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At least 379 records · Page 21
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Work Function Matching Passive Lunar Dust Mitigation Coating Preparation for Lunar Flight Opportunity

With the Artemis program, NASA isplanning longer stays on the surface, with more activities that have the potential to put the astronauts and equipment in contact with greater quantities of lunar dust. The success of these missions will depend on our understanding of material interactions with lunar dust and the development of ways to mitigate dust effects. This is particularly truein cases where exposure to dust will lead to failure of components, unacceptable loss of power or thermal control, unacceptable loss of visibility, or health issues.Optically transparent, sputter deposited,work function matching coatings are being developed at NASA Glenn Research Center to reduce adhesion of dust to windows, lenses and display panels by matching the minimum energy to remove an electron from the surface to that oflunar dust in order to reduce adhesion due to charge transfer. One of these work function matching coatings will be tested as part of Aegis Aerospace Inc.’s Regolith Adherence Characterization experiment going to the lunar surface on a Commercial Lunar Payload Services (CLPS) lander in 2023. Preparation of the work function matching coating and initial characterization prior to delivery for flight integration will be discussed.

Lunar dust, passive mitigation, CLPS demonstration↗
NASA NTRSDate not supplied

Artemis Deep Space Habitation: Enabling a Sustained Human Presence on the Moon and Beyond

As NASA and its partners’ capabilities for human exploration of deep space continue to mature, so too does its roadmap toward a sustained crewed presence on the surface of the Moon and eventual human missions to Mars. The first launch of the Space Launch System and Orion crew vehicle, the contract award for the first demonstrations of a Human Landing System, and the beginning of construction on the initial elements of the lunar Gateway have marked major milestones toward NASA’s near-term exploration goals: a long-duration outpost in orbit around the Moon and the next footsteps on the lunar surface. At the same time, NASA is in the early phases of planning the capabilities that will be needed for long-term exploration. Among the common elements that will be required by long-duration stays on the lunar surface, transit to Mars, and Martian surface expeditions will be new habitats unlike any flown to date. NASA is currently working on development of both architectures for those habitats and on the technological advancements that will enable them, with an eye toward systems that will not only extend mission operations but also provide for living quarters that will keep the crew happy and healthy throughout their expeditions. Beyond the Gateway habitation needs, these capabilities will need to be defined and advanced to support the initial lunar surface missions and to prepare for human missions to the Mars system. The Surface Habitat is the current concept in consideration to serve as this initial surface habitat that will extend the crew mission durations. It will provide 30-to-60-day habitability for a crew of up to four allowing for the astronauts to explore farther and longer on each visit to the lunar surface. NASA is also currently reviewing opportunities to use current or near-term in-space habitation systems as proving grounds or precursors for keeping astronauts safe and healthy during future transits to Mars. Already, the International Space Station (ISS) is being used for implementation of next-generation life-support systems that will inform those used in exploration habitats, and the operations approach for ISS is providing lessons-learned for future science operations around or on the Moon.1U.S. Government work not protected by U.S. copyright While a suite of habitation concepts is currently under study within NASA, the agency is also working closely with U.S. industry through the Next Space Technologies for Exploration Partnerships (NextSTEP) activity to understand their concepts for commercially provided habitation capabilities as well as close coordination with international partners to understand their desires for in-space and surface habitation. This paper will provide a status of these concepts and partnership activities as well as potential future technology and architecture development paths.

Habitat↗
NASA NTRSDate not supplied

Lunar Dust and Dust Mitigation Testing

Lunar dust was one of the most persistent problems for the Apollo astronauts due to its’ abrasiveness and strong adherence to surfaces. With the Artemis program, NASA is planning longer stays on the lunar surface, with more activities that have the potential to put the astronauts and equipment in contact with greater quantities of lunar dust. The success of these missions will depend on our understanding of material interactions with lunar dust and the development of ways to mitigate dust effects. This is particularly true in cases where exposure to dust will lead to failure of components, unacceptable loss of power or thermal control, unacceptable loss of visibility, or health issues. Lunar dust, issues with lunar dust, and ground testing with lunar simulant will be discussed as well as the development of and planned flight testing of optically transparent work function matching coatings to reduce adhesion of dust on the lunar surface.

Lunar dust↗
NASA NTRSDate not supplied

Modeling of Condensations in Coronal Loops Produced by Nanoflares with Variable Frequency and Location

The presence of condensations in active regions has the potential to be an important diagnostic of coronal heating. We present the results of models of nanoflare heated coronal loops using the 1-D hydrodynamic ARGOS code. The nanoflares are modeled by discrete pulses of energy along the loop. We explore the occurrence of cold condensations due to the effective equivalent of thermal non-equilibrium (TNE) in loops with steady heating, and examine its dependence on nanoflare timing and intensity and also nanoflares location along the loop, including of randomized distributions of nanoflares. We find that randomizing nanoflare distributions, both in time/intensity and location, tends to diminish the likelihood of condensations compared to regularly occurring nanoflares with the same average properties, but that condensations can sometimes occur in regimes where regular nanoflares would not produce TNE. Also, the condensations stay in the loop for a shorter amount of time when the nanoflares distributions are random. These properties can be used in the future to investigate diagnostics of coronal heating mechanisms.

T A Kucera↗
NASA NTRS2024

Lunar Vehicle Active Charge Control System (LVACCS)+

The Lunar Vehicle Active Charge Control System (LVACCS) is an instrument in development that will measure the electrical potential of a spacecraft or rover under both positive and negative charge conditions, actively discharge negative charge, and charge the vehicle to a safe positive potential. All surfaces immersed in a plasma charge to non-zero potentials. In very low-density plasma (< 100 cm^-3), space vehicle charging can interfere with plasma probe measurements, degrade avionics performance, or cause a total system failure. LVACCS provides real-time in-situ space situational awareness that overcome these challenges in a small package. LVACCS has been awarded a NASA PICASSO grant to bring the instrument to technology readiness level 5. LVACCS consists of two main components: a collimated photoelectron gun (CPEG) and a Spacecraft Charge Detector (SCD).Monitoring charge build up on the lunar surface isa critical first step to understand hazards for crew, rovers, and instrumentation operating there.The LVACCS instrument will be able to fill in this gap providing robust lunar surface potential measurements and active charge dissipation.

Moon↗
NASA NTRS1997

Mid-Atlantic Technology Applications Center

Mid-atlantic Technology Application Center (MTAC) pursued a number of initiatives designed to enhance the strategic position of the Langley Research Center (LaRC) and NASA in industry. Among these was a closer association with the ISA, International Society for Measurement and Control. During 1997, MTAC placed articles regarding NASA-developed technologies in each In Tech magazine. The monthly magazine is sent to 46,000 sensors and instrumentation professionals. In addition, MTAC coordinated NASXs participation in the ISA Tech 97 Conference, securing $112,000 of free exhibit space, 1500 NASA sensors posters at no cost to NASA, and thousands of dollars of free publicity. MTAC was awarded a contract by ISA to operate its Technical Resource Center (TRC). The goal of this project is to determine what user needs are in order to identify opportunities for collaboration between NASA centers and companies. In addition, the TRC work will lay the groundwork for the Technology Development Consortium (TDC) proposed by MTAC. The purpose of the TDC is to: match current industry needs with NASA technologies available now, and to identify future needs of NASA and industry which may lead to dual use projects. The goal of these activities is twofold: to infuse NASA technologies into the sensors and instrumentation industry and to secure industry funds to support NASA technology development projects. The instrumentation and sensors industry is valued at $30 billion worldwide, with $12 billion in sales in the United States. The growth rate averages 13.5%, so that by the year 2000, the industry will produce products worth $49 billion. More than 80% of instruments, sensors and control systems are currently manufactured in the United States. NASA and the industry do not have a history of collaborative projects; MTAC's initiatives in this area are designed to foster working relationships between the two parties that will help maintain U.S. leadership in this field. Mid-atlantic Technology Applications Center (MTAC) continued to work on LaRC-SI and Thin Layer Unimorph Driver and Sensor activities. MTAC helped develop the "master license" concept and identified additional applications and potential clients. The goal of these activities was to increase the financial return to Langley Research Center, to ensure the diffusion of the technologies throughout the economy, and to attract partners for future NASA technology development efforts. In an attempt to market LaRC-SI and the Thin Layer Unimorph Driver and Sensor, MTAC developed and pioneered the use of the USRTTC Technology Commercialization Team. As a result, MTAC's sister RTTCs identified both applications and potential users for the two technologies. MTAC also benefitted from its affiliate network to locate companies throughout the region that were interested in the two technologies. MTAC is working with Allegheny Ludlum to monitor the progress of the installation and testing of ultrasonic equipment purchased as a result of Langley Research Center's assistance.

Source record↗
NASA NTRS1999

A History of Suction-Type Laminar Flow Control with Emphasis on Flight Research

Laminar-flow control is an area of aeronautical research that has a long history at NASA's Langley Research Center, Dryden Flight Research Center, their predecessor organizations, and elsewhere. In this monograph, the author, who spent much of his career at Langley working with this research, presents a history of that portion of laminar-flow technology known as active laminar-flow control, which employs suction of a small quantity of air through airplane surfaces. This important technique offers the potential for significant reduction in drag and, thereby, for large increases in range or reductions in fuel usage for aircraft. For transport aircraft, the reductions in fuel consumed as a result of laminar-flow control may equal 30 percent of present consumption. Given such potential, it is obvious that active laminar-flow control with suction is an important technology. In this study, the author covers the early history of the subject and brings the story all the way to the mid-1990s with an emphasis on flight research, much of which has occurred at Dryden. This is an important monograph that not only encapsulates a lot of history in a brief compass but also does so in language that is accessible to non-technical readers. NASA is publishing it in a format that will enable it to reach the wide audience the subject deserves.

Braslow, Albert L.↗
NASA NTRS1995

Regulation of cyclic nucleotide-gated channels and membrane excitability in olfactory receptor cells by carbon monoxide

1. The effect of the putative neural messenger carbon monoxide (CO) and the role of the cGMP second-messenger system for olfactory signal generation was examined in isolated olfactory receptor neurons (ORNs) of the tiger salamander. 2. With the use of whole cell voltage-clamp recordings in combination with a series of ionic and pharmological tests, it is demonstrated that exogenously applied CO is a potent activator (K1/2 = 2.9 microM) of cyclic nucleotide-gated (CNG) channels previously described to mediate odor transduction. 3. Several lines of evidence suggest that CO mediates its effect through stimulation of a soluble guanylyl cyclase (sGC) leading to formation of the second-messenger cGMP. This conclusion is based on the findings that CO responses show an absolute requirement for guanosine 5'-triphosphate (GTP) in the internal solution, that no direct effect of CO on CNG currents in the absence of GTP is detectable, and that a blocker of sGC activation, LY85383 (10 microM), completely inhibits the CO response. 4. The dose-response curve for cGMP at CNG channels is used as a calibration to provide a quantitative estimate of the CO-stimulated cGMP formation. This analysis implies that CO is a potent activator of olfactory sGC. 5. Perforated patch recordings using amphotericin B demonstrate that low micromolar doses of CO effectively depolarize the membrane potential of ORNs through tonic activation of CNG channels. This effect in turn regulates excitable and adaptive properties of ORNs and modulates neuronal responsiveness. 6. These data argue for an important role of the cGMP pathway in olfactory signaling and support the idea that CO may function as a diffusible messenger in the olfactory system.

NASA Discipline Neuroscience↗
NASA NTRS2006

Characterizing the Mineralogy of Potential Lunar Landing Sites

Many processes active on the early Moon are common to most terrestrial planets, including the record of early and late impact bombardment. The Moon's surface provides a record of the earliest era of terrestrial planet evolution, and the type and composition of minerals that comprise a planetary surface are a direct result of the initial composition and subsequent thermal and physical processing. Lunar mineralogy seen today is thus a direct record of the early evolution of the lunar crust and subsequent geologic processes. Specifically, the distribution and concentration of specific minerals is closely tied to magma ocean products, lenses of intruded or remelted plutons, basaltic volcanism and fire-fountaining, and any process (e.g. cratering) that might redistribute or transform primary and secondary lunar crustal materials. The association of several lunar minerals with key geologic processes is illustrated in Figure 1. The geologic history of potential landing sites on the Moon can be read from the character and context of local mineralogy.

Pieters, Carle↗
NASA NTRS1993

Pioneer Venus data analysis for the retarding potential analyzer

This report describes the data analysis and archiving activities, analysis results, and instrument performance of the orbiter retarding potential analyzer (ORPA) flown on the Pioneer Venus Orbiter spacecraft during the period, Aug. 1, 1988 to Sept. 30, 1993. During this period, the periapsis altitude of the Orbiter spacecraft descended slowly from 1900 km altitude, at which altitude the spacecraft was outside the Venus ionosphere, to approximately 130 km altitude in Oct. 1992 at which time communication with the spacecraft ceased as a result of entry of the spacecraft into the Venus atmosphere. The quantity of ORPA data returned during this reporting period was greatly reduced over that recovered in the previous years of the mission because of the reduced power capability of the spacecraft, loss of half of the onboard data storage, and partial failure of the ORPA. Despite the reduction in available data, especially ionospheric data, important scientific discoveries resulted from this extended period of the Pioneer Venus mission. The most significant discovery was that of a strong solar cycle change in the size of the dayside ionosphere and the resulting shutoff of flow of dayside ions into the nightside hemisphere. The large, topside O+ F2 ionospheric layer observed during the first three years of the Pioneer Venus mission, a period of solar cycle maximum activity, is absent during the solar cycle minimum activity period.

Knudsen, William C.↗
NASA NTRS1995

Active Flow Control: Instrumentation Automation and Experimental Technique

In investigating the potential of a new actuator for use in an active flow control system, several objectives had to be accomplished, the largest of which was the experimental setup. The work was conducted at the NASA Langley 20x28 Shear Flow Control Tunnel. The actuator named Thunder, is a high deflection piezo device recently developed at Langley Research Center. This research involved setting up the instrumentation, the lighting, the smoke, and the recording devices. The instrumentation was automated by means of a Power Macintosh running LabVIEW, a graphical instrumentation package developed by National Instruments. Routines were written to allow the tunnel conditions to be determined at a given instant at the push of a button. This included determination of tunnel pressures, speed, density, temperature, and viscosity. Other aspects of the experimental equipment included the set up of a CCD video camera with a video frame grabber, monitor, and VCR to capture the motion. A strobe light was used to highlight the smoke that was used to visualize the flow. Additional effort was put into creating a scale drawing of another tunnel on site and a limited literature search in the area of active flow control.

Gimbert, N. Wes↗
NASA NTRS1975

Study of active cooling for supersonic transports

The potential benefits of using the fuel heat sink of hydrogen fueled supersonic transports for cooling large portions of the aircraft wing and fuselage are examined. The heat transfer would be accomplished by using an intermediate fluid such as an ethylene glycol-water solution. Some of the advantages of the system are: (1) reduced costs by using aluminum in place of titanium, (2) reduced cabin heat loads, and (3) more favorable environmental conditions for the aircraft systems. A liquid hydrogen fueled, Mach 2.7 supersonic transport aircraft design was used for the reference uncooled vehicle. The cooled aircraft designs were analyzed to determine their heat sink capability, the extent and location of feasible cooled surfaces, and the coolant passage size and spacing.

Brewer, G. D.↗
NASA NTRS2017

The Potential for Health Monitoring in Expandable Space Modules: The Bigelow Expandable Activity Module on the ISS

Expandable modules for use in space and on the Moon or Mars offer a great opportunity for volume and mass savings in future space exploration missions. This type of module can be compressed into a relatively small shape on the ground, allowing them to fit into space vehicles with a smaller cargo/fairing size than a traditional solid, metallic structure based module would allow. In April 2016, the Bigelow Expandable Activity Module (BEAM) was berthed to the International Space Station (ISS). BEAM is the first human-rated expandable habitat/module to be deployed and crewed in space. BEAM is a NASA managed ISS payload project in partnership with Bigelow Aerospace. BEAM is intended to stay attached to ISS for an operational period of 2 years to help advance the technology readiness for future expandable modules. BEAM has been instrumented with a suite of space flight certified sensors systems which will help characterize the module's performance for thermal, radiation shielding and impact monitoring against potential Micro Meteoroid/Orbital Debris (MM/OD) providing fundamental information on the BEAM environment for potential health monitoring requirements and capabilities. This paper will provide an overview of how the sensors/instrumentation systems were developed, tested, installed and an overview of the current sensor system operations. It will also discuss how the MM/OD impact detection system referred to as the Distributed Impact Detection System (DIDS) data is being processed and reviewed on the ground by the principle investigators.

Wells, Nathan D.↗
NASA NTRS1987

Hollow cathode plasma source for active spacecraft charge control

A prototype plasma source spacecraft discharge device has been developed to control overall and differential spacecraft surface charging. The plasma source is based on a unique hollow cathode discharge, where the plasma generation process is contained completely within the cathode. This device can be operated on argon, krypton, or xenon and has a rapid cold start time of less than 4 s. The discharge system design includes a spacecraft-discharge/net-charge sensing circuit which provides the ability to measure the polarity, magnitude, pulse shape, and time duration of a discharging event. Ion currents of up to 325 microA and electron currents ranging from 0.02 to 6.0 A have been extracted from the device. In addition, the spacecraft discharge device successfully discharged capacitively biased plates, from as high as + or - 2500 V, to ground potential, and discharged and clamped actively biased plates at +5 V with respect to ground potential during ground simulation testing.

Deininger, William D.↗
NASA NTRS2012

Forecasting the Solar Drivers of Severe Space Weather from Active-Region Magnetograms

Large flares and fast CMEs are the drivers of the most severe space weather including Solar Energetic Particle Events (SEP Events). Large flares and their co-produced CMEs are powered by the explosive release of free magnetic energy stored in non-potential magnetic fields of sunspot active regions. The free energy is stored in and released from the low-beta regime of the active region s magnetic field above the photosphere, in the chromosphere and low corona. From our work over the past decade and from similar work of several other groups, it is now well established that (1) a proxy of the free magnetic energy stored above the photosphere can be measured from photospheric magnetograms, and (2) an active region s rate of production of major CME/flare eruptions in the coming day or so is strongly correlated with its present measured value of the free-energy proxy. These results have led us to use the large database of SOHO/MDI full-disk magnetograms spanning Solar Cycle 23 to obtain empirical forecasting curves that from an active region s present measured value of the free-energy proxy give the active region s expected rates of production of major flares, CMEs, fast CMEs, and SEP Events in the coming day or so (Falconer et al 2011, Space Weather, 9, S04003). We will present these forecasting curves and demonstrate the accuracy of their forecasts. In addition, we will show that the forecasts for major flares and fast CMEs can be made significantly more accurate by taking into account not only the value of the free energy proxy but also the active region s recent productivity of major flares; specifically, whether the active region has produced a major flare (GOES class M or X) during the past 24 hours before the time of the measured magnetogram. By empirically determining the conversion of the value of free-energy proxy measured from a GONG or HMI magnetogram to that which would be measured from an MDI magnetogram, we have made GONG and HMI magnetograms useable with our MDI-based forecasting curves to forecast event rates.

Falconer, David A.↗
NASA NTRS2012

Forecasting the Solar Drivers of Severe Space Weather from Active-Region Magnetograms

Large flares and fast CMEs are the drivers of the most severe space weather including Solar Energetic Particle Events (SEP Events). Large flares and their co-produced CMEs are powered by the explosive release of free magnetic energy stored in non-potential magnetic fields of sunspot active regions. The free energy is stored in and released from the low-beta regime of the active region s magnetic field above the photosphere, in the chromosphere and low corona. From our work over the past decade and from similar work of several other groups, it is now well established that (1) a proxy of the free magnetic energy stored above the photosphere can be measured from photospheric magnetograms, and (2) an active region s rate of production of major CME/flare eruptions in the coming day or so is strongly correlated with its present measured value of the free-energy proxy. These results have led us to use the large database of SOHO/MDI full-disk magnetograms spanning Solar Cycle 23 to obtain empirical forecasting curves that from an active region s present measured value of the free-energy proxy give the active region s expected rates of production of major flares, CMEs, fast CMEs, and SEP Events in the coming day or so (Falconer et al 2011, Space Weather, 9, S04003). We will present these forecasting curves and demonstrate the accuracy of their forecasts. In addition, we will show that the forecasts for major flares and fast CMEs can be made significantly more accurate by taking into account not only the value of the free energy proxy but also the active region s recent productivity of major flares; specifically, whether the active region has produced a major flare (GOES class M or X) during the past 24 hours before the time of the measured magnetogram. By empirically determining the conversion of the value of free-energy proxy measured from a GONG or HMI magnetogram to that which would be measured from an MDI magnetogram, we have made GONG and HMI magnetograms useable with our MDI-based forecasting curves to forecast event rates.

Falconer, David A.↗