Maxar Technologies (United States)

Through the combination of several innovative erosion control measures, the tailings pile cover for the Atlas Corporation (Atlas) uranium mill and tailings disposal area was designed to address long-term climatic, geomorphological, hydrological, and geotechnical concerns. These included the effects of a probable maximum flood, potential channel migration of the adjacent Colorado River and Moab Wash, potential rock falls and landslides, and migrating sand dunes. The erosion protection measures for the tailings pile cover include a rock armor cap, riprap protected tailings pile side slopes and drainage channels, rock aprons to minimize the potential for head cutting at the outlets of the drainage channels, toe protection against scour, a buried rock wall to protect from potential Moab Wash migration, and a self-launching apron to protect from potential Colorado River migration. This paper addresses the techniques and methods used to design and size the erosion protection riprap for the tailings pile cover and diversion channels in accordance with NRC requirements and guidelines.

The Power and Propulsion Element (PPE) is the first piece of the Artemis Lunar Gateway. This spacecraft will host a 50kW-class state of the art electric propulsion subsystem, containing a combination of never-before-flown 6kW and 12kW thrusters, large Carbon Fiber Overwrapped Pressure Vessel xenon tanks, and a refueling interface. The combination of the high degree of new hardware within the propulsion system, the inclusion of PPE within the larger human-rated Artemis Gateway, and the high level of Lanteris Space Systems heritage with the Lanteris 1300 platform required a tailored safety and hazard process for the program. This paper details the system safety and hazard analysis methods applied during the design phase, summarizes key hazard identification and mitigation activities, and discussed how these influenced the final architecture of the electric propulsion subsystem.

We describe a citizen science asteroid detection system developed by the International Astronomical Search Collaboration (IASC) and the Institute for Astronomy at the University of Hawaii, utilizing data from the Pan-STARRS telescopes. The goals of this project are to (i) educate and engage citizen scientists (mostly high school students) in science and astronomy, (ii) search for new asteroids to extend the limiting magnitudes of existing asteroid surveys, and (iii) find missed Near-Earth Objects (NEOs—objects with perihelia q < 1.3 au) to support planetary defense efforts. Over the past 15 yr, 50,000 citizen scientists from 96 countries around the world have detected ∼12,000 main-belt asteroids and ∼5 NEOs. Citizen scientists use the software Astrometrica during scheduled campaigns to search for and measure asteroid astrometry and photometry, and submit the data to IASC for vetting. Candidate detections not already submitted by Pan-STARRS are then submitted to the Minor Planet Center, and are typically ∼0.30 ± 0.07 mag fainter.

Heterozygous SPINK1 mutations are strong risk factors for chronic pancreatitis in humans, yet heterozygous disruption of mouse Spink1 yielded no pancreatic phenotype. To resolve this contradiction, we usedCRISPR/Cas9-mediated genome editing to generate heterozygous Spink1-deleted mice (Spink1-KOhet) in the C57BL/6N strain and studied the effect of this allele in trypsin-independent and trypsin-dependent pancreatitis models. We investigated severity of acute pancreatitis and progression to chronic pancreatitis in Spink1-KOhet mice after transient (10 injections) and prolonged (2× 8 injections) cerulein hyperstimulation. We crossed Spink1-KOhet mice with T7D23A and T7D22N,K24R mice that carry strongly autoactivating trypsinogen mutants and exhibit spontaneous chronic pancreatitis. Prolonged but not transient cerulein stimulation resulted in increased intrapancreatic trypsin activity and more severe acute pancreatitis in Spink1-KOhet mice relative to the C57BL/6N control strain. After the acute episode, Spink1-KOhet mice developed progressive disease with chronic pancreatitis-like features, whereas C57BL/6N mice recovered rapidly. Trypsinogen mutant mice carrying the Spink1-KOhet allele exhibited strikingly more severe chronic pancreatitis than the respective parent strains. Heterozygous Spink1 deficiency caused more severe acute pancreatitis after prolonged cerulein stimulation and promoted chronic pancreatitis after the cerulein-induced acute episode, and in two strains of trypsinogen mutant mice with spontaneous disease. In contrast, acute pancreatitis induced with limited cerulein hyperstimulation was unaffected by heterozygous Spink1 deletion, in agreement with recent observations that trypsin activity does not mediate pathologic responses in this model. Taken together, the findings strongly support the notion that loss-of-function SPINK1 mutations inhumans increase chronic pancreatitis risk in a trypsin-dependent manner.

There is a need for Solid State Power Amplifiers (SSPA's) to be used in High Throughput Satellites (HTS) for commercial applications. Specifically when the amount of information passed through the transponders, i.e. capacity, is determined mainly by the quantity of beams the satellite can generate. This application is well suited for SSPA's over the conventional TWTA solution as they are smaller and lighter weight enabling a simplification of HTS payload architectures, higher density physical integration, and the ability to support active array transmit solutions all of which increases the quantity of beams and thus capacity. More specifically, Gallium Nitride (GaN) Power Amplifiers (PA's) have shown the ability to generate high RF output power levels with small size and high efficiency thereby enabling step function improvement in capacity [1], [2]. This paper will describe a 20GHz fully space qualified GaN PA module developed for KaBand commercial satellite downlinks. The design techniques, test results, and screening regimen required to meet the demanding performance and reliability requirements will be given. The result is a 20GHz module with >55dB of gain, >10W of Pout, >30% peak PAE, and NPR >15dB. To the authors knowledge this is the best fully space-qualified module performance at this frequency published to date.

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Mejoras en el peso de vellón de sucio (PVe) y diámetro medio de la fibra (DMF) favorece los ingresos de los productores de alpacas; sin embargo, estas variables están relacionadas directamente, complicando el mejoramiento simultáneo de ambas características. Por tanto, se requiere buscar nuevos criterios de selección para la mejora simultánea de ambas características. El propósito del estudio fue caracterizar la densidad de fibras (DenFib), densidad de conductos pilosos (DenCond) y la relación N.° de fibras/conductos (R_Fib/Cond) como posibles criterios de selección. Asimismo, determinar el tipo de relación entre ellas y con el PVe y DMF, y construir y evaluar índices de selección formales bajo escenarios con diferentes mediciones disponibles, considerando en todos los casos PVe y DMF debidamente ponderados por sus pesos económicos, como objetivos de selección. Para ello, se tomaron muestras de fibras, imágenes de piel y se registraron el PVe de alpacas de cuatro rebaños criadas en Huancavelica y Caylloma-Arequipa (Perú) entre 2018 y 2020. Las características de densidad fueron obtenidas mediante el procedimiento denominado Fiber Den, mientras que el DMF se evaluó mediante el FIBER EC, y el PVe se registró con una balanza. En la construcción de los índices de selección para PVe y DMF se aplicó la teoría de índices de selección de Hazel, considerando los valores indicados en la bibliografía y en el presente trabajo. La DenFib, DenCon y R_Fib/Cond varía entre 8.8 a 60 fib/mm2, 3.8 a 21.2 cond/mm2 y 2.0 a 4.3 fib/cond, respectivamente. Se encontraron conductos pilosos de hasta 8 fibras, siendo los más frecuentes los conductos con 1, 2 o 3 fibras. Se concluye que la DenFib y DenCond tienen relación lineal y directa con el PVe e inversa con el DMF, y que la inclusión de la DenFib y DenCond como criterios de selección dentro de un índice de selección mejorarían la exactitud de 0.53 a 0.63, pudiéndose obtener mayores progresos genéticos entre 15 y 18%, con mejores beneficios económicos, que cuando solo se utiliza el PVe y DMF.

The objective of the Ground to Space CALibration Experiment (G-SCALE) is to demonstrate the use of convex mirrors as a radiometric and spatial calibration and validation technology for Earth Observation assets, operating at multiple altitudes and spatial scales. Specifically, point sources with NIST-traceable absolute radiance signal are evaluated for simultaneous vicarious calibration of multi- and hyperspectral sensors in the VNIR/SWIR range, aboard Unmanned Aerial Vehicles (UAVs), manned aircraft, and satellite platforms. We introduce the experimental process, field site, instrumentation, and preliminary results of the G-SCALE, providing context for forthcoming papers that will detail the results of intercomparison between sensor technologies and remote sensing applications utilizing the mirror-based calibration approach, which is scalable across a wide range of pixel sizes with appropriate facilities. The experiment was carried out at the Rochester Institute of Technology’s Tait Preserve in Penfield, NY, USA on 23 July 2021. The G-SCALE represents a unique, international collaboration between commercial, academic, and government entities for the purpose of evaluating a novel method to improve vicarious calibration and validation for Earth Observation.

Satellite imagery provides impartial, inclusive, and timely geospatial data regarding global issues, supplementing traditional ground-based methods. The volume, velocity, and variety of satellite imagery present novel capabilities to support the United Nations' Sustainable Development Goals by providing repeatable data to assess progress and support reliable statistics connecting policy with evidence. Currently, the relationship between spatial resolution and accurate detection of sub-meter- to meter-scale objects supporting policy-making remains unexplored. This study investigates the resolution-performance trade-off by comparing results of object detection models and their implications for two sustainability-motivated use cases. These include vehicle detection, used to inform traffic flow and density for understanding infrastructure needs and lockdown policies, and solar panel detection, where accuracy is crucial in monitoring green energy production and sustainable energy access. The results show a largely linear degradation of object detection models using imagery at 30, 40, 50, and 60 cm resolutions simulated from 7 cm aerial imagery. Object detection models using 30 cm imagery improve F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> score by 65% compared to 60 cm models. Further investigation into a pre-processing step using 30 cm imagery to generate 15 cm imagery shows an average F <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1</sub> score increase by 5% for detection of small objects across multiple use cases. The results and analysis provide a basis for more robust investigations into the capabilities of very high resolution satellite imagery to support the Sustainable Development Goals.