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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
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NASA NTRS2022

Frequency Agile Solar Radiotelescope

The Frequency Agile Solar Radiotelescope (FASR) has been strongly endorsed as a top community priority by both Astronomy & Astrophysics Decadal Surveys and Solar & Space Physics Decadal Surveys in the past two decades. Although it was developed to a high state of readiness in previous years (it went through a CATE analysis and was declared “doable now”), the NSF has not had the funding mechanisms in place to fund this mid-scale program. Now it does, and the community must seize this opportunity to modernize the FASR design and build the instrument in this decade. The concept and its science potential have been abundantly proven by the pathfinding Expanded Owens Valley Solar Array (EOVSA), which has demonstrated a small subset of FASR’s key capabilities such as dynamically measuring the evolving magnetic field in eruptive flares, the temporal and spatial evolution of the electron energy distribution in flares, and the extensive coupling among dynamic components (flare, flux rope, current sheet). The FASR concept, which is orders of magnitude more powerful than EOVSA, is low-risk and extremely high reward, exploiting a fundamentally new research domain in solar and space weather physics. Utilizing dynamic broadband imaging spectropolarimetry at radio wavelengths, with its unique sensitivity to coronal magnetic fields and to both thermal plasma and nonthermal electrons from large flares to extremely weak transients, the ground-based FASR will make synoptic measurements of the coronal magnetic field and map emissions from the chromosphere to the middle corona in 3D. With its high spatial, spectral, and temporal resolution, as well as its superior imaging fidelity and dynamic range, FASR is poised to provide a system-wide perspective on myriad coupled phenomena. FASR will be a highly complementary and synergistic component of solar and heliospheric observing capabilities that is critically needed to support the next generation of solar science.

Dale E. Gary↗
NASA NTRS1978

Spacecraft-generated plasma interaction with high voltage solar array

Calculations are made of the effect of interactions of spacecraft-generated plasmas and high voltage solar array components on an advanced Solar Electric Propulsion system. The plasma consists of mercury ions and electrons resulting from the operation of ion thrusters and associated hollow cathode neutralizers. Because large areas of the solar array are at high potential and not completely insulated from the surrounding plasma, the array can, under some conditions, collect excessive electron currents. Results are given for the parasitic currents collected by the solar arrays and means for reducing these currents are considered.

Parks, D. E.↗
NASA NTRS1978

A search for space energy alternatives

This paper takes a look at a number of schemes for converting radiant energy in space to useful energy for man. These schemes are possible alternatives to the currently most studied solar power satellite concept. Possible primary collection and conversion devices discussed include the space particle flux devices, solar windmills, photovoltaic devices, photochemical cells, photoemissive converters, heat engines, dielectric energy conversion, electrostatic generators, plasma solar collectors, and thermionic schemes. Transmission devices reviewed include lasers and masers.

Gilbreath, W. P.↗
NASA NTRS1982

Solar particle propagation and modulation theory

Developments related to solar flare particle propagation theory are considered, taking into account the transport equation currently employed to describe the propagation of solar flare particles. This equation does not take into consideration convection with the solar wind, drifts, and changes in particle energy. The equation was solved numerically to generate typical solar flare particle time profiles at 1 AU. The results, however, were not satisfactory. It was found that the numerical method used was apparently in error. New advances which provide approximate analytical solutions to the equation are reported. Questions of galactic cosmic ray propagation in interplanetary space are also discussed.

Lee, M. A.↗
NASA NTRS2005

Materials on the International Space Station - Forward Technology Solar Cell Experiment

This paper describes a space solar cell experiment currently being built by the Naval Research Laboratory (NRL) in collaboration with NASA Glenn Research Center (GRC), and the US Naval Academy (USNA). The experiment has been named the Forward Technology Solar Cell Experiment (FTSCE), and the purpose is to rapidly put current and future generation space solar cells on orbit and provide validation data for these technologies. The FTSCE is being fielded in response to recent on-orbit and ground test anomalies associated with space solar arrays that have raised concern over the survivability of new solar technologies in the space environment and the validity of present ground test protocols. The FTSCE is being built as part of the Fifth Materials on the International Space Station (MISSE) Experiment (MISSE-5), which is a NASA program to characterize the performance of new prospective spacecraft materials when subjected to the synergistic effects of the space environment. Telemetry, command, control, and communication (TNC) for the FTSCE will be achieved through the Amateur Satellite Service using the PCSat2 system, which is an Amateur Radio system designed and built by the USNA. In addition to providing an off-the-shelf solution for FTSCE TNC, PCSat2 will provide a communications node for the Amateur Radio satellite system. The FTSCE and PCSat2 will be housed within the passive experiment container (PEC), which is an approximately 2ft x2ft x 4in metal container built by NASA Langley Research Center (NASA LaRC) as part of the MISSE-5 program. NASA LaRC has also supplied a thin film materials experiment that will fly on the exterior of the thermal blanket covering the PCSat2. The PEC is planned to be transported to the ISS on a Shuttle flight. The PEC will be mounted on the exterior of the ISS by an astronaut during an extravehicular activity (EVA). After nominally one year, the PEC will be retrieved and returned to Earth. At the time of writing this paper, the subsystems of the experiment are being integrated at NRL, and we are preparing to commence environmental testing.

Walters, R. J.↗
NASA NTRSDate not supplied

Overview of Nasa's Watts on the Moon Challenge Phase 1

As NASA works to extend human exploration of the solar system, unprecedented capacity for electrical and thermal energy will be needed to support sustained human presence and the beginning of industrial activity on the Moon. Solar energy is abundant on the lunar surface but extended night hours (up to 350 consecutive hours) and extreme temperature change from daylight to nighttime operation creates complexity for solar power use. Analogous issues arise on Earth, where demand for additional renewable energy generation, including solar, is rising, but better power management, distribution, and energy storage solutions are needed to address intermittency and resiliency, among other issues. To accelerate the development of technologies for power distribution and energy storage that can operate in extreme lunar conditions, NASA’s Centennial Challenges Program launched the Watts on the Moon Challenge in September 2020. Submissions for Phase 1 of the challenge were due in March 2021 and winners were announced in May 2021. This paper provides an overview of the challenge, key technical requirements, outcomes from Phase 1, and an update on Phase 2 of the challenge, which is currently ongoing.

Denise P. Morris↗
NASA NTRS1986

Manned Mars mission solar physics: Solar energetic particle prediction and warning

There are specific risks to the crew of the manned Mars mission from energetic particles generated by solar activity. Therefore, mission planning must provide for solar monitoring and solar activity forecasts. The main need is to be able to anticipate the energetic particle events associated with some solar flares and, occasionally, with erupting filaments. A second need may be for forecasts of solar interference with radio communication between the manned Mars mission (during any of its three phases) and Earth. These two tasks are compatible with a small solar observatory that would be used during the transit and orbital phases of the mission. Images of the Sun would be made several times per hour and, together with a solar X-ray detector, used to monitor for the occurrence of solar activity. The data would also provide a basis for research studies of the interplanetary medium utilizing observations covering more of the surface of the Sun than just the portion facing Earth.

Suess, S. T.↗
NASA NTRS1985

The solar-flare induced earth's environment

A composite numerical simulation model developed from a series of MHD models was used to compute the solar-flare-generated disturbances of physical parameters, such as density, temperature, velocity, and magnetic field from the solar surface (i.e., the photospheric level) to the earth's environment. It is shown that the disturbed earth's environment at high latitudes can be approximated by starting with the knowledge of the occurrence and the strength of a solar flare, then simulating the evolutionary consequences of the solar disturbance through interplanetary space up to and through the magnetosphere.

Wu, S. T.↗
NASA NTRS1989

Space Station Freedom photovoltaic power module design status

Electric power generation for Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during Phase 1 operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units (ORU's) to achieve modularization. Design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Jimenez, Amador P.↗
NASA NTRS1996

Testing for Dark Matter Trapped in the Solar System

We consider the possibility of dark matter trapped in the solar system in bound solar orbits. If there exist mechanisms for dissipating excess kinetic energy by an amount sufficient for generating bound solar orbits, then trapping of galactic dark matter might have taken place during formation of the solar system, or could be an ongoing process. Possible locations for acumulation of trapped dark matter are orbital resonances with the planets or regions in the outer solar system. It is posible to test for the presence of unseen matter by detecting its gravitational effects. Current results for dynamical limits obtained from analyses of planetary ephemeris data and spacecraft tracking data are presented. Possible future improvements are discussed.

dark matter bound solar orbits galactic dark matte↗
NASA NTRS1974

Interplanetary shock waves associated with solar flares

The interaction of the earth's magnetic field with the solar wind is discussed with emphasis on the influence of solar flares. The geomagnetic storms are considerered to be the result of the arrival of shock wave generated by solar flares in interplanetary space. Basic processes in the solar atmosphere and interplanetary space, and hydromagnetic disturbances associated with the solar flares are discussed along with observational and theoretical problems of interplanetary shock waves. The origin of interplanetary shock waves is also discussed.

Chao, J. K.↗
NASA NTRS1983

Cost Effectiveness of Hybrid Solar Powerplants

Report discusses cost effectiveness of high-temperature thermal storage system for representative parabolic dish solar powerplant. Economic viability of thermal storage system assesses; cost and performance projections made; cost of electricity generated by solar power plant also calculated.

Wen, L. C.↗
NASA NTRS1989

Space Station Freedom photovoltaic power module design status

Electric power generation for the Space Station Freedom will be provided by four photovoltaic (PV) power modules using silicon solar cells during phase I operation. Each PV power module requires two solar arrays with 32,800 solar cells generating 18.75 kW of dc power for a total of 75 kW. A portion of this power will be stored in nickel-hydrogen batteries for use during eclipse, and the balance will be processed and converted to 20 kHz ac power for distribution to end users through the power management and distribution system. The design incorporates an optimized thermal control system, pointing and tracking provision with the application of gimbals, and the use of orbital replacement units to achieve modularization. The design status of the PV power module, as derived from major trade studies, is discussed at hardware levels ranging from component to system. Details of the design are presented where appropriate.

Jimenez, Amador P.↗
NASA NTRS1994

On sound generation by turbulent convection: A new look at old results

We have revisited the problem of acoustic wave generation by turbulent convection in stellar atmospheres. The theory of aerodynamically generated sound, originally developed by Lighthill and later modified by Stein to include the effects of stratification, has been used to estimate the acoustic wave energy flux generated in solar and stellar convection zones. We correct the earlier computations by incorporating an improved description of the spatial and temporal spectrum of the turbulent convection. We show the dependence of the resulting wave fluxes on the nature of the turbulence, and compute the wave energy spectra and wave energy fluxes generated in the Sun on the basis of a mixing-length model of the solar convection zone. In contrast to the previous results, we show that the acoustic energy generation does not depend very sensitively on the turbulent energy spectrum. However, typical total acoustic fluxes of order F(sub A) = 5 x 10(exp 7) ergs/sq cm/s with a peak of the acoustic frequency spectrum near omega = 100 mHz are found to be comparable to those previously calculated. The acoustic flux turns out to be strongly dependent on the solar model, scaling with the mixing-length parameter alpha as alpha(exp 3.8). The computed fluxes most likely constitute a lower limit on the acoustic energy produced in the solar convection zone if recent convection simulations suggesting the presence of shocks near the upper layers of the convection zone apply to the Sun.

Musielak, Z. E.↗
NASA NTRS1984

User's guide for ERB-7 SEFDT. Volume 3: Quality control report for year-2

Problems in the solar data generated by the Nimbus 7 satellite are discussed specifically for scientific users. Major and minor data flaws in the Solar and Earth Flux Data Tape (SEFDT) were identified, defined and categorized. Solar channel assembly misalignment, data gaps, and algorithm errors were among the problems described in detail. Solar flux density data derived from SEFDT are presented in graphical form.

Vasanth, K. L.↗
NASA NTRS2004

Charged Particle Effects on Solar Sails - An Overview

The NASA In-Space Propulsion Program is currently sponsoring a comprehensive look at the effects of the charged particle environment on the first generation of Solar Sail propulsion systems. As part of this, a joint NASA MSFC/JPL team is investigating the effects of spacecraft charging on the preliminary ISP Solar Sail mission designs. This paper will begin by reviewing the plasma environments being proposed for such missions-these range from the ambient solar wind at approximately 1 AU in the ecliptic plane, approximately 0.5 AU solar-polar orbit, and geosynchronous orbit. Following a discussion of the critical design issues associated with Solar Sails from a charging standpoint, a simple Sail configuration for modeling purposes will be presented. Results for the various environments will be illustrated in terms of the estimated surface potentials for the Solar Sail using the NASCAP-2K charging analysis program. Based on these potentials, representative plasma flow fields and potential contours surrounding the Solar Sail will then be presented. The implications of these results--the surface potentials and plasma flow--will be discussed in the context of their effects on Solar Sail operations and structural configurations.

spacecraft charging↗