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NASA NTRS2010

The VASIMR[registered trademark] VF-200-1 ISS Experiment as a Laboratory for Astrophysics

The VASIMR[R] Flight Experiment (VF-200-1) will be tested in space aboard the International Space Station (ISS) in about four years. It will consist of two 100 kW parallel plasma engines with opposite magnetic dipoles, resulting in a near zero-torque magnetic system. Electrical energy will come from ISS at low power level, be stored in batteries and used to fire the engine at 200 kW. The VF-200-1 project will provide a unique opportunity on the ISS National Laboratory for astrophysicists and space physicists to study the dynamic evolution of an expanding and reconnecting plasma loop. Here, we review the status of the project and discuss our current plans for computational modeling and in situ observation of a dynamic plasma loop on an experimental platform in low-Earth orbit. The VF-200-1 project is still in the early stages of development and we welcome new collaborators.

Glover Tim W.↗

NASA NTRSDate not supplied

M2-SCREAM: A Stratospheric Composition Reanalysis of Aura MLS

Stratospheric composition and transport patterns are changing because of increasing greenhouse gas concentrations and declining levels of ozone depleting substances. Superimposed on forced trends are: dynamical variability at a range of time scales and unforeseen perturbations such as those resulting from injections of volcanic material and smoke from PyroCb events. Chemical reanalyses can be powerful tools for studying the composition of the stratosphere and disentangling forced responses from internal variability. This presentation introduces a new chemical reanalysis of stratospheric constituents developed and produced at NASA’s Global Modeling and Assimilation Office (GMAO) using the recently developed GMAO Constituent Data Assimilation System. Called the MERRA-2 Stratospheric Composition Reanalysis with Aura MLS (M2-SCREAM), this reanalysis consists of assimilated global three-dimensional fields of stratospheric ozone, water vapor, hydrogen chloride (HCl), nitric acid (HNO3) and nitrous oxide (N2O) mixing ratios and covers the period since the beginning of MLS observations in September 2004 to the present. M2-SCREAM assimilates version 4.2 MLS profiles of the five constituents alongside total ozone column from the Ozone Monitoring Instrument. The dynamics and tropospheric water vapor are constrained by assimilated meteorological fields from MERRA-2. The assimilated constituent fields and meteorology are provided to users at a 50-km horizontal resolution and a three-hourly frequency. Monthly analysis uncertainties and flags are also provided to the users. M2-SCREAM is an accurate and dynamically consistent high-resolution data record of the five constituents, all of which are of primary importance to stratospheric chemistry and transport studies. We will present a description of M2-SCREAM and selected results of a process-based evaluation of this product using independent data. As an illustration, we will discuss the perturbation to stratospheric composition from the eruption of Hunga Tonga–Hunga Ha'apai in January 2022 as seen in the reanalysis. We will also propose potential scientific applications of M2-SCREAM and outline plans for an upcoming comprehensive composition reanalysis that is being developed at NASA GMAO.

MERRA-2↗

NASA NTRS2008

Ares I-X Flight Test--The Future Begins Here

In less than one year, the National Aeronautics and Space Administration (NASA) will launch the Ares I-X mission. This will be the first flight of the Ares I crew launch vehicle, which, together with the Ares V cargo launch vehicle, will send humans to the Moon and beyond. Personnel from the Ares I-X Mission Management Office (MMO) are finalizing designs and fabricating vehicle hardware for a 2009 launch. Ares I-X will be a suborbital development flight test that will gather critical data about the flight dynamics of the integrated launch vehicle stack; understand how to control its roll during flight; better characterize the severe stage separation environments that the upper stage engine will experience during future flights; and demonstrate the first stage recovery system. NASA also will modify the launch infrastructure and ground and mission operations. The Ares I-X Flight Test Vehicle (FTV) will incorporate flight and mockup hardware similar in mass and weight to the operational vehicle. It will be powered by a four-segment Solid Rocket Booster (SRB), which is currently in Shuttle inventory, and will include a fifth spacer segment and new forward structures to make the booster approximately the same size and weight as the five-segment SRB. The Ares I-X flight profile will closely approximate the flight conditions that the Ares I will experience through Mach 4.5, up to approximately 130,000 feet (39,600 meters (m)) and through maximum dynamic pressure ('Max Q') of approximately 800 pounds per square foot (38.3 kilopascals (kPa)). Data from the Ares I-X flight will support the Ares I Critical Design Review (CDR), scheduled for 2010. Work continues on Ares I-X design and hardware fabrication. All of the individual elements are undergoing CDRs, followed by a two-part integrated vehicle CDR in March and July 2008. The various hardware elements are on schedule to begin deliveries to Kennedy Space Center (KSC) in early September 2008. Ares I-X is the first step in the long journey to the Moon and farther destinations. This suborbital test will be NASA's first flight of a new human-rated launch vehicle in more than a generation. This promises to be an exciting time for NASA and the nation, as we reach for new goals in space exploration. A visual presentation is included.

Davis, Stephan R.↗

NASA NTRS1984

A new multifunction acousto-optic signal processor

An acousto-optic architecture for simultaneously obtaining time integration correlation and high-speed power spectrum analysis was constructed using commercially available TeO2 modulators and photodiode detector-arrays. The correlator section of the processor uses coherent interferometry to attain maximum bandwidth and dynamic range while achieving a time-bandwidth product of 1 million. Two correllator outputs are achieved in this system configuration. One is optically filtered and magnified 2 : 1 to decrease the spatial frequency to a level where a 25-MHz bandwidth may be sampled by a 62-mm array with elements on 25-micro centers. The other output is magnified by a factor of 10 such that the center 4 microseconds of information is available for estimation of time-difference-of-arrival to within 10 ns. The Bragg cell spectrum-analyzer section, which also has two outputs, resolves a 25-MHz instantaneous bandwidth to 25 kHz and can determine discrete-frequency reception time to within 15 microseconds. A microprocessor combines spectrum analysis information with that obtained from the correlator.

Berg, N. J.↗

NASA NTRS1989

LACE flight dynamics experiment

The Low Power Atmospheric Compensation Experiment (LACE) is scheduled for launch in late 1989 into a 556 km altitude circular orbit of 43 deg inclination. The LACE flight dynamics experiment is an experiment secondary to the primary LACE mission. The purpose of the experiment is to provide on-orbit systems identification of the LACE spacecraft. The structure of the LACE spacecraft is of special interest to the CSI community. It incorporates 3 deployable/retractable booms of maximum length 45.72 m (150 ft) mounted on a rectangular parallelepiped bus of mass 1,200 kg. The zenith directed gravity gradient boom is mounted on the top of the bus; the retroreflector boom is mounted forward and deployed along the velocity vector, the balance boom is mounted and pointed aft. Attitude stabilization is accomplished by means of gravity gradient torques and by a momentum wheel. The LACE flight dynamics experiment is designed to measure modal frequencies, damping ratios, and oscillation amplitudes of the LACE spacecraft, as well as the vibration intensity generated by boom deployments and retractions. It is anticipated that this experiment will provide an opportunity for improvements in the accuracy of computer simulations of flexible structures and multibody dynamics.

Fisher, Shalom↗

NASA NTRS1999

Fractal fluctuations in cardiac time series

Human heart rate, controlled by complex feedback mechanisms, is a vital index of systematic circulation. However, it has been shown that beat-to-beat values of heart rate fluctuate continually over a wide range of time scales. Herein we use the relative dispersion, the ratio of the standard deviation to the mean, to show, by systematically aggregating the data, that the correlation in the beat-to-beat cardiac time series is a modulated inverse power law. This scaling property indicates the existence of long-time memory in the underlying cardiac control process and supports the conclusion that heart rate variability is a temporal fractal. We argue that the cardiac control system has allometric properties that enable it to respond to a dynamical environment through scaling.

NASA Discipline Cardiopulmonary↗

NASA NTRS2009

Microdosimeter Instrument (MIDN-II) for Personnel Dosimetry

This group of collaborators has been funded, by the National Space Biomedical Research Institute (NSBRI) and the U. S. National Aeronautics and Space Administration (NASA) as of February, 2009 to develop a prototypic dosimeter/microdosimeter instrument that measures in real time the radiation risk to personnel in a time varying radiation field of possibly unknown composition. The microdosimetric detectors will be solid-state devices more compact, more rugged than conventional microdosimetric proportional counters used previously in space and will consume less power. The proposed detector will be based on the heritage of the MIDN-MidSTAR microdosimeter launched on the MidSTAR spacecraft on March, 2007, the only solid-state microdosimeter ever flown in space. The system will be suitable for measurements in spacesuits, spacecrafts, remote rovers, or other dynamic or static environments. Measurements as a function of time will not only provide the instantaneous and average absorbed physical dose but also corresponding microdosimetric spectra, dose rates, the dose equivalents, and the dose equivalent rates. Values of the dose equivalents are used to establish relative risks for humans exposed to radiation and to determine regulatory limits. Because these parameters will be available to the astronauts and mission control in real time, these systems can be used not only to quantify exposures and limits, but also to allow appropriate actions to be taken to reduce radiation exposures and their consequences. Earlier prototypes have been used successfully to characterize beams of energetic protons and heavier ions including carbon, oxygen, silicon, titanium, and iron at the NASA Space Radiation Laboratory at Brookhaven National Laboratory. The initial design will be presented and discussed and spectra will be presented.

Pisacane, V. L.↗

NASA NTRS2019

Experimental Forward Flight Rotor Performance Testing from Terrestrial to Martian Atmospheric Densities

With the recent interest in Martian exploration using Unmanned Aerial Vehicles (UAV), an experimental study was conducted to investigate rotor performance at Martian atmospheric conditions. Both simulation and testing of rotors is vital for the evaluation of performance and behavior of rotor, especially for operations at Martian atmospheric densities and pressures. Testing and measuring rotor forward flight performance at Martian atmospheric conditions is a relatively unexplored area. Therefore, an experimental study was performed in a wind tunnel to investigate helicopter forward flight performance and to demonstrate successful rotor operation at Martian atmospheric densities. This work was a continuation of the first ever wind tunnel test of a simulated rotorcraft in forward flight at Martian atmospheric densities. A test was conducted in a facility, which could be evacuated to the atmospheric pressure and density of Mars. A 40-in diameter rotor, roughly approximating the scale of the proposed Mars Helicopter design by the NASA Jet Propulsion Laboratory (JPL), was tested in forward flight at Mars atmospheric pressure at the NASA Ames Planetary Aeolian Laboratory (PAL). In this forward flight testing, the drive system of the Martian Surface Wind Tunnel (MARSWIT) was never turned on. The goal of this experiment was to collect rotor thrust, rotational speed, power, torque, and wind speed measurements. Subsequently, these results can be used for correlation with simulated cases using a mid-fidelity Computational Fluid Dynamics (CFD) simulation. Rotor thrust and power seem to decrease approximately proportional to the decrease in density. However, the Reynolds number has an effect on rotor performance that might also be contributing to the change in thrust and power. This effect plays a vital role in rotor performance at reduced pressure that cannot be neglected in the simulation. Despite the challenges involved in testing at a large difference of atmospheric densities between Earth and Mars, repeatable data is obtained in all the measurements at Martian atmospheric conditions.

Martian↗

NASA NTRS2021

SMD Technology Highlights

Six technology highlights from the Science Mission Directorate (SMD) Heliophysics, Astrophysics, Earth, and Biological and Physical Sciences divisions. Technologies featured include 1. the 1653 m2 Solar Cruiser Solar Sail Propulsion system to enable missions to reach novel and otherwise difficult or impossible destinations for observing the Sun. 2. Technology sponsored by NASA and developed by MIT Space Nanotechnology Lab is developing high-performance space instrumentation for more powerful future X-ray telescopes that will study the dynamics of the high-energy universe. 3. Active thermal control technology that will help enable large ultra-stable telescopes needed to detect and characterize Earth-like planets around other stars. 4. SMD sponsored high-performance infrared sensors with reduced requirements for cooling onboard satellites and these sensors could potentially be flown on small satellite platforms like CubeSats. 5. A new technology that will utilize electron beams/ultraviolet light to remove dust that could help protect future space assets and astronauts from dangerous effects that arise from Moon/Mars dust exposure. 6. Studies using model organisms on ISS to understand the impact of the spaceflight environment on organisms in preparation for long-duration missions.

solar sail↗

NASA NTRS1997

Identification of Rotorcraft Structural Dynamics from Flight and Wind Tunnel Data

Excessive vibration remains one one of the most difficult problems that faces the helicopter industry today, affecting all production helicopters at some phase of their development. Vibrations in rotating structures may arise from external periodic dynamic airloads whose frequencies are are close to the natural frequencies of the rotating system itself. The goal for the structures engineer would thus be to design a structure as free from resonance effects as possible. In the case of a helicopter rotor blade these dynamic loads are a consequence of asymmetric airload distribution on the rotor blade in forward flight, leading to a rich collection of higher harmonic airloads that force rotor and airframe response. Accurate prediction of the dynamic characteristics of a helicopter rotor blade will provide the opportunity to affect in a positive manner noise intensity, vibration level, durability, reliability and operating costs by reducing objectionable frequencies or moving them to a different frequency range and thus providing us with a lower vibration rotor. In fact, the dynamic characteristics tend to define the operating limits of a rotorcraft. As computing power has increased greatly over the last decade, researchers and engineers have turned to analyzing the vibrational characteristics of aerospace structures at the design and development stage of the production of an aircraft. Modern rotor blade construction methods lead to products with low mass and low inherent damping so careful design and analysis is required to avoid resonance and an undesirable dynamic performance. In addition, accurate modal analysis is necessary for several current approaches in elastic system identification and active control.

McKillip, Robert M., Jr.↗

NASA NTRS2007

High Fidelity Thermal Simulators for Non-Nuclear Testing: Analysis and Initial Results

Non-nuclear testing can be a valuable tool in the development of a space nuclear power system, providing system characterization data and allowing one to work through various fabrication, assembly and integration issues without the cost and time associated with a full ground nuclear test. In a non-nuclear test bed, electric heaters are used to simulate the heat from nuclear fuel. Testing with non-optimized heater elements allows one to assess thermal, heat transfer, and stress related attributes of a given system, but fails to demonstrate the dynamic response that would be present in an integrated, fueled reactor system. High fidelity thermal simulators that match both the static and the dynamic fuel pin performance that would be observed in an operating, fueled nuclear reactor can vastly increase the value of non-nuclear test results. With optimized simulators, the integration of thermal hydraulic hardware tests with simulated neutronie response provides a bridge between electrically heated testing and fueled nuclear testing, providing a better assessment of system integration issues, characterization of integrated system response times and response characteristics, and assessment of potential design improvements' at a relatively small fiscal investment. Initial conceptual thermal simulator designs are determined by simple one-dimensional analysis at a single axial location and at steady state conditions; feasible concepts are then input into a detailed three-dimensional model for comparison to expected fuel pin performance. Static and dynamic fuel pin performance for a proposed reactor design is determined using SINDA/FLUINT thermal analysis software, and comparison is made between the expected nuclear performance and the performance of conceptual thermal simulator designs. Through a series of iterative analyses, a conceptual high fidelity design can developed. Test results presented in this paper correspond to a "first cut" simulator design for a potential liquid metal (NaK) cooled reactor design that could be applied for Lunar surface power. Proposed refinements to this simulator design are also presented.

Bragg-Sitton, Shannon M.↗

NASA NTRS1981

Plasma dynamics in the rapidly rotating magnetosphere of Jupiter

The major Voyager findings concerning the low energy plasma in the Jovian magnetosphere are reviewed. The magnetosphere of Jupiter is unique in the solar system because of its large extent and rapid rotation, and because of the prodigious source of plasma provided by the satellite Io. Io injects 10 to the 29th power AMU/sec of freshly ionized material into the Jovian magnetosphere, producing a plasma dominated by heavy ions which are mostly various ionization states of oxygen and sulfur. This injected material is the source for the Io plasma torus, which is centered at Io's L-shell with a scale height of 1 Jovian radii and a mass of approximately 10 to the 36th power AMU. Ninety percent of the injected plasma diffuses outward, forming the Jovian magnetodisk. Io interacts with the plasma torus via the generation of an Alfven wave which propagates from Io into the ionosphere of Jupiter, carrying an energy flux of approximately 10 to the 12th power watts.

Belcher, J. W.↗

NASA NTRSDate not supplied

Design and Testing of a Prototype Electrodynamic Regolith Conveyor for Lunar ISRU

NASA’s Swamp Works Electrostatics and Surface Physics Laboratory (ESPL) is developing a 4-phaseelectrodynamic regolith conveyor (ERC) that could convey regolith without the risk of rotating or vibratory actuation, which could jam or require regular maintenance due to the abrasive nature of lunar regolith. Another goal of electrodynamic conveying is the reduction of conveying power, which is important considering the limited capacity of early-stage lunar power systems. The current state of the art(SOA) for lunar regolith conveying is based on recent NASA system studies for oxygen production plants. These plant designs require conveying rates around 100 kg/hr, to produce 10 mT/yr of oxygen from the regolith. To accomplish this, conventional augers and vibratory spiral conveyors have been identified as the SOA or the leading candidates due to their extensive use in the terrestrial material handling industry. At NASA KSC, the use of dynamic electric fields, generated by alternating high voltage on electrodes, has been developed as a dust mitigation solution known as the Electrodynamic Dust Shield (EDS). The EDS is being developed for lenses, solar panels, radiators, fabric and seals and is scheduled for a technology demonstration mission on the Moon in 2023. ESPL researchers have shown the ability to move thin layers (~ a few mm) of dust with mW of power. In Academia, researchers have shown the ability to electrodynamically convey regolith up to ~1 kg/hr with a 4-phase EDS and electromagnetically convey particles that would suggest a lunar regolith conveying rate of ~25 kg/hr. This paper will describe the design and testing of a prototype ERC that could scale to support transporting regolith at ISRU relevant flow rates.

Aaron D S Olson↗

NASA NTRSDate not supplied

Design and Testing of a Prototype Electrodynamic Regolith Conveyor For Lunar ISRU

NASA’s Kennedy Space Center’s (KSC) Swamp Works Electrostatics and Surface Physics Laboratory (ESPL) is developing a 4-phase Electrodynamic Regolith Conveyor (ERC) that could convey regolith without the risk of rotating or vibratory actuation, which could jam or require regular maintenance due to the abrasive nature of lunar regolith. Another goal of electrodynamic conveying is the reduction of conveying power, which is important considering the limited capacity of early-stage lunar power systems. The current state of the art (SOA) for lunar regolith conveying is based on recent NASA system studies for oxygen production plants. These plant designs require conveying rates around 100 kg/hr, to produce 10 mT/yr of oxygen from the regolith. To accomplish this, conventional augers and vibratory spiral conveyors have been identified as the SOA or the leading candidates due to their extensive use in the terrestrial material handling industry. At NASA KSC, the use of dynamic electric fields, generated by alternating high voltage on electrodes, has been developed as a dust mitigation solution known as the Electrodynamic Dust Shield (EDS). The EDS is being developed for lenses, solar panels, radiators, fabric and seals and is scheduled for a technology demonstration mission on the Moon in 2023. ESPL researchers have shown the ability to move thin layers (a few mm) of dust with mW of power. In Academia, researchers have shown the ability to electrodynamically convey regolith up to 1 kg/hr with a 4-phase EDS. This paper will describe the design and testing of a prototype ERC that could scale to support transporting regolith at ISRU relevant flow rates.

Conveyor↗

NASA NTRSDate not supplied

Design and Testing of a Prototype Electrodynamic Regolith Conveyor for Lunar ISRU

Lunar↗

NASA NTRS2008

A Multi-Scale Modeling System with Unified Physics

Numerical cloud models, which are based the non-hydrostatic equations of motion, have been extensively applied to cloud-scale and mesoscale processes during the past four decades. Because cloud-scale dynamics are treated explicitly, uncertainties stemming from convection that have to be parameterized in (hydrostatic) large-scale models are obviated, or at least mitigated, in cloud models. Global models will use the non-hydrostatic framework when their horizontal resolution becomes about 10 km, the theoretical limit for the hydrostatic approximation. This juncture will be reached one to two decades from now. In recent years, exponentially increasing computer power has extended cloud-resolving-mode1 integrations from hours to months, the number of computational grid points from less than a thousand to close to ten million. Three-dimensional models are now more prevalent. Much attention is devoted to precipitating cloud systems where the crucial 1-km scales are resolved in horizontal domains as large as 10,000 km in two-dimensions, and 1,000 x 1,000 km2 in three-dimensions. Cloud resolving models now provide statistical information useful for developing more realistic physically based parameterizations for climate models and numerical weather prediction models. It is also expected that NWP and mesoscale model can be run in grid size similar to cloud resolving model through nesting technique.

Tao, Wei-Kuo↗

NASA NTRS2002

An Illumination Modeling System for Human Factors Analyses

Seeing is critical to human performance. Lighting is critical for seeing. Therefore, lighting is critical to human performance. This is common sense, and here on earth, it is easily taken for granted. However, on orbit, because the sun will rise or set every 45 minutes on average, humans working in space must cope with extremely dynamic lighting conditions. Contrast conditions of harsh shadowing and glare is also severe. The prediction of lighting conditions for critical operations is essential. Crew training can factor lighting into the lesson plans when necessary. Mission planners can determine whether low-light video cameras are required or whether additional luminaires need to be flown. The optimization of the quantity and quality of light is needed because of the effects on crew safety, on electrical power and on equipment maintainability. To address all of these issues, an illumination modeling system has been developed by the Graphics Research and Analyses Facility (GRAF) and Lighting Environment Test Facility (LETF) in the Space Human Factors Laboratory at NASA Johnson Space Center. The system uses physically based ray tracing software (Radiance) developed at Lawrence Berkeley Laboratories, a human factors oriented geometric modeling system (PLAID) and an extensive database of humans and environments. Material reflectivity properties of major surfaces and critical surfaces are measured using a gonio-reflectometer. Luminaires (lights) are measured for beam spread distribution, color and intensity. Video camera performances are measured for color and light sensitivity. 3D geometric models of humans and the environment are combined with the material and light models to form a system capable of predicting lighting conditions and visibility conditions in space.

Huynh, Thong↗

NASA NTRS1970

Environmental application of remote sensing methods to coastal zone land use and marine resources management

The interrelationships of biophysical environmental systems are investigated. Social decision-making affecting the environments of a coastal megapolis are examined. Remote sensing from high altitude aircraft and satellites afforded a powerful and indepensible tool for inventory and planning for urban development. Repetitive low to medium altitude photography is also used for studying environmental dynamics, and to document the cultural impact of man on his environment.

Goodell, H. G.↗