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At least 19 records

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NASA NTRS2014

Venus Landsailer Zephyr

Imagine sailing across the hot plains of Venus! A design for a craft to do just this was completed by the COncurrent Multidisciplinary Preliminary Assessment of Space Systems (COMPASS) Team for the NASA Innovative Advanced Concepts (NIAC) project. The robotic craft could explore over 30 kilometers of the surface of Venus, driven by the power of the wind. The Zephyr Venus Landsailer is a science mission concept for exploring the surface of Venus with a mobility and science capability roughly comparable to the Mars Exploration Rovers (MER) mission, but using the winds of the thick atmosphere of Venus for propulsion. It would explore the plains of Venus in the year 2025, near the Venera 10 landing site, where wind velocities in the range of 80 to 120 centimeters per second (cm/s) were measured by earlier Soviet landing missions. These winds are harnessed by a large wing/sail which would also carry the solar cells to generate power. At around 250 kilograms (kg), Zephyr would carry an 8 meter tall airfoil sail (12 square meters area), 25 kg of science equipment (mineralogy, grinder, and weather instruments) and return 2 gigabytes of science over a 30 day mission. Due to the extreme temperatures (450 degrees Centigrade) and pressures (90 bar) on Venus, Zephyr would have only basic control systems (based on high temperature silicon carbide (SiC)electronics) and actuators. Control would come from an orbiter which is in turn controlled from Earth. Due to the time delay from the Earth a robust control system would need to exist on the orbiter to keep Zephyr on course. Data return and control would be made using a 250 megahertz link with the orbiter with a maximum data rate of 2 kilobits per second. At the minimal wind speed required for mobility of 35 cm/s, the vehicle move at a slow but steady 4 cm/s by positioning the airfoil and use of one wheel that is steered for pointing control. Navigation commands from the orbiter will be based upon navigation cameras, simple accelerometers and stability sensors; Zephyr's stability is robust, using a wide wheel base along with controls to "feather" or "luff" the airfoil and apply brakes to stop the vehicle in the case of unexpected conditions. This would be the science gathering configuration. The vehicle itself would need to be made from titanium (Ti) as the structural material, with a corrosion-barrier overcoating due to extreme temperatures on the surface.

Wind Sailing↗

NASA NTRS2014

Zephyr: A Landsailing Rover for Venus

With an average temperature of 450C and a corrosive atmosphere at a pressure of 90 bars, the surface of Venus is the most hostile environment of any planetary surface in the solar system. Exploring the surface of Venus would be an exciting goal, since Venus is a planet with significant scientific mysteries, and interesting geology and geophysics. Technology to operate at the environmental conditions of Venus is under development. A rover on the surface of Venus with capability comparable to the rovers that have been sent to Mars would push the limits of technology in high-temperature electronics, robotics, and robust systems. Such a rover would require the ability to traverse the landscape on extremely low power levels. We have analyzed an innovative concept for a planetary rover: a sail-propelled rover to explore the surface of Venus. Such a rover can be implemented with only two moving parts; the sail, and the steering. Although the surface wind speeds are low (under 1 m/s), at Venus atmospheric density even low wind speeds develop significant force. Under funding by the NASA Innovative Advanced Concepts office, a conceptual design for such a rover has been done. Total landed mass of the system is 265 kg, somewhat less than that of the MER rovers, with a 12 square meter rigid sail. The rover folds into a 3.6 meter aeroshell for entry into the Venus atmosphere and subsequent parachute landing on the surface. Conceptual designs for a set of hightemperature scientific instruments and a UHF communication system were done. The mission design lifetime is 50 days, allowing operation during the sunlit portion of one Venus day. Although some technology development is needed to bring the high-temperature electronics to operational readiness, the study showed that such a mobility approach is feasible, and no major difficulties are seen.

rover↗

NASA NTRS2019

NASA Innovative Advanced Concepts (NIAC) Phase 1 Final Report: Venus Landsailer Zephyr

Landis, Geoffrey A.↗

DOE OSTI2021

Firmware Re-hosting Support for Zephyr RTOS.

Abstract not provided.

Beardall, Chad↗

DOE OSTI2023

Moving Beyond Mortality: Development and Application of a Desirability of Outcome Ranking (DOOR) Endpoint for Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia

Abstract Background Hospital-acquired and ventilator-associated bacterial pneumonia (HABP/VABP) are frequently caused by multidrug-resistant organisms. Patient-centered endpoints in clinical trials are needed to develop new antibiotics for HABP/VABP. Desirability of outcome ranking (DOOR) is a paradigm for the design, analysis, and interpretation of clinical trials based on a patient-centered, benefit-risk evaluation. Methods A multidisciplinary committee created an infectious diseases DOOR endpoint customized for HABP/VABP, incorporating infectious complications, serious adverse events, and mortality. We applied this to 2 previously completed, large randomized controlled trials for HABP/VABP. ZEPHyR compared vancomycin to linezolid and VITAL compared linezolid to tedizolid. For each trial, we evaluated the DOOR distribution and probability, including DOOR component and partial credit analyses. We also applied DOOR in subgroup analyses. Results In both trials, the HABP/VABP DOOR demonstrated similar overall clinical outcomes between treatment groups. In ZEPHyR, the probability that a participant treated with linezolid would have a more desirable outcome than a participant treated with vancomycin was 50.2% (95% confidence interval [CI], 45.1%−55.3%). In VITAL, the probability that a participant treated with tedizolid would have a more desirable outcome than a participant treated with linezolid was 48.7% (95% CI, 44.8%–52.6%). The DOOR component analysis revealed that participants treated with tedizolid had a less desirable outcome than those treated with linezolid when considering clinical response alone. However, participants with decreased renal function had improved overall outcomes with tedizolid. Conclusions The HABP/VABP DOOR provided more granular information about clinical outcomes than is typically presented in clinical trials. HABP/VABP trials would benefit from prospectively using DOOR.

Immunology↗

NASA NTRS2024

DAVINCI: Venus Atmospheric Model Comparisons

The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging(DAVINCI) mission aims to answer long-standing questions regarding Venus’ origin using Zephyr, an atmospheric descent probe. Zephyr will be the first probe to take high-resolution aerial photographs of a mountainous tesserae surface as it descends over the Alpha Regio highlands region, which has the oldest surfaces of Venus. The Zephyr’s descent trajectory that determines the touchdown in the Alpha Regio, which is crucial for the DAVINCI mission, depends on Venus’ atmospheric properties and winds. Unfortunately, the atmospheric data for Venus from previous missions is sparse. Therefore, it is essential to consider various atmospheric models and scenarios from past flight data to predict Zephyr’s flight performance, specifically landing ellipse. To this end, this work compares three atmospheric models: the Venus Global Reference Atmospheric Model (Venus-GRAM), the Venus Climate Database(VCD), and an empirical wind model developed by Ralph Lorenz for the DAVINCI trajectory simulation and modeling. This paper compares the mean and variations of different atmospheric properties and winds from these atmospheric models. In addition, this work combines the atmospheric properties and the wind variability from the Venus-GRAM with the winds from the Lorenz-based model to have more stressing Venus wind dispersions that allow for more conservative trajectory analysis. Furthermore, this work relies on the DAVINCI landing ellipse size as a metric to measure how robust the trajectory analysis will be to the change in the atmospheric properties and winds of the Venus atmosphere.

Pardha Sai Chadalavada↗

DOE OSTI2023

2022 Prototype Installation and Testing Awardee: Windward Engineering

The 60-kilowatt (kW) Zephyr 21/60 wind turbine from Windward Engineering uses a low-cost, full-span independent pitch system that can act as a redundant aerodynamic braking system. This design uses a relatively simple pneumatic rotary vane actuator, allowing each of the turbine's three blades to be pitched independently and any single blade to activate emergency braking for the entire turbine. A previous Competitiveness Improvement Project (CIP) funding award enabled Windward Engineering to design and develop the Zephyr 21/60 wind turbine's aeroelastic model and pitch system. At the end of this current Competitiveness Improvement Project award, a fully validated aeroelastic model will make it possible to certify Windward Engineering's Zephyr 21/60 design and quantify the technology's levelized cost of energy in preparation for certification and entry into the distributed wind market. The Zephyr 21/60 will feature an attractive levelized cost of energy, improved reliability, and a full-span pitch system for safe and redundant protection against rotor overspeed (which occurs when the rotor turns beyond its design limit).

CIP↗

NASA NTRSDate not supplied

Entry, Descent, and Landing Simulation for DAVINCI

The Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging(DAVINCI) mission is currently scheduled to launch in June 2029 to explore Venus via two flybys and a probe descent scheduled for June 2031. The goals of this mission is to study the origin, evolution, and current state of Venus, especially the deep Venusian atmosphere using an atmospheric probe named Zephyr. The Zephyr will take key measurements in the deep atmosphere of Venus and be the first probe to take high-resolution aerial photographs of a mountainous tesserae surface as it descends over the Alpha Regio highlands region, which has the oldest surfaces of Venus. The Zephyr’s descent trajectory, which determines the flight over the Alpha Regio, is crucial to meet the science objectives of the DAVINCI mission. To ensure the success of the DAVINCI mission, the Entry, Descent, and Landing (EDL) modeling has undergone several developments to track its trajectory, its uncertainties, and calculate metrics on the science data that can be transmitted. This paper will cover these developments and the current status of the EDL modeling.

davinci↗

DOE OSTI2025

Comparing three generations of D-Wave quantum annealers for minor embedded combinatorial optimization problems

Abstract Quantum annealing (QA) is a novel type of analog computation that aims to use quantum mechanical fluctuations to search for optimal solutions of Ising problems. QA in the transverse Ising model, implemented on D-Wave quantum processing units, are available as cloud computing resources. In this study we report concise benchmarks across three generations of D-Wave quantum annealers, consisting of four different devices, for the NP-hard discrete combinatorial optimization problems unweighted maximum clique and unweighted maximum cut on random graphs. The Ising, or equivalently quadratic unconstrained binary optimization, formulation of these problems do not require auxiliary variables for order reduction, and their overall structure and weights are not highly variable, which makes these problems simple test cases to understand the sampling capability of current D-Wave quantum annealers. All-to-all minor embeddings of size 52, with relatively uniform chain lengths, are used for a direct comparison across the Chimera, Pegasus, and Zephyr device topologies. A grid-search over annealing times and the minor embedding chain strengths is performed in order to determine the level of reasonable performance for each device and problem type. Experiment metrics that are reported are approximation ratios for non-broken chain samples, chain break proportions, and time-to-solution for the maximum clique problem instances. How fairly the quantum annealers sample optimal maximum cliques, for instances which contain multiple maximum cliques, is quantified using entropy of the measured ground state distributions. The newest generation of quantum annealing hardware, which has a Zephyr hardware connectivity, performed the best overall with respect to approximation ratios and chain break frequencies.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS2024

Wind Tunnel Test of A Scale Model of A Venus Probe to Determine Aeroacoustics Environment

The Zephyr probe for NASA’s DAVINCI project is being designed to fly to Venus and collect measurements to characterize the Venusian atmosphere while it descends towards the surface. Despite a slow descent speed as the probe approaches the surface, the very dense atmosphere means the vibro-acoustic environment that the probe must withstand could be very harsh. A wind tunnel test campaign was conducted to characterize the surface-pressure fluctuations (acoustics) on the external surface of the probe during the descent. The goal was to provide forcing functions for vibro-acoustic analysis of all instruments inside the probe. A 25% scale-model of the Zephyr probe was manufactured, instrumented with 18 microphones, and tested in two wind tunnels located in the Fluid Mechanics Lab at NASA Ames Research Center at velocities ranging from 13 m/s to 48 m/s. Trip strips were added to the model to ensure a turbulent boundary layer on the model. Microphones were located appropriately to provide spectra of pressure fluctuations in regions with different flow characteristics as well as for calculating various two-point statistics. The acoustic spectra measured in the wind tunnel tests were scaled up to flight-scale using the estimated flight trajectory information. Besides fluctuating surface-pressure measurements, hot-film velocity measurements as well as smoke-laser flow visualization were conducted to better understand the flow around the probe. Lastly, several different geometry configurations were tested to see whether any reduction in acoustic levels could be achieved, but none of the configurations that were tested offered significant improvements. The flow visualization showed 3 primary flow regimes on the model: an attached turbulent boundary layer on the front of the model, a region of separated flow upstream of the flared lip, and a large, separated wake at the rear of the model. The acoustic spectra generally show three different shapes corresponding to these flow regions, with the highest levels seen at the rear of the model, and directly in front of the drag plate. The scaled overall levels of pressure fluctuations were found to be high: in the range of 130dB to 155dB.

planetary probe↗

DOE OSTI2025

Increasing the hardness of posiform planting using random QUBOs for programmable quantum annealer benchmarking

Posiform planting is a method for constructing QUBO instances with a unique planted solution that can be tailored to arbitrary connectivity graphs. In this study we investigate making posiform planted QUBOs computationally harder by fusing many smaller random Ising models, whose global minimum is computed classically, with posiform planted QUBOs. The unique ground state of the resulting QUBO is the concatenation of (exactly one of) the ground states of each smaller problem. Our method generates QUBO instances that have a unique solution, are native to the hardware graph, and have tunable computational hardness. We use our QUBOs to benchmark three D-Wave quantum annealing processors (with 563–5627 qubits), and compare them against simulated annealing and Gurobi. Surprisingly, we find that the D-Wave ground state sampling success rate is not dependent on the glued random QUBO size, and that some QUBO classes are solved at high success rates at short annealing times on the Zephyr processors.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2022

Computed Tomography Scanning and Geophysical Measurements of State 16-2 Well in the Paradox Basin

The computed tomography (CT) facilities and the Multi-Sensor Core Logger (MSCL) at the National Energy Technology Laboratory (NETL) in Morgantown, West Virginia, were used to characterize Paradox Basin core from Grand County, Utah. The primary impetus of this work is a collaboration between the U.S. Department of Energy (DOE), the Utah Geological Survey, the University of Utah, and Zephyr Energy to characterize and make publicly available core information from the Cane Creek interval of the Paradox Basin. This stratigraphic well and the core data produced in this report will aid in understanding the structural complexities of the Cane Creek interval and its production potential.

58 GEOSCIENCES↗

DOE OSTI2023

Posiform planting: generating QUBO instances for benchmarking

We are interested in benchmarking both quantum annealing and classical algorithms for minimizing quadratic unconstrained binary optimization (QUBO) problems. Such problems are NP-hard in general, implying that the exact minima of randomly generated instances are hard to find and thus typically unknown. While brute forcing smaller instances is possible, such instances are typically not interesting due to being too easy for both quantum and classical algorithms. In this contribution, we propose a novel method, called posiform planting , for generating random QUBO instances of arbitrary size with known optimal solutions, and use those instances to benchmark the sampling quality of four D-Wave quantum annealers utilizing different interconnection structures (Chimera, Pegasus, and Zephyr hardware graphs) and the simulated annealing algorithm. Posiform planting differs from many existing methods in two key ways. It ensures the uniqueness of the planted optimal solution, thus avoiding groundstate degeneracy, and it enables the generation of QUBOs that are tailored to a given hardware connectivity structure, provided that the connectivity is not too sparse. Posiform planted QUBOs are a type of 2-SAT boolean satisfiability combinatorial optimization problems. Our experiments demonstrate the capability of the D-Wave quantum annealers to sample the optimal planted solution of combinatorial optimization problems with up to 5, 627 qubits.

97 MATHEMATICS AND COMPUTING↗

NASA NTRS1988

Global meteorological data facility for real-time field experiments support and guidance

A Global Meteorological Data Facility (GMDF) has been constructed to provide economical real-time meteorological support to atmospheric field experiments. After collection and analysis of meteorological data sets at a central station, tailored meteorological products are transmitted to experiment field sites using conventional ground link or satellite communication techniques. The GMDF supported the Global Tropospheric Experiment Amazon Boundary Layer Experiment (GTE-ABLE II) based in Manaus, Brazil, during July and August 1985; an arctic airborne lidar survey mission for the Polar Stratospheric Clouds (PSC) experiment during January 1986; and the Genesis of Atlantic Lows Experiment (GALE) during January, February and March 1986. GMDF structure is similar to the UNIDATA concept, including meteorological data from the Zephyr Weather Transmission Service, a mode AAA GOES downlink, and dedicated processors for image manipulation, transmission and display. The GMDF improved field experiment operations in general, with the greatest benefits arising from the ability to communicate with field personnel in real time.

Shipham, Mark C.↗

NASA NTRS1998

Capacitively Stabilized Etalon Technology for Spaceborne Wind Lidar Application

Global monitoring by satellites is important for many types of environmental studies. Among these, the wind field is the single most important atmospheric state variable required for understanding atmospheric motion and predicting weather. Studies indicate that a global determination of the tropospheric wind field to an accuracy of 1-5 m/sec is critical for improved numerical weather forecasting. This measurement could be carried out with a spaceborne lidar system sensing the Doppler shift of a laser signal backscattered from the atmosphere. Over the past four years we have developed a ground-based Edge Technique lidar system and demonstrated wind measurements through the troposphere with high accuracy (1-6 m/s) and high spatial resolution. Recently, we began the design of a shuttle based wind measurement system for technology demonstration as part of the Zephyr program. In this paper, we present the characteristics of the high spectral resolution etalon filter technology for lidar wind measurement with the Edge Technique. In conclusion, a spacecraft motion compensation method has been discussed. We demonstrated experimentally that the etalon can be tuned to compensate for any satellite induced Doppler shift to an accuracy of better than 0.6 m/s over a time period of 2.5 ms.

Li, Steven X.↗

NASA NTRS2011

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes.

Gaier, James R.↗

NASA NTRS2011

Evaluation of Brushing as a Lunar Dust Mitigation Strategy for Thermal Control Surfaces

Evaluation of brushing to remove lunar simulant dust from thermal control surfaces is described. First, strip brushes made with nylon, PTFE, or Thunderon (Nihon Sanmo Dyeing Company Ltd.) bristles were used to remove JSC-1AF dust from AZ93 thermal control paint or aluminized FEP (AlFEP) thermal control surface under ambient laboratory conditions. Nylon and PTFE bristles removed a promising amount of dust from AZ93, and nylon and Thunderon bristles from AlFEP. But when these were tested under simulated lunar conditions in the lunar dust adhesion bell jar (LDAB), they were not effective. In a third effort, seven brushes made up of three different materials, two different geometries, and different bristle lengths and thicknesses were tested under laboratory conditions against AZ93 and AlFEP. Two of these brushes, the Zephyr fiberglass fingerprint brush and the Escoda nylon fan brush, removed over 90 percent of the dust, and so were tested in the fourth effort in the LDAB. They also performed well under these conditions recovering 80 percent or more of the original thermal performance (solar absorptance/thermal emittance) of both AZ93 and AgFEP after 20 strokes, and 90 or more percent after 200 strokes

Gaier, James R.↗

NASA NTRS2012

Psychophysiological Assessment of Fatigue in Commercial Aviation Operations

The overall goal of this study is to improve our understanding of crew work hours, workload, sleep, fatigue, and performance, and the relationships between these variables on actual flight deck performance. Specifically, this study will provide objective measures of physiology and performance, which may benefit investigators in identifying fatigue levels of operators in commercial aviation and provide a way to better design strategies to limit crew fatigue. This research was supported by an agreement between NASA Ames Research Center and easyJet Airline Company, Ltd., Luton, UK. Twenty commercial pilots volunteered to participant in the study that included 15 flight duty days. Participants wore a Zephyr Bioharness ambulatory physiological monitor each flight day, which measured their heart rate, respiration rate, skin temperature, activity and posture. In addition, pilots completed sleep log diaries, self-report scales of mood, sleepiness and workload, and a Performance Vigilance Task (PVT). All data were sent to NASA researchers for processing and analyses. Heart rate variability data of several subjects were subjected to a spectral analysis to examine power in specific frequency bands. Increased power in low frequency band was associated with reports of higher subjective sleepinesss in some subjects. Analyses of other participants data are currently underway.

Hernandez, Norma↗