2963 /cm (CH3) peaks from room temperature to 200-300 C indicating desorption of volatile contaminants. These results indicate that careful preparation and storage are essential for FTIR measurements on precious astromaterial samples such as meteorites, IDPs and samples returned from comets, asteroids and Mars. Every possible contamination source should be evaluated before anything is done to these samples.

Zolensky, Michael E.↗
DOE OSTI2026

An Acid-Free, Temperature-Based Cation Contamination Removal Strategy for PEM Water Electrolysis

It is widely understood that the durability and reliability of polymer electrolyte membrane (PEM) water electrolyzers are heavily dependent on feedwater purity, with cation contaminants that originate from incomplete water purification and balance of plant materials significantly harming electrolyzer performance. However, contamination remains a challenge and a common cause of failure at the stack level, indicating the need for strategies to recover the performance of contaminated cells. In this study, we investigate the effects of temperature on the uptake, electrochemical impacts, and removal of contaminant calcium and iron cations. Lower operating temperatures increase the sensitivity of the cell performance to contaminant cations, while also decreasing cation uptake and promoting contaminant removal. Computational charge transfer modelling shows that lower temperature increases the concentration of contaminant at the cathode and facilitates their removal from the cell. By testing single cells under scenarios designed to mimic stack temperature dynamics, we investigate low-temperature operation as an approach to stack-relevant contaminant recovery. Together, these results demonstrate that the low-temperature recovery approach is a promising approach for acid-free contamination recovery for PEM water electrolysis to promote stack reliability and durability.

08 HYDROGEN↗
NASA NTRS2020

Micro Raman Spectroscopy for Characterizing Molecular Contamination on Space Flight Hardware

In the field of contamination control,many unknowns exist. Often, contamination control engineers have to utilize multiple spectroscopic, macroscopic, and microscopic tools to identify contamination sources when there is a potential contamination exposure to space flight hardware. Understanding the chemical composition of the molecular contamination provides an opportunity for contamination control engineers to determine if this contamination is problematic or benign. In this study, an existing witness plate program for monitoring space flight hardware during the assembly, integration, and testing phases is coupled with micro Raman spectroscopy analysis. The main goal of this study is to determine the limitations, reproducibility, and throughput of micro Raman spectroscopy for characterizing molecular contamination. Micro Raman Spectroscopy will be an additional tool used by contamination control engineers to monitor the cleanliness of space flight hardware.

Microscope↗
NASA NTRS1984

Spacecraft contamination: Sources and prevention; Thermophysics Conference, 18th, Montreal, Canada, June 1-3, 1983, Selected Papers

Results of current research in the field of spacecraft contamination are presented. An overview of the various sources of contamination is given, showing the many and diverse mechanisms associated with the degradation of thermal and optical performance of spacecraft surfaces and optics. Some of the causes of contamination are discussed, including spallation of foam insulation on cryogenic fuel tanks, dispersion of particle contamination about a spacecraft, particle contamination of optical sensors, and the influence of the location of venting systems. Contamination prevention is addressed. Infrared transmittance and infrared optical properties of contaminants are considered along with the effects and properties of mixtures of exhaust species, of plume boundary layer flow, and of the contamination associated with bipropellant attitude control thrusters proposed for the Galileo spacecraft. Also discussed are: degradation of 'clean' thermal control surfaces over four years in orbit, in-orbit measurement of solar absorptance, and contamination from postfire efflux of a solid-propellant rocket motor.

Roux, J. A.↗
NASA NTRS1990

Spacecraft contamination programs within the Air Force Systems Command Laboratories

Spacecraft contamination programs exist in five independent AFSC organizations: Geophysics Laboratory (GL), Arnold Engineering and Development Center (AEDC), Rome Air Development Center (RADC/OSCE), Wright Research and Development Center (MLBT), Armament Laboratory (ATL/SAI), and Space Systems Division (SSD/OL-AW). In addition, a sizable program exists at Aerospace Corp. These programs are complementary, each effort addressing a specific area of expertise: GL's effort is aimed at addressing the effects of on-orbit contamination; AEDC's effort is aimed at ground simulation and measurement of optical contamination; RADC's effort addresses the accumulation, measurement, and removal of contamination on large optics; MLBT's effort is aimed at understanding the effect of contamination on materials; ATL's effort is aimed at understanding the effect of plume contamination on systems; SSD's effort is confined to the integration of some contamination experiments sponsored by SSD/CLT; and Aerospace Corp.'s effort is aimed at supporting the needs of the using System Program Offices (SPO) in specific areas, such as contamination during ground handling, ascent phase, laboratory measurements aimed at understanding on-orbit contamination, and mass loss and mass gain in on-orbit operations. These programs are described in some detail, with emphasis on GL's program.

Murad, Edmond↗
NASA NTRS2006

The Hubble Space Telescope (HST) Contamination Control Program

Over the past two decades, the Hubble Space Telescope (HST) Contamination Control Program has evolved from a ground-based integration program to a space-based science-sustaining program. On-orbit, the telescope s primary contamination requirement was maintaining a low contamination flux in the telescope s optical path. In addition, to maintain the scientific capability of the telescope, the contamination requirements and specific contamination controls from the second- and third-generation Scientific Instruments and Orbital Replacement Units were captured within the HST Contamination Control Program. Contamination controls were developed for on-orbit operations and four Servicing Missions (Orbiter, Astronauts, and mission). Long-term on-orbit scientific data has shown that these contamination controls successfully protected the HST from contamination.

Hansen, Patricia A.↗
NASA NTRS2000

Mir Contamination Observations and Implications to the International Space Station

A series of external contamination measurements were made on the Russian Mir Space Station. The Mir external contamination observations summarized in this paper were essential in assessing the system level impact of Russian Segment induced contamination on the International Space Station (ISS). Mir contamination observations include results from a series of flight experiments: CNES Comes-Aragatz, retrieved NASA camera bracket, Euro-Mir '95 ICA, retrieved NASA Trek blanket, Russian Astra-II, Mir Solar Array Return Experiment (SARE), etc. Results from these experiments were studied in detail to characterize Mir induced contamination. In conjunction with Mir contamination observations, Russian materials samples were tested for condensable outgassing rates in the U.S. These test results were essential in the characterization of Mir contamination sources. Once Mir contamination sources were identified and characterized, activities to assess the implications to ISS were implemented. As a result, modifications in Russian materials selection and/or usage were implemented to control contamination and mitigate risk to ISS.

Soares, Carlos↗
NASA NTRS2018

The Importance of Contamination Knowledge - Insights into Mars Sample Return

The Astromaterials Acquisition and Curation Office at NASA Johnson Space Center (JSC), in Houston, TX (henceforth Curation Office) manages the curation of all past, present, and future extraterrestrial samples returned by NASA missions and shared collections from international partners, preserving their integrity for future scientific study while providing the samples to the international community in a fair and unbiased way. The Curation Office also curates all reference and witness materials for each mission (e.g., flight and non-flight hardware coupons; lubricants; non-flight, flight-like, and flown witness plates). These reference and witness materials provide the scientific community with the fundamental ability to reconstruct the contamination/alteration history of the sample collection through the course of the mission, with the overall goal of strengthening the scientific conclusions drawn from the study of returned materials. The information gained from characterizing the physical, biological, inorganic, and organic chemical properties of reference and witness materials is defined as the Contamination Knowledge (CK) of the sample collection. Unlike the data collected for Contamination Control (CC) and Planetary Protection (PP), CK is exclusively concerned with preserving reference and witness materials for study by future scientists upon sample return. Although CC and PP data collected for sample integrity and forward contamination purposes can be complementary to CK, they are two separate data sets with distinct objectives. A robust collection of samples for CK is necessary to allow the extraterrestrial material in a returned sample to be distinguished from terrestrial contamination. Traditionally CK is utilized by sample scientists in order to accomplish the mission’s scientific objectives, however this information can also be utilized by the Office of Planetary Protection to help evaluate the presence of any back contamination. Mars 2020, the first phase of a potential multipart Mars Sample Return (MSR) campaign, is expected to contribute to NASA’s Mars Exploration Program Science Goals by filling in knowledge gaps concerning: 1) the existence of past or present life on Mars, 2) the past and present climate of Mars, 3) the geology of Mars, and 4) hazards associated with human exploration of Mars. Although there is debate concerning which samples will best answer these questions, the necessity for proper sample blanks is well-understood. The CC and PP requirements, driven by the restricted Class V mission designation, are the most stringent of any sample return mission in recent history. The extremely low levels of allowable terrestrial contamination on the spacecraft and rover can complicate these analyses given the detection limits of current analytical instrumentation, especially in the case of biological contamination. By collecting and curating unanalyzed samples specifically for CK, future sample scientists will not be relegated to: 1) relying on data collected using possibly obsolete tools and techniques for return sample blanks, or 2) using remnants of extracted and/or cultured samples from ATLO (Assembly, Test, and Launch Operations), which could be incompatible with the desired experimental endpoints or state-of-the-art techniques available at the time of sample return.The addition of biological experimental endpoints to a sample return campaign’s objectives broadens the requisite range in preservation environments (e.g. inert ultra-pure nitrogen gaseous environment at 18 degrees Centigrade versus less than or equal to minus 80 degrees Centigrade) and types of CK samples. As a result, the Curation Office will also curate the following CK samples at less than or equal to minus 80 degrees Centigrade for the Mars 2020 mission: 1) unanalyzed swabs and wipes in sterile containers, 2) all recirculation filters from the clean rooms used for sample and caching subsystem assembly and all filters from the laminar flow benches used to assemble sample intimate hardware, and 3) witness plates collecting airborne contamination within the assembly clean rooms. It has been Curation Office policy since the Apollo missions to preserve as many pristine samples as possible for future scientific research. Although CK is required to be collected for all stages of the MSR campaign, the CK for the Mars 2020 mission is the most critical for understanding contamination in the returned samples given the intimacy between the Martian samples and the Mars 2020 flight hardware. This presentation highlights the importance of CK for sample return missions as well as the traditional and novel types of CK samples required for a successful MSR campaign.

Harrington, A. D.↗
NASA NTRS2018

Blind to Chemistry: Molecular Contaminant Films We Could Be Missing During Visual Inspections and the Potential Impact to System Performance

Throughout the assembly, integration and test process, molecular contamination levels of space mission hardware are monitored to meet system performance requirements. Qualitatively, reflective surfaces and witness mirrors are continuously inspected for the visible presence of molecular contaminant films. Quantitatively, periodic reflectance measurements of witness mirrors indicate changes of mirror reflectivity over time due to the accumulation of molecular contaminant films. However, both methods only consider the presence of a contaminant film and not the molecular composition. Additionally, there is a risk that hardware may appear to be “visibly clean” even with a molecular contaminant film present on critical surfaces. To address these issues, experiments were performed to quantify the maximum molecular contaminant film that could be missed in visual inspections on witness mirrors with five different contaminants present. The corresponding changes in mirror reflectivity were modeled using the program STACK to determine the impact to space mission hardware performance. The results of this study not only show the criticality in considering the chemical make-up of molecular contaminant films on system performance, but also the need to recognize and understand the limitations of traditional visual inspection techniques on detecting molecular contaminant films.

Seasly, Elaine↗
NASA NTRSDate not supplied

A METHOD TO REDUCE BIOBURDEN IN ASTROMATERIALS CURATION FACILITIES WITHOUT INTRODUCING UNWANTED CONTAMINATION

Introduction: NASA curates its Astromaterials collections in cleanrooms that are carefully monitored for particulate, inorganic and trace metal contamination. Current sample collections are not particularly susceptible to organic contamination or biological alteration. However, new collections like those from the OSIRIS-REx and Hayabusa2 missions will have organic contamination requirements and are susceptible to biodegradation. It will be necessary sterilize or at least disinfect curation labs, as well as tools and equipment in a manner that does not introduce additional contamination and does not affect the samples 1. Current curation cleaning procedures utilize isopropyl alcohol which offers some bioburden reduction, but is not effective against spore-forming bacteria or fungal spores 2. We present a modified disinfection method that uses ultrapure hydrogen peroxide to reduce bioburden inside curation labs and glove boxes without introducing contamination or damaging curation equipment. We tested this method in the meteorite processing lab as well as on a glovebox being cleaned for use in processing ANGSA (Apollo Next Generation Sample Analysis) samples and present the results of those tests. We discuss the limitations of this method and describe potential situations in which it will not be applicable. The CDC guidelines for disinfection andsterilization in healthcare facilities discusses over 15different methods for reducing bioburden in hospitalsettings 3. The most common method, steamsterilization, is well suited to sterilizing curationprocessing tools but cannot easily be used to sterilizecleanroom surfaces or large equipment likegloveboxes. Chemical sterilization with bleach(NaOCl) is also a common strategy in healthcare andpharmaceutical settings that presents materialcompatibility issues as well as serious inorganiccontamination concerns for curation facilities.Introducing a new source of Na and Cl into curationlabs is not acceptable. Other chemical methods likeethylene oxide, formaldehyde, iodophors andquaternary ammonium compounds could introduceorganic and inorganic contamination. We chose tofocus on hydrogen peroxide because it is generallycompatible with commonly used curation materialslike stainless steel, aluminum and Teflon and becauseit decomposes to oxygen and water. The CDCguidelines for hydrogen peroxide specify using a 7.5wt% solution at 25 ̊C with a contact time of 30 minutesfor high level disinfection and 6 hours for sterilization.High level disinfection is defined as a technique thatwill kill all microorganisms except large numbers ofbacterial spores 3. Methods: We prepared a solution of 7.5 wt%hydrogen peroxide from a stock solution of ultrapure30 wt% peroxide (JT Baker) and curation gradeultrapure water. This ultrapure water is already used incuration cleaning procedures and thus is not consideredand additional source of contamination. We conducteda materials compatibility test by exposing unanodizedand anodized 6061 T6 Al alloy to the peroxide solutionfor up to six hours and periodically inspecting thesurfaces for visible defects. We used this peroxide todisinfect the floor of the meteorite processing lab andthe interior of a curation glovebox by exposing thesesurfaces to the peroxide solution for 30 min. Thesurfaces were swabbed with a dry macrofoam swabbefore (Puritan Brand 2518051PFRNDFD) and afterperoxide treatment to collect microbes present on thesurfaces. Microbes were extracted by sonication fromthe swab into 15 ml of PBS (phosphate buffered saline)and inoculated onto the following media: TSA (trypticsoy agar) BA (blood agar), R2A (Reasoners 2 agar),Potato Dextrose Agar, Saboraud Dextrose Agar andSaboraud Dextrose Agar with 0.1 mg/ mlchloramphenicol. Four TSA plates and two BA plateswere inoculated with 0.1 ml of PBS each andincubated at 35 and 37 for 48 hours. Two R2A°C°Cplates (0.1 ml of PBS each) were incubated at 25 .°CThe remaining plates were inoculated with 0.2ml ofPBS and incubated at 30 ̊C for seven days. Afterincubation bacterial and fungal isolates were countedand transferred to new plates for identification usingthe VITEK24 automated system or by sequencing aportion of the barcode gene (16S rRNA for bacteria,small subunit gene for fungi) on an ABI 3500 Sangersequencer. Negative controls consisted of swabs thatwere opened in the sampling environment andanalyzed alongside the experimental samples.Results: A 6 hour exposure to hydrogen peroxideresulted in visible pitting on un-anodized 6061 Al, butnot on anodized surfaces. No visible pitting occurredafter a 30 minute exposure. Therefore, we decided tolimit our experimental tests to 30 min. exposures. 17bacterial CFU (colony forming units) representing 4distinct organisms were isolated from the meteorite processing lab floor prior to hydrogen peroxidetreatment. We were unable culture any organisms afterperoxide treatment. In the glovebox we were able toculture three bacterial CFU representing three distinctspecies, including a spore forming bacterium prior todisinfection with peroxide. After the peroxidetreatment we were unable to culture any organisms.Routine monitoring of the meteorite processing lab andthe glovebox did not indicate any increase in unwantedinorganic contamination after these peroxidetreatments. Discussion: A 30 minute treatment with 7.5 wt%peroxide appears to be an effective method forreducing bioburden on typical cleanroom surfaces. Themethod does not introduce unwanted organic orinorganic contamination and is compatible withcommonly used curation materials like stainless steel,Teflon and anodized aluminum alloys. Special careshould be taken with un-anodized aluminum.Prolonged exposure to hydrogen peroxide can causepitting on this material. We recommend using thismethod to disinfect curation labs and equipment whenbiological alteration is a concern. This method iseffective at room temperature and cannot be used todisinfect labs and equipment where the ambienttemperature is < 0 ̊C. Astromaterials samples shouldbe removed from the area where disinfection is tooccur. Hydrogen peroxide is a powerful oxidizingagent and will react with any organic carbon present inthe sample. References: [1.] Mccubbin, F. M. et al.Sp. Sci Rev(2019) doi:10.1007/s11214-019-0615-9. [2.] Mogul, R.et al.Astrobiology 18, ast.2017.1814 (2018). [3.]Rutala, W. A. & Weber, D. J. Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008. [4.] Pincus, D. H. in Encyclopedia of Rapid Microbiological Methods (2005).

A. B. Regberg↗