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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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NASA NTRS1977

The economic viability of pursuing a space power system concept

The development of a space power system requires no fundamental technological breakthroughs. There are, however, uncertainties regarding the degree to which necessary developments can be achieved or exceeded. An analysis is conducted concerning the implementation of a 5000 MW space-based solar power system based on photovoltaic conversion of solar energy to electrical energy. The solar array is about 13 km long and 5 km wide. Placed in geosynchronous orbit, it provides power to the earth for 30 years. Attention is given to the economic feasibility of a space power system, a risk analysis for space power systems, and the use of the presented methodology for comparing alternative technology development programs.

Hazelrigg, G. A., Jr.↗

NASA NTRS1987

Past, present, and future activities in space power technology in the United States of America

Space power technology research in the U.S. is examined. The objectives for advanced power systems are long life, safety, flexibility, modularity, growth capability, and autonomy. Research in the areas of photovoltaic arrays, electrical energy storage, and the development of solar dynamic power systems and radio thermal generators is described. The applications of advances in power generation, energy storage, and power management and distribution to the Space Station are discussed.

Ambrus, Judith H.↗

NASA NTRS1994

Low Power Ground-Based Laser Illumination for Electric Propulsion Applications

A preliminary evaluation of low power, ground-based laser powered electric propulsion systems is presented. A review of available and near-term laser, photovoltaic, and adaptive optic systems indicates that approximately 5-kW of ground-based laser power can be delivered at an equivalent one-sun intensity to an orbit of approximately 2000 km. Laser illumination at the proper wavelength can double photovoltaic array conversion efficiencies compared to efficiencies obtained with solar illumination at the same intensity, allowing a reduction in array mass. The reduced array mass allows extra propellant to be carried with no penalty in total spacecraft mass. The extra propellant mass can extend the satellite life in orbit, allowing additional revenue to be generated. A trade study using realistic cost estimates and conservative ground station viewing capability was performed to estimate the number of communication satellites which must be illuminated to make a proliferated system of laser ground stations economically attractive. The required number of satellites is typically below that of proposed communication satellite constellations, indicating that low power ground-based laser beaming may be commercially viable. However, near-term advances in low specific mass solar arrays and high energy density batteries for LEO applications would render the ground-based laser system impracticable.

Lapointe, Michael R.↗

NASA NTRS1994

BMDO photovoltaics program overview

This is an overview of the Ballistic Missile Defense Organization (BMDO) Photovoltaic Program. Areas discussed are: (1) BMDO advanced Solar Array program; (2) Brilliant Eyes type satellites; (3) Electric propulsion; (4) Contractor Solar arrays; (5) Iofee Concentrator and Cell development; (6) Entech linear mini-dome concentrator; and (7) Flight test update/plans.

Caveny, Leonard H.↗

NASA NTRS2018

High Temperature Photovoltaics Silicone Adhesives for Venus Surface

The harsh environment at the surface of Venus, with a low solar intensity, red-rich solar spectrum, high temperatures, and a corrosive acid environment, makes it a challenging location to use photovoltaics. For the design of photovoltaic power generation for future missions to Venus, solar arrays that can function at high temperatures under low light intensity must be developed, and a significant difficulty in this is achieving a long lifetime without degradation under Venus conditions. One issue that must be addressed is the encapsulation to protect the solar cells from the environment, and most particularly the transparent adhesive affixing the coverglass to the cells. In this paper the factors affecting the reliability and degradation of transparent silicone adhesives under Venus conditions are discussed.

Katampe, Ibrahim↗

NASA NTRSDate not supplied

Government Reference Concept for a 10 kW Lunar South Pole Solar Array

Deployable and relocatable free-standing, solar arrays will be required for future lunar South Pole missions. Major design requirements for these arrays will be low mass, compact launch stowage, and highly reliable deployment and retraction performance. A novel conceptual design referred to as the Relocatable Solar Array (RSA) is presented fora 10 kW solar array to address these requirements. Simply stated, the concept is a pair of solar cell blankets freely hanging from a horizontal cross arm that is supported by a vertical slender telescoping mast, all of which, rests on a deployable tripod base. A major factor in simplifying this array is that the force exerted by lunar gravity is used to deploy and maintain the extension of the hanging array blankets. The other major factor in achieving the desired low mass and high volumetric efficiency is that the resulting array system operates in the vacuum, low-gravity, lunar environment with no deployed vibration frequency requirement. Such an environment enables the use of extraordinarily slender and low mass structural members to support the hanging array blankets. This concept was developed, in part, to serve as a NASA reference solar array concept against which other proposed arrays can be compared.

Space solar arrays, solar array structures, lunar ↗

NASA NTRS2004

High Temperature Solar Cell Development

The majority of satellites and near-earth probes developed to date have used photovoltaic arrays for power generation. If future mission to probe environments close to the sun will be able to use photovoltaic power, solar cells that can function at high temperatures, under high light intensity, and high radiation conditions must be developed. In this paper, we derive the optimum bandgap as a function of the operating temperature.

Landis, Geoffrey A.↗

NASA NTRSDate not supplied

Photovoltaic Systems for Lunar Surface Survivability During the Lunar Day and Night

While photovoltaic systems will not be operating during the lunar night, it is still important to ensure that the cells, structure, and other components are able to survive the extreme low temperature conditions during times of low to no illumination. The Photovoltaics team at NASA GRC has expertise in low temperature solar cell operation, thermal cycling of solar cell coupons and array components, and the design of lunar solar arrays for long duration surface missions.

Solar power↗

NASA NTRS2012

Coating Processes Boost Performance of Solar Cells

NASA currently has spacecraft orbiting Mercury (MESSENGER), imaging the asteroid Vesta (Dawn), roaming the red plains of Mars (the Opportunity rover), and providing a laboratory for humans to advance scientific research in space (the International Space Station, or ISS). The heart of the technology that powers those missions and many others can be held in the palm of your hand - the solar cell. Solar, or photovoltaic (PV), cells are what make up the panels and arrays that draw on the Sun s light to generate electricity for everything from the Hubble Space Telescope s imaging equipment to the life support systems for the ISS. To enable NASA spacecraft to utilize the Sun s energy for exploring destinations as distant as Jupiter, the Agency has invested significant research into improving solar cell design and efficiency. Glenn Research Center has been a national leader in advancing PV technology. The Center s Photovoltaic and Power Technologies Branch has conducted numerous experiments aimed at developing lighter, more efficient solar cells that are less expensive to manufacture. Initiatives like the Forward Technology Solar Cell Experiments I and II in which PV cells developed by NASA and private industry were mounted outside the ISS have tested how various solar technologies perform in the harsh conditions of space. While NASA seeks to improve solar cells for space applications, the results are returning to Earth to benefit the solar energy industry.

Source record↗

NASA NTRS1990

Applications of thin film technology toward a low-mass solar power satellite

Previous concepts for solar power satellites have used conventional-technology photovoltaics and microwave tubes. The authors propose using thin film photovoltaics and an integrated solid state phased array to design an ultra-lightweight solar power satellite, resulting in a potential reduction in weight by a factor of ten to a hundred over conventional concepts for solar power satellites.

Landis, Geoffrey A.↗

NASA NTRS2018

A Breakthrough Propulsion Architecture for Interstellar Precursor Missions: Phase I Final Report

Our breakthrough propulsion architecture is an innovative way to take advantage of kilometer-scale, multi-hundred megawatt, space-based, phased-array lasers to enable rapid transportation throughout the solar system. In this architecture, the laser would beam power over distances of up to 40 AU increasing the available power density relative to solar insolation by two orders of magnitude. The receiving vehicle would have a photovoltaic array with cells tuned to the laser frequency that outputs a voltage of 6 kV to directly-drive a lithium-fueled gridded ion thruster system at an ultra-high specific impulse of 40,000 s. Such a system could enable final spacecraft speeds of greater than 40 AU/year, potentially enabling missions to the solar gravity lens focus at 550 AU in less than 15 years. This is the propulsion architecture of the 22nd century.

Brophy, John↗

NASA NTRS1983

Multibandgap photovoltaic receiver using back surface reflectors

Requirements for prime power generation from solar arrays are expected to increase for the next generation of spacecraft power systems. An enhancement of the efficiency of the conversion of incident sunlight to electricity would have a number of advantages, provided the cost involved in achieving this enhancement would not be too great. Solar input response can be improved by splitting the solar spectrum into component wavelength bands and directing these bands to solar cells of different bandgaps. Two approaches have been proposed for achieving spectrum splitting photovoltaics. One approach involves multiple-cell systems using dichroic mirrors, while the other employs monolithic multibandgap solar cells. The present investigation is concerned with a procedure which has the advantages of both approaches, while avoiding many of the drawbacks of each.

Stern, T. G.↗

NASA NTRS2005

Solar Array Sails: Possible Space Plasma Environmental Effects

An examination of the interactions between proposed "solar sail" propulsion systems with photovoltaic energy generation capabilities and the space plasma environments. Major areas of interactions ere: Acting from high voltage arrays, ram and wake effects, V and B current loops and EMI. Preliminary analysis indicates that arcing will be a major risk factor for voltages greater than 300V. Electron temperature enhancement in the wake will be produce noise that can be transmitted via the wake echo process. In addition, V and B induced potential will generate sheath voltages with potential tether like breakage effects in the thin film sails. Advocacy of further attention to these processes is emphasized so that plasma environmental mitigation will be instituted in photovoltaic sail design.

Mackey, Willie R.↗

NASA NTRS1979

Glass fiber reinforced concrete for terrestrial photovoltaic arrays

The use of glass-fiber-reinforced concrete (GRC) as a low-cost structural substrate for terrestrial solar cell arrays is discussed. The properties and fabrication of glass-reinforced concrete structures are considered, and a preliminary design for a laminated solar cell assembly built on a GRC substrate is presented. A total cost for such a photovoltaic module, composed of a Korad acrylic plastic film front cover, an aluminum foil back cover, an ethylene/vinyl acetate pottant/adhesive and a cotton fabric electrical isolator in addition to the GRC substrate, of $9.42/sq m is projected, which is less than the $11.00/sq m cost goal set by the Department of Energy. Preliminary evaluations are concluded to have shown the design capabilities and cost effectiveness of GRC; however, its potential for automated mass production has yet to be evaluated.

Maxwell, H.↗

NASA NTRSDate not supplied

Thermoplastic Space Point Design (TSPD) Tall Tower Lunar Thermal Analysis

The Thermoplastics Development for Exploration Applications (TDEA) project seeks to advance NASA’s thermoplastic composites capabilities by developing structurally efficient joining solutions for large-scale space structures to support NASA’s future exploration missions. A key objective is to develop and understand advanced thermoplastic joining techniques relevant to space environments and applicable to unitized and/or reconfigurable composite structures. The TDEA project uses NASA Langley’s Tall Lunar Tower (TLT) concept as a target application for the design and development of in-space assembled thermoplastic composites. TLT is a 50-meter-tall tower constructed on the lunar surface near the south pole. The tower’s height at this location on the moon allows for extended durations of incident solar flux which can be used to generate power via photovoltaic arrays. The thermal environment present on lunar south pole represents a challenging environment for any space-based asset. This study provides an overview of the analysis techniques used to determine the temperature extremes, gradients, and timelines of a tall composite tower over a one-year duration at the Shackleton Connecting Ridge. The developed thermal model includes tower and lunar surface elements with anisotropic and temperature-dependent material properties and incorporates a solar vector orbit with time-varying solar flux. Study topics include: a comparison between the effects of simplified lunar surface topologies on thermal results, prediction of surface temperature values versus Lunar Reconnaissance Orbiter (LRO) flight data, and tower structural-thermal deformation.

Lunar↗

NASA NTRS1981

Low cost solar array project production process and equipment task. A Module Experimental Process System Development Unit (MEPSDU)

Technical readiness for the production of photovoltaic modules using single crystal silicon dendritic web sheet material is demonstrated by: (1) selection, design and implementation of solar cell and photovoltaic module process sequence in a Module Experimental Process System Development Unit; (2) demonstration runs; (3) passing of acceptance and qualification tests; and (4) achievement of a cost effective module.

Source record↗

NASA NTRS1999

Retrieval of Mir Solar Array

A Russian solar array panel removed in November 1997 from the non-articulating photovoltaic array on the Mir core module was returned to Earth on STS-89 in January 1998. The panel had been exposed to low Earth orbit (LEO) for 10 years prior to retrieval. The retrieval provided a unique opportunity to study the effects of the LEO environment on a functional solar array. To take advantage of this opportunity, a team composed of members from RSC-Energia (Russia), the Boeing Company, and the following NASA Centers--Johnson Space Center, Kennedy Space Center, Langley Research Center, Marshall Space Flight Center, and Lewis Research Center--was put together to analyze the array. After post-retrieval inspections at the Spacehab Facility at Kennedy in Florida, the array was shipped to Lewis in Cleveland for electrical performance tests, closeup photodocumentation, and removal of selected solar cells and blanket material. With approval from RSC-Energia, five cell pairs and their accompanying blanket and mesh material, and samples of painted handrail materials were selected for removal on the basis of their ability to provide degradation information. Sites were selected that provided different sizes and shapes of micrometeoroid impacts and different levels of surface contamination. These materials were then distributed among the team for round robin testing.

Rutledge, Sharon K.↗

NASA NTRS1982

Photovoltaic array: Power conditioner interface characteristics

The electrical output (power, current, and voltage) of flat plate solar arrays changes constantly, due primarily to changes in cell temperature and irradiance level. As a result, array loads such as dc-to-ac power conditioners must be capable of accommodating widely varying input levels while maintaining operation at or near the maximum power point of the array. The array operating characteristics and extreme output limits necessary for the systematic design of array load interfaces under a wide variety of climatic conditions are studied. A number of interface parameters are examined, including optimum operating voltage, voltage energy, maximum power and current limits, and maximum open circuit voltage. The effect of array degradation and I-V curve fill factor or the array power conditioner interface is also discussed. Results are presented as normalized ratios of power conditioner parameters to array parameters, making the results universally applicable to a wide variety of system sizes, sites, and operating modes.

Gonzalez, C. C.↗