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At least 271 records · Page 15

Early Radiometric Performance of Landsat-9 Thermal Infrared Sensor

Landsat-9, launched on September 27, 2021, carries the Thermal Infrared Sensor (TIRS). The Landsat-9 TIRS is a close copy of the Landsat-8 TIRS instrument; it is a two spectral-band, pushbroom sensor with three Sensor Chip Assemblies (SCAs) that cover the 15-degree field-of-view. The primary radiometric change between the instruments is the addition of baffling in the Landsat-9 TIRS telescope to mitigate the stray light issue that has impacted the radiometric quality of Landsat-8 TIRS. The on-orbit radiometric performance is monitored using the on-board variable temperature blackbody and views of deep space. Maneuvers to look at and around the moon have provided an assessment of the stray light. The absolute calibration is monitored by vicarious calibration techniques by teams at NASA/Jet Propulsion Lab and the Rochester Institute of Technology. Landsat-9 completed a three-month commissioning phase in January 2022 and has been operational since February 2022. The instrument has demonstrated excellent radiometric performance, as assessed from the on-orbit measurements. The TIRS instrument is radiometrically stable to 0.1% within a power cycle, and has noise levels below 0.1K. The lunar scans and the vicarious calibration data provide evidence that the stray light has been effectively mitigated.

Landsat-9↗

Evaluating Rock Pool Hydroperiod Fluctuation using Climate Variables to Inform Habitat Monitoring and Protection in the Western Sonoran Desert

As warming and drying trends continue to impact the greater American Southwest, effective ecosystem management increasingly relies upon understanding the relationships between climate and water resources. Ephemeral freshwater rock pools, known as tinajas, have great ecological and cultural importance as some of the only sources of surface water in the western Sonoran Desert (WSD). Tinaja flooding and drying cycles, known as hydroperiods, vary based on meteorologic and climatologic conditions; however, a lack of extensive research relating climatic impacts to tinajas puts these critical ecosystems further at risk. Tinajas throughout the WSD are monitored by the National Park Service (NPS) using resource intensive strategies including in situ trail camera observation and direct measurement. To aid NPS monitoring efforts, this research used remotely sensed climate data to analyze spatiotemporal climate trends and relationships between climate variables and tinaja hydroperiods in the WSD between 1979–2022. Using Aqua and Terra Moderate Resolution Imaging Spectroradiometers (MODIS), University of Idaho Gridded Surface Meteorological Dataset (gridMET), and OpenET data, the project analyzed land surface temperature, evapotranspiration, precipitation, wind velocity, and solar radiation. The team generated climate anomaly time series and climate normal maps for the WSD, identifying statistically significant spatial and temporal trends. These data were then compared to daily, qualitative in situ hydroperiod observations taken between 2019–2022. This work will be used by the NPS to inform the monitoring and protection of tinajas in the WSD. Findings contribute to a limited body of research concerning climate and tinajas, which are often overlooked despite their disproportionate ecological importance.

Annie Britton↗

Utilizing Earth Observations to Model Probable Coastal Wetland Extent, Sea-Level Rise Inundation Risk, and Assess Impacts on Historic Hawaiian Lands

Climate induced sea-level rise poses a risk to coastal areas on the Island of Hawai’i, and many of the island’s historic cultural lands are in danger of becoming overtaken by wetlands or inundation. In partnership with the County of Hawai’i, State of Hawai’i Department of Land and Natural Resources, and Arizona State University, NASA DEVELOP mapped wetland extent and short-term sea-level rise inundation risk. We utilized Earth observations over a 10-year span (2013 – 2022) that included the NASA MEaSUREs Gridded Sea Surface Height Anomalies and MEaSUREs Group for High Resolution Sea Surface Temperature datasets, United States Geological Survey (USGS) Hawaii Digital Elevation Models (DEM), and in situ tidal gauge data. Flood risk index values were acquired for 5 known Hawai’i flood events between 2019 – 2021 from the Global Flood Mapper tool on Google Earth Engine. We used a random forest model to predict short-term sea-level rise inundation risk along the entire coast of Hawai’i. Current wetland extents and probabilistic locations of new wetlands were modeled with the most recently available data from PlanetScope Surface Reflectance optical imagery (2022), USGS 3D Elevation Program (3DEP) 10m DEM (2020), temperature and precipitation data from the Hawai’i Climate Atlas, and soils data from the Hawai’i Soil Atlas (2014) using the Wetland Intrinsic Potential tool. Results indicated locations that had the highest probability of wetland creation. The end products aimed to help the partners prioritize efforts to meeting regulation requirements for wetlands protection, evaluate the inundation risk to historical features, and support decision-making for their Shoreline Setback and Climate Adaption plans.

Lisa Tanh↗

The Generation of Mixing Across the Stratospheric Polarvortex Edge By Breaking Gravity Waves

Modern high resolution global atmospheric analyses are capable of resolving larger gravity waves, including their generation, propagation, and breaking. Orographically generated gravity waves that break in the middle stratosphere often appear as disturbances in maps of potential vorticity, a key stratospheric dynamical quantity. Using analyses from the NASA Global Modeling and Assimilation Office, we show how gravity waves not only disturb the local flow above them but can generate flow instabilities leading to eddies that propagate around the stratospheric polar vortex, creating significant mixing across the vortex edge and into the polar region. These disturbances and mixing events are especially noticeable during NH winter months with low planetary scale wave activity such as in January 2022. During January 2022, the initially circular flow around the polar vortex was disrupted by breaking gravity waves, leading to unstable flow that created a chain of eddies around the vortex edge. The mixing associated with this process led to increased ozone in the upper stratosphere polar region.

Polar Vortex↗

MaGIXS 2: Preparations for the Second Flight of the Marshall Grazing Incidence X-ray Spectrometer

Overview MaGIXS is a slitless soft X-ray (SXR) imaging spectrometer designed to observe solar active regions. - The instrument produces spatially resolved SXR spectra, known as “overlappograms.” (Athiray et al. 2019 & Champey et al., 2022) The first sounding rocket flight of the Marshall Grazing Incidence X-ray Spectrometer occurred on July 30, 2021 from the White Sands Missile Range, New Mexico. - Spectrally pure images of X-ray bright points were obtained through the inversion of overlappograms, e.g. Fig. 3 (Savage et al., 2022). MaGIXS 2 is a simplified version of the original design, less the spectrometer mirror pair. - Eliminating the spectrometer mirror pair improves spatial resolution, increases effective area and the field of view (Table 1). No field stop in this design, data will be an overlappogram with the same spatial and spectral plate scale.

x-ray spectrometer, x-ray optics, solar corona, so↗

Colorado Eastern Plains Agriculture: Rangeland Monitoring to Inform Grazing Management in Eastern Colorado

Adaptive management on cattle ranches requires rangeland managers to decide the location and duration of the cattle grazing activity across different pastures. Biodiversity, forage availability, and cattle health are all affected by rangeland management. Virtual fencing is a tool that rangeland managers can use to potentially increase biodiversity and improve ranching operations. NASA DEVELOP and Colorado State University (CSU) collaborated with the Nature Conservancy (TNC), and Red Top Ranch to demonstrate the efficacy of virtual fencing. We sought to identify annual and monthly biomass patterns on the ranch through the creation of monthly max biomass productivity maps. We utilized a dataset from the Agricultural Research Service (ARS) to calculate biomass on the ranch. To validate our remotely-sensed results, we compared model-predicted biomass values to field-collected biomass clipping data and an additional biomass dataset from the Rangeland Analysis Platform (RAP). We used satellite imagery from Landsat 5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), Landsat 8 Operational Land Imager (OLI), Landsat 9 –OLI-2, and Sentinel-2 MultiSpectral Instrument (MSI) for 2021 and 2022. We found that there was heterogeneity in biomass across the ranch, with higher biomass on the western side. The highest peak of biomass was in the summer months, with a smaller peak in mid-September. The ARS biomass dataset had a significant relationship with RAP for 2021. ARS biomass did not have a significant relationship with the biomass field data collected in 2022. The results of our study are aimed to support rotation management, ranch production, biodiversity, and conservation management.

cattle↗

Overview of the Bedrock Geochemistry and Mineralogy Observed By Supercam During Perseverance’S Delta Front Campaign

In February 2021, the Perseverance rover landed in Jezero crater, Mars. The crater floor was found to be composed of lava flows and cumulate rocks. These magmatic rocks appear to have undergone some limited aqueous alteration; however, it is not clear whether this alteration is related to the lacustrine phase of the crater. After completing its exploration of the crater floor, Perseverance reached the foot of the Jezero western fan in late April 2022 (sol ~422). Long-distance images acquired earlier in the mission had already confirmed the deltaic nature of the fan, which had long been suspected from orbital observations. Between April and December 2022, Perseverance investigated the basal layers of the delta at two locations named Hawksbill Gap and Cape Nukshak, which are ~400 m apart. Here, we present an overview of the geochemistry and mineralogy of the delta rocks as observed by SuperCam and show that these rocks record a diversity of past aqueous alteration environments.

E. Dehouck↗

The NASA Astrobiology Program’s Professional Advancement Workshop Series: Next Steps

Introduction: In the modern-day competitive job search, it is not enough for a candidate to have an excellent academic resume. Candidates must also present themselves well in various styles of interviews, have managerial skills, and be capable of engaging in complex interpersonal relationships and team building. The NASA Astrobiology Program’s Professional Advancement Workshop Series (PAWS) addresses the need for professional skills development that is not traditionally taught in graduate programs. PAWS is designed to supplement academic teachings by providing a space where early career scientists can learn new skills to help them explore, interview for, and be hired in the jobs and careers they want. This is especially true for jobs that are outside of the traditional academic “pipeline” (the path of student to postdoc to tenure-track professor). PAWS embraces the braided river model of career development [1], which emphasizes flexibility as a scientist’s needs change throughout their life. PAWS also presents an opportunity for other early career scientists to meet and network with each other outside of conferences and other formal events. This is especially important as the world emerges from the ongoing COVID-19 pandemic. Finally, PAWS creates an informative space full of resources available to everyone, which lowers institutional barriers regarding knowledge of opportunities and potentially provides mentorship to those in need. Both items are identified as supportive of a more diverse and inclusive future workforce [2–4]. PAWS began in August 2021 and was originally intended to last until the Astrobiology Science Conference in May 2022. The NASA Astrobiology Program initially sponsored PAWS, allowing the PAWS Leadership to bring in expert speakers from outside of NASA. These external speakers exposed the event attendees to new techniques and perspectives. PAWS has been able to continue beyond May 2022 because of many people volunteering their time for panels and a good balance between panels and expert-led workshops. Here, we share how PAWS works, what the results have been so far, and the future plans for PAWS.

Worshop↗

Increasing Cognitive Ability/Reserve Using Software – Pilot (ICARUS-Pilot)

Background: This research study was competitively awarded under the 2022 JSC Innovation Charge Account (ICA) program administered by NASA Johnson Space Center’s Joint Technology Working Group. Study period of performance was May through September 2022, with a maximum allowed procurement budget of $10K. The study sought to quantify and assess the potential benefit of using commercial-off-the-shelf (COTS) cognitive training software to improve cognitive performance in an astronaut-like terrestrial population. Methods: Five volunteer research participants were recruited from the JSC employee population to mimic certain demographic characteristics of the NASA astronaut population (age, education/discipline). Participant cognitive performance was assessed before and after executing eighteen sessions of remote cognitive training executed nominally three times per week using six exercises within an adaptive app-based COTS software package (BrainHQ, Posit Science) on study-provided tablets. Pre- and post-training cognitive performance was measured using internal assessments in BrainHQ as well as Cognition Test Battery (CTB) version ISS B01 v3 (3.0.9-201710021500), an independent software test developed specifically for NASA and used currently in research studies on astronauts. BrainHQ exercises were posited to map well or partially to several CTB sub-tests. Participants provided feedback on their study experience formally via semi-structured interview at the conclusion of testing and informally throughout the study if they encountered issues. Results: The enrolled ICARUS-Pilot study participants generally matched Artemis crew demographic characteristics. Four of five participants have completed study training and assessment activities as of the writing of this abstract. These test participants complied well with desired training session frequency and duration yielding an average cumulative active training duration of 15 hours over an average of 45 days; participants showed 78% average improvement in metric performance for the six trained exercises, with an associated overall 33%ile ranking increase against performance of the entire BrainHQ subscribing population for internal pre/post assessment, agreeing with post-study survey self-reported performance increases. CTB overall feedback scoring, not corrected for learning effects, showed an average of 19% performance improvement across its 10 performance measures over the training period for the completed participants. Detailed analyses will be conducted once participant data collection for the study is complete and the resulting dataset is fully populated. Discussion: These preliminary results provide a positive trend for the effectiveness of the training approach, but further analysis will be needed to establish significance, investigate far transfer, and suggest the needed participant pool size for subsequent efforts to achieve statistically significant outcomes given similar results. The pilot study has already been helpful by allowing the study team to learn a great deal about the capabilities and limitations of the COTS software package that will be reflected in future proposals along with revised timelines for study execution and test participant management. From participant feedback, one common thread regarding the COTS training was that it felt overly repetitive – future proposals should reassess overall training duration, available levels for each trained exercise, and the behavior of the BrainHQ internal scheduler in determining which exercises should be trained and for how long. If the final analysis of this feasibility study ultimately supports it, the study team will recommend further investigation to fully evaluate this potential countermeasure and optimize its implementation. Future proposals would cite this feasibility study’s outcome and would seek to refine the training protocol and obtain statistically significant results for cognitive performance increases as well as retention data.

cognitive training↗

Verification Testing and Veg-05 Tomato Crop Production on the International Space Station

Production of fresh, nutritious, and tasty produce for astronauts during spaceflight may provide health-promoting, bioavailable nutrients and enhance the dietary experience as we move into longer-duration missions. Growing and caring for plants may also reduce the psychological stresses associated with spaceflight and enhance connections to Earth. Requirements to consistently grow a diversity of crops under spaceflight environmental conditions remain poorly defined. The VEG-05 experiment is part of a series of experiments with pick-and-eat salad crops to better define best practices for crop production and handling in space. VEG-05 and predecessor experiments VEG-04A and VEG-04B, use the Veggie vegetable production facilities on the International Space Station to grow salad crops under different spectral compositions. In VEG-04A and B, mizuna mustard was cultivated with two different red: blue light treatments, and in VEG-05 we are cultivating ‘Red Robin’ dwarf cherry tomatoes under the same light spectra. Light can impact the growth habit, yield, nutritional composition, microbial levels, and even flavor attributes within crops, and our team will assess these characteristics for this crop during VEG-05. Prior to launch and installation on ISS in late 2022, both a science verification test (SVT), and an experiment verification test (EVT) were conducted at Kennedy Space Center in ISS Environment Simulator Chambers. Science verification testing, and a previous fertilizer test, grew plants in both plant pillows and PONDS (Passive Orbital Nutrient Delivery System) units and tested two different fertilizer treatments in both sets of hardware, with each test under only one of the light conditions. Because of challenges validating the PONDS hardware on ISS, and with good crop production in plant pillows, the EVT moved forward using only plant pillows with the highest fertilizer composition tested during SVT, and two Veggie units were utilized. One Veggie had light settings consisting of equal levels of red: blue light (150 µmol/m2/s for each color) plus green light (30 µmol/m2/s) while the second Veggie had a 90:10 ratio of red: blue light (270 µmol/m2/s red and 30 µmol/m2/s blue) plus green, so each unit provided 330 µmol/m2/s of photosynthetically active radiation to the tomato crops on average. Our original plan, based on prior ground testing, was to grow the crop for 104 days and harvest at 80, 90 and 104 days after initiation. For SVT, under the equal red: blue light treatment, fruit ripening in plant pillows was delayed and fruit were not ripe by day 80, so actual harvest days were days 90, 97, and 104. For EVT we saw fruit ripening earlier, especially in the high red treatment, and so we harvested at days 83, 90, and 99 days after initiation. In SVT we had mostly daily watering, and this led to excess water in plant pillows, which leaked out. This excess water also caused fungus to grow on one leaf and a couple of plant stems. To reduce this excess moisture, we throttled back the watering for EVT, and used the root mat reservoir more frequently. This led to watering only every other day, reducing crew time needed for plant care, however, two wilting events occurred during this EVT, at days 51 and 75. Plants recovered from these wilting events, but these events may have influenced the rate of fruit ripening and flower formation. Regardless, more than 10 fruit were produced from each plant on average, with the high red treatment producing slightly heavier fruit. Microbial testing from fruit during SVT indicated that fruit were safe for consumption with microbial levels below detection limits. VEG-05 flight and ground operations are expected to run between December 2022 and March 2023. This research was co-funded by the Human Research Program and Space Biology (MTL#1075) in the ILSRA 2015 NRA call.

Gioia D. Massa↗

Summer Monsoons in the UTLS as Observed By Recent NASA Airborne Campaigns.

During boreal summer, the circulation of the northern hemisphere upper troposphere and lower stratosphere (UTLS) is dominated by two quasi-stationary anticyclonic eddies driven by latent heat released in the troposphere: the Asian Monsoon Anticyclone (AMA) and the North American Monsoon Anticyclone (NAMA). Deep convection rapidly transports boundary layer air to the UTLS, and the monsoon anticyclones act to partially confine and isolate air from the surrounding atmosphere. The interactions between chemistry and circulation within these systems are crucial for understanding the sensitivity of these regions to changes in climate and air quality. Satellite observations show that within the summer monsoon anticyclones is a region of enhanced water vapor, aerosol, and trace gases of boundary layer origin near the tropopause level. However, satellite data do not provide necessary details for process studies and for diagnosing their representations in models. In response to this need, NASA conducted two airborne missions to investigate these summer monsoon systems and their roles in climate. NASA Earth Venture Suborbital 3 (EVS-3) mission called Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) completed two deployments in Salina, Kansas during summers 2021 and 2022 to study the NAMA. The Asian Summer Monsoon Chemical and Climate Impact Project (ACCLIP) was a multi-agency effort to investigate the AMA from Osan, South Korea in summer 2022.

Summer↗

Fire Station #1 Area, SWMU 116 Per- and Polyfluoroalkyl Substances (PFAS) Site Assessment Progress Report Kennedy Space Center, Florida

This Per- and Polyfluoroalkyl Substances (PFAS) Site Assessment (SA) Progress Report (SAPR) discusses the investigation activities and findings for the Fire Station #1 (FS1) Area (formerly known as Fire Station #4) located at Kennedy Space Center (KSC), Florida (Figure 1-1). This site has been designated Solid Waste Management Unit (SWMU) 116 under KSC’s Resource Conservation and Recovery Act (RCRA) Corrective Action Program. This PFAS SA is being managed under SWMU 116 as the fire station was identified as a potential source of PFAS to the environment. This PFAS SAPR was prepared by Tetra Tech, Inc., for the National Aeronautics and Space Administration (NASA) under Indefinite Delivery Indefinite Quantity Contract 80KSC019D0011-80KSC019F0070. This is the first progress report to document on-going SA activities; supplemental progress reports will be provided as additional data is collected. During the SA, a total of six soil, 48 groundwater direct push technology (DPT), eight groundwater monitoring well, and one surface water sample were collected between October 2021 and March 2022. The samples were analyzed for 28 PFAS compounds using the Department of Defense Quality Systems Manual-compliant Method. SA sample results were used along with historical results to evaluate the extent of PFAS impacts to the environment in the FS1 Area. Data generated to date and prior results were screened against the United States Environmental Protection Agency (USEPA) May 2022 Tap Water Regional Screening Levels (RSLs) for groundwater and residential RSLs for soil (hazard quotient of 0.1). Surface water results were screened against the State of Florida Human Health Surface Water Screening Levels (SWSLs). Overall, results from the SA showed exceedances of the applicable screening criteria for soil, groundwater and surface water. Considering the current and historical dataset, perfluorooctanesulfonic acid (PFOS) is the prevalent PFAS compound, which is indicative of AFFF releases. Based on results of the SA, additional groundwater DPT and surface water sampling should be considered, focused on evaluating surface water bodies in the southeast portion of the Industrial Area, which discharge into the Banana River. Additionally, installation of monitoring wells should be considered to evaluate the interaction between groundwater and surface water in the FS1 Area.

PFAS↗

The ESA Hera Mission: Detailed Investigation of the NASA Dart Impact Outcome and Characterization of the Binary Asteroid Didymos

The Hera mission is in development in the Space Safety Program of the European Space Agency (ESA) in collaboration with JAXA for launch in October 2024. It will rendezvous with the binary asteroid (65803) Didymos in early 2027 and over the following 6 months will investigate the properties of Didymos and its small moon Dirmorphos, including the effects of the successful impact of the NASA DART probe. DART was launched on 24 November 2021 at 06:21 UTC and successfully impacted at about 6.1 km/s on the 160 meter-size Dimorphos on 26 September 2022 at 23:14 UTC. Two weeks before impact, it deployed the Light Italian Cubesat for Imaging of Asteroids (LICIACube) that provided images during the few minutes following the impact. A campaign of observations from Earth and space provided distant images of the event, which were used to determine a reduction of 33 min in the orbital period of Dimorphos around Didymos. The Hera mission will investigate the outcome of the DART impact in detail. In particular, it will determine the effects of the impact on Dimorphos’ surface, e.g., whether it produced a crater, and if so its properties, and/or whether it led to global reshaping of Dimorphos. It will accurately measure the mass of Dimorphos, which will allow quantification of the momentum enhancement factor, which is a crucial parameter to evaluate the efficiency of the kinetic impactor technique. Hera will also determine in detail the physical, thermal and compositional properties of the asteroid, including first time measurements of the internal properties, which have a critical influence on the impact outcome. With Hera and DART together, we will have a fully documented deflection test and impact experiment that will allow us to verify our numerical impact models, to be able to extrapolate this deflection test to other asteroids and to improve our understanding of the complex geological properties and response of small asteroids. Hera consists of a mother spacecraft and two cubesats. It will perform the first rendezvous with a binary asteroid, arriving at Didymos about 4 years after DART. Hera will not only contribute significantly to the planetary defense effort by documenting entirely the outcome of the DART impact, it will also greatly advance our understanding of processes in the very low gravity regime of a small asteroidv (Dimorphos) as well as our knowledge of binary asteroids and asteroid geophysics. The mission development is progressing nominally, with the Critical Design Review having been passed in Nov. 2022. The various working groups of the Hera Science Team are working intensively to support this development and be best prepared for the surprises that Hera will offer during its visit to Didymos in 2027.

Asteroid deflection↗

Heat Transfer and Interfacial Flow Physics of Microgravity Flow Boiling in Single-Side-Heated Rectangular Channel with Subcooled Inlet Conditions – Experiments Onboard the International Space Station

This study is the culmination of a long-term collaborative effort between researchers from the Purdue University Boiling and Two-Phase Flow Laboratory (PU-BTPFL) and the NASA Glenn Research Center to investigate gravitational effects on flow boiling and flow condensation. The science and design concepts for this large-scale effort were initiated in 2011 and included several studies detailing various aspects of two-phase fluid physics in both Earth gravity and microgravity, culminating in construction of the large-scale experimental facility named “Flow Boiling and Condensation Experiment (FBCE)”. The experiment was launched to the International Space Station (ISS) in August 2021. Following the successful installation of FBCE, equipped with the Flow Boiling Module (FBM), onboard the ISS and completion of several safety checks, flow boiling experiments were performed for five months from February 2022 until July 2022. This resulted in a large flow boiling database covering broad ranges of operating parameters and heating configurations spanning several research objectives. This study investigates microgravity flow boiling of n-perfluorohexane with subcooled inlet in a single-side-heated rectangular channel of dimensions 114.6-mm heated length, 2.5-mm heated width, and 5.0-mm height. Key operating parameters investigated are mass velocity (199.90 – 3200.13 kg/m 2 s), inlet subcooling (0.10 – 45.76°C), and inlet pressure (113.30 – 164.29 kPa). Images and image sequences acquired via high-speed-video are presented to elucidate the interfacial flow physics. To analyze and explain the effects of various parameters in microgravity, heat transfer results are presented as flow boiling curves, streamwise profiles of wall temperature and heat transfer coefficient, and parametric trends of local and averaged heat transfer coefficient. Mass velocity and inlet subcooling significantly influenced most of the aforementioned aspects of flow boiling, whereas effects of inlet pressure were comparatively insignificant. Although the data and observed flow physics might be different, the parametric effects and trends in microgravity are similar to vertical upflow in Earth gravity. Some cases, especially low mass velocities, high heat fluxes, and large degrees of inlet subcooling, experienced temporally anomalous flow behaviors caused by two-phase flow instabilities manifesting as flow reversals and resulted in deviations in overall trends. Severe thermodynamic non-equilibrium is observed throughout the channel. Overall, FBCE’s ISS experiments were successful for subcooled inlet with single-sided heating of rectangular channel, and the collected data well established the various effects on flow boiling physics in highly controlled long-term microgravity conditions.

flow boiling↗

Triple Oxygen Isotope Kinetics of Sulfate From Pyrite Oxidation

Sulfates from low temperature terrestrial and marine environments are out of equilibrium with their oxygen sources. Instead, oxygen isotope compositions of sulfate imply they are dominated by kinetic signatures of oxidative and reductive processes (Killingsworth et al., 2022) that are under-constrained compared to equilibrium effects (Hayles and Killingsworth, 2022). Consequently, the specific role of pyrite oxidation in setting the oxygen isotope composition of sulfate is also under-constrained. This scenario inhibits a more nuanced understanding of small variations in the oxygen isotopes of sulfate and their implications for tracing oxygen sources and sulfur cycle transformations, particularly in low-temperature relatively sulfate-limited freshwater systems such as rivers, lakes, aquifers, and mining-affected environments. To alleviate these knowledge gaps, we conduct pyrite oxidation experiments at time scales spanning minutes to years, analyze the triple oxygen isotope compositions (∆ 17 O and δ 18 O) of sulfate products, and interpret results using molecular modeling. Our preliminary results show isotopic relationships of 1) pyrite-derived sulfate ∆ 17 O reaching above the meteoric water line as its δ 18 O becomes lighter than water, and 2) sulfate ∆ 17 O and δ 18 O extending between water and O 2 . From these results we interpret a kinetic isotope effect between sulfate and water and mixing between sulfate end members containing most of their oxygen atoms from water and from O 2 .

Oxygen isotopes↗

The Cross Equatorial Transport of the Hunga Tonga-Hunga Ha’apai Eruption Plume

On 15 January 2022, the Hunga Tonga-Hunga Ha'apai (HT) eruption injected SO 2 and water into the middle stratosphere. Shortly after the eruption, the water vapor anomaly moved northward toward and across the equator. This northward movement appears to be due to equatorial Rossby waves forced by the excessive infrared water vapor cooling. Following the early eruption stage, persistent mid-stratospheric water vapor and aerosol layers were mostly confined to Southern Hemisphere tropics (Eq. to 30°S). However, during the spring of 2022, the westerly phase of the tropical quasi-biennial oscillation (QBO) descended through the tropics. The HT water vapor and aerosol anomalies were observed to again move across the equator coincident with the shift in the Brewer-Dobson circulation and the descent of the QBO shear zone.

Atmospheric Science↗

The Cross Equatorial Transport of the Hunga Tonga-Hunga Ha'apai Eruption Plume

On 15 January 2022, the Hunga Tonga-Hunga Ha'apai (HT) eruption injected SO 2 and water into the middle stratosphere. Shortly after the eruption, the water vapor anomaly moved northward toward and across the equator. This northward movement appears to be due to equatorial Rossby waves forced by the excessive infrared water vapor cooling. Following the early eruption stage, persistent mid-stratospheric water vapor and aerosol layers were mostly confined to Southern Hemisphere tropics (Eq. to 30°S). However, during the spring of 2022, the westerly phase of the tropical quasi-biennial oscillation (QBO) descended through the tropics. The HT water vapor and aerosol anomalies were observed to again move across the equator coincident with the shift in the Brewer-Dobson circulation and the descent of the QBO shear zone.

water↗

The Completion of a Geosynchronous Earth Orbit Survey with the Eugene Stansbery-Meter Class Autonomous Telescope

The Eugene Stansbery-Meter Class Autonomous Telescope (ES-MCAT) is the primary optical sensor used by the NASA Orbital Debris Program Office (ODPO) to statistically characterize the geosynchronous Earth orbit (GEO) debris environment and support future Orbital Debris Engineering Model (ORDEM) releases. The ES-MCAT completed its first optical survey of the GEO region from 2020 to 2022. The primary goal of this survey was to autonomously collect and process GEO data with calculated photometric and astrometric uncertainties. A pointing plan was developed to provide uniform sampling within the region of interest (ROI) while accounting for predicted downtime due to insufficient observing conditions. Detections are autonomously correlated to the Space Surveillance Network (SSN) catalog to determine if objects are correlated targets (CTs) or uncorrelated targets (UCTs), the latter of which are of interest for modeling the GEO orbital debris environment. To assess the size detection sensitivity over time and monitor the general performance of the telescope’s optics and software, the optical throughput of the system and limiting magnitudes are evaluated on a routine basis. While the telescope’s ability to operate autonomously and remotely allowed for the GEO survey to continue throughout the COVID-19 pandemic, travel restrictions hampered routine cleaning of the optics during this time, and the primary mirror degraded enough to require recoating. The mirror was removed in 2022, concluding the first GEO survey. The primary mirror received a new coating designed to be more robust against the harsh environment surrounding the ES-MCAT’s location on Ascension Island, accounting for experience gained during operations over the first GEO survey. In early 2023, the recoated primary mirror was reinstalled, and the second GEO survey was initiated. The primary goal of the second GEO survey is to characterize the evolving GEO debris environment with updated optics, software, and pointing strategies while allowing for the inclusion of non-GEO regimes or those that are outside of the ROI. While the pointing method implemented in the first survey allowed for adequate coverage of the ROI over two years, it has been improved to include pointings that avoid the Moon’s position and the galactic plane to reduce software processing time and maximize the detection capabilities of fainter objects. This method also accounts for the changing weather patterns throughout the year and reduces coverage gaps in the ROI. Provided the success of the first two-year GEO survey using autonomous operations, the ODPO is actively collaborating with the United States Space Force (USSF) to make the ES-MCAT a contributing sensor to the SSN. This paper presents results from the first GEO survey including magnitude distributions and orbital parameters for CTs and UCTs. Details are provided for the automated processing pipeline and the optical system throughput for the previous and current primary mirror coatings. In addition, an updated strategy for the second GEO survey to optimize coverage over the ROI is discussed, as are preliminary results from the ongoing second survey.

Corbin Cruz↗