Encapsulation task of the low-cost silicon solar array project. Investigation of test methods, material properties, and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.; Baum, B.; White, R. A.

1978-01-01

The results of an investigation of solar module encapsulation systems applicable to the Low-Cost Solar Array Project 1986 cost and performance goals are presented. Six basic construction elements were identified and their specific uses in module construction defined. A uniform coating basis was established for each element. The survey results were also useful in revealing price ranges for classes of materials and estimating the cost allocation for each element within the encapsulating cost goal. The six construction elements were considered to be substrates, superstrates, pottants, adhesives, outer covers and back covers.

The SCARLET{trademark} array for high power GEO satellites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spence, B.R.; Jones, P.A.; Eskenazi, M.I.

1997-12-31

The GEO satellite market is demanding increasingly capable spacecraft which, in turn, drives commercial spacecraft manufacturers to require significantly higher power solar arrays. As satellite capability increases the demand for high power array systems which are both cost and performance competitive becomes more crucial. Conventional rigid panel planar arrays, although suitable in the past, negatively impact spacecraft competitiveness for these new applications. The Solar Concentrator Array with Refractive Linear Element Technology (SCARLET{trademark}) represents an economically attractive solution for meeting these new high power requirements. When compared to conventional planar arrays, SCARLET provides substantially lower cost and higher deployed stiffness, competitivemore » mass, better producibility, and affordable use of high efficiency multijunction cells. This paper compares cost/performance characteristics of the SCARLET array to conventional planar arrays for high power GEO spacecraft applications. High power SCARLET array configurations are described, and inherent spacecraft and array level cost/performance benefits are presented.« less

Promising Results from Three NASA SBIR Solar Array Technology Development Programs

NASA Technical Reports Server (NTRS)

Eskenazi, Mike; White, Steve; Spence, Brian; Douglas, Mark; Glick, Mike; Pavlick, Ariel; Murphy, David; O'Neill, Mark; McDanal, A. J.; Piszczor, Michael

2005-01-01

Results from three NASA SBIR solar array technology programs are presented. The programs discussed are: 1) Thin Film Photovoltaic UltraFlex Solar Array; 2) Low Cost/Mass Electrostatically Clean Solar Array (ESCA); and 3) Stretched Lens Array SquareRigger (SLASR). The purpose of the Thin Film UltraFlex (TFUF) Program is to mature and validate the use of advanced flexible thin film photovoltaics blankets as the electrical subsystem element within an UltraFlex solar array structural system. In this program operational prototype flexible array segments, using United Solar amorphous silicon cells, are being manufactured and tested for the flight qualified UltraFlex structure. In addition, large size (e.g. 10 kW GEO) TFUF wing systems are being designed and analyzed. Thermal cycle and electrical test and analysis results from the TFUF program are presented. The purpose of the second program entitled, Low Cost/Mass Electrostatically Clean Solar Array (ESCA) System, is to develop an Electrostatically Clean Solar Array meeting NASA s design requirements and ready this technology for commercialization and use on the NASA MMS and GED missions. The ESCA designs developed use flight proven materials and processes to create a ESCA system that yields low cost, low mass, high reliability, high power density, and is adaptable to any cell type and coverglass thickness. All program objectives, which included developing specifications, creating ESCA concepts, concept analysis and trade studies, producing detailed designs of the most promising ESCA treatments, manufacturing ESCA demonstration panels, and LEO (2,000 cycles) and GEO (1,350 cycles) thermal cycling testing of the down-selected designs were successfully achieved. The purpose of the third program entitled, "High Power Platform for the Stretched Lens Array," is to develop an extremely lightweight, high efficiency, high power, high voltage, and low stowed volume solar array suitable for very high power (multi-kW to MW) applications. These objectives are achieved by combining two cutting edge technologies, the SquareRigger solar array structure and the Stretched Lens Array (SLA). The SLA SquareRigger solar array is termed SLASR. All program objectives, which included developing specifications, creating preliminary designs for a near-term SLASR, detailed structural, mass, power, and sizing analyses, fabrication and power testing of a functional flight-like SLASR solar blanket, were successfully achieved.

Commerical (terrestrial) and modified solar array design studies for low cost, low power space applications

NASA Technical Reports Server (NTRS)

Kolecki, J. C.; Riley, T. J.

1980-01-01

The suitability of commercial (terrestrial) solar arrays for use in low Earth orbit is examined. It is shown that commercial solar arrays degrade under thermal cycling because of material flexure, and that certain types of silicones used in the construction of these arrays outgas severely. Based on the results, modifications were made. The modified array retains the essential features of typical commercial arrays and can be easily built by commercial fabrication techniques at low cost. The modified array uses a metal tray for containment, but eliminates the high outgassing potting materials and glass cover sheets. Cells are individually mounted with an adhesive and individually covered with glass cover slips, or clear plastic tape. The modified array is found to withstand severe thermal cycling for long intervals of time.

Evaluation of solar cells and arrays for potential solar power satellite applications

NASA Technical Reports Server (NTRS)

Almgren, D. W.; Csigi, K.; Gaudet, A. D.

1978-01-01

Proposed solar array designs and manufacturing methods are evaluated to identify options which show the greatest promise of leading up to the develpment of a cost-effective SPS solar cell array design. The key program elements which have to be accomplished as part of an SPS solar cell array development program are defined. The issues focussed on are: (1) definition of one or more designs of a candidate SPS solar array module, using results from current system studies; (2) development of the necessary manufacturing requirements for the candidate SPS solar cell arrays and an assessment of the market size, timing, and industry infrastructure needed to produce the arrays for the SPS program; (3) evaluation of current DOE, NASA and DOD photovoltaic programs to determine the impacts of recent advances in solar cell materials, array designs and manufacturing technology on the candidate SPS solar cell arrays; and (4) definition of key program elements for the development of the most promising solar cell arrays for the SPS program.

LSSA (Low-cost Silicon Solar Array) project

NASA Technical Reports Server (NTRS)

1976-01-01

The Photovoltaic Conversion Program was established to find methods of economically generating enough electrical power to meet future requirements. Activities and progress in the following areas are discussed: silicon-refinement processes; silicon-sheet-growth techniques; encapsulants; manufacturing of off-the-shelf solar arrays; and procurement of semistandardized solar arrays.

Gallium arsenide solar array subsystem study

NASA Technical Reports Server (NTRS)

Miller, F. Q.

1982-01-01

The effects on life cycle costs of a number of technology areas are examined for a gallium arsenide space solar array. Four specific configurations were addressed: (1) a 250 KWe LEO mission - planer array; (2) a 250 KWe LEO mission - with concentration; (3) a 50 KWe GEO mission planer array; (4) a 50 KWe GEO mission - with concentration. For each configuration, a baseline system conceptual design was developed and the life cycle costs estimated in detail. The baseline system requirements and design technologies were then varied and their relationships to life cycle costs quantified. For example, the thermal characteristics of the baseline design are determined by the array materials and masses. The thermal characteristics in turn determine configuration, performance, and hence life cycle costs.

Concentrator enhanced solar arrays design study

NASA Technical Reports Server (NTRS)

Lott, D. R.

1978-01-01

The analysis and preliminary design of a 25 kW concentrator enhanced lightweight flexible solar array are presented. The study was organized into five major tasks: (1) assessment and specification of design requirements; (2) mechanical design; (3) electric design; (4) concentrator design; and (5) cost projection. The tasks were conducted in an iterative manner so as to best derive a baseline design selection. The objectives of the study are discussed and comparative configurations and mass data on the SEP (Solar Electric Propulsion) array design, concentrator design options and configuration/mass data on the selected concentrator enhanced solar array baseline design are presented. Design requirements supporting design analysis and detailed baseline design data are discussed. The results of the cost projection analysis and new technology are also discussed.

Low-cost Solar Array (LSA) project

NASA Technical Reports Server (NTRS)

1978-01-01

Progress made by the Low-Cost Silicon Solar Array Project during the period January through March 1978 is reported. It includes task reports on silicon material processing, large-area silicon sheet development, encapsulation materials testing and development, project engineering and operations, and manufacturing techniques, plus the steps taken to integrate these efforts.

Low-cost solar array project and Proceedings of the 15th Project Integration Meeting

NASA Technical Reports Server (NTRS)

1980-01-01

Progress made by the Low-Cost Solar Array Project during the period December 1979 to April 1980 is described. Project analysis and integration, technology development in silicon material, large area silicon sheet and encapsulation, production process and equipment development, engineering, and operation are included.

Flat-plate solar array project of the US Department of Energy's National Photovoltaics Program: Ten years of progress

NASA Technical Reports Server (NTRS)

Christensen, Elmer

1985-01-01

The Flat-Plate Solar Array (FSA) Project, a Government-sponsored photovoltaics project, was initiated in January 1975 (previously named the Low-Cost Silicon Solar Array Project) to stimulate the development of PV systems for widespread use. Its goal then was to develop PV modules with 10% efficiency, a 20-year lifetime, and a selling price of $0.50 per peak watt of generating capacity (1975 dollars). It was recognized that cost reduction of PV solar-cell and module manufacturing was the key achievement needed if PV power systems were to be economically competitive for large-scale terrestrial use.

Solar-Assisted Hemodialysis

PubMed Central

Agar, John W. M.; Perkins, Anthony; Tjipto, Alwie

2012-01-01

Summary Background and objectives Hemodialysis resource use—especially water and power, smarter processing and reuse of postdialysis waste, and improved ecosensitive building design, insulation, and space use—all need much closer attention. Regarding power, as supply diminishes and costs rise, alternative power augmentation for dialysis services becomes attractive. The first 12 months of a solar-assisted dialysis program in southeastern Australia is reported. Design, setting, participants, & measurements A 24-m2, 3-kWh rated solar array and inverter—total cost of A$16,219—has solar-assisted the dialysis-related power needs of a four-chair home hemodialysis training service. All array-created, grid-donated power and all grid-drawn power to the four hemodialysis machines and minireverse osmosis plant pairings are separately metered. After the grid-drawn and array-generated kilowatt hours have been billed and reimbursed at their respective commercial rates, financial viability, including capital repayment, can be assessed. Results From July of 2010 to July of 2011, the four combined equipment pairings used 4166.5 kWh, 9% more than the array-generated 3811.0 kWh. Power consumption at 26.7 c/kWh cost A$1145.79. Array-generated power reimbursements at 23.5 c/kWh were A$895.59. Power costs were, thus, reduced by 76.5%. As new reimbursement rates (60 c/kWh) take effect, system reimbursements will more than double, allowing both free power and potential capital pay down over 7.7 years. With expected array life of ∼30 years, free power and an income stream should accrue in the second and third operative decades. Conclusions Solar-assisted power is feasible and cost-effective. Dialysis services should assess their local solar conditions and determine whether this ecosensitive power option might suit their circumstance. PMID:22223614

Study of solar array switching power management technology for space power system

NASA Technical Reports Server (NTRS)

Cassinelli, J. E.

1982-01-01

This report documents work performed on the Solar Array Switching Power Management Study. Mission characteristics for three missions were defined to the depth necessary to determine their power management requirements. Solar array switching concepts were identified that could safisfy the mission requirements. These switching concepts were compared with a conventional buck regulator system on the basis of cost, weight and volume, reliability, efficiency and thermal control. For the missions reviewed, solar array switching provided significant advantages in all areas of comparison.

Study of solar array switching power management technology for space power system

NASA Technical Reports Server (NTRS)

Cassinelli, J. E.

1982-01-01

This report documents work performed on the Solar Array Switching Power Management Study. Mission characteristics for three missions were defined to the depth necessary to determine their power management requirements. Solar array switching concepts which could satisfy the mission requirements were identified. The switching concepts were compared with a conventional buck regulator system for cost, weight and volume, reliability, efficiency and thermal control. Solar array switching provided significant advantages in all areas of comparison for the reviewed missions.

Solar Power for Future NASA Missions

NASA Technical Reports Server (NTRS)

Bailey, Sheila G.; Landis, Geoffrey A.

2014-01-01

An overview of NASA missions and technology development efforts are discussed. Future spacecraft will need higher power, higher voltage, and much lower cost solar arrays to enable a variety of missions. One application driving development of these future arrays is solar electric propulsion.

NREL Adds Solar Array Field to Help Inform Consumers | NREL

Science.gov Websites

PV modules at NREL's new solar array field. Workers install PV modules just north of the NREL parking be Added Each Year Once completed, the new solar array field will house four rows of PV modules. The the lifetime of a PV system, and that increases the per-kilowatt-hour cost of generating solar

Study of multi-kilowatt solar arrays for Earth orbit applications

NASA Technical Reports Server (NTRS)

Patterson, R. E.

1983-01-01

A miniaturized Cassegrainian concentrator (MCC) solar array concept is being developed with the objective of significantly reducing the recurring cost of multikilowatt solar arrays. The desired cost reduction is obtained as a result of using very small high efficiency solar cells in conjuction with low cost optics. The MCC single element concept incident slar radiation is reflected rom a primary parabolic reflector to a secondary hyperbolic reflector and finally to a 4 millimeter diameter solar cell. A light catcher cone is used to improve off axis performance. The solar cell is mounted to a heat fin. An element is approximately 13 millimeters thick which permits efficient launch stowage of the concentrator system panels without complex optical component deployments or retractions. The MCC elements are packed in bays within graphite epoxy frames and are electrically connected into appropriate series-parallel circuits. A MCC sngle element with a 21 sq cm entrance aperture and a 20 efficient, 0.25 sq cm gallium arsenide solar cell has the same power output as 30 sq cm of 11-percent efficiency (at 68 C) silicon solar cells.

FACT, Mega-ROSA, SOLAROSA

NASA Technical Reports Server (NTRS)

Spence, Brian; White, Steve; Schmid, Kevin; Douglas Mark

2012-01-01

The Flexible Array Concentrator Technology (FACT) is a lightweight, high-performance reflective concentrator blanket assembly that can be used on flexible solar array blankets. The FACT concentrator replaces every other row of solar cells on a solar array blanket, significantly reducing the cost of the array. The modular design is highly scalable for the array system designer, and exhibits compact stowage, good off-pointing acceptance, and mass/cost savings. The assembly s relatively low concentration ratio, accompanied by a large radiative area, provides for a low cell operating temperature, and eliminates many of the thermal problems inherent in high-concentration-ratio designs. Unlike other reflector technologies, the FACT concentrator modules function on both z-fold and rolled flexible solar array blankets, as well as rigid array systems. Mega-ROSA (Mega Roll-Out Solar Array) is a new, highly modularized and extremely scalable version of ROSA that provides immense power level range capability from 100 kW to several MW in size. Mega-ROSA will enable extremely high-power spacecraft and SEP-powered missions, including space-tug and largescale planetary science and lunar/asteroid exploration missions. Mega-ROSA's inherent broad power scalability is achieved while retaining ROSA s solar array performance metrics and missionenabling features for lightweight, compact stowage volume and affordability. This innovation will enable future ultra-high-power missions through lowcost (25 to 50% cost savings, depending on PV and blanket technology), lightweight, high specific power (greater than 200 to 400 Watts per kilogram BOL (beginning-of-life) at the wing level depending on PV and blanket technology), compact stowage volume (greater than 50 kilowatts per cubic meter for very large arrays), high reliability, platform simplicity (low failure modes), high deployed strength/stiffness when scaled to huge sizes, and high-voltage operation capability. Mega-ROSA is adaptable to all photovoltaic and concentrator flexible blanket technologies, and can readily accommodate standard multijunction and emerging ultra-lightweight IMM (inverted metamorphic) photovoltaic flexible blanket assemblies, as well as ENTECHs Stretched Lens Array (SLA) and DSSs (Deployable Space Systems) FACT, which allows for cost reduction at the array level.

SMEX-Lite Modular Solar Array Architecture

NASA Technical Reports Server (NTRS)

Lyons, John W.; Day, John (Technical Monitor)

2002-01-01

The NASA Small Explorer (SMEX) missions have typically had three years between mission definition and launch. This short schedule has posed significant challenges with respect to solar array design and procurement. Typically, the solar panel geometry is frozen prior to going out with a procurement. However, with the SMEX schedule, it has been virtually impossible to freeze the geometry in time to avoid scheduling problems with integrating the solar panels to the spacecraft. A modular solar array architecture was developed to alleviate this problem. This approach involves procuring sufficient modules for multiple missions and assembling the modules onto a solar array framework that is unique to each mission. The modular approach removes the solar array from the critical path of the SMEX integration and testing schedule. It also reduces the cost per unit area of the solar arrays and facilitates the inclusion of experiments involving new solar cell or panel technologies in the SMEX missions.

An Economic Basis for Littoral Land-Based Production of Low Carbon Fuel from Renewable Electrical Energy and Seawater for Naval Use: Diego Garcia Evaluation

DTIC Science & Technology

2015-08-13

installed is $1.54 billion. Table 3 provides the cost breakdown of the various major components ( solar PV arrays, the carbon/hydrogen production units...barges or modular floats made from high density polymer HDP (Jet Dock and Versa Dock). These floats could support the entire solar PV array process...the restricted area is reached. Since the capital cost of the wind turbines is half that of the solar PV per Watt ($2.40/watt), the total cost

Solar photovoltaic power stations

NASA Technical Reports Server (NTRS)

Chowaniec, C. R.; Pittman, P. F.; Ferber, R. R.; Marshall, B. W.

1977-01-01

The subsystems of a solar photovoltaic central power system are identified and the cost of major components are estimated. The central power system, which would have a peak power capability in the range of 50 to 1000 MW, utilizes two types of subsystems - a power conditioner and a solar array. Despite differences in costs of inverters, the overall cost of the total power conditioning subsystem is about the same for all approaches considered. A combination of two inverters operating from balanced dc buses as a pair of 6-pulse groups is recommended. A number of different solar cell modules and tracking array structures were analyzed. It is concluded that when solar cell costs are high (greater than $500/kW), high concentration modules are more cost effective than those with low concentration. Vertical-axis tracking is the most effective of the studied tracking modes. For less expensive solar cells (less than $400/kW), fixed tilt collector/reflector modules are more cost effective than those which track.

Discussion on the solar concentrating thermoelectric generation using micro-channel heat pipe array

NASA Astrophysics Data System (ADS)

Li, Guiqiang; Feng, Wei; Jin, Yi; Chen, Xiao; Ji, Jie

2017-11-01

Heat pipe is a high efficient tool in solar energy applications. In this paper, a novel solar concentrating thermoelectric generation using micro-channel heat pipe array (STEG-MCHP) was presented. The flat-plate micro-channel heat pipe array not only has a higher heat transfer performance than the common heat pipe, but also can be placed on the surface of TEG closely, which can further reduce the thermal resistance between the heat pipe and the TEG. A preliminary comparison experiment was also conducted to indicate the advantages of the STEG-MCHP. The optimization based on the model verified by the experiment was demonstrated, and the concentration ratio and selective absorbing coating area were also discussed. In addition, the cost analysis was also performed to compare between the STEG-MCHP and the common solar concentrating TEGs in series. The outcome showed that the solar concentrating thermoelectric generation using micro-channel heat pipe array has the higher electrical efficiency and lower cost, which may provide a suitable way for solar TEG applications.

Flat-plate solar array project. Volume 3: Silicon sheet: Wafers and ribbons

NASA Technical Reports Server (NTRS)

Briglio, A.; Dumas, K.; Leipold, M.; Morrison, A.

1986-01-01

The primary objective of the Silicon Sheet Task of the Flat-Plate Solar Array (FSA) Project was the development of one or more low cost technologies for producing silicon sheet suitable for processing into cost-competitive solar cells. Silicon sheet refers to high purity crystalline silicon of size and thickness for fabrication into solar cells. Areas covered in the project were ingot growth and casting, wafering, ribbon growth, and other sheet technologies. The task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the task cost goals were not achieved.

Spraylon fluorocarbon encapsulation for silicon solar cell arrays

NASA Technical Reports Server (NTRS)

1977-01-01

A development program was performed for evaluating, modifying, and optimizing the Lockheed formulated liquid transparent filmforming Spraylon fluorocarbon protective coating for silicon solar cells and modules. The program objectives were designed to meet the requirements of the low-cost automated solar cell array fabrication process. As part of the study, a computer program was used to establish the limits of the safe working stress in the coated silicon solar cell array system under severe thermal shock.

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Astrophysics Data System (ADS)

Dinetta, L. C.; Hannon, M. H.

1995-10-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

Monolithically interconnected GaAs solar cells: A new interconnection technology for high voltage solar cell output

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Hannon, M. H.

1995-01-01

Photovoltaic linear concentrator arrays can benefit from high performance solar cell technologies being developed at AstroPower. Specifically, these are the integration of thin GaAs solar cell and epitaxial lateral overgrowth technologies with the application of monolithically interconnected solar cell (MISC) techniques. This MISC array has several advantages which make it ideal for space concentrator systems. These are high system voltage, reliable low cost monolithically formed interconnections, design flexibility, costs that are independent of array voltage, and low power loss from shorts, opens, and impact damage. This concentrator solar cell will incorporate the benefits of light trapping by growing the device active layers over a low-cost, simple, PECVD deposited silicon/silicon dioxide Bragg reflector. The high voltage-low current output results in minimal 12R losses while properly designing the device allows for minimal shading and resistance losses. It is possible to obtain open circuit voltages as high as 67 volts/cm of solar cell length with existing technology. The projected power density for the high performance device is 5 kW/m for an AMO efficiency of 26% at 1 5X. Concentrator solar cell arrays are necessary to meet the power requirements of specific mission platforms and can supply high voltage power for electric propulsion systems. It is anticipated that the high efficiency, GaAs monolithically interconnected linear concentrator solar cell array will enjoy widespread application for space based solar power needs. Additional applications include remote man-portable or ultra-light unmanned air vehicle (UAV) power supplies where high power per area, high radiation hardness and a high bus voltage or low bus current are important. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. There is also a high potential for a large number of consumer products. Dual-use applications can include battery chargers and remote power supplies for consumer electronics products such as portable telephones/beepers, portable radios, CD players, dashboard radar detectors, remote walkway lighting, etc.

Thin-Film Photovoltaic Solar Array Parametric Assessment

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Jacobs, Mark K.; Ponnusamy, Deva

2000-01-01

This paper summarizes a study that had the objective to develop a model and parametrically determine the circumstances for which lightweight thin-film photovoltaic solar arrays would be more beneficial, in terms of mass and cost, than arrays using high-efficiency crystalline solar cells. Previous studies considering arrays with near-term thin-film technology for Earth orbiting applications are briefly reviewed. The present study uses a parametric approach that evaluated the performance of lightweight thin-film arrays with cell efficiencies ranging from 5 to 20 percent. The model developed for this study is described in some detail. Similar mass and cost trends for each array option were found across eight missions of various power levels in locations ranging from Venus to Jupiter. The results for one specific mission, a main belt asteroid tour, indicate that only moderate thin-film cell efficiency (approx. 12 percent) is necessary to match the mass of arrays using crystalline cells with much greater efficiency (35 percent multi-junction GaAs based and 20 percent thin-silicon). Regarding cost, a 12 percent efficient thin-film array is projected to cost about half is much as a 4-junction GaAs array. While efficiency improvements beyond 12 percent did not significantly further improve the mass and cost benefits for thin-film arrays, higher efficiency will be needed to mitigate the spacecraft-level impacts associated with large deployed array areas. A low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is briefly described. The paper concludes with the observation that with the characteristics assumed for this study, ultra-lightweight arrays using efficient, thin-film cells on flexible substrates may become a leading alternative for a wide variety of space missions.

Terrestrial adaptation of the thermal heliotrope.

NASA Technical Reports Server (NTRS)

Fairbanks, J. W.; Morse, F. H.

1971-01-01

The principle of using bimetal helical coils to cause solar arrays to track the sun in space is presently under consideration for array orientation on several spacecraft. Adaptation of this thermal heliotrope to terrestrial applications introduces additional design considerations. The dominance of solar-radiation energy input to the helical coil over convective energy losses has to be ensured, and wind effects must be minimized. As long as the cost of solar cells remains high, orientation will always result in a significant cost saving for the converter.

Large-scale terrestrial solar cell power generation cost: A preliminary assessment

NASA Technical Reports Server (NTRS)

Spakowski, A. E.; Shure, L. I.

1972-01-01

A cost study was made to assess the potential of the large-scale use of solar cell power for terrestrial applications. The incentive is the attraction of a zero-pollution source of power for wide-scale use. Unlike many other concepts for low-pollution power generation, even thermal pollution is avoided since only the incident solar flux is utilized. To provide a basis for comparison and a perspective for evaluation, the pertinent technology was treated in two categories: current and optimistic. Factors considered were solar cells, array assembly, power conditioning, site preparation, buildings, maintenance, and operation. The capital investment was assumed to be amortized over 30 years. The useful life of the solar cell array was assumed to be 10 years, and the cases of zero and 50-percent performance deg-radation were considered. Land costs, taxes, and profits were not included in this study because it was found too difficult to provide good generalized estimates of these items. On the basis of the factors considered, it is shown that even for optimistic projections of technology, electric power from large-sclae terrestrial use of solar cells is approximately two to three orders of magnitude more costly than current electric power generation from either fossil or nuclear fuel powerplants. For solar cell power generation to be a viable competitor on a cost basis, technological breakthroughs would be required in both solar cell and array fabrication and in site preparation.

Photovoltaic solar array technology required for three wide scale generating systems for terrestrial applications: rooftop, solar farm, and satellite

NASA Technical Reports Server (NTRS)

Berman, P. A.

1972-01-01

Three major options for wide-scale generation of photovoltaic energy for terrestrial use are considered: (1) rooftop array, (2) solar farm, and (3) satellite station. The rooftop array would use solar cell arrays on the roofs of residential or commercial buildings; the solar farm would consist of large ground-based arrays, probably in arid areas with high insolation; and the satellite station would consist of an orbiting solar array, many square kilometers in area. The technology advancement requirements necessary for each option are discussed, including cost reduction of solar cells and arrays, weight reduction, resistance to environmental factors, reliability, and fabrication capability, including the availability of raw materials. The majority of the technology advancement requirements are applicable to all three options, making possible a flexible basic approach regardless of the options that may eventually be chosen. No conclusions are drawn as to which option is most advantageous, since the feasibility of each option depends on the success achieved in the technology advancement requirements specified.

Effects of design on cost of flat-plate solar photovoltaic arrays for terrestrial central station power applications

NASA Technical Reports Server (NTRS)

Tsou, P.; Stolte, W.

1978-01-01

The paper examines the impact of module and array designs on the balance-of-plant costs for flat-plate terrestrial central station power applications. Consideration is given to the following types of arrays: horizontal, tandem, augmented, tilt adjusted, and E-W tracking. The life-cycle cost of a 20-year plant life serves as the costing criteria for making design and cost tradeoffs. A tailored code of accounts is developed for determining consistent photovoltaic power plant costs and providing credible photovoltaic system cost baselines for flat-plate module and array designs by costing several varying array design approaches.

Silicon materials task of the low-cost solar array project. Phase 4: Effects of impurities and processing on silicon solar cells

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Hanes, M. H.; Davis, J. R.; Rohatgi, A.; Rai-Choudhury, P.; Mollenkopf, H. C.

1981-01-01

The effects of impurities, various thermochemical processes, and any impurity-process interactions upon the performance of terrestrial solar cells are defined. The results form a basis for silicon producers, wafer manufacturers, and cell fabricators to develop appropriate cost benefit relationships for the use of less pure, less costly solar grade silicon.

The Automated Array Assembly Task of the Low-cost Silicon Solar Array Project, Phase 2

NASA Technical Reports Server (NTRS)

Coleman, M. G.; Grenon, L.; Pastirik, E. M.; Pryor, R. A.; Sparks, T. G.

1978-01-01

An advanced process sequence for manufacturing high efficiency solar cells and modules in a cost-effective manner is discussed. Emphasis is on process simplicity and minimizing consumed materials. The process sequence incorporates texture etching, plasma processes for damage removal and patterning, ion implantation, low pressure silicon nitride deposition, and plated metal. A reliable module design is presented. Specific process step developments are given. A detailed cost analysis was performed to indicate future areas of fruitful cost reduction effort. Recommendations for advanced investigations are included.

SAMICS marketing and distribution model

NASA Technical Reports Server (NTRS)

1978-01-01

A SAMICS (Solar Array Manufacturing Industry Costing Standards) was formulated as a computer simulation model. Given a proper description of the manufacturing technology as input, this model computes the manufacturing price of solar arrays for a broad range of production levels. This report presents a model for computing these marketing and distribution costs, the end point of the model being the loading dock of the final manufacturer.

Glass for low-cost photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Bouquet, F. L.

1980-01-01

Various aspects of glass encapsulation that are important for the designer of photovoltaic systems are discussed. Candidate glasses and available information defining the state of the art of glass encapsulation materials and processes for automated, high volume production of terrestrial photovoltaic devices and related applications are presented. The criteria for consideration of the glass encapsulation systems were based on the low-cost solar array project goals for arrays: (1) a low degradation rate, (2) high reliability, (3) an efficiency greater than 10 percent, (4) a total array price less than $500/kW, and (5) a production capacity of 500,000 kW/yr. The glass design areas discussed include the types of glass, sources and costs, physical properties, and glass modifications, such as antireflection coatings.

Planetary and deep space requirements for photovoltaic solar arrays

NASA Technical Reports Server (NTRS)

Bankston, C. P.; Bennett, R. B.; Stella, P. M.

1995-01-01

In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, the majority of missions now being planned will use photovoltaic solar arrays. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. The paper will discuss representative requirements for a range of planetary missions now in the planning stages. Insofar as inner planets are concerned, a Mercury orbiter is being studied with many special requirements. Solar arrays would be exposed to high temperatures and a potentially high radiation environment, and will need to be increasingly pointed off sun as the vehicle approaches Mercury. Identification and development of cell materials and arrays at high incidence angles will be critical to the design. Missions to the outer solar system that have been studied include a Galilean orbiter and a flight to the Kuiper belt. While onboard power requirements would be small (as low as 10 watts), the solar intensity will require relatively large array areas. As a result, such missions will demand extremely compact packaging and low mass structures to conform to launch vehicle constraints. In turn, the large are, low mass designs will impact allowable spacecraft loads. Inflatable array structures, with and without concentration, and multiband gap cells will be considered if available. In general, the highest efficiency cell technologies operable under low intensity, low temperature conditions are needed. Solar arrays will power missions requiring as little as approximately 100 watts, up to several kilowatts (at Earth) in the case of solar electric propulsion missions. Thus, mass and stowage volume minimization will be required over a range of array sizes. Concentrator designs, inflatable structures, and the combination of solar arrays with the telecommunications system have been proposed. Performance, launch vehicle constraints, an cost will be the principal parameters in the design trade space. Other special applications will also be discussed, including requirements relating to planetary landers and probes. In those cases, issues relating to shock loads on landing, operability in (possibly dusty) atmospheres, and extreme temperature cycles must be considered, in addition to performance, stowed volume, and costs.

Product pricing in the Solar Array Manufacturing Industry - An executive summary of SAMICS

NASA Technical Reports Server (NTRS)

Chamberlain, R. G.

1978-01-01

Capabilities, methodology, and a description of input data to the Solar Array Manufacturing Industry Costing Standards (SAMICS) are presented. SAMICS were developed to provide a standardized procedure and data base for comparing manufacturing processes of Low-cost Solar Array (LSA) subcontractors, guide the setting of research priorities, and assess the progress of LSA toward its hundred-fold cost reduction goal. SAMICS can be used to estimate the manufacturing costs and product prices and determine the impact of inflation, taxes, and interest rates, but it is limited by its ignoring the effects of the market supply and demand and an assumption that all factories operate in a production line mode. The SAMICS methodology defines the industry structure, hypothetical supplier companies, and manufacturing processes and maintains a body of standardized data which is used to compute the final product price. The input data includes the product description, the process characteristics, the equipment cost factors, and production data for the preparation of detailed cost estimates. Activities validating that SAMICS produced realistic price estimates and cost breakdowns are described.

Accelerated/abbreviated test methods for predicting life of solar cell encapsulants to Jet Propulsion Laboratory California Institute of Technology for the encapsulation task of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Kolyer, J. M.

1978-01-01

An important principle is that encapsulants should be tested in a total array system allowing realistic interaction of components. Therefore, micromodule test specimens were fabricated with a variety of encapsulants, substrates, and types of circuitry. One common failure mode was corrosion of circuitry and solar cell metallization due to moisture penetration. Another was darkening and/or opacification of encapsulant. A test program plan was proposed. It includes multicondition accelerated exposure. Another method was hyperaccelerated photochemical exposure using a solar concentrator. It simulates 20 year of sunlight exposure in a short period of one to two weeks. The study was beneficial in identifying some cost effective encapsulants and array designs.

Initial results for the silicon monolithically interconnected solar cell product

NASA Technical Reports Server (NTRS)

Dinetta, L. C.; Shreve, K. P.; Cotter, J. E.; Barnett, A. M.

1995-01-01

This proprietary technology is based on AstroPower's electrostatic bonding and innovative silicon solar cell processing techniques. Electrostatic bonding allows silicon wafers to be permanently attached to a thermally matched glass superstrate and then thinned to final thicknesses less than 25 micron. These devices are based on the features of a thin, light-trapping silicon solar cell: high voltage, high current, light weight (high specific power) and high radiation resistance. Monolithic interconnection allows the fabrication costs on a per watt basis to be roughly independent of the array size, power or voltage, therefore, the cost effectiveness to manufacture solar cell arrays with output powers ranging from milliwatts up to four watts and output voltages ranging from 5 to 500 volts will be similar. This compares favorably to conventionally manufactured, commercial solar cell arrays, where handling of small parts is very labor intensive and costly. In this way, a wide variety of product specifications can be met using the same fabrication techniques. Prototype solar cells have demonstrated efficiencies greater than 11%. An open-circuit voltage of 5.4 volts, fill factor of 65%, and short-circuit current density of 28 mA/sq cm at AM1.5 illumination are typical. Future efforts are being directed to optimization of the solar cell operating characteristics as well as production processing. The monolithic approach has a number of inherent advantages, including reduced cost per interconnect and increased reliability of array connections. These features make this proprietary technology an excellent candidate for a large number of consumer products.

Feasibility Study of Solar Dome Encapsulation of Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

1978-01-01

The technical and economic advantages of using air-supported plastic enclosures to protect flat plate photovoltaic arrays are described. Conceptual designs for a fixed, latitude-tilt array and a fully tracking array were defined. Detailed wind loads and strength analyses were performed for the fixed array. Detailed thermal and power output analyses provided array performance for typical seasonal and extreme temperature conditions. Costs of each design as used in a 200 MWe central power station were defined from manufacturing and material cost estimates. The capital cost and cost of energy for the enclosed fixed-tilt array were lower than for the enclosed tracking array. The enclosed fixed-tilt array capital investment was 38% less, and the levelized bus bar energy cost was 26% less than costs for a conventional, glass-encapsulated array design. The predicted energy cost for the enclosed fixed array was 79 mills/kW-h for direct current delivered to the power conditioning units.

Light-trapping surface coating with concave arrays for efficiency enhancement in amorphous silicon thin-film solar cells

NASA Astrophysics Data System (ADS)

Liu, Daiming; Wang, Qingkang

2018-08-01

Light trapping is particularly important because of the desire to produce low-cost solar cells with the thinnest possible photoactive layers. Herein, along the research line of "optimization →fabrication →characterization →application", concave arrays were incorporated into amorphous silicon thin-film solar cell for lifting its photoelectric conversion efficiency. In advance, based on rigorous coupled wave analysis method, optics simulations were performed to obtain the optimal period of 10 μm for concave arrays. Microfabrication processes were used to etch concave arrays on glass, and nanoimprint was devoted to transfer the pattern onto polymer coatings with a high fidelity. Spectral characterizations prove that the concave-arrays coating enjoys excellent the light-trapping behaviors, by reducing the reflectance to 7.4% from 8.6% of bare glass and simultaneously allowing a high haze ratio of ∼ 70% in 350-800 nm. Compared with bare cell, the concave-arrays coating based amorphous silicon thin-film solar cell possesses the improving photovoltaic performances. Relative enhancements are 3.46% and 3.57% in short circuit current and photoelectric conversion efficiency, respectively. By the way, this light-trapping coating is facile, low-cost and large-scale, and can be straightforward introduced in other ready-made solar devices.

Life-cycle costs of high-performance cells

NASA Technical Reports Server (NTRS)

Daniel, R.; Burger, D.; Reiter, L.

1985-01-01

A life cycle cost analysis of high efficiency cells was presented. Although high efficiency cells produce more power, they also cost more to make and are more susceptible to array hot-spot heating. Three different computer analysis programs were used: SAMICS (solar array manufacturing industry costing standards), PVARRAY (an array failure mode/degradation simulator), and LCP (lifetime cost and performance). The high efficiency cell modules were found to be more economical in this study, but parallel redundancy is recommended.

Phase 1 of the automated array assembly task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Coleman, M. G.; Pryor, R. A.; Grenon, L. A.; Lesk, I. A.

1977-01-01

The state of technology readiness for the automated production of solar cells and modules is reviewed. Individual process steps and process sequences for making solar cells and modules were evaluated both technically and economically. High efficiency with a suggested cell goal of 15% was stressed. It is concluded that the technology exists to manufacture solar cells which will meet program goals.

Stretched Lens Array Photovoltaic Concentrator Technology Developed

NASA Technical Reports Server (NTRS)

Piszczor, Michael F., Jr.; O'Neill, Mark J.

2004-01-01

Solar arrays have been and continue to be the mainstay in providing power to nearly all commercial and government spacecraft. Light from the Sun is directly converted into electrical energy using solar cells. One way to reduce the cost of future space power systems is by minimizing the size and number of expensive solar cells by focusing the sunlight onto smaller cells using concentrator optics. The stretched lens array (SLA) is a unique concept that uses arched Fresnel lens concentrators to focus sunlight onto a line of high-efficiency solar cells located directly beneath. The SLA concept is based on the Solar Concentrator Array with Refractive Linear Element Technology (SCARLET) design that was used on NASA's New Millennium Deep Space 1 mission. The highly successful asteroid/comet rendezvous mission (1998 to 2001) demonstrated the performance and long-term durability of the SCARLET/SLA solar array design and set the foundation for further improvements to optimize its performance.

Flat-plate solar array project. Volume 5: Process development

NASA Technical Reports Server (NTRS)

Gallagher, B.; Alexander, P.; Burger, D.

1986-01-01

The goal of the Process Development Area, as part of the Flat-Plate Solar Array (FSA) Project, was to develop and demonstrate solar cell fabrication and module assembly process technologies required to meet the cost, lifetime, production capacity, and performance goals of the FSA Project. R&D efforts expended by Government, Industry, and Universities in developing processes capable of meeting the projects goals during volume production conditions are summarized. The cost goals allocated for processing were demonstrated by small volume quantities that were extrapolated by cost analysis to large volume production. To provide proper focus and coverage of the process development effort, four separate technology sections are discussed: surface preparation, junction formation, metallization, and module assembly.

Array automated assembly task low cost silicon solar array project, phase 2

NASA Technical Reports Server (NTRS)

Olson, C.

1980-01-01

Analyses of solar cell and module process steps for throughput rate, cost effectiveness, and reproductibility are reported. In addition to the concentration on cell and module processing sequences, an investigation was made into the capability of using microwave energy in the diffusion, sintering, and thick film firing steps of cell processing. Although the entire process sequence was integrated, the steps are treated individually with test and experimental data, conclusions, and recommendations.

STS-74/MIR Photogrammetric Appendage Structural Dynamics Experiment Preliminary Data Analysis

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.; Welch, Sharon S.; Pappa, Richard S.; Demeo, Martha E.

1997-01-01

The Photogrammetric Appendage Structural Dynamics Experiment was designed, developed, and flown to demonstrate and prove measurement of the structural vibration response of a Russian Space Station Mir solar array using photogrammetric methods. The experiment flew on the STS-74 Space Shuttle mission to Mir in November 1995 and obtained video imagery of solar array structural response to various excitation events. The video imagery has been digitized and triangulated to obtain response time history data at discrete points on the solar array. This data has been further processed using the Eigensystem Realization Algorithm modal identification technique to determine the natural vibration frequencies, damping, and mode shapes of the solar array. The results demonstrate that photogrammetric measurement of articulating, nonoptically targeted, flexible solar arrays and appendages is a viable, low-cost measurement option for the International Space Station.

Proceedings of the First ERDA Semiannual Solar Photovoltaic Conversion Program Conference

NASA Technical Reports Server (NTRS)

1975-01-01

Organization, basic research and applied technology for the Solar Photovoltaic Conversion Program are outlined. The program aims to provide a technology base for low cost thin film solar cells and solar arrays.

Wire Array Solar Cells: Fabrication and Photoelectrochemical Studies

NASA Astrophysics Data System (ADS)

Spurgeon, Joshua Michael

Despite demand for clean energy to reduce our addiction to fossil fuels, the price of these technologies relative to oil and coal has prevented their widespread implementation. Solar energy has enormous potential as a carbon-free resource but is several times the cost of coal-produced electricity, largely because photovoltaics of practical efficiency require high-quality, pure semiconductor materials. To produce current in a planar junction solar cell, an electron or hole generated deep within the material must travel all the way to the junction without recombining. Radial junction, wire array solar cells, however, have the potential to decouple the directions of light absorption and charge-carrier collection so that a semiconductor with a minority-carrier diffusion length shorter than its absorption depth (i.e., a lower quality, potentially cheaper material) can effectively produce current. The axial dimension of the wires is long enough for sufficient optical absorption while the charge-carriers are collected along the shorter radial dimension in a massively parallel array. This thesis explores the wire array solar cell design by developing potentially low-cost fabrication methods and investigating the energy-conversion properties of the arrays in photoelectrochemical cells. The concept was initially investigated with Cd(Se, Te) rod arrays; however, Si was the primary focus of wire array research because its semiconductor properties make low-quality Si an ideal candidate for improvement in a radial geometry. Fabrication routes for Si wire arrays were explored, including the vapor-liquid-solid growth of wires using SiCl4. Uniform, vertically aligned Si wires were demonstrated in a process that permits control of the wire radius, length, and spacing. A technique was developed to transfer these wire arrays into a low-cost, flexible polymer film, and grow multiple subsequent arrays using a single Si(111) substrate. Photoelectrochemical measurements on Si wire array/polymer composite films showed that their energy-conversion properties were comparable to those of an array attached to the growth substrate. High quantum efficiencies were observed relative to the packing density of the wires, particularly with illumination at high angles of incidence. The results indicate that an inexpensive, solid-state Si wire array solar cell is possible, and a plan is presented to develop one.

Phase 2 of the Array Automated Assembly Task for the Low Cost Silicon Solar Array Project

NASA Technical Reports Server (NTRS)

Wihl, M.; Torro, J.; Scheinine, A.; Anderson, J.

1978-01-01

An automated process sequence, to manufacture photovoltaic modules at a capacity of approximately 500 MW per year at a cost of approximately $0.50 per peak watt is described. Verification tests were performed and are reported along with cost predictions.

Thin-Film Solar Cells on Metal Foil Substrates for Space Power

NASA Technical Reports Server (NTRS)

Raffaelle, Ryne P.; Hepp, Aloysius F.; Hoffman, David J.; Dhere, N.; Tuttle, J. R.; Jin, Michael H.

2004-01-01

Photovoltaic arrays have played a key role in power generation in space. The current technology will continue to evolve but is limited in the important mass specific power metric (MSP or power/weight ratio) because it is based on bulk crystal technology. The objective of this research is to continue development of an innovative photovoltaic technology for satellite power sources that could provide up to an order of magnitude saving in both weight and cost, and is inherently radiation-tolerant through use of thin film technology and thin foil substrates such as 5-mil thick stainless steel foil or 1-mil thick Ti. Current single crystal technology for space power can cost more than $300 per watt at the array level and weigh more than 1 kg/sq m equivalent to specific power of approx. 65 W/kg. Thin film material such as CuIn(1-x),Ga(x)S2, (CIGS2), CuIn(1-x), G(x)Se(2-y),S(y), (CIGSS) or amorphous hydrogenated silicon (a-Si:H) may be able to reduce both the cost and mass per unit area by an order of magnitude. Manufacturing costs for solar arrays are an important consideration for total spacecraft budget. For a medium sized 5kW satellite, for example, the array manufacturing cost alone may exceed $2 million. Moving to thin film technology could reduce this expense to less than $500 K. Previous work at FSEC demonstrated the potential of achieving higher efficiencies from CIGSS thin film solar cells on 5-mil thick stainless steel foil as well as initial stages of facility augmentation for depositing thin film solar cells on larger (6"x 4") substrates. This paper presents further progress in processing on metal foil substrates. Also, previous work at DayStar demonstrated the feasibility of flexible-thin-film copper-indium-gallium-diselenide (CIGS) solar cells with a power-to-weight ratio in excess of 1000 W/kg. We will comment on progress on the critical issue of scale-up of the solar cell absorber deposition process. Several important technical issues need to be resolved to realize the benefits of lightweight technologies for solar arrays, such as: monolithic interconnects, lightweight array structures, and new ultra-light support and deployment mechanisms. Once the technology has gained spaceflight certification it should find rapid acceptance in specific satellite markets.

High-performance, flexible, deployable array development for space applications

NASA Technical Reports Server (NTRS)

Gehling, Russell N.; Armstrong, Joseph H.; Misra, Mohan S.

1994-01-01

Flexible, deployable arrays are an attractive alternative to conventional solar arrays for near-term and future space power applications, particularly due to their potential for high specific power and low storage volume. Combined with low-cost flexible thin-film photovoltaics, these arrays have the potential to become an enabling or an enhancing technology for many missions. In order to expedite the acceptance of thin-film photovoltaics for space applications, however, parallel development of flexible photovoltaics and the corresponding deployable structure is essential. Many innovative technologies must be incorporated in these arrays to ensure a significant performance increase over conventional technologies. For example, innovative mechanisms which employ shape memory alloys for storage latches, deployment mechanisms, and array positioning gimbals can be incorporated into flexible array design with significant improvement in the areas of cost, weight, and reliability. This paper discusses recent activities at Martin Marietta regarding the development of flexible, deployable solar array technology. Particular emphasis is placed on the novel use of shape memory alloys for lightweight deployment elements to improve the overall specific power of the array. Array performance projections with flexible thin-film copper-indium-diselenide (CIS) are presented, and government-sponsored solar array programs recently initiated at Martin Marietta through NASA and Air Force Phillips Laboratory are discussed.

Study of multi-kW solar arrays for Earth orbit application

NASA Technical Reports Server (NTRS)

1980-01-01

Low cost low Earth orbit (LOW) and geosynchronous Earth orbit (GEO) Solar Array concepts in the 300 to 1000 kW range which could be reduced to hardware in the mid 1980's, are identified. Size scaling factors and longer life demands are recognized as the prime drivers for the designs if low life cycle costs for energy are to be achieved. Technology is identified which requires further development in order to assure component readiness and availability. Use of the low concentration ratio (CR) concentrator, which uses gallium arsenide solar cells for both LEO and GEO applications, is recommended.

Large area low-cost space solar cell development

NASA Technical Reports Server (NTRS)

Baraona, C. R.; Cioni, J. L.

1982-01-01

A development program to produce large-area (5.9 x 5.9 cm) space quality silicon solar cells with a cost goal of 30 $/watt is descibed. Five cell types under investigation include wraparound dielectric, mechanical wraparound and conventional contact configurations with combinations of 2 or 10 ohm-cm resistivity, back surface reflectors and/or fields, and diffused or ion implanted junctions. A single step process to cut cell and cover-glass simultaneously is being developed. A description of cell developments by Applied Solar Energy Corp., Spectrolab and Spire is included. Results are given for cell and array tests, performed by Lockheed, TRW and NASA. Future large solar arrays that might use cells of this type are discussed.

Heterostructured TiO2/NiTiO3 Nanorod Arrays for Inorganic Sensitized Solar Cells with Significantly Enhanced Photovoltaic Performance and Stability.

PubMed

Li, Yue-Ying; Wang, Jian-Gan; Sun, Huan-Huan; Wei, Bingqing

2018-04-11

Organic dyes used in the conventional dye-sensitized solar cells (DSSCs) suffer from poor light stability and high cost. In this work, we demonstrate a new inorganic sensitized solar cell based on ordered one-dimensional semiconductor nanorod arrays of TiO 2 /NiTiO 3 (NTO) heterostructures prepared via a facile two-step hydrothermal approach. The semiconductor heterostructure arrays are highly desirable and promising for DSSCs because of their direct charge transport capability and slow charge recombination rate. The low-cost NTO inorganic semiconductor possesses an appropriate band gap that matches well with TiO 2 , which behaves like a "dye" to enable efficient light harvesting and fast electron-hole separation. The solar cells constructed by the ordered TiO 2 /NTO heterostructure photoanodes show a significantly improved power conversion efficiency, high fill factor, and more promising, outstanding life stability. The present work will open up an avenue to design heterostructured inorganics for high-performance solar cells.

A SEP Mission to Jupiter Using the Stretched Lens Array

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W.; Rodiek, Julie A.; Ferguson, Dale C.; O'Neill, Mark J.; Piszczor, Michael F.; Oleson, Steve

2008-01-01

As space exploration continues to be a primary focus of NASA, solar electric propulsion (SEP) becomes a forerunner in the mode of transportation to reach other planets in our solar system. Several critical issues emerge as potential barriers to this approach such as reducing solar array radiation damage, operating the array at high voltage (>300 V) for extended times for Hall or ion thrusters, and designing an array that will be resistant to micrometeoroid impacts and the differing environmental conditions as the vehicle travels further into space. It is also of great importance to produce an array that is light weight to preserve payload mass fraction and to do this at a cost that is lower than today's arrays. This paper will describe progress on an array that meets all these requirements and will detail its use in a solar electric mission to Jupiter. From 1998-2001, NASA flew the Deep Space 1 mission that validated the use of ion propulsion for extended space missions. This highly successful two-year mission also used a novel SCARLET solar array that concentrated sunlight eight-fold onto small area solar cells. This array performed flawlessly and within 2% of its projected performance over the entire mission. That design has evolved into the Stretched Lens Array (SLA) shown in figure 1. The primary difference between SCARLET and the SLA is that no additional glass cover is used over the silicone lens. This has led to significant mass, cost and complexity reductions. The module shown in figure 1 is the latest version of the design. This design leads to a specific power exceeding 300 W/kg at voltages exceeding 300 V. In addition, this module has been tested to voltages over 1000 V while under hypervelocity particle impact in a plasma environment with no arcing. Furthermore array segments are under test for corona breakdown that can become a critical issue for long term, high voltage missions.

Analysis and evaluation in the production process and equipment area of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Wolf, M.

1981-01-01

The effect of solar cell metallization pattern design on solar cell performance and the costs and performance effects of different metallization processes are discussed. Definitive design rules for the front metallization pattern for large area solar cells are presented. Chemical and physical deposition processes for metallization are described and compared. An economic evaluation of the 6 principal metallization options is presented. Instructions for preparing Format A cost data for solar cell manufacturing processes from UPPC forms for input into the SAMIC computer program are presented.

Use of Glass Reinforced Concrete (GRC) as a substrate for photovoltaic modules

NASA Technical Reports Server (NTRS)

Eirls, J. L.

1980-01-01

A substrate for flat plate photovoltaic solar panel arrays using a glass fiber reinforced concrete (GRC) material was developed. The installed cost of this GRC panel is 30% less than the cost goal of the Near Term Low-Cost Flat Plate Photovoltaic Solar Array Program. The 4 ft by 8 ft panel is fabricated from readily available inexpensive materials, weighs a nominal 190 lbs., has exceptionally good strength and durability properties (rigid and resists weathering), is amenable to mass production and is easily installed on simple mountings. Solar cells are encapsulated in ethylene/vinyl acetate with Tedlar backing and Korad cover film. The laminates are attached to the GRC substrate with acrylic transfer tape and edge sealed with silicone RTV adhesive.

A normative price for a manufactured product: The SAMICS methodology. Volume 2: Analysis

NASA Technical Reports Server (NTRS)

Chamberlain, R. G.

1979-01-01

The Solar Array Manufacturing Industry Costing Standards provide standard formats, data, assumptions, and procedures for determining the price a hypothetical solar array manufacturer would have to be able to obtain in the market to realize a specified after-tax rate of return on equity for a specified level of production. The methodology and its theoretical background are presented. The model is sufficiently general to be used in any production-line manufacturing environment. Implementation of this methodology by the Solar Array Manufacturing Industry Simultation computer program is discussed.

A Robust Design Approach to Cost Estimation: Solar Energy for Marine Corps Expeditionary Operations

DTIC Science & Technology

2014-07-14

solutions in such areas as photovoltaic arrays for power harvesting, light emitting diodes (LED) for decreased energy consumption, and improved battery...generation and conversion system that allows Marines to power systems with solar energy. Each GREENS is comprised of eight photovoltaic array panels...renewable power sources such as photovoltaic arrays and wind turbines. The HOMER model has been utilized for years by organizations and companies

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

The results of a study for Task 3 of the Low Cost Solar Array Project, directed toward the development of a cost effective encapsulation system for photovoltaic modules using silicon based materials, are reported. Results of the following are discussed: (1) weather-ometer stressing vs. weathering history of silicon and silicon modified materials; (2) humidity/temperature cycling exposure; (3) exposure at high humidity/high temperature; (4) outdoor exposure stress; (5) thermal cycling stress; and (6) UV screening agents. The plans for the next quarter are outlined.

Flexible Dye-Sensitized Solar Cell Based on Vertical ZnO Nanowire Arrays

PubMed Central

2011-01-01

Flexible dye-sensitized solar cells are fabricated using vertically aligned ZnO nanowire arrays that are transferred onto ITO-coated poly(ethylene terephthalate) substrates using a simple peel-off process. The solar cells demonstrate an energy conversion efficiency of 0.44% with good bending tolerance. This technique paves a new route for building large-scale cost-effective flexible photovoltaic and optoelectronic devices. PMID:27502660

Lightweight Integrated Solar Array and Transceiver. [Improving Electrical Power and Communication Capabilities in Small Spacecraft

NASA Technical Reports Server (NTRS)

Carr, John; Martinez, Andres; Petro, Andrew

2015-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) project will leverage several existing and on-going efforts at Marshall Space Flight Center (MSFC) for the design, development, fabrication, and test of a launch stowed, orbit deployed structure on which thin-film photovoltaics for power generation and antenna elements for communication, are embedded. Photovoltaics is a method for converting solar energy into electricity using semiconductor materials. The system will provide higher power generation with a lower mass, smaller stowage volume, and lower cost than the state of the art solar arrays, while simultaneously enabling deployable antenna concepts.

Considerations with respect to the design of solar photovoltaic power systems for terrestrial applications

NASA Technical Reports Server (NTRS)

Berman, P. A.

1972-01-01

The various factors involved in the development of solar photovoltaic power systems for terrestrial application are discussed. The discussion covers the tradeoffs, compromises, and optimization studies which must be performed in order to develop a viable terrestrial solar array system. It is concluded that the technology now exists for the fabrication of terrestrial solar arrays but that the economics are prohibitive. Various approaches to cost reduction are presented, and the general requirements for materials and processes to be used are delineated.

Chemical Vapor Deposition for Ultra-lightweight Thin-film Solar Arrays for Space

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Raffaelle, Ryne P.; Banger, Kulbinder K.; Jin, Michael H.; Lau, Janice E.; Harris, Jerry D.; Cowen, Jonathan E.; Duraj, Stan A.

2002-01-01

The development of thin-film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power, (W/kg). The use of a polycrystalline chalcopyrite absorber layer for thin film solar cells is considered as the next generation photovoltaic devices. A key technical issues outlined in the 2001 U.S. Photovoltaic Roadmap, is the need to develop low cost, high throughput manufacturing for high-efficiency thin film solar cells. At NASA GRC we have focused on the development of new single-source-precursors (SSPs) and their utility to deposit the chalcopyrite semi-conducting layer (CIS) onto flexible substrates for solar cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering is described. Thin-film fabrication studies demonstrate the SSPs can be used in a spray CVD process, for depositing CIS at reduced temperatures, which display good electrical properties, suitable for PV devices.

Large solar arrays

NASA Technical Reports Server (NTRS)

Crabtree, W. L.

1980-01-01

A spectrophotovoltaic converter, a thermophotovoltaic converter, a cassegrainian concentrator, a large silicon cell blanket, and a high flux approach are among the concepts being investigated as part of the multihundred kW solar array program for reducing the cost of photovoltaic energy in space. These concepts involve a range of technology risks, the highest risk being represented by the thermophotovoltaics and spectrophotovoltaics approaches which involve manipulation to of the incoming spectrum to enhance system efficiency. The planar array (solar blanket) has no technology risk and a moderate payback. The primary characteristics, components, and technology concerns of each of these concepts are summarized. An orbital power platform mission in the late 1980's is being used to allow a coherent technology advancement program in order to achieve a ten year life with maintenance at a capital recurring cost of $30/watt based on 1978 dollars.

A Robust Design Approach to Cost Estimation: Solar Energy for Marine Corps Expeditionary Operations

DTIC Science & Technology

2014-04-30

areas as photovoltaic arrays for power harvesting, light emitting diodes (LED) for decreased energy consumption, and improved battery and smart power ...conversion system that allows Marines to power systems with solar energy. Each GREENS is comprised of eight photovoltaic array panels, four high-energy...Brandon Newell conducted an experiment where he assessed the capabilities of the HOMER model in forecasting the power output of a solar panel at the

The Lightweight Integrated Solar Array and Transceiver (LISA-T): Second Generation Advancements and the Future of SmallSat Power Generation

NASA Technical Reports Server (NTRS)

Carr, John A.; Boyd, Darren; Martinez, Armando; SanSoucie, Michael; Johnson, Les; Laue, Greg; Farmer, Brandon; Smith, Joseph C.; Robertson, Barrett; Johnson, Mark

2016-01-01

This paper describes the second generation advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. LISA-T is a launch stowed, orbit deployed array on which thin-film photovoltaic and antenna elements are embedded. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between power, communications, and GN&C (guidance navigation and control) subsystems. This restricts payload capability and limits the value of these low-cost satellites. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft. A matrix of options are in development, including planar (pointed) and omnidirectional (non-pointed) arrays. The former is seeking the highest performance possible while the latter is seeking GN&C simplicity. In both cases, power generation ranges from tens of watts to several hundred with an expected specific power >250W/kg and a stowed power density >200kW/m(sub 3). Options for leveraging both high performance, 'typical cost' triple junction thin-film solar cells as well as moderate performance, low cost cells are being developed. Alongside, both UHF (ultra high frequency) and S-band antennas are being integrated into the array to move their space claim away from the spacecraft and open the door for omnidirectional communications and electronically steered phase arrays.

Concept designs for NASA's Solar Electric Propulsion Technology Demonstration Mission

NASA Technical Reports Server (NTRS)

Mcguire, Melissa L.; Hack, Kurt J.; Manzella, David H.; Herman, Daniel A.

2014-01-01

Multiple Solar Electric Propulsion Technology Demonstration Mission were developed to assess vehicle performance and estimated mission cost. Concepts ranged from a 10,000 kilogram spacecraft capable of delivering 4000 kilogram of payload to one of the Earth Moon Lagrange points in support of future human-crewed outposts to a 180 kilogram spacecraft capable of performing an asteroid rendezvous mission after launched to a geostationary transfer orbit as a secondary payload. Low-cost and maximum Delta-V capability variants of a spacecraft concept based on utilizing a secondary payload adapter as the primary bus structure were developed as were concepts designed to be co-manifested with another spacecraft on a single launch vehicle. Each of the Solar Electric Propulsion Technology Demonstration Mission concepts developed included an estimated spacecraft cost. These data suggest estimated spacecraft costs of $200 million - $300 million if 30 kilowatt-class solar arrays and the corresponding electric propulsion system currently under development are used as the basis for sizing the mission concept regardless of launch vehicle costs. The most affordable mission concept developed based on subscale variants of the advanced solar arrays and electric propulsion technology currently under development by the NASA Space Technology Mission Directorate has an estimated cost of $50M and could provide a Delta-V capability comparable to much larger spacecraft concepts.

Silicon materials task of the low cost solar array project, part 2

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Davis, J. R.; Rai-Choudhury, P.; Blais, P. D.; Mccormick, J. R.

1976-01-01

Purity requirements for solar cell grade silicon material was developed and defined by evaluating the effects of specific impurities and impurity levels on the performance of silicon solar cells. Also, data was generated forming the basis for cost-tradeoff analyses of silicon solar cell material. Growth, evaluation, solar cell fabrication and testing was completed for the baseline boron-doped Czochralski material. Measurements indicate Cn and Mn seriously degrade cell performance, while neither Ni nor Cu produce any serious reduction in cell efficiency.

Performance, size, mass, and cost estimates for projected 1kW EOL Si, InP, and GaAs arrays

NASA Technical Reports Server (NTRS)

Slifer, Luther W., Jr.

1991-01-01

One method of evaluating the potential of emerging solar cell and array technologies is to compare their projected capabilities in space flight applications to those of established Si solar cells and arrays. Such an application-oriented comparison provides an integrated view of the elemental comparisons of efficiency, radiation resistance, temperature sensitivity, size, mass, and cost in combination. In addition, the assumptions necessary to make the comparisons provide insights helpful toward determining necessary areas of development or evaluation. Finally, as developments and evaluations progress, the results can be used in more precisely defining the overall potential of the new technologies in comparison to existing technologies. The projected capabilities of Si, InP, and GaAs cells and arrays are compared.

Development of a low cost integrated 15 kW A.C. solar tracking sub-array for grid connected PV power system applications

NASA Astrophysics Data System (ADS)

Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

1997-02-01

Utility Power Group has achieved a significant reduction in the installed cost of grid-connected PV systems. The two part technical approach focused on 1) The utilization of a large area factory assembled PV panel, and 2) The integration and packaging of all sub-array power conversion and control functions within a single factory produced enclosure. Eight engineering prototype 15kW ac single axis solar tracking sub-arrays were designed, fabricated, and installed at the Sacramento Municipal Utility District's Hedge Substation site in 1996 and are being evaluated for performance and reliability. A number of design enhancements will be implemented in 1997 and demonstrated by the field deployment and operation of over twenty advanced sub-array PV power systems.

Wire Array Photovoltaics

NASA Astrophysics Data System (ADS)

Turner-Evans, Dan

Over the past five years, the cost of solar panels has dropped drastically and, in concert, the number of installed modules has risen exponentially. However, solar electricity is still more than twice as expensive as electricity from a natural gas plant. Fortunately, wire array solar cells have emerged as a promising technology for further lowering the cost of solar. Si wire array solar cells are formed with a unique, low cost growth method and use 100 times less material than conventional Si cells. The wires can be embedded in a transparent, flexible polymer to create a free-standing array that can be rolled up for easy installation in a variety of form factors. Furthermore, by incorporating multijunctions into the wire morphology, higher efficiencies can be achieved while taking advantage of the unique defect relaxation pathways afforded by the 3D wire geometry. The work in this thesis shepherded Si wires from undoped arrays to flexible, functional large area devices and laid the groundwork for multijunction wire array cells. Fabrication techniques were developed to turn intrinsic Si wires into full p-n junctions and the wires were passivated with a-Si:H and a-SiNx:H. Single wire devices yielded open circuit voltages of 600 mV and efficiencies of 9%. The arrays were then embedded in a polymer and contacted with a transparent, flexible, Ni nanoparticle and Ag nanowire top contact. The contact connected >99% of the wires in parallel and yielded flexible, substrate free solar cells featuring hundreds of thousands of wires. Building on the success of the Si wire arrays, GaP was epitaxially grown on the material to create heterostructures for photoelectrochemistry. These cells were limited by low absorption in the GaP due to its indirect bandgap, and poor current collection due to a diffusion length of only 80 nm. However, GaAsP on SiGe offers a superior combination of materials, and wire architectures based on these semiconductors were investigated for multijunction arrays. These devices offer potential efficiencies of 34%, as demonstrated through an analytical model and optoelectronic simulations. SiGe and Ge wires were fabricated via chemical-vapor deposition and reactive ion etching. GaAs was then grown on these substrates at the National Renewable Energy Lab and yielded ns lifetime components, as required for achieving high efficiency devices.

The Stretched Lens Array (SLA): A Low-Risk, Cost-Effective Array Offering Wing-Level Performance of 180 W/KG and 300 W/M2 at 300 VDC

NASA Technical Reports Server (NTRS)

ONeill, Mark; Piszczor, Michael F.; Eskenazi, Michael I.; McDanal, A. J.; George, Patrick J.; Botke, Matthew M.; Brandhorst, Henry W.; Edwards, David L.; Jaster, Paul A.; Lyons, Valerie J. (Technical Monitor)

2002-01-01

At IECEC 2001, our team presented a paper on the new stretched lens array (SLA), including its evolution from the successful SCARLET array on the NASA/JPL Deep Space 1 spacecraft. Since that conference, the SLA team has made significant advances in the SLA technology, including component-level improvements, array-level optimization, space environment exposure testing, and prototype hardware fabrication and evaluation. This paper describes the evolved version of the SLA, highlighting recent improvements in the lens, solar cell, photovoltaic receiver, rigid panel structure, and complete solar array wing.

Summary of flat-plate solar array project documentation. Abstracts of published documents, 1975 to June 1982

NASA Technical Reports Server (NTRS)

1982-01-01

Technologies that will enable the private sector to manufacture and widely use photovoltaic systems for the generation of electricity in residential, commercial, industrial, and government applications at a cost per watt that is competitive with other means is investigated. Silicon refinement processes, advanced silicon sheet growth techniques, solar cell development, encapsulation, automated fabrication process technology, advanced module/array design, and module/array test and evaluation techniques are developed.

Telescoping Solar Array Concept for Achieving High Packaging Efficiency

NASA Technical Reports Server (NTRS)

Mikulas, Martin; Pappa, Richard; Warren, Jay; Rose, Geoff

2015-01-01

Lightweight, high-efficiency solar arrays are required for future deep space missions using high-power Solar Electric Propulsion (SEP). Structural performance metrics for state-of-the art 30-50 kW flexible blanket arrays recently demonstrated in ground tests are approximately 40 kW/cu m packaging efficiency, 150 W/kg specific power, 0.1 Hz deployed stiffness, and 0.2 g deployed strength. Much larger arrays with up to a megawatt or more of power and improved packaging and specific power are of interest to mission planners for minimizing launch and life cycle costs of Mars exploration. A new concept referred to as the Compact Telescoping Array (CTA) with 60 kW/cu m packaging efficiency at 1 MW of power is described herein. Performance metrics as a function of array size and corresponding power level are derived analytically and validated by finite element analysis. Feasible CTA packaging and deployment approaches are also described. The CTA was developed, in part, to serve as a NASA reference solar array concept against which other proposed designs of 50-1000 kW arrays for future high-power SEP missions could be compared.

Point-Focus Concentration Compact Telescoping Array: Extreme Environments Solar Power Base Phase Final Report

NASA Technical Reports Server (NTRS)

McEachen, Michael E.; Murphy, Dave; Meinhold, Shen; Spink, Jim; Eskenazi, Mike; O'Neill, Mark

2017-01-01

Orbital ATK, in partnership with Mark ONeill LLC (MOLLC), has developed a novel solar array platform, PFC-CTA, which provides a significant advance in performance and cost reduction compared to all currently available space solar systems. PFC refers to the Point Focus Concentration of light provided by MOLLCs thin, flat Fresnel optics. These lenses focus light to a point of approximately 100 times the intensity of the ambient light, onto a solar cell of approximately 125th the size of the lens. CTA stands for Compact Telescoping Array, which is the solar array blanket structural platform originally devised by NASA and currently being advanced by Orbital ATK and partners under NASA and AFRL funding to a projected TRL 5+ by late-2018.The NASA Game Changing Development Extreme Environment Solar Power (EESP) Base Phase study has enabled Orbital ATK to refine component designs, perform component level and system performance analyses, and test prototype hardware of the key elements of PFC-CTA, and increased the TRL of PFC-specific technology elements to TRL 4. Key performance metrics currently projected are as follows: Scalability from 5 kW to 300 kW per wing (AM0); Specific Power 500 Wkg (AM0); Stowage Efficiency 100 kWm3; 5:1 margin on pointing tolerance vs. capability; 50 launched cost savings; Wide range of operability between Venus and Saturn by active andor passive thermal management.

Novel anti-reflection technology for GaAs single-junction solar cells using surface patterning and Au nanoparticles.

PubMed

Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Kim, Sangin; Rotermund, Fabian; Lim, Hanjo; Lee, Jaejin

2012-07-01

Single-junction GaAs solar cell structures were grown by low-pressure MOCVD on GaAs (100) substrates. Micro-rod arrays with diameters of 2 microm, 5 microm, and 10 microm were fabricated on the surfaces of the GaAs solar cells via photolithography and wet chemical etching. The patterned surfaces were coated with Au nanoparticles using an Au colloidal solution. Characteristics of the GaAs solar cells with and without the micro-rod arrays and Au nanoparticles were investigated. The short-circuit current density of the GaAs solar cell with 2 microm rod arrays and Au nanoparticles increased up to 34.9% compared to that of the reference cell without micro-rod arrays and Au nanoparticles. The conversion efficiency of the GaAs solar cell that was coated with Au nanoparticles on the patterned surface with micro-rod arrays can be improved from 14.1% to 19.9% under 1 sun AM 1.5G illumination. These results show that micro-rod arrays and Au nanoparticle coating can be applied together in surface patterning to achieve a novel cost-effective anti-reflection technology.

Overview - Flat-plate technology. [review of Low Cost Solar Array Project

NASA Technical Reports Server (NTRS)

Callaghan, W. T.

1981-01-01

Progress and continuing plans for the joint NASA/DoE program at the JPL to develop the technologies and industrial processes necessary for mass production of low-cost solar arrays (LSA) which produce electricity from solar cells at a cost of less than $0.70/W are reviewed. Attention is given to plans for a demonstration Si refinement plant capable of yielding 1000 MT/yr, and to a CVD process with chlorosilane, which will yield material at a cost of $21/kg. Ingot and shaped-sheet technologies, using either Czochralski growth and film fed growth methods have yielded AM1 15% efficient cells in an automated process. Encapsulation procedures have been lowered to $14/sq m, and robotics have permitted assembled cell production at a rate of 10 sec/cell. Standards are being defined for module safety features. It is noted that construction of a pilot Si purification plant is essential to achieving the 1986 $0.70/W cost goals.

Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

NASA Technical Reports Server (NTRS)

Lockett, Tiffany Russell; Martinez, Armando; Boyd, Darren; SanSouice, Michael; Farmer, Brandon; Schneider, Todd; Laue, Greg; Fabisinski, Leo; Johnson, Les; Carr, John A.

2015-01-01

This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans.

Advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) Small Spacecraft System

NASA Technical Reports Server (NTRS)

Russell, Tiffany; Martinez, Armando; Boyd, Darren; SanSoucie, Michael; Farmer, Brandon; Schneider, Todd; Fabisinski, Leo; Johnson, Les; Carr, John A.

2015-01-01

This paper describes recent advancements of the Lightweight Integrated Solar Array and Transceiver (LISA-T) currently being developed at NASA's Marshall Space Flight Center. The LISA-T array comprises a launch stowed, orbit deployed structure on which thin-film photovoltaic (PV) and antenna devices are embedded. The system provides significant electrical power generation at low weights, high stowage efficiency, and without the need for solar tracking. Leveraging high-volume terrestrial-market PVs also gives the potential for lower array costs. LISA-T is addressing the power starvation epidemic currently seen by many small-scale satellites while also enabling the application of deployable antenna arrays. Herein, an overview of the system and its applications are presented alongside sub-system development progress and environmental testing plans/initial results.

Development of an all-metal thick film cost effective metallization system for solar cells

NASA Technical Reports Server (NTRS)

Ross, B.; Parker, J.

1983-01-01

Improved thick film solar cell contacts for the high volume production of low cost silicon solar arrays are needed. All metal screenable pastes made from economical base metals and suitable for application to low to high conductivity silicon were examined. Silver fluoride containing copper pastes and fluorocarbon containing copper pastes were discussed. The effect of hydrogen on the adhesion of metals to silicon was investigated. A cost analysis of various paste materials is provided.

Photovoltaic Roofs

NASA Technical Reports Server (NTRS)

Drummond, R. W., Jr.; Shepard, N. F., Jr.

1984-01-01

Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

Assessment of Present State-of-the-art Sawing Technology of Large Diameter Ingots for Solar Sheet Material

NASA Technical Reports Server (NTRS)

Yoo, H. I.

1978-01-01

Work is reported on: (1) slicing of the ingots with the multiblade slurry saw, the multiwire slurry saw and the I.D. saw, (2) characterization of the sliced wafers, and (3) analysis of add-on slicing cost based on Solar Array Manufacturing Industry Costing Standard.

First Thin Film Festival

NASA Astrophysics Data System (ADS)

Samson, Philippe

2005-05-01

The constant evolution of the satellite market is asking for better technical performances and reliability for a reduced cost. Solar array is in front line of this challenge.This can be achieved by present technologies progressive improvement in cost reduction or by technological breakthrough.To reach an effective End Of Live performance100 W/kg of solar array is not so easy, even if you suppose that the mass of everything is nothing!Thin film cells are potential candidate to contribute to this challenge with certain confidence level and consequent development plan validation and qualification on ground and flight.Based on a strong flight heritage in flexible Solar Array design, the work has allowed in these last years, to pave the way on road map of thin film technologies . This is encouraged by ESA on many technological contracts put in concurrent engineering.CISG was selected cell and their strategy of design, contributions and results will be presented.Trade-off results and Design to Cost solutions will discussed.Main technical drivers, system design constraints, market access, key technologies needed will be detailed in this paper and the resulting road-map and development plan will be presented.

A High-Efficiency Si Nanowire Array/Perovskite Hybrid Solar Cell.

PubMed

Yan, Xin; Zhang, Chen; Wang, Jiamin; Zhang, Xia; Ren, Xiaomin

2017-12-01

A low-cost Si nanowire array/perovskite hybrid solar cell is proposed and simulated. The solar cell consists of a Si p-i-n nanowire array filled with CH 3 NH 3 PbI 3 , in which both the nanowires and perovskite absorb the incident light while the nanowires act as the channels for transporting photo-generated electrons and holes. The hybrid structure has a high absorption efficiency in a broad wavelength range of 300~800 nm. A large short-circuit current density of 28.8 mA/cm 2 and remarkable conversion efficiency of 13.3% are obtained at a thin absorber thickness of 1.6 μm, which are comparable to the best results of III-V nanowire solar cells.

Current Approach in Surface Plasmons for Thin Film and Wire Array Solar Cell Applications

PubMed Central

Zhou, Keya; Guo, Zhongyi; Liu, Shutian; Lee, Jung-Ho

2015-01-01

Surface plasmons, which exist along the interface of a metal and a dielectric, have been proposed as an efficient alternative method for light trapping in solar cells during the past ten years. With unique properties such as superior light scattering, optical trapping, guide mode coupling, near field concentration, and hot-electron generation, metallic nanoparticles or nanostructures can be tailored to a certain geometric design to enhance solar cell conversion efficiency and to reduce the material costs. In this article, we review current approaches on different kinds of solar cells, such as crystalline silicon (c-Si) and amorphous silicon (a-Si) thin film solar cells, organic solar cells, nanowire array solar cells, and single nanowire solar cells. PMID:28793457

Development of an all-metal thick film cost affective metallization system for solar cells

NASA Technical Reports Server (NTRS)

Ross, B.

1981-01-01

An economical thick film solar cell contact for high volume production of low cost silicon solar array modules was investigated. All metal screenable pastes using base metals were studied. Solar cells with junction depths varying by a factor of 3.3, with and without a deposited oxide coating were used. Cells were screened and fired by a two step firing process. Adhesion and metallurgical results are unsatisfactory. No electrical information is obtained due to inadequate contact adhesion.

Assessment of High-Voltage Photovoltaic Technologies for the Design of a Direct Drive Hall Effect Thruster Solar Array

NASA Technical Reports Server (NTRS)

Mikellides, I. G.; Jongeward, G. A.; Schneider, T.; Carruth, M. R.; Peterson, T.; Kerslake, T. W.; Snyder, D.; Ferguson, D.; Hoskins, A.

2004-01-01

A three-year program to develop a Direct Drive Hall-Effect Thruster system (D2HET) begun in 2001 as part of the NASA Advanced Cross-Enterprise Technology Development initiative. The system, which is expected to reduce significantly the power processing, complexity, weight, and cost over conventional low-voltage systems, will employ solar arrays that operate at voltages higher than (or equal to) 300 V. The lessons learned from the development of the technology also promise to become a stepping-stone for the production of the next generation of power systems employing high voltage solar arrays. This paper summarizes the results from experiments conducted mainly at the NASA Marshal Space Flight Center with two main solar array technologies. The experiments focused on electron collection and arcing studies, when the solar cells operated at high voltages. The tests utilized small coupons representative of each solar array technology. A hollow cathode was used to emulate parts of the induced environment on the solar arrays, mostly the low-energy charge-exchange plasma (1012-1013 m-3 and 0.5-1 eV). Results and conclusions from modeling of electron collection are also summarized. The observations from the total effort are used to propose a preliminary, new solar array design for 2 kW and 30-40 kW class, deep space missions that may employ a single or a cluster of Hall- Effect thrusters.

The Array Automated Assembly Task for the Low Cost Solar Array Project, Phase 2

NASA Technical Reports Server (NTRS)

Campbell, R. B. (Editor); Farukhi, S. (Editor)

1978-01-01

During the program a process sequence was proposed and tested for the fabrication of dendritic welb silicon into solar modules. This sequence was analyzed as to yield and cost and these data suggest that the price goals of 1986 are attainable. Specifically, it was shown that a low cost POCL3 is a suitable replacement for the semiconductor grade, and that a suitable CVD oxide can be deposited from a silane/air mixture using a Silox reactor. A dip coating method was developed for depositing an antireflection coating from a metalorganic precursor. Application of photoresist to define contact grids was made cost effective through use of a dip coating technique. Electroplating of both Ag and Cu was shown feasible and cost effective for producing the conductive metal grids on the solar cells. Laser scribing was used to separate the cells from the dendrites without degradation. Ultrasonic welding methods were shown to be feasible for interconnecting the cells. A study of suitable low cost materials for encapsulation suggest that soda lime glass and phenolic filled board are preferred.

Silicon material task - Low cost solar array project /JPL/DOE/

NASA Technical Reports Server (NTRS)

Lutwack, R.

1979-01-01

The paper describes the silicon material task of the low-cost solar array project, which has the objective of establishing a silicon production capability equivalent to 500 mW per year at a price less than 10 dollars/kg (1975 dollars) in 1986. The task program is divided into four phases: technical feasibility, scale-up studies (the present phase), experimental process system development units, and implementation of large-scale production plants, and it involves the development of processes for two groups of materials, that is, semiconductor grade and solar cell grade. In addition, the effects of impurities on solar cell performance are being investigated. Attention is given to problem areas of the task program, such as environmental protection, material compatibility between the reacting chemicals and materials of construction of the equipment, and waste disposal.

Uses of infrared thermography in the low-cost solar array program

NASA Technical Reports Server (NTRS)

Glazer, S. D.

1982-01-01

The Jet Propulsion Laboratory has used infrared thermography extensively in the Low-Cost Solar Array (LSA) photovoltaics program. A two-dimensional scanning infrared radiometer has been used to make field inspections of large free-standing photovoltaic arrays and smaller demonstration sites consisting of integrally mounted rooftop systems. These field inspections have proven especially valuable in the research and early development phases of the program, since certain types of module design flaws and environmental degradation manifest themselves in unique thermal patterns. The infrared camera was also used extensively in a series of laboratory tests on photovoltaic cells to obtain peak cell temperatures and thermal patterns during off-design operating conditions. The infrared field inspections and the laboratory experiments are discussed, and sample results are presented.

Automated Array Assembly, Phase 2. Low-cost Solar Array Project, Task 4

NASA Technical Reports Server (NTRS)

Lopez, M.

1978-01-01

Work was done to verify the technological readiness of a select process sequence with respect to satisfying the Low Cost Solar Array Project objectives of meeting the designated goals of $.50 per peak watt in 1986 (1975 dollars). The sequence examined consisted of: (1) 3 inches diameter as-sawn Czochralski grown 1:0:0 silicon, (2) texture etching, (3) ion implanting, (4) laser annealing, (5) screen printing of ohmic contacts and (6) sprayed anti-reflective coatings. High volume production projections were made on the selected process sequence. Automated processing and movement of hardware at high rates were conceptualized to satisfy the PROJECT's 500 MW/yr capability. A production plan was formulated with flow diagrams integrating the various processes in the cell fabrication sequence.

Analysis of Roll Steering for Solar Electric Propulsion Missions

NASA Technical Reports Server (NTRS)

Pederson, Dylan, M.; Hojnicki, Jeffrey, S.

2012-01-01

Nothing is more vital to a spacecraft than power. Solar Electric Propulsion (SEP) uses that power to provide a safe, reliable, and, most importantly, fuel efficient means to propel a spacecraft to its destination. The power performance of an SEP vehicle s solar arrays and electrical power system (EPS) is largely influenced by the environment in which the spacecraft is operating. One of the most important factors that determines solar array power performance is how directly the arrays are pointed to the sun. To get the most power from the solar arrays, the obvious solution is to point them directly at the sun at all times. Doing so is not a problem in deep space, as the environment and pointing conditions that a spacecraft faces are fairly constant and are easy to accommodate, if necessary. However, large and sometimes rapid variations in environmental and pointing conditions are experienced by Earth orbiting spacecraft. SEP spacecraft also have the additional constraint of needing to keep the thrust vector aligned with the velocity vector. Thus, it is important to analyze solar array power performance for any vehicle that spends an extended amount of time orbiting the Earth, and to determine how much off-pointing can be tolerated to produce the required power for a given spacecraft. This paper documents the benefits and drawbacks of perfectly pointing the solar arrays of an SEP spacecraft spiraling from Earth orbit, and how this might be accomplished. Benefits and drawbacks are defined in terms of vehicle mass, power, volume, complexity, and cost. This paper will also look at the application of various solar array pointing methods to future missions. One such pointing method of interest is called roll steering . Roll steering involves rolling the entire vehicle twice each orbit. Roll steering, combined with solar array gimbal tracking, is used to point the solar arrays perfectly towards the sun at all points in the orbit, while keeping the vehicle thrusters aligned in the velocity direction. Roll steering is particularly attractive for a recently proposed mission that involves a spiral trajectory from low Earth orbit (LEO) to the Earth-Moon Lagrange Point 1 (E-M L1). During the spiral, the spacecraft will spend over 300 days experiencing the full spectrum of near-earth environments and solar array pointing conditions. An extensive study of the application of SEP (and roll steering) to this spiral mission is included, highlighting the ultimate goal of reduced vehicle cost and mass. Tools used for this analysis include the Systems Power Analysis for Capability Evaluation (Refs. 1 and 2) (SPACE) electrical power systems code, and SEP trajectory simulation tools developed at NASA Glenn Research Center.

PEP solar array definition study

NASA Technical Reports Server (NTRS)

1979-01-01

The power extension package (PEP) is a solar array system that will be used on the space transportation system to augment the power of the Orbiter vehicle and to extend the time the vehicle may stay in orbit. The baseline configuration of the PEP is reviewed. The programmatic aspects of the design covering the development plan, the manufacturing facility plan and the estimated costs and risks are presented.

Highly efficient ultrathin-film amorphous silicon solar cells on top of imprinted periodic nanodot arrays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Wensheng, E-mail: yws118@gmail.com; Gu, Min, E-mail: mgu@swin.edu.au; Tao, Zhikuo

2015-03-02

The addressing of the light absorption and conversion efficiency is critical to the ultrathin-film hydrogenated amorphous silicon (a-Si:H) solar cells. We systematically investigate ultrathin a-Si:H solar cells with a 100 nm absorber on top of imprinted hexagonal nanodot arrays. Experimental evidences are demonstrated for not only notable silver nanodot arrays but also lower-cost ITO and Al:ZnO nanodot arrays. The measured external quantum efficiency is explained by the simulation results. The J{sub sc} values are 12.1, 13.0, and 14.3 mA/cm{sup 2} and efficiencies are 6.6%, 7.5%, and 8.3% for ITO, Al:ZnO, and silver nanodot arrays, respectively. Simulated optical absorption distribution shows high lightmore » trapping within amorphous silicon layer.« less

Stretched Lens Array (SLA) for Collection and Conversion of Infrared Laser Light: 45% Efficiency Demonstrated for Near-Term 800 W/kg Space Power System

NASA Technical Reports Server (NTRS)

O'Neill, Mark; Howell, Joe; Fikes, John; Fork, Richard; Phillips, Dane; Aiken, Dan; McDanal, A. J.

2006-01-01

For the past 2% years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system.

Lightweight diaphragm mirror module system for solar collectors

DOEpatents

Butler, Barry L.

1985-01-01

A mirror module system is provided for accurately focusing solar radiation on a point or a line as defined by an array of solar collectors. Each mirror module includes a flexible membrane stretched over a frame in a manner similar to that of a drum or a trampoline and further includes a silvered glass or plastic mirror for forming an optical reflecting surface. The configuration of the optical reflecting surface is variably adjustable to provide for the accurate focusing of the solar energy on a given collector array, e.g., a point or a linear array arrangement. The flexible mirror-membrane combination is lightweight to facilitate installation and reduce system cost yet structurally strong enough to provide for the precise focusing of the incident solar radiation in a semi-rigid reflector system in which unwanted reflector displacement is minimized.

Lightweight diaphragm mirror module system for solar collectors

DOEpatents

Butler, B.L.

1984-01-01

A mirror module system is provided for accurately focusing solar radiation on a point or a line as defined by an array of solar collectors. Each mirror module includes a flexible membrane stretched over a frame in a manner similar to that of a drum or a trampoline and further includes a silvered glass or plastic mirror for forming an optical reflecting surface. The configuration of the optical reflecting surface is variably adjustable to provide for the accurate focusing of the solar energy on a given collector array, e.g., a point or a linear array arrangement. The flexible mirror-membrane combination is lightweight to facilitate installation and reduce system cost yet structurally strong enough to provide for the precise focusing of the incident solar radiation in a semi-rigid reflector system in which unwanted reflector displacement is minimized.

Development of CIGS2 Thin Films on Ultralightweight Flexible Large Area Foil Sunstrates

NASA Technical Reports Server (NTRS)

Dhere, Neelkanth G.; Gade, Vivek S.; Kadam, Ankur A.; Jahagirdar, Anant H.; Kulkarni, Sachin S.; Bet, Sachin M.

2005-01-01

The development of thin film solar cells is aimed at reducing the costs for photovoltaic systems. Use of thin film technology and thin foil substrate such as 5-mil thick stainless steel foil or 1-mil thick Ti would result in considerable costs savings. Another important aspect is manufacturing cost. Current single crystal technology for space power can cost more than $ 300 per watt at the array level and weigh more than 1 kg/sq m equivalent to specific power of approx. 65 W/kg. Thin film material such as CuIn1-xGaxS2 (CIGS2), CuIn(1-x)Ga(x)Se(2-y)S(y) (CIGSS) or amorphous hydrogenated silicon (a-Si:H) may be able to reduce both the cost and mass per unit area by an order of magnitude. Manufacturing costs for solar arrays are an important consideration for total spacecraft budget. For a medium sized 5kW satellite for example, the array manufacturing cost alone may exceed $ 2 million. Moving to thin film technology could reduce this expense to less than $ 500K. Earlier publications have demonstrated the potential of achieving higher efficiencies from CIGSS thin film solar cells on 5-mil thick stainless steel foil as well as initial stages of facility augmentation for depositing thin film solar cells on larger (6 in x 4 in) substrates. This paper presents the developmental study of achieving stress free Mo coating; uniform coatings of Mo back contact and metallic precursors. The paper also presents the development of sol gel process, refurbishment of selenization/sulfurization furnace, chemical bath deposition (CBD) for n-type CdS and scrubber for detoxification of H2S and H2Se gases.

Research and development of low cost processes for integrated solar arrays. Final report, April 15, 1974--January 14, 1976

DOE Office of Scientific and Technical Information (OSTI.GOV)

Graham, C.D.; Kulkarni, S.; Louis, E.

1976-05-01

Results of a program to study process routes leading to a low cost large area integrated silicon solar array manufacture for terrestrial applications are reported. Potential processes for the production of solar-grade silicon are evaluated from thermodynamic, economic, and technical feasibility points of view. Upgrading of the present arc-furnace process is found most favorable. Experimental studies of the Si/SiF/sub 4/ transport and purification process show considerable impurity removal and reasonable transport rates. Silicon deformation experiments indicate production of silicon sheet by rolling at 1350/sup 0/C is feasible. Significant recrystallization by strain-anneal technique has been observed. Experimental recrystallization studies using anmore » electron beam line source are discussed. A maximum recrystallization velocity of approximately 9 m/hr is calculated for silicon sheet. A comparative process rating technique based on detailed cost analysis is presented.« less

Costs of solar and wind power variability for reducing CO2 emissions.

PubMed

Lueken, Colleen; Cohen, Gilbert E; Apt, Jay

2012-09-04

We compare the power output from a year of electricity generation data from one solar thermal plant, two solar photovoltaic (PV) arrays, and twenty Electric Reliability Council of Texas (ERCOT) wind farms. The analysis shows that solar PV electricity generation is approximately one hundred times more variable at frequencies on the order of 10(-3) Hz than solar thermal electricity generation, and the variability of wind generation lies between that of solar PV and solar thermal. We calculate the cost of variability of the different solar power sources and wind by using the costs of ancillary services and the energy required to compensate for its variability and intermittency, and the cost of variability per unit of displaced CO(2) emissions. We show the costs of variability are highly dependent on both technology type and capacity factor. California emissions data were used to calculate the cost of variability per unit of displaced CO(2) emissions. Variability cost is greatest for solar PV generation at $8-11 per MWh. The cost of variability for solar thermal generation is $5 per MWh, while that of wind generation in ERCOT was found to be on average $4 per MWh. Variability adds ~$15/tonne CO(2) to the cost of abatement for solar thermal power, $25 for wind, and $33-$40 for PV.

Modeling and reconfiguration of solar photovoltaic arrays under non-uniform shadow conditions

NASA Astrophysics Data System (ADS)

Nguyen, Dung Duc

Mass production and use of electricity generated from solar energy has become very common recently because of the environmental threats arising from the production of electricity from fossil fuels and nuclear power. The obvious benefits of solar energy are clean energy production and infinite supply of daylight. The main disadvantage is the high cost. In these photovoltaic systems, semiconductor materials convert the solar light into electrical energy. Current versus voltage characteristics of the solar cells are nonlinear, thus leading to technical control challenges. In the first order approximation, output power of a solar array is proportional to the irradiance of sunlight. However, in many applications, such as solar power plants, building integrated photovoltaic or solar tents, the solar photovoltaic arrays might be illuminated non-uniformly. The cause of non-uniform illumination may be the shadow of clouds, the trees, booms, neighbor's houses, or the shadow of one solar array on the other, etc. This further leads to nonlinearities in characteristics. Because of the nature of the electrical characteristics of solar cells, the maximum power losses are not proportional to the shadow, but magnify nonlinearly [1]. Further, shadows of solar PV array can cause other undesired effects: (1) The power actually generated from the solar PV array is much less than designed. At some systems, the annual losses because of the shadow effects can be reached 10%. Thus, the probability for "loss of load" increases [2]. (2) The local hot spot in the shaded part of the solar PV array can damage the solar cells. The shaded solar cells may be work on the negative voltage region and become a resistive load and absorb power. Bypass diodes are sometimes connected parallel to solar cells to protect them from damage. However, in most cases, just one diode is connected in parallel to group of solar cells [3], and this hidden the potential power output of the array. This proposed research will focus on the development of an adaptable solar array that is able to optimize power output, reconfigure itself when solar cells are damaged and create controllable output voltages and currents. This study will be a technological advancement over the existing technology of solar PV. Presently solar arrays are fixed arrays that require external device to control their output. In this research, the solar array will be able to self-reconfigure, leading to the following advantages: (1) Higher efficiency because no external devices are used. (2) Can reach maximum possible output power that is much higher than the maximum power of fixed solar arrays by arranging the solar cells in optimized connections. (3) Elimination of the hot spot effects. The proposed research has the following goals: First, to create a modeling and computing algorithm, which is able to simulate and analyze the effects of non-uniform changing shadows on the output power of solar PV arrays. Our model will be able to determine the power losses in each solar cell and the collective hot spots of an array. Second, to propose new methods, which are able to predict the performance of solar PV arrays under shadow conditions for long term (days, months, years). Finally, to develop adaptive reconfiguration algorithms to reconfigure connections within solar PV arrays in real time, under shadow conditions, in order to optimize output power.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Astrophysics Data System (ADS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-10-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

Flat-plate solar array project. Volume 7: Module encapsulation

NASA Technical Reports Server (NTRS)

Cuddihy, E.; Coulbert, C.; Gupta, A.; Liang, R.

1986-01-01

The objective of the Encapsulation Task was to develop, demonstrate, and qualify photovoltaic (PV) module encapsulation systems that would provide 20 year (later decreased to 30 year) life expectancies in terrestrial environments, and which would be compatible with the cost and performance goals of the Flat-Plate Solar Array (FSA) Project. The scope of the Encapsulation Task included the identification, development, and evaluation of material systems and configurations required to support and protect the optically and electrically active solar cell circuit components in the PV module operating environment. Encapsulation material technologies summarized include the development of low cost ultraviolet protection techniques, stable low cost pottants, soiling resistant coatings, electrical isolation criteria, processes for optimum interface bonding, and analytical and experimental tools for evaluating the long term durability and structural adequacy of encapsulated modules. Field testing, accelerated stress testing, and design studies have demonstrated that encapsulation materials, processes, and configurations are available that meet the FSA cost and performance goals.

Silicon-on-ceramic process: Silicon sheet growth and device development for the large-area silicon sheet task of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Whitehead, A. B.; Zook, J. D.; Grung, B. L.; Heaps, J. D.; Schmit, F.; Schuldt, S. B.; Chapman, P. W.

1981-01-01

The technical feasibility of producing solar cell quality sheet silicon to meet the DOE 1986 cost goal of 70 cents/watt was investigated. The silicon on ceramic approach is to coat a low cost ceramic substrate with large grain polycrystalline silicon by unidirectional solidification of molten silicon. Results and accomplishments are summarized.

Terrestrial solar cell module automated array assembly, task 4

NASA Technical Reports Server (NTRS)

1978-01-01

A cost effective design and manufacturing process which would produce solar cell modules capable of meeting qualification test criteria was developed. Emphasis was placed on the development of an aluminum paste back contact process.

Progressing Deployment of Solar Photovoltaic Installations in the United States

NASA Astrophysics Data System (ADS)

Kwan, Calvin Lee

2011-07-01

This dissertation evaluates the likelihood of solar PV playing a larger role in national and state level renewable energy portfolios. I examine the feasibility of large-scale solar PV arrays on college campuses, the financials associated with large-scale solar PV arrays and finally, the influence of environmental, economic, social and political variables on the distribution of residential solar PV arrays in the United States. Chapter two investigates the challenges and feasibility of college campuses adopting a net-zero energy policy. Using energy consumption data, local solar insolation data and projected campus growth, I present a method to identify the minimum sized solar PV array that is required for the City College campus of the Los Angeles Community College District to achieve net-zero energy status. I document how current energy demand can be reduced using strategic demand side management, with remaining energy demand being met using a solar PV array. Chapter three focuses on the financial feasibility of large-scale solar PV arrays, using the proposed City College campus array as an example. I document that even after demand side energy management initiatives and financial incentives, large-scale solar PV arrays continue to have ROIs greater than 25 years. I find that traditional financial evaluation methods are not suitable for environmental projects such as solar PV installations as externalities are not taken into account and therefore calls for development of alternative financial valuation methods. Chapter four investigates the influence of environmental, social, economic and political variables on the distribution of residential solar PV arrays across the United States using ZIP code level data from the 2000 US Census. Using data from the National Renewable Energy Laboratory's Open PV project, I document where residential solar PVs are currently located. A zero-inflated negative binomial model was run to evaluate the influence of selected variables. Using the same model, predicted residential solar PV shares were generated and illustrated using GIS software. The results of this model indicate that solar insolation, state energy deregulation and cost of electricity are statistically significant factors positively correlated with the adoption of residential solar PV arrays. With this information, policymakers at the towns and cities level can establish effective solar PV promoting policies and regulations for their respective locations.

Investigation of test methods, material properties, and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.

1983-01-01

A study of potentially useful low cost encapsulation materials for the Flat-Plate Solar Array project is discussed. The goal is to identify, evaluate, test and recommend encapsulant materials and processes for the production of cost-effective, long life solar cell modules. Technical investigations included studies of aging and degradation of candidate encapsulation materials, continued identification of primers for durable bonding of module interfaces, continued evaluation of soil resistant treatments for the sunlit surface of the module and testing of corrosion protective coatings for use low cost mild steel substrates.

Automated array assembly task, phase 1

NASA Technical Reports Server (NTRS)

Carbajal, B. G.

1977-01-01

An assessment of state-of-the-art technologies that are applicable to silicon solar cell and solar cell module fabrication is provided. The assessment consists of a technical feasibility evaluation and a cost projection for high-volume production of silicon solar cell modules. The cost projection was approached from two directions; a design-to-cost analysis assigned cost goals to each major process element in the fabrication scheme, and a cost analysis built up projected costs for alternate technologies for each process element. A technical evaluation was used in combination with the cost analysis to identify a baseline low cost process. A novel approach to metal pattern design based on minimum power loss was developed. These design equations were used as a tool in the evaluation of metallization technologies.

Automated array assembly

NASA Technical Reports Server (NTRS)

Daiello, R. V.

1977-01-01

A general technology assessment and manufacturing cost analysis was presented. A near-term (1982) factory design is described, and the results of an experimental production study for the large-scale production of flat-panel silicon and solar-cell arrays are detailed.

Integrating Residential Photovoltaics With Power Lines

NASA Technical Reports Server (NTRS)

Borden, C. S.

1985-01-01

Report finds rooftop solar-cell arrays feed excess power to electric-utility grid for fee are potentially attractive large-scale application of photovoltaic technology. Presents assessment of breakeven costs of these arrays under variety of technological and economic assumptions.

SAMICS support study. Volume 1: Cost account catalog

NASA Technical Reports Server (NTRS)

1977-01-01

The Jet Propulsion Laboratory (JPL) is examining the feasibility of a new industry to produce photovoltaic solar energy collectors similar to those used on spacecraft. To do this, a standardized costing procedure was developed. The Solar Array Manufacturing Industry Costing Standards (SAMICS) support study supplies the following information: (1) SAMICS critique; (2) Standard data base--cost account structure, expense item costs, inflation rates, indirect requirements relationships, and standard financial parameter values; (3) Facilities capital cost estimating relationships; (4) Conceptual plant designs; (5) Construction lead times; (6) Production start-up times; (7) Manufacturing price estimates.

Broadband High Efficiency Fractal-Like and Diverse Geometry Silicon Nanowire Arrays for Photovoltaic Applications

NASA Astrophysics Data System (ADS)

AL-Zoubi, Omar H.

Solar energy has many advantages over conventional sources of energy. It is abundant, clean and sustainable. One way to convert solar energy directly into electrical energy is by using the photovoltaic solar cells (PVSC). Despite PVSC are becoming economically competitive, they still have high cost and low light to electricity conversion efficiency. Therefore, increasing the efficiency and reducing the cost are key elements for producing economically more competitive PVSC that would have significant impact on energy market and saving environment. A significant percentage of the PVSC cost is due to the materials cost. For that, thin films PVSC have been proposed which offer the benefits of the low amount of material and fabrication costs. Regrettably, thin film PVSC show poor light to electricity conversion efficiency because of many factors especially the high optical losses. To enhance conversion efficiency, numerous techniques have been proposed to reduce the optical losses and to enhance the absorption of light in thin film PVSC. One promising technique is the nanowire (NW) arrays in general and the silicon nanowire (SiNW) arrays in particular. The purpose of this research is to introduce vertically aligned SiNW arrays with enhanced and broadband absorption covering the entire solar spectrum while simultaneously reducing the amount of material used. To this end, we apply new concept for designing SiNW arrays based on employing diversity of physical dimensions, especially radial diversity within certain lattice configurations. In order to study the interaction of light with SiNW arrays and compute their optical properties, electromagnetic numerical modeling is used. A commercial numerical electromagnetic solver software package, high frequency structure simulation (HFSS), is utilized to model the SiNW arrays and to study their optical properties. We studied different geometries factors that affect the optical properties of SiNW arrays. Based on this study, we found that the optical properties of SiNW arrays are strongly affected by the radial diversity, the arrangement of SiNW in a lattice, and the configuration of such lattice. The proper selection of these parameters leads to broaden and enhance the light absorption of the SiNW arrays. Inspired by natural configurations, fractal geometry and diamond lattice structures, we introduced two lattice configurations: fractal-like array (FLA) that is inspired by fractal geometry, and diamond-like array (DLA) that is inspired by diamond crystal lattice structure. Optimization, using parametric analysis, of the introduced arrays parameters for the light absorption level and the amount of used material has been performed. Both of the introduced SiNW arrays show broadband, strong light absorption coupled with reduction of the amount of the used material. DLA in specific showed significantly enhanced absorption covering the entire solar spectrum of interest, where near-unity absorption spectrum could be achieved. We studied the optical properties of complete PVSC devices that are based on SiNW array. Moreover, the performance of PVSC device that is based on SiNW has been investigated by using numerical modeling. SILVACO software package is used for performing the numerical simulation of the PVSC device performance, which can simultaneously handle the different coupled physical mechanisms contributing to the photovoltaic effect. The effect of the geometry of PVSC device that is based on SiNW is investigated, which shows that the geometry of such PVSC has a role in enhancing its electrical properties. The outcome of this study introduces new SiNW array configurations that have enhanced optical properties using a low amount of material that can be utilized for producing higher efficiency thin film PVCS. The overall conclusion of this work is that a weak absorption indirect band gap material, silicon, in the form of properly designed SiNW and SiNC arrays has the potentials to achieve near-unity ideal absorption spectrum using reduced amount of material, which can lead to produce new generation of lower cost and enhanced efficiency thin film PVSC.

Terrestrial Photovoltaic System Analysis.

DTIC Science & Technology

1980-07-01

the photovoltaic arrays was detertttined to be the roof on the building adjacent to the plating facilit.. Sult ficitut roof area is available to...indicated here: Component 50 kW System 300 kW System Solar Array $10/W $"’/W Inverter $38/W $I/W (dlitereut supplier) The life-cycle cost analysis...27 15. Various solar energy concem t rating systems .......... 3 I. Varionts photovoltaic concentrators developed under PRDA- 15

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

The results for Task 3 of the Low Cost Solar Array Project are presented. Task 3 is directed toward the development of a cost effective encapsulating system for photovoltaic modules using silicon based materials. The technical approach of the contract effort is divided into four special tasks: (1) technology review; (2) generation of concepts for screening and processing silicon encapsulation systems; (3) assessment of encapsulation concepts; and (4) evaluation of encapsulation concepts. The candidate silicon materials are reviewed. The silicon and modified silicon resins were chosen on the basis of similarity to materials with known weatherability, cost, initial tangential modulus, accelerated dirt pick-up test results and the ratio of the content of organic phenyl substitution of methyl substitution on the backbone of the silicon resin.

Recent Advances in Solar Cell Technology

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Bailey, Sheila G.; Piszczor, Michael F., Jr.

1996-01-01

The advances in solar cell efficiency, radiation tolerance, and cost over the last decade are reviewed. Potential performance of thin-film solar cells in space are discussed, and the cost and the historical trends in production capability of the photovoltaics industry are considered with respect to the requirements of space power systems. Concentrator cells with conversion efficiency over 30%, and nonconcentrating solar cells with efficiency over 25% are now available, and advanced radiation-tolerant cells and lightweight, thin-film arrays are both being developed. Nonsolar applications of solar cells, including thermophotovoltaics, alpha- and betavoltaics, and laser power receivers, are also discussed.

Solar power satellite system definition study, phase 2.

NASA Technical Reports Server (NTRS)

1979-01-01

A program plan for the Solar Power Satellite Program is presented. The plan includes research, development, and evaluation phase, engineering and development and cost verification phase, prototype construction, and commercialization. Cost estimates and task requirements are given for the following technology areas: (1) solar arrays; (2) thermal engines and thermal systems; (3) power transmission (to earth); (4) large space structures; (5) materials technology; (6) system control; (7) space construction; (8) space transportation; (9) power distribution, and space environment effects.

Theory and applications for optimization of every part of a photovoltaic system

NASA Technical Reports Server (NTRS)

Redfield, D.

1978-01-01

A general method is presented for quantitatively optimizing the design of every part and fabrication step of an entire photovoltaic system, based on the criterion of minimum cost/Watt for the system output power. It is shown that no element or process step can be optimized properly by considering only its own cost and performance. Moreover, a fractional performance loss at any fabrication step within the cell or array produces the same fractional increase in the cost/Watt of the entire array, but not of the full system. One general equation is found to be capable of optimizing all parts of a system, although the cell and array steps are basically different from the power-handling elements. Applications of this analysis are given to show (1) when Si wafers should be cut to increase their packing fraction; and (2) what the optimum dimensions for solar cell metallizations are. The optimum shadow fraction of the fine grid is shown to be independent of metal cost and resistivity as well as cell size. The optimum thicknesses of both the fine grid and the bus bar are substantially greater than the values in general use, and the total array cost has a major effect on these values. By analogy, this analysis is adaptable to other solar energy systems.

Ultra-Lightweight Hybrid Thin-Film Solar Cells: A Survey of Enabling Technologies for Space Power Applications

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; McNatt, Jeremiah S.; Bailey, Sheila G.; Dickman, John E.; Raffaelle, Ryne P.; Landi, Brian J.; Anctil, Annick; DiLeo, Roberta; Jin, Michael H.-C.; Lee, Chung-Young;

Operational performance of a low cost, air mass 2 solar simulator

NASA Technical Reports Server (NTRS)

Yass, K.; Curtis, H. B.

1975-01-01

Modifications and improvements on a low cost air mass 2 solar simulator are discussed. The performance characteristics of total irradiance, uniformity of irradiance, spectral distribution, and beam subtense angle are presented. The simulator consists of an array of tungsten halogen lamps hexagonally spaced in a plane. A corresponding array of plastic Fresnel lenses shapes the output beam such that the simulator irradiates a 1.2 m by 1.2 m area with uniform collimated irradiance. Details are given concerning individual lamp output measurements and placement of the lamps. Originally, only the direct component of solar irradiance was simulated. Since the diffuse component may affect the performance of some collectors, the capability to simulate it is being added. An approach to this diffuse addition is discussed.

Automated aray assembly, phase 2

NASA Technical Reports Server (NTRS)

Daiello, R. V.

1979-01-01

A manufacturing process suitable for the large-scale production of silicon solar array modules at a cost of less than $500/peak kW is described. Factors which control the efficiency of ion implanted silicon solar cells, screen-printed thick film metallization, spray-on antireflection coating process, and panel assembly are discussed. Conclusions regarding technological readiness or cost effectiveness of individual process steps are presented.

Quality assessment of solar UV irradiance measured with array spectroradiometers

NASA Astrophysics Data System (ADS)

Egli, L.; Gröbner, J.; Hülsen, G.; Bachmann, L.; Blumthaler, M.; Dubard, J.; Khazova, M.; Kift, R.; Hoogendijk, K.; Serrano, A.; Smedley, A. R. D.; Vilaplana, J.-M.

2015-12-01

The reliable quantification of ultraviolet (UV) radiation at the Earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers are small, light, robust and cost effective instruments and are increasingly used for spectral irradiance measurements. Within the European EMRP-ENV03 project "Solar UV", new devices, guidelines, and characterization methods have been developed to improve solar UV measurements with array spectroradiometers and support to the end-user community has been provided. In order to assess the quality of 14 end-user array spectroradiometers, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the intercomparison revealed that array spectroradiometers, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema weighted UV index - in particular at low solar zenith angles - due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available array spectroradiometer within 5 % compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range or solar zenith angle. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 to 400 nm under all atmospheric conditions.

Proceedings of the Flat-Plate Solar Array Project Workshop on Low-Cost Polysilicon for Terrestrial Photovoltaic Solar-Cell Applications

NASA Technical Reports Server (NTRS)

1986-01-01

Sessions conducted included: polysilicon material requirements; economics; process development in the U.S.; international process development; and polysilicon market and forecasts. Twenty-one papers were presented and discussed.

SAMICS: Input data preparation. [Solar Array Manufacturing Industry Costing Standards

NASA Technical Reports Server (NTRS)

Chamberlain, R. G.; Aster, R. W.

1979-01-01

The Solar Array Manufacturing Industry Costing Standards (SAMICS) provide standard formats, data, assumptions, and procedures for estimating the price that a manufacturer would have to charge for the product of a specified manufacturing process sequence. A line-by-line explanation is given of those standard formats which describe the economically important characteristics of the manufacturing processes and the technological structure of the companies and the industry. This revision provides an updated presentation of Format A Process Description, consistent with the October 1978 version of that form. A checklist of items which should be entered on Format A as direct expenses is included.

Glass fiber reinforced concrete for terrestrial photovoltaic arrays

NASA Technical Reports Server (NTRS)

Maxwell, H.

1979-01-01

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.

Stretched Lens Array Squarerigger (SLASR) Technology Maturation

NASA Technical Reports Server (NTRS)

O'Neill, Mark; McDanal, A.J.; Howell, Joe; Lollar, Louis; Carrington, Connie; Hoppe, David; Piszczor, Michael; Suszuki, Nantel; Eskenazi, Michael; Aiken, Dan;

Analysis of Solar Census Remote Solar Access Value Calculation Methodology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nangle, J.; Dean, J.; Van Geet, O.

2015-03-01

The costs of photovoltaic (PV) system hardware (PV panels, inverters, racking, etc.) have fallen dramatically over the past few years. Nonhardware (soft) costs, however, have failed to keep pace with the decrease in hardware costs, and soft costs have become a major driver of U.S. PV system prices. Upfront or 'sunken' customer acquisition costs make up a portion of an installation's soft costs and can be addressed through software solutions that aim to streamline sales and system design aspects of customer acquisition. One of the key soft costs associated with sales and system design is collecting information on solar accessmore » for a particular site. Solar access, reported in solar access values (SAVs), is a measurement of the available clear sky over a site and is used to characterize the impacts of local shading objects. Historically, onsite shading studies have been required to characterize the SAV of the proposed array and determine the potential energy production of a photovoltaic system.« less

Feasibility study of a solar domestic hot water system for Oliver Hall, the University of Kansas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shen, J.C.W.

1985-01-01

Solar water heating represents a low-temperature use of solar energy. It has been proven cost effective in residential applications with renewable energy tax credits. However, tax credits for solar application are not available for state owned buildings, which incur higher system costs and may not economically justify solar energy. The purpose of this project was to design a site assembled solar hot water heating system to reduce system costs. Oliver Hall, a dormitory building at the University of Kansas, was chosen for this research project. The optimum size of the solar system was determined via several different methods to bemore » approximately 1800 square feet. The site chosen for the location of solar arrays was a ground-mounting on the west side of the dormitory due to the adjacency to the mechanical room, ease of maintenance, and lower initial cost. System components and equipment were chosen as the product of performance, cost, maintenance and product life. After completion of the system design, the unit cost data for each component was collected and the initial system cost was estimated to be $49,244 which translates into a payback period of 16 years.« less

Technology requirements for GaAs photovoltaic arrays

NASA Technical Reports Server (NTRS)

Scott-Monck, J.; Rockey, D.

1981-01-01

An analysis based on percent GaAs solar cell weight and cost is performed to assess the utility of this cell for future space missions. It is shown that the GaAs substrate cost and the end-of-life (EOL) advantage the cell can provide over the space qualified silicon solar cell are the dominant factors determining potential use. Examples are presented to show that system level advantages resulting from reduction in solar panel area may warrant the use of GaAs at its current weight and projected initial cost provided the EOL advantage over silicon is at least 20 percent.

A high volume cost efficient production macrostructuring process. [for silicon solar cell surface treatment

NASA Technical Reports Server (NTRS)

Chitre, S. R.

1978-01-01

The paper presents an experimentally developed surface macro-structuring process suitable for high volume production of silicon solar cells. The process lends itself easily to automation for high throughput to meet low-cost solar array goals. The tetrahedron structure observed is 0.5 - 12 micron high. The surface has minimal pitting with virtually no or very few undeveloped areas across the surface. This process has been developed for (100) oriented as cut silicon. Chemi-etched, hydrophobic and lapped surfaces were successfully texturized. A cost analysis as per Samics is presented.

Summary of flat-plate solar array project documentation: Abstracts of published documents, 1975-1986, revision 1

NASA Technical Reports Server (NTRS)

Phillips, M. J.

1986-01-01

Abstracts of final reports, or the latest quarterly or annual, of the Flat-Plate Solar Array (FSA) Project Contractor of Jet Propulsion Laboratory (JPL) in-house activities are presented. Also presented is a list of proceedings and publications, by author, of work connected with the project. The aim of the program has been to stimulate the development of technology that will enable the private sector to manufacture and widely use photovoltaic systems for the generation of electricity in residential, commercial, industrial, and Government applications at a cost per watt that is competitive with utility generated power. FSA Project activities have included the sponsoring of research and development efforts in silicon refinement processes, advanced silicon sheet growth techniques, higher efficiency solar cells, solar cell/module fabrication processes, encapsulation, module/array engineering and reliability, and economic analyses.

Concentrators Enhance Solar Power Systems

NASA Technical Reports Server (NTRS)

2013-01-01

"Right now, solar electric propulsion is being looked at very seriously," says Michael Piszczor, chief of the photovoltaic and power technologies branch at Glen Research Center. The reason, he explains, originates with a unique NASA mission from the late 1990s. In 1998, the Deep Space 1 spacecraft launched from Kennedy Space Center to test a dozen different space technologies, including SCARLET, or the Solar Concentrator Array with Refractive Linear Element Technology. As a solar array that focused sunlight on a smaller solar cell to generate electric power, SCARLET not only powered Deep Space 1 s instruments but also powered its ion engine, which propelled the spacecraft throughout its journey. Deep Space 1 was the first spacecraft powered by a refractive concentrator design like SCARLET, and also utilized multi-junction solar cells, or cells made of multiple layers of different materials. For the duration of its 38-month mission, SCARLET performed flawlessly, even as Deep Space 1 flew by Comet Borrelly and Asteroid Braille. "Everyone remembers the ion engine on Deep Space 1, but they tend to forget that the SCARLET array powered it," says Piszczor. "Not only did both technologies work as designed, but the synergy between the two, solar power and propulsion together, is really the important aspect of this technology demonstration mission. It was the first successful use of solar electric propulsion for primary propulsion." More than a decade later, NASA is keenly interested in using solar electric propulsion (SEP) for future space missions. A key issue is cost, and SEP has the potential to substantially reduce cost compared to conventional chemical propulsion technology. "SEP allows you to use spacecraft that are smaller, lighter, and less costly," says Piszczor. "Even though it might take longer to get somewhere using SEP, if you are willing to trade time for cost and smaller vehicles, it s a good trade." Potentially, SEP could be used on future science missions in orbit around the Earth or Moon, to planets or asteroids, on deep space science missions, and even on exploration missions. In fact, electric propulsion is already being used on Earth-orbiting satellites for positioning.

High Voltage Solar Array ARC Testing for a Direct Drive Hall Effect Thruster System

NASA Technical Reports Server (NTRS)

Schneider, T.; Vaughn, J.; Carruth, M. R.; Mikellides, I. G.; Jongeward, G. A.; Peterson, T.; Kerslake, T. W.; Snyder, D.; Ferguson, D.; Hoskins, A.

2003-01-01

The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (112HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration "trigger" arcs as well as long duration "sustained" arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of vo!tage, (current and power. The data will be used to propose a new, high-voltage (>300 V) solar array design for which the likelihood of damage from arcing is minimal.

High Voltage Solar Array Arc Testing for a Direct Drive Hall Effect Thruster System

NASA Technical Reports Server (NTRS)

Schneider, Todd; Carruth, M. R., Jr.; Vaughn, J. A.; Jongeward, G. A.; Mikellides, I. G.; Ferguson, D.; Kerslake, T. W.; Peterson, T.; Snyder, D.; Hoskins, A.

2004-01-01

The deleterious effects of spacecraft charging are well known, particularly when the charging leads to arc events. The damage that results from arcing can severely reduce system lifetime and even cause critical system failures. On a primary spacecraft system such as a solar array, there is very little tolerance for arcing. Motivated by these concerns, an experimental investigation was undertaken to determine arc thresholds for a high voltage (200-500 V) solar array in a plasma environment. The investigation was in support of a NASA program to develop a Direct Drive Hall-Effect Thruster (D2HET) system. By directly coupling the solar array to a Hall-effect thruster, the D2HET program seeks to reduce mass, cost and complexity commonly associated with the power processing in conventional power systems. In the investigation, multiple solar array technologies and configurations were tested. The cell samples were biased to a negative voltage, with an applied potential difference between them, to imitate possible scenarios in solar array strings that could lead to damaging arcs. The samples were tested in an environment that emulated a low-energy, HET-induced plasma. Short duration trigger arcs as well as long duration sustained arcs were generated. Typical current and voltage waveforms associated with the arc events are presented. Arc thresholds are also defined in terms of voltage, current and power. The data will be used to propose a new, high-voltage (greater than 300 V) solar array design for which the likelihood of damage from arcing is minimal.

SEP solar array Shuttle flight experiment

NASA Technical Reports Server (NTRS)

Elms, R. V., Jr.; Young, L. E.; Hill, H. C.

1981-01-01

An experiment to verify the operational performance of a full-scale Solar Electric Propulsion (SEP) solar array is described. Scheduled to fly on the Shuttle in 1983, the array will be deployed from the bay for ten orbits, with dynamic excitation to test the structural integrity being furnished by the Orbiter verniers; thermal, electrical, and sun orientation characteristics will be monitored, in addition to safety, reliability, and cost effective performance. The blanket, with aluminum and glass as solar cell mass simulators, is 4 by 32 m, with panels (each 0.38 by 4 m) hinged together; two live Si cell panels will be included. The panels are bonded to stiffened graphite-epoxy ribs and are storable in a box in the bay. The wing support structure is detailed, noting the option of releasing the wing into space by use of the Remote Manipulator System if the wing cannot be refolded. Procedures and equipment for monitoring the array behavior are outlined, and comprise both analog data and TV recording for later playback and analysis. The array wing experiment will also aid in developing measurement techniques for large structure dynamics in space.

Proceedings of the Flat-Plate Solar Array Project Research Forum on the Design of Flat-Plate Photovoltaic Arrays for Central Stations

NASA Technical Reports Server (NTRS)

1983-01-01

The Flat Plate Solar Array Project, focuses on advancing technologies relevant to the design and construction of megawatt level central station systems. Photovoltaic modules and arrays for flat plate central station or other large scale electric power production facilities require the establishment of a technical base that resolves design issues and results in practical and cost effective configurations. Design, qualification and maintenance issues related to central station arrays derived from the engineering and operating experiences of early applications and parallel laboratory reserch activities are investigated. Technical issues are examined from the viewpoint of the utility engineer, architect/engineer and laboratory researcher. Topics on optimum source circuit designs, module insulation design for high system voltages, array safety, structural interface design, measurements, and array operation and maintenance are discussed.

Shedding Light on Solar Power

NASA Technical Reports Server (NTRS)

2002-01-01

Glenn Research Center sponsored an SBIR contract with ENTECH, in which the company worked to mold its successful terrestrial concentrator technology into applications that would generate solar power for space missions. ENTECH's first application made use of small, dome-shaped Fresnel lenses to direct sunlight onto high- efficiency photovoltaic cells. After some key adjustments, the mini- dome lens array was flown as part of the U.S. Air Force/NASA Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) flight experiment in 1994. Due to their three-dimensional shape, the mini- dome lenses entailed construction by a batch molding process, which is naturally more costly than a continuous process. To overcome this disadvantage and meet the requirement for precise solar pointing in two axes, ENTECH started developing solar concentrator arrays for space using a line-focus lens that can be mass-produced by a continuous process. This new technology, named Solar Concentrator Array with Refractive Linear Element Technology (SCARLET), was created with support from Glenn and the Ballistic Missile Defense Organization, and was used to power the NASA/Jet Propulsion Laboratory Deep Space 1 spacecraft.

Low-cost solar array structure development

NASA Astrophysics Data System (ADS)

Wilson, A. H.

1981-06-01

Early studies of flat-plate arrays have projected costs on the order of $50/square meter for installed array support structures. This report describes an optimized low-cost frame-truss structure that is estimated to cost below $25/square meter, including all markups, shipping an installation. The structure utilizes a planar frame made of members formed from light-gauge galvanized steel sheet and is supposed in the field by treated-wood trusses that are partially buried in trenches. The buried trusses use the overburden soil to carry uplift wind loads and thus to obviate reinforced-concrete foundations. Details of the concept, including design rationale, fabrication and assembly experience, structural testing and fabrication drawings are included.

Low-cost solar array structure development

NASA Technical Reports Server (NTRS)

Wilson, A. H.

1981-01-01

Early studies of flat-plate arrays have projected costs on the order of $50/square meter for installed array support structures. This report describes an optimized low-cost frame-truss structure that is estimated to cost below $25/square meter, including all markups, shipping an installation. The structure utilizes a planar frame made of members formed from light-gauge galvanized steel sheet and is supposed in the field by treated-wood trusses that are partially buried in trenches. The buried trusses use the overburden soil to carry uplift wind loads and thus to obviate reinforced-concrete foundations. Details of the concept, including design rationale, fabrication and assembly experience, structural testing and fabrication drawings are included.

Commercial/industrial photovoltaic module and array requirement study. Low-cost solar array project engineering area

NASA Technical Reports Server (NTRS)

1981-01-01

Design requirements for photovoltaic modules and arrays used in commercial and industrial applications were identified. Building codes and referenced standards were reviewed for their applicability to commercial and industrial photovoltaic array installation. Four general installation types were identified - integral (replaces roofing), direct (mounted on top of roofing), stand-off (mounted away from roofing), and rack (for flat or low slope roofs, or ground mounted). Each of the generic mounting types can be used in vertical wall mounting systems. This implies eight mounting types exist in the commercial/industrial sector. Installation costs were developed for these mounting types as a function of panel/module size. Cost drivers were identified. Studies were performed to identify optimum module shapes and sizes and operating voltage cost drivers. The general conclusion is that there are no perceived major obstacles to the use of photovoltaic modules in commercial/industrial arrays.

Multi-wire slurry wafering demonstrations. [slicing silicon ingots for solar arrays

NASA Technical Reports Server (NTRS)

Chen, C. P.

1978-01-01

Ten slicing demonstrations on a multi-wire slurry saw, made to evaluate the silicon ingot wafering capabilities, reveal that the present sawing capabilities can provide usable wafer area from an ingot 1.05m/kg (e.g. kerf width 0.135 mm and wafer thickness 0.265 mm). Satisfactory surface qualities and excellent yield of silicon wafers were found. One drawback is that the add-on cost of producing water from this saw, as presently used, is considerably higher than other systems being developed for the low-cost silicon solar array project (LSSA), primarily because the saw uses a large quantity of wire. The add-on cost can be significantly reduced by extending the wire life and/or by rescue of properly plated wire to restore the diameter.

Study of multi-kW solar arrays for Earth orbit application

NASA Technical Reports Server (NTRS)

1980-01-01

Planar and concentrator solar array configurations based on silicon and gallium arsenide solar cells were conceptualized and on-orbit maintainability was addressed. Four basic categories emerged: (1) planar (non concentrated) with silicon cells, (2) low-CR (concentration ratio = 3.4) with silicon cells, (3) low-CR with GaAs, and (4) high-CR (concentration ratio = 62.5) with GaAs. A very high-CR (concentration ratio = 200) was investigated but rejected on thermal grounds. Nonrecurring and recurring cost elements for each of the four concepts selected were compared over a 15 year life cycle. Under conditions where the gallium arsenide cells can be produced for less than $25 per 2 x 2 cm, the low CR concentrator emerges as the most cost effective configuration. However, the producibility risk remains higher on the gallium arsenide cell.

Systems analysis of Mars solar electric propulsion vehicles

NASA Technical Reports Server (NTRS)

Hickman, J. M.; Curtis, H. B.; Kenny, B. H.; Sefcik, R. J.

1990-01-01

Mission performance, mass, initial power, and cost are determined for solar electric propulsion vehicles across a range of payload masses, reference powers, and mission trajectories. Thick radiation shielding is added to arrays using indium phosphide or III-V multijunction solar cells to reduce the damage incurred through the radiation belts. Special assessments of power management and distribution systems, atmospheric drag, and energy storage are made. It is determined that atmospheric drag is of no great concern and that the energy storage used in countering drag is unnecessary. A scheme to package the arrays, masts, and ion thrusters into a single fairing is presented.

Dye-sensitized solar cells with vertically aligned TiO2 nanowire arrays grown on carbon fibers.

PubMed

Cai, Xin; Wu, Hongwei; Hou, Shaocong; Peng, Ming; Yu, Xiao; Zou, Dechun

2014-02-01

One-dimensional semiconductor TiO2 nanowires (TNWs) have received widespread attention from solar cell and related optoelectronics scientists. The controllable synthesis of ordered TNW arrays on arbitrary substrates would benefit both fundamental research and practical applications. Herein, vertically aligned TNW arrays in situ grown on carbon fiber (CF) substrates through a facile, controllable, and seed-assisted thermal process is presented. Also, hierarchical TiO2 -nanoparticle/TNW arrays were prepared that favor both the dye loading and depressed charge recombination of the CF/TNW photoanode. An impressive conversion efficiency of 2.48 % (under air mass 1.5 global illumination) and an apparent efficiency of 4.18 % (with a diffuse board) due to the 3D light harvesting of the wire solar cell were achieved. Moreover, efficient and inexpensive wire solar cells made from all-CF electrodes and completely flexible CF-based wire solar cells were demonstrated, taking into account actual application requirements. This work may provide an intriguing avenue for the pursuit of lightweight, cost-effective, and high-performance flexible/wearable solar cells. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Constellations Solar Array Design, Industrialization And In-Flight Results

NASA Astrophysics Data System (ADS)

Combet, Yannick; Clapper, Paul

2011-10-01

Constellations has become a recurring opportunities in Thales Alenia Space since 3 majors programs had been awarded: Globalstar was the pathfinder with 48 flight sets followed by O3b with 8 an the latest is Iridium Next with 81 models. For these 3 programs, the Solar Array is fully developed, validated and produced by Thales Alenia Space with major subcontractors. This new segment of the activity leads to new development, design and industrialization approaches. This paper describes the Solar Array design and the alternative to current approach build and applied with the following drivers: - the low recurring cost and mass of the flight hardware, with particular attention on the Solar Array, - high robustness for system integration and in-orbit operations, - a long mission duration (typically 15 years in LEO) leading to take into account high number of thermal cycles (60 to 72.000 cycles), - new production concept with strict schedule management, - design segmented in subassemblies to reduce the integration time as well as a improved trouble shooting management, - delivery rate up to 1 wing per week and after learning curve effect, a integration duration divided by 3 compared to current production, - a delivery of a qualified PFM solar array in 22 months including the design to producibility constrains, This demanding requirement for delivery scheme and cost target did not jeopardize the requirements and standards for space application. After a brief description of the way the main drivers have been considered, the paper presents the main features and performances of the subsystem and shows the main validation test results. The first launch was successful in October 2010 and the first in-orbit results are presented.

Low cost solar cell arrays

NASA Technical Reports Server (NTRS)

Iles, P. A.; Mclennan, H.

1975-01-01

Limitations in both space and terrestial markets for solar cells are described. Based on knowledge of the state-of-the-art, six cell options are discussed; as a result of this discussion, the three most promising options (involving high, medium and low efficiency cells respectively) were selected and analyzed for their probable costs. The results showed that all three cell options gave promise of costs below $10 per watt in the near future. Before further cost reductions can be achieved, more R and D work is required; suggestions for suitable programs are given.

Comparison of photovoltaic energy systems for the solar village

NASA Astrophysics Data System (ADS)

Piercefrench, Eric C.

1988-08-01

Three different solar photovoltaic (PV) energy systems are compared to determine if the electrical needs of a solar village could be supplied more economically by electricity generated by the sun than by existing utility companies. The solar village, a one square mile community of 900 homes and 50 businesses, would be located in a semi-remote area of the Arizona desert. A load survey is conducted and information on the solar PV industry is reviewed for equipment specifications, availability, and cost. Three specific PV designs, designated as Stand-Alone, Stand-Alone with interconnection, and Central Solar Plant, were created and then economically compared through present worth analysis against utility supplied electrical costs. A variety of technical issues, such as array protection, system configuration and operation, and practicability, are discussed for each design. The present worth analysis conclusively shows none of the solar PV designs could supply electricity to the solar village for less cost than utility supplied electricity, all other factors being equal. No construction on a solar village should begin until the cost of solar generated electricity is more competitive with electricity generated by coal, oil, and nuclear energy. However, research on ways to reduce solar PV equipment costs and on ways to complement solar PV energy, such as the use of solar thermal ponds for heating and cooling, should continue.

Synthesis and Characterization of Doped ZnO Nanomaterials: Potential Application in Third Generation Solar Cells

NASA Astrophysics Data System (ADS)

Adcock Smith, Echo D.

ZnO nanomaterials are being incorporated into next-generation solar cell designs including dye-sensitized solar cells, multijunction solar cells, and quantum dot sensitized solar cells. ZnO nanorod (NR) arrays and nanoparticles (NP) used in these devices are typically fabricated using chemical vapor deposition and/or high-temperature reaction conditions. These methods are costly, require high energy, pressure or excessive time, but produce repeatable, defined growth that is capable of easily incorporating metal dopants. Less expensive methods of fabrication such as chemical bath deposition (CBD) eliminate the costly steps but can suffer from undefined growth, excessive waste and have a difficult time incorporating dopants into ZnO materials without additives or increased pH. This dissertation presents a novel method of growing cobalt and vanadium doped ZnO nanomaterials through microwave synthesis. The cobalt growth was compared to standard CBD and found to be faster, less wasteful, reproducible and better at incorporating cobalt ions into the ZnO lattice than typical oven CBD method. The vanadium doped ZnO microwave synthesis procedure was found to produce nanorods, nanorod arrays, and nanoparticles simultaneously. Neither the cobalt nor the vanadium growth required pH changes, catalysts or additives to assist in doping and therefore use less materials than traditional CBD. This research is important because it offers a simple, quick way to grow ZnO nanostructures and is the first to report on growing both cobalt and vanadium doped zinc oxide nanorod arrays using microwave synthesis. This synthesis method presented is a viable candidate for replacing conventional growth synthesis which will result in lowering the cost and time of production of photovoltaics while helping drive forward the development of next-generation solar cells.

High Flux Microchannel Receiver Development with Adap-tive Flow Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Drost, Kevin

This project is focused on the demonstration of a microchannel-based solar receiver (MSR). The MSR concept consists of using a modular arrangement of arrayed microchannels to heat a working fluid in a concentrating solar receiver, allowing a much higher solar flux on the receiver and consequently a significant reduction in thermal losses, size, and cost.

Orange County Government Solar Demonstration and Research Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parker, Renee; Cunniff, Lori

Orange County Florida completed the construction of a 20 kilowatt Solar Demonstration and Research Facility in March 2015. The system was constructed at the Orange County/University of Florida Cooperative Extension Center whose electric service address is 6021 South Conway Road, Orlando, Florida 32802. The Solar Demonstration and Research Facility is comprised of 72 polycrystalline photovoltaic modules and 3 inverters which convert direct current from the solar panels to alternating current electricity. Each module produces 270 watts of direct current power, for a total canopy production of just under 20,000 watts. The solar modules were installed with a fixed tilt ofmore » 5 degrees and face south, toward the equator to maximize the amount of sunlight captures. Each year, the electricity generated by the solar array will help eliminate 20 metric tons of carbon dioxide emissions as well as provide covered parking for staff and visitors vehicles. The solar array is expected to generate 27,000 kilowatt hours of electricity annually equating to an estimated $266 savings in the monthly electric bill, or $3,180 annually for the Orange County/University of Florida Cooperative Extension Center. In addition to reducing the electric bill for the Extension Center, Orange County’s solar array also takes advantage of a rebate incentive offered by the local utility, Orlando Utility Commission, which provided a meter that measures the amount of power produced by the solar array. The local utility company’s Solar Photovoltaic Production Incentive will pay Orange County $0.05 per kilowatt hour for the power that is produced by the solar array. This incentive is provided in addition to Net Metering benefits, which is an effort to promote the use of clean, renewable energy on the electric grid. The Photovoltaic Solar Demonstration and Research Facility also serves an educational tool to the public; the solar array is tied directly into a data logger that provides real time power generation accessible for public viewing on an interactive kiosk located in the Orange County/University of Florida Cooperative Extension Center’s lobby where visitors can review “real time” power generation, cost savings and environmental benefits of the system. Site commissioning with the software program was delayed due to Internal Security Software issues within Orange County that needed to be resolved, therefore the “real time” capture of the production data for the solar array using the software program commenced on May 1, 2015. In addition an educational flyer was developed and is available in the Orange County Education Center’s main lobby. The project completed under this grant award assisted Orange County in demonstrating leadership by installing the application of a renewable energy technology combined with energy efficiency measures; resulting in reduced energy costs for the Orange County University of Florida Cooperative Extension Center, and helping Orange County citizens and visitors move towards the goals of greater energy independence and climate protection. The addition of the new Solar Demonstration and Research Facility has advanced the Orange County/University of Florida Cooperative Extension Center’s mission of extending, educating and providing research-based information to residents and visitors of Orange County by demonstrating the application of renewable energy technology combined with energy efficiency measures; resulting in reduced energy costs, and helping Orange County move towards the goal of greater energy independence and climate protection. In 2014, the Orange County Cooperative Extension Center hosted nearly 10,800 visitors to their on-site Exploration Gardens plus 12,686 walk-in visitors to their office plant clinic and other services. The Education Center held 2,217 educational events that were attended by 46,434 adults and youth, but about half of those events occurred off-site. Based on the visitation numbers in 2014 the Orange County Cooperative Extension Center Education is a vital partner to Orange County’s continued outreach and education efforts concerning renewable energy technologies and greenhouse gas emission reduction well in the current 2015 year and future years of operation of the solar array to the future visitors of the Center which help stimulate market demand that will continue to advance the commercialization and the widespread application and use of renewable energy technologies in Orange County and the state of Florida. The project period performance date for this grant was November 1, 2009 through March 1, 2015. The Final Project costs to complete the project as reported in the FINAL SF 425 were $195,512.50 (50% recipient cost share was satisfied as required by grant terms and conditions).« less

The next generation of solar panel substrates?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gledhill, K.M.; Boswell, R.L.; Paul, J.G.

For over 25 years, satellite power system designers have used rigid honeycomb panels as solar array substrates. Those years have seen very little improvement in the performance of these rigid systems. A new technology under development at the Phillips Laboratory, however, may undo this stagnancy. Composite isogrid panel structures offer a number of potential advantages over honeycomb sandwich structures for solar array applications, including stiffness, weight, and cost improvements. Phillips Laboratory will be performing a series of evaluative tests on the isogrid structure to determine its suitability as a substitute for honeycomb sandwiches in solar panel applications. Testing will includemore » three-point bending, thermal vacuum, and thermal cycling.« less

Solar-cell interconnect design for terrestrial photovoltaic modules

NASA Technical Reports Server (NTRS)

Mon, G. R.; Moore, D. M.; Ross, R. G., Jr.

1984-01-01

Useful solar cell interconnect reliability design and life prediction algorithms are presented, together with experimental data indicating that the classical strain cycle (fatigue) curve for the interconnect material does not account for the statistical scatter that is required in reliability predictions. This shortcoming is presently addressed by fitting a functional form to experimental cumulative interconnect failure rate data, which thereby yields statistical fatigue curves enabling not only the prediction of cumulative interconnect failures during the design life of an array field, but also the quantitative interpretation of data from accelerated thermal cycling tests. Optimal interconnect cost reliability design algorithms are also derived which may allow the minimization of energy cost over the design life of the array field.

Solar-cell interconnect design for terrestrial photovoltaic modules

NASA Astrophysics Data System (ADS)

Mon, G. R.; Moore, D. M.; Ross, R. G., Jr.

1984-11-01

Useful solar cell interconnect reliability design and life prediction algorithms are presented, together with experimental data indicating that the classical strain cycle (fatigue) curve for the interconnect material does not account for the statistical scatter that is required in reliability predictions. This shortcoming is presently addressed by fitting a functional form to experimental cumulative interconnect failure rate data, which thereby yields statistical fatigue curves enabling not only the prediction of cumulative interconnect failures during the design life of an array field, but also the quantitative interpretation of data from accelerated thermal cycling tests. Optimal interconnect cost reliability design algorithms are also derived which may allow the minimization of energy cost over the design life of the array field.

Integrated residential photovoltaic array development

NASA Technical Reports Server (NTRS)

Shepard, N. F., Jr.

1981-01-01

The design details of an optimized integrated residential photovoltaic module/array are presented. This selected design features a waterproofing and mounting scheme which was devised to simplify the installation procedures by the avoidance of complex gasketed or caulked joints, while still maintaining a high confidence that the watertight integrity of the integral roofing surface will be achieved for the design lifetime of the system. The production and installation costs for the selected module/array design are reported for a range of annual production rates as a function of the cost of solar cells.

The DS1 Mission and the Validation of the SCARLET Advanced Array

NASA Technical Reports Server (NTRS)

Stella, Paul M.; Nieraeth, Donald G.; Murphy, David M.; Eskenazi, Michael I.

2000-01-01

On October 24, 1998, the first of the NASA New Millenium Spacecraft, DS1, was successfully launched into Space. The objectives for this spacecraft are to test advanced technologies that can reduce the cost or risk of future missions. One of these technologies is the SCARLET concentrating solar array. Although part of the advanced technology validation study, the array is also the spacecraft's power source. Funded by BMDO, the SCARLET concentrator solar array is the first application of a refractive lens concentrator designed for space applications. As part of the DS1 validation process, the amount of diagnostics data that will be acquired is more extensive than would be the norm for a more conventional solar array. These data include temperature measurements at numerous locations on the 2-wing, 4-panel per wing, solar array. For each panel, one 5-cell module in one of the circuit strings is wired so that a complete I-V curve can be obtained. This data is used to verify sun pointing accuracy and array output performance. In addition, the spacecraft power load can be varied in a number of discrete steps from a small fraction of the array total power capability, up to maximum power. For each of the power loads, array operating voltage can be measured along with the current output from each wing. Preliminary in-space measurements suggest SCARLET performance is within one (1) percent of predictions made from ground data. This paper will briefly discuss the SCARLET configuration and critical features. Emphasis will be given to the results of the in-space validation, including array performance as a function of changing solar distance and array performance compared to pre-launch predictions.

Mechanical design of a low concentration ratio solar array for a space station application

NASA Technical Reports Server (NTRS)

Biss, M. S.; Hsu, L.

1983-01-01

This paper describes a preliminary study and conceptual design of a low concentration ratio solar array for a space station application with approximately a 100 kW power requirement. The baseline design calls for a multiple series of inverted, truncated, pyramidal optical elements with a geometric concentration ratio (GCR) of 6. It also calls for low life cycle cost, simple on-orbit maintainability, 1984 technology readiness date, and gallium arsenide (GaAs) of silicon (Si) solar cell interchangeability. Due to the large area needed to produce the amount of power required for the baseline space station, a symmetrical wing design, making maximum use of the commonality of parts approach, was taken. This paper will describe the mechanical and structural design of a mass-producible solar array that is very easy to tailor to the needs of the individual user requirement.

Solar tracker motor having a fixed caliper and a translating caliper each with an electromagnetic brake system

DOEpatents

Rau, Scott James

2013-01-29

Concepts and technologies described herein provide for an accurate and cost-effective method for rotating a solar array disk for tracking the movement of the sun. According to various aspects, a motor includes a fixed caliper and a translating caliper positioned adjacent to one another. Electromagnetically controlled brakes on the translating caliper grip the solar array disk while adjacent, but spaced apart, electromagnets on the fixed caliper and the translating caliper are energized to create an attractive force that pulls the translating caliper with the solar array disk toward the fixed caliper. After reaching the fixed caliper, brakes on the fixed caliper are engaged with the disk, brakes on the translating caliper are released from the disk, and the translating caliper is pushed back to the starting location where the process repeats until the desired rotation is completed.

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

NASA Technical Reports Server (NTRS)

1981-01-01

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.

Impacts of Severe Weather, Climate Zone, and Energy Factors on Base Realignment and Closure (BRAC)

DTIC Science & Technology

2015-03-26

hydroelectric, solar photovoltaic , and wind power . Aside from locations and facilities that use electricity to heat, natural gas is the only...have large photovoltaic solar arrays with unique buy-back contracts or power -purchase agreements. These renewable energy projects benefit primarily...these costs, a Monte Carlo simulation is used to forecast annual costs and account for uncertainty with tornado and hurricane risks, along with

Ion propulsion cost effectivity

NASA Technical Reports Server (NTRS)

Zafran, S.; Biess, J. J.

1978-01-01

Ion propulsion modules employing 8-cm thrusters and 30-cm thrusters were studied for Multimission Modular Spacecraft (MMS) applications. Recurring and nonrecurring cost elements were generated for these modules. As a result, ion propulsion cost drivers were identified to be Shuttle charges, solar array, power processing, and thruster costs. Cost effective design approaches included short length module configurations, array power sharing, operation at reduced thruster input power, simplified power processing units, and power processor output switching. The MMS mission model employed indicated that nonrecurring costs have to be shared with other programs unless the mission model grows. Extended performance missions exhibited the greatest benefits when compared with monopropellant hydrazine propulsion.

Investigation of test methods, material properties, and processes for solar cell encapsulants. Encapsulation task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

1977-01-01

During this quarter, flat-plate solar collector systems were considered and six basic construction elements were identified: outer coatings, superstrates, pottants, substrates, undercoats, and adhesives. Materials surveys were then initiated to discover either generic classes or/and specific products to function as each construction element. Cost data included in the surveys permit ready evaluation of each material. Silicones, fluorocarbons, glass, and acrylic polymers have the highest inherent weatherability of materials studied to date. Only acrylics, however, combine low costs, environmental resistance, and potential processability. This class will receive particular emphasis.

A high specific power solar array for low to mid-power spacecraft

NASA Technical Reports Server (NTRS)

Jones, P. Alan; White, Stephen F.; Harvey, T. Jeffery; Smith, Brian S.

1993-01-01

UltraFlex is the generic term for a solar array system which delivers on-orbit power in the 400 to 6,000 watt per wing sizes with end-of-life specific power performance ranging to 150 watts-per-kilogram. Such performance is accomplished with off-the-shelf solar cells and state-of the-art materials and processes. Much of the recent work in photovoltaics is centered on advanced solar cell development. Successful as such work has been, no integrated solar array system has emerged which meets NASA's stated goals of 'increasing the end-of-life performance of space solar cells and arrays while minimizing their mass and cost.' This issue is addressed; namely, is there an array design that satisfies the usual requirements for space-rated hardware and that is inherently reliable, inexpensive, easily manufactured and simple, which can be used with both advanced cells currently in development and with inexpensive silicon cells? The answer is yes. The UltraFlex array described incorporates use of a blanket substrate which is thermally compatible with silicon and other materials typical of advanced multi-junction devices. The blanket materials are intrinsically insensitive to atomic oxygen degradation, are space rated, and are compatible with standard cell bonding processes. The deployment mechanism is simple and reliable and the structure is inherently stiff (high natural frequency). Mechanical vibration modes are also readily damped. The basic design is presented as well as supporting analysis and development tests.

A high specific power solar array for low to mid-power spacecraft

NASA Astrophysics Data System (ADS)

Jones, P. Alan; White, Stephen F.; Harvey, T. Jeffery; Smith, Brian S.

1993-05-01

UltraFlex is the generic term for a solar array system which delivers on-orbit power in the 400 to 6,000 watt per wing sizes with end-of-life specific power performance ranging to 150 watts-per-kilogram. Such performance is accomplished with off-the-shelf solar cells and state-of the-art materials and processes. Much of the recent work in photovoltaics is centered on advanced solar cell development. Successful as such work has been, no integrated solar array system has emerged which meets NASA's stated goals of 'increasing the end-of-life performance of space solar cells and arrays while minimizing their mass and cost.' This issue is addressed; namely, is there an array design that satisfies the usual requirements for space-rated hardware and that is inherently reliable, inexpensive, easily manufactured and simple, which can be used with both advanced cells currently in development and with inexpensive silicon cells? The answer is yes. The UltraFlex array described incorporates use of a blanket substrate which is thermally compatible with silicon and other materials typical of advanced multi-junction devices. The blanket materials are intrinsically insensitive to atomic oxygen degradation, are space rated, and are compatible with standard cell bonding processes. The deployment mechanism is simple and reliable and the structure is inherently stiff (high natural frequency). Mechanical vibration modes are also readily damped. The basic design is presented as well as supporting analysis and development tests.

The role of radiation hard solar cells in minimizing the costs of global satellite communication systems

NASA Technical Reports Server (NTRS)

Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

1996-01-01

An analysis embodied in a PC computer program is presented, which quantitatively demonstrates how the availability of radiation hard solar cells can help minimize the cost of a global satellite communications system. An important distinction between the currently proposed systems, such as Iridium, Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation at orbital altitudes within the earth's radiation belts (10(exp 3) to 10(exp 4)km) can reduce the total cost of a system by several hundred percent, so long as radiation hard components including solar cells can be used. A detailed evaluation of the predicted performance of photovoltaic arrays using several different planar solar cell technologies is given, including commercially available Si and GaAs/Ge, and InP/Si which is currently under development. Several examples of applying the program are given, which show that the end of life (EOL) power density of different technologies can vary by a factor of ten for certain missions. Therefore, although a relatively radiation-soft technology can usually provide the required EOL power by simply increasing the size of the array, the impact upon the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate, these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global-coverage systems range from $1B to $9B, the availability of radiation-hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

NASA Solar Array Demonstrates Commercial Potential

NASA Technical Reports Server (NTRS)

Creech, Gray

2006-01-01

A state-of-the-art solar-panel array demonstration site at NASA's Dryden Flight Research Center provides a unique opportunity for studying the latest in high-efficiency solar photovoltaic cells. This five-kilowatt solar-array site (see Figure 1) is a technology-transfer and commercialization success for NASA. Among the solar cells at this site are cells of a type that was developed in Dryden Flight Research Center s Environmental Research Aircraft and Sensor Technology (ERAST) program for use in NASA s Helios solar-powered airplane. This cell type, now denoted as A-300, has since been transferred to SunPower Corporation of Sunnyvale, California, enabling mass production of the cells for the commercial market. High efficiency separates these advanced cells from typical previously commercially available solar cells: Whereas typical previously commercially available cells are 12 to 15 percent efficient at converting sunlight to electricity, these advanced cells exhibit efficiencies approaching 23 percent. The increase in efficiency is due largely to the routing of electrical connections behind the cells (see Figure 2). This approach to increasing efficiency originated as a solution to the problem of maximizing the degree of utilization of the limited space available atop the wing of the Helios airplane. In retrospect, the solar cells in use at this site could be used on Helios, but the best cells otherwise commercially available could not be so used, because of their lower efficiencies. Historically, solar cells have been fabricated by use of methods that are common in the semiconductor industry. One of these methods includes the use of photolithography to define the rear electrical-contact features - diffusions, contact openings, and fingers. SunPower uses these methods to produce the advanced cells. To reduce fabrication costs, SunPower continues to explore new methods to define the rear electrical-contact features. The equipment at the demonstration site includes two fixed-angle solar arrays and one single-axis Sun-tracking array. One of the fixed arrays contains typical less-efficient commercial solar cells and is being used as a baseline for comparison of the other fixed array, which contains the advanced cells. The Sun-tracking array tilts to follow the Sun, using an advanced, real-time tracking device rather than customary pre-programmed mechanisms. Part of the purpose served by the demonstration is to enable determination of any potential advantage of a tracking array over a fixed array. The arrays are monitored remotely on a computer that displays pertinent information regarding the functioning of the arrays.

Phase 2 of the array automated assembly task for the low cost solar array project

NASA Technical Reports Server (NTRS)

Campbell, R. B.; Davis, J. R.; Ostroski, J. W.; Rai-Choudhury, P.; Rohatgi, A.; Seman, E. J.; Stapleton, R. E.

1979-01-01

The process sequence for the fabrication of dendritic web silicon into solar panels was modified to include aluminum back surface field formation. Plasma etching was found to be a feasible technique for pre-diffusion cleaning of the web. Several contacting systems were studied. The total plated Pd-Ni system was not compatible with the process sequence; however, the evaporated TiPd-electroplated Cu system was shown stable under life testing. Ultrasonic bonding parameters were determined for various interconnect and contact metals but the yield of the process was not sufficiently high to use for module fabrication at this time. Over 400 solar cells were fabricated according to the modified sequence. No sub-process incompatibility was seen. These cells were used to fabricate four demonstration modules. A cost analysis of the modified process sequence resulted in a selling price of $0.75/peak watt.

Electric power - Photovoltaic or solar dynamic?

NASA Technical Reports Server (NTRS)

Thomas, R. L.; Hallinan, G. J.; Hieatt, J. L.

1985-01-01

The design of the power system for supplying the Space Station with insolation-generated electricity is the main Phase B task at NASA-Lewis Center. The advantages and limitations of two types of power systems, the photovoltaic arrays (PV) and the solar dynamic system (SD), are discussed from the points of view of cost, overall systems integration, and growth. Subsystems of each of these options are described, and a sketch of a projected SD system is shown. The PV technology is well developed and proven, but its low efficiency calls for solar arrays of large areas, which affect station dynamics, control, and drag compensation. The SD systems would be less costly to operate than VP, and are more efficient, needing less deployed area. The major drawback of the SD is its infancy. The conservative and forgiving designs for some of its components must still be created and tested, and the development risks assessed.

Small space station electrical power system design concepts

NASA Technical Reports Server (NTRS)

Jones, G. M.; Mercer, L. N.

1976-01-01

A small manned facility, i.e., a small space station, placed in earth orbit by the Shuttle transportation system would be a viable, cost effective addition to the basic Shuttle system to provide many opportunities for R&D programs, particularly in the area of earth applications. The small space station would have many similarities with Skylab. This paper presents design concepts for an electrical power system (EPS) for the small space station based on Skylab experience, in-house work at Marshall Space Flight Center, SEPS (Solar Electric Propulsion Stage) solar array development studies, and other studies sponsored by MSFC. The proposed EPS would be a solar array/secondary battery system. Design concepts expressed are based on maximizing system efficiency and five year operational reliability. Cost, weight, volume, and complexity considerations are inherent in the concepts presented. A small space station EPS based on these concepts would be highly efficient, reliable, and relatively inexpensive.

Development of High Efficiency (14%) Solar Cell Array Module

NASA Technical Reports Server (NTRS)

Iles, P. A.; Khemthong, S.; Olah, S.; Sampson, W. J.; Ling, K. S.

1979-01-01

High efficiency solar cells required for the low cost modules was developed. The production tooling for the manufacture of the cells and modules was designed. The tooling consisted of: (1) back contact soldering machine; (2) vacuum pickup; (3) antireflective coating tooling; and (4) test fixture.

Process research of non-cz silicon material. Low cost solar array project, cell and module formation research area

NASA Technical Reports Server (NTRS)

1982-01-01

Liquid diffusion masks and liquid applied dopants to replace the CVD Silox masking and gaseous diffusion operations specified for forming junctions in the Westinghouse baseline process sequence for producing solar cells from dendritic web silicon were investigated.

Space-based solar power conversion and delivery systems study. Volume 2: Engineering analysis of orbital systems

NASA Technical Reports Server (NTRS)

1976-01-01

Program plans, schedules, and costs are determined for a synchronous orbit-based power generation and relay system. Requirements for the satellite solar power station (SSPS) and the power relay satellite (PRS) are explored. Engineering analysis of large solar arrays, flight mechanics and control, transportation, assembly and maintenance, and microwave transmission are included.

Advanced Solar Cells for Satellite Power Systems

NASA Technical Reports Server (NTRS)

Flood, Dennis J.; Weinberg, Irving

1994-01-01

The multiple natures of today's space missions with regard to operational lifetime, orbital environment, cost and size of spacecraft, to name just a few, present such a broad range of performance requirements to be met by the solar array that no single design can suffice to meet them all. The result is a demand for development of specialized solar cell types that help to optimize overall satellite performance within a specified cost range for any given space mission. Historically, space solar array performance has been optimized for a given mission by tailoring the features of silicon solar cells to account for the orbital environment and average operating conditions expected during the mission. It has become necessary to turn to entirely new photovoltaic materials and device designs to meet the requirements of future missions, both in the near and far term. This paper will outline some of the mission drivers and resulting performance requirements that must be met by advanced solar cells, and provide an overview of some of the advanced cell technologies under development to meet them. The discussion will include high efficiency, radiation hard single junction cells; monolithic and mechanically stacked multiple bandgap cells; and thin film cells.

Advanced solar cells for satellite power systems

NASA Astrophysics Data System (ADS)

Flood, Dennis J.; Weinberg, Irving

1994-11-01

The multiple natures of today's space missions with regard to operational lifetime, orbital environment, cost and size of spacecraft, to name just a few, present such a broad range of performance requirements to be met by the solar array that no single design can suffice to meet them all. The result is a demand for development of specialized solar cell types that help to optimize overall satellite performance within a specified cost range for any given space mission. Historically, space solar array performance has been optimized for a given mission by tailoring the features of silicon solar cells to account for the orbital environment and average operating conditions expected during the mission. It has become necessary to turn to entirely new photovoltaic materials and device designs to meet the requirements of future missions, both in the near and far term. This paper will outline some of the mission drivers and resulting performance requirements that must be met by advanced solar cells, and provide an overview of some of the advanced cell technologies under development to meet them. The discussion will include high efficiency, radiation hard single junction cells; monolithic and mechanically stacked multiple bandgap cells; and thin film cells.

Studies of encapsulant materials for terrestrial solar-cell arrays

NASA Technical Reports Server (NTRS)

Carmichael, D. C. (Compiler)

1975-01-01

Study 1 of this contract is entitled ""Evaluation of World Experience and Properties of Materials for Encapsulation of Terrestrial Solar-Cell Arrays.'' The approach of this study is to review and analyze world experience and to compile data on properties of encapsulants for photovoltaic cells and for related applications. The objective of the effort is to recommend candidate materials and processes for encapsulating terrestrial photovoltaic arrays at low cost for a service life greater than 20 years. The objectives of Study 2, ""Definition of Encapsulant Service Environments and Test Conditions,'' are to develop the climatic/environmental data required to define the frequency and duration of detrimental environmental conditions in a 20-year array lifetime and to develop a corresponding test schedule for encapsulant systems.

Planetary and Deep Space Requirements for Photovoltaic Solar Arrray

NASA Technical Reports Server (NTRS)

Bankston, C.; Bennett, R.; Stella, P.

1995-01-01

Most spacecraft are powered by nuclear sources. Now, on smaller, low-cost missions, photovoltaic arrays are being planned. Because they may be exposed to high temperatures and radiation when exploring the inner planets, cell materials and array structures must be able to perform at high incidence angles.

Designing Flat-Plate Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1984-01-01

Report presents overview of state of art in design techniques for flat-plate solar photovoltaic modules and arrays. Paper discusses design requirements, design analyses, and test methods identified and developed for this technology over past several years in effort to reduce cost and improve utility and reliability for broad spectrum of terrestrial applications.

Lightweight Innovative Solar Array (LISA): Providing Higher Power to Small Spacecraft

NASA Technical Reports Server (NTRS)

Johnson, Les; Carr, John; Fabisinski, Leo; Russell,Tiffany; Smith, Leigh

2015-01-01

Affordable and convenient access to electrical power is essential for all spacecraft and is a critical design driver for the next generation of smallsats, including cubesats, which are currently extremely power limited. The Lightweight Innovative Solar Array (LISA), a concept designed, prototyped, and tested at the NASA Marshall Space Flight Center (MSFC) in Huntsville, Alabama provides an affordable, lightweight, scalable, and easily manufactured approach for power generation in space. This flexible technology has many wide-ranging applications from serving small satellites to providing abundant power to large spacecraft in GEO and beyond. By using very thin, ultra-flexible solar arrays adhered to an inflatable structure, a large area (and thus large amount of power) can be folded and packaged into a relatively small volume. The LISA array comprises a launch-stowed, orbit-deployed structure on which lightweight photovoltaic devices and, potentially, transceiver elements are embedded. The system will provide a 2.5 to 5 fold increase in specific power generation (Watts/kilogram) coupled with a >2x enhancement of stowed volume (Watts/cubic-meter) and a decrease in cost (dollars/Watt) when compared to state-of-the-art solar arrays.

Development of a Solar Array Drive Assembly for CubeSat

NASA Technical Reports Server (NTRS)

Passaretti, Mike; Hayes, Ron

2010-01-01

Small satellites and in particular CubeSats, have increasingly become more viable as platforms for payloads typically requiring much larger bus structures. As advances in technology make payloads and instruments for space missions smaller, lighter and more power efficient, a niche market is emerging from the university community to perform rapidly developed, low-cost missions on very small spacecraft - micro, nano, and picosatellites. In just the last few years, imaging, biological and new technology demonstration missions have been either proposed or have flown using variations of the CubeSat structure as a basis. As these missions have become more complex, and the CubeSat standard has increased in both size (number of cubes) and mass, available power has become an issue. Body-mounted solar cells provide a minimal amount of power; deployable arrays improve on that baseline but are still limited. To truly achieve maximum power, deployed tracked arrays are necessary. To this end, Honeybee Robotics Spacecraft Mechanisms Corporation, along with MMA of Nederland Colorado, has developed a solar array drive assembly (SADA) and deployable solar arrays specifically for CubeSat missions. In this paper, we discuss the development of the SADA.

Integral glass encapsulation for solar arrays

NASA Technical Reports Server (NTRS)

Landis, G. A.

1981-01-01

Electrostatic bonding technology, an encapsulation technique for terrestrial solar array was developed. The process produces full integral, hermetic bonds with no adhesives or pottants. Panels of six solar cells on a simple glass superstrate were produced. Electrostatic bonding for making the cell front contact was also developed. A metal mesh is trapped into contact with the cell front during the bonding process. Six cell panels using the bonded mesh as the only cell front contact were produced. The possibility of using lower cost glass, with a higher thermal expansion mismatch to silicon, by making lower temperature bonds is developed. However, this requires a planar surface cell.

JPL encapsulation task

NASA Technical Reports Server (NTRS)

Willis, P.

1986-01-01

A detailed summary of the diverse encapsulation materials and techniques that evolved to meet the cost goals of the Flat-plate Solar Array (FSA) Project is presented. A typical solar cell now consists of low iron glass, two layers of ethylene vinyl acetate (EVA) polymers, a porous space, primers/adhesives, a back cover of Tedlar, and a gasket/seal for a volume cost of $1.30/sq ft. This compares well with the project goal of $1.40/sq ft.

30-kW SEP Spacecraft as Secondary Payloads for Low-Cost Deep Space Science Missions

NASA Technical Reports Server (NTRS)

Brophy, John R.; Larson, Tim

2013-01-01

The Solar Array System contracts awarded by NASA's Space Technology Mission Directorate are developing solar arrays in the 30 kW to 50 kW power range (beginning of life at 1 AU) that have significantly higher specific powers (W/kg) and much smaller stowed volumes than conventional rigid-panel arrays. The successful development of these solar array technologies has the potential to enable new types of solar electric propulsion (SEP) vehicles and missions. This paper describes a 30-kW electric propulsion vehicle built into an EELV Secondary Payload Adapter (ESPA) ring. The system uses an ESPA ring as the primary structure and packages two 15-kW Megaflex solar array wings, two 14-kW Hall thrusters, a hydrazine Reaction Control Subsystem (RCS), 220 kg of xenon, 26 kg of hydrazine, and an avionics module that contains all of the rest of the spacecraft bus functions and the instrument suite. Direct-drive is used to maximize the propulsion subsystem efficiency and minimize the resulting waste heat and required radiator area. This is critical for packaging a high-power spacecraft into a very small volume. The fully-margined system dry mass would be approximately 1120 kg. This is not a small dry mass for a Discovery-class spacecraft, for example, the Dawn spacecraft dry mass was only about 750 kg. But the Dawn electric propulsion subsystem could process a maximum input power of 2.5 kW, and this spacecraft would process 28 kW, an increase of more than a factor of ten. With direct-drive the specific impulse would be limited to about 2,000 s assuming a nominal solar array output voltage of 300 V. The resulting spacecraft would have a beginning of life acceleration that is more than an order of magnitude greater than the Dawn spacecraft. Since the spacecraft would be built into an ESPA ring it could be launched as a secondary payload to a geosynchronous transfer orbit significantly reducing the launch costs for a planetary spacecraft. The SEP system would perform the escape from Earth and then the heliocentric transfer to the science target.

Solar Electric Propulsion for Future NASA Missions

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Oleson, Steven R.; Mercer, Carolyn R.

2015-01-01

Use of high-power solar arrays, at power levels ranging from approximately 500 KW to several megawatts, has been proposed for a solar-electric propulsion (SEP) demonstration mission, using a photovoltaic array to provide energy to a high-power xenon-fueled engine. One of the proposed applications of the high-power SEP technology is a mission to rendezvous with an asteroid and move it into lunar orbit for human exploration, the Asteroid Retrieval mission. The Solar Electric Propulsion project is dedicated to developing critical technologies to enable trips to further away destinations such as Mars or asteroids. NASA needs to reduce the cost of these ambitious exploration missions. High power and high efficiency SEP systems will require much less propellant to meet those requirements.

Recent developments in nickel hydrogen technology

NASA Astrophysics Data System (ADS)

Beauchamp, R. L.; Dunlop, J. D.

1988-05-01

A program to design and develop a multikilowatt-hour nickel hydrogen battery for storing electricity from photovoltaic or other power sources is continuing under a cost sharing contract with Sandia National Laboratories. The challenge has been to dramatically reduce the first cost of the battery to make it economically competitive, on a life-cycle cost basis, with other energy storage batteries used in terrestrial applications. The advantages offered by nickel hydrogen batteries are: (1) long cycle life, (2) no maintenance, and (3) a high tolerance to abuse. The last being the most important, implying that there is no need for a charge controller between the solar array and the battery. This would have a beneficial effect on the installation's long term reliability and cost. It also means that one can take full advantage of the maximum output of the solar array, in contrast to systems where the controller isolates the battery during times of maximum insolation. Couple this to the battery's excellent energy efficiency and there can be a significant reduction in the size of the array. In addition, since the state-of-charge is directly related to pressure, the battery can be used as a load management system.

The design of low cost structures for extensive ground arrays

NASA Technical Reports Server (NTRS)

Franklin, H. A.; Leonard, R. S.

1980-01-01

The development of conceptual designs of solar array support structures and their foundations including considerations of the use of concrete, steel, aluminum, or timber are reported. Some cost trends were examined by varying selected parameters to determine optimum configurations. Detailed civil/structural design criteria were developed. Using these criteria, eight detailed designs for support structures and foundations were developed and cost estimates were made. As a result of the study wind was identified as the major loading experienced by these low height structures, whose arrays are likely to extend over large tracts of land. Proper wind load estimating is considered essential to developing realistic structural designs and achieving minimum cost support structures. Wind tunnel testing of a conceptual array field was undertaken and some of the resulting wind design criteria are presented. The SPS rectenna system designs may be less sensitive to wind load estimates, but consistent design criteria remain important.

SOSPAC- SOLAR SPACE POWER ANALYSIS CODE

NASA Technical Reports Server (NTRS)

Selcuk, M. K.

1994-01-01

The Solar Space Power Analysis Code, SOSPAC, was developed to examine the solar thermal and photovoltaic power generation options available for a satellite or spacecraft in low earth orbit. SOSPAC is a preliminary systems analysis tool and enables the engineer to compare the areas, weights, and costs of several candidate electric and thermal power systems. The configurations studied include photovoltaic arrays and parabolic dish systems to produce electricity only, and in various combinations to provide both thermal and electric power. SOSPAC has been used for comparison and parametric studies of proposed power systems for the NASA Space Station. The initial requirements are projected to be about 40 kW of electrical power, and a similar amount of thermal power with temperatures above 1000 degrees Centigrade. For objects in low earth orbit, the aerodynamic drag caused by suitably large photovoltaic arrays is very substantial. Smaller parabolic dishes can provide thermal energy at a collection efficiency of about 80%, but at increased cost. SOSPAC allows an analysis of cost and performance factors of five hybrid power generating systems. Input includes electrical and thermal power requirements, sun and shade durations for the satellite, and unit weight and cost for subsystems and components. Performance equations of the five configurations are derived, and the output tabulates total weights of the power plant assemblies, area of the arrays, efficiencies, and costs. SOSPAC is written in FORTRAN IV for batch execution and has been implemented on an IBM PC computer operating under DOS with a central memory requirement of approximately 60K of 8 bit bytes. This program was developed in 1985.

Fabrication of nanostructured CIGS solar cells

NASA Astrophysics Data System (ADS)

Zhang, Hongwang; Wang, Fang; Parry, James; Perera, Samanthe; Zeng, Hao

2012-02-01

We present the work on Cu(In,Ga)(Se,S)2 based nanostructured solar cells based on nanowire arrays. CIGS as the light absorber for thin-film solar cells has been widely studied recently, due to its high absorption coefficient, long-term stability, and low-cost of fabrication. Recently, solution phase processed CIGS thin film solar cells attracted great attention due to their extremely low fabrication cost. However, the performance is lower than vacuum based thin films possibly due to higher density of defects and lower carrier mobility. On the other hand, one dimensional ordered nanostructures such as nanowires and nanorods can be used to make redial junction solar cells, where the orthogonality between light absorption and charge carrier separation can lead to enhanced PV performance. Since the charge carriers only need to traverse a short distance in the radial direction before they are separated at the heterojunction interface, the radial junction scheme can be more defect tolerant than their planar junction scheme. In this work, a wide band gap nanowire or nanotube array such as TiO2 is used as a scaffold where CIGS is conformally coated using solution phase to obtain a radial heterojunction solar cell. Their performance is compared that of the planar thin film solar cells fabricated with the same materials.

Proceedings of the Flat-plate Solar Array Project Research Forum on the High-speed Growth and Characterization of Crystals for Solar Cells

NASA Technical Reports Server (NTRS)

Dumas, K. A. (Editor)

1984-01-01

Theoretical and experimental phenomena, applications, and characterization including stress/strain and other problem areas that limit the rate of growth of crystals suitable for processing into efficient, cost-effective solar cells are discussed. Melt spinning, ribbon growth, rapid solidification, laser recrystallization, and ignot growth of silicon and metals are also discussed.

Low cost silicon solar arrays

NASA Technical Reports Server (NTRS)

Ravi, K. V.; Serreze, H. B.; Bates, H. E.; Morrison, A. D.; Jewett, D. N.; Ho, J. C. T.; Schwuttke, G. H.; Ciszek, T. F.; Kran, A.

1975-01-01

Continuous growth methodology for silicon solar cell ribbons deals with capillary effects, die effects, thermal effects and crystal shape effects. Emphasis centers on the shape of the meniscus at the ribbon edge as a factor contributing to ribbon quality with respect to defect densities. Structural and electrical characteristics of edge defined, film-fed grown silicon ribbons are elaborated. Ribbon crystal solar cells produce AMO efficiencies of 6 to 10%.

Flexible, FEP-Teflon covered solar cell module development

NASA Technical Reports Server (NTRS)

Rauschenbach, H. S.; Cannady, M. D.

1976-01-01

Techniques and equipment were developed for the large scale, low-cost fabrication of lightweight, roll-up and fold-up, FEP-Teflon encapsulated solar cell modules. Modules were fabricated by interconnecting solderless single-crystal silicon solar cells and heat laminating them at approximately 300 C between layers of optically clear FEP and to a loadbearing Kapton substrate sheet. Modules were fabricated from both conventional and wraparound contact solar cells. A heat seal technique was developed for mechanically interconnecting modules into an array. The electrical interconnections for both roll-up and fold-up arrays were also developed. The use of parallel-gap resistance welding, ultrasonic bonding, and thermocompression bonding processes for attaching interconnects to solar cells were investigated. Parallel-gap welding was found to be best suited for interconnecting the solderless solar cells into modules. Details of the fabrication equipment, fabrication processes, module and interconnect designs, environmental test equipment, and test results are presented.

Straw man trade between multi-junction, gallium arsenide, and silicon solar cells

NASA Technical Reports Server (NTRS)

Gaddy, Edward M.

1995-01-01

Multi-junction (MJ), gallium arsenide (GaAs), and silicon (Si) solar cells have respective test efficiencies of approximately 24%, 18.5% and 14.8%. Multi-junction and gallium arsenide solar cells weigh more than silicon solar cells and cost approximately five times as much per unit power at the cell level. A straw man trade is performed for the TRMM spacecraft to determine which of these cell types would have offered an overall performance and price advantage to the spacecraft. A straw man trade is also performed for the multi-junction cells under the assumption that they will cost over ten times that of silicon cells at the cell level. The trade shows that the TRMM project, less the cost of the instrument, ground systems and mission operations, would spend approximately $552 thousand dollars per kilogram to launch and service science in the case of the spacecraft equipped with silicon solar cells. If these cells are changed out for gallium arsenide solar cells, an additional 31 kilograms of science can be launched and serviced at a price of approximately $90 thousand per kilogram. The weight reduction is shown to derive from the smaller area of the array and hence reductions in the weight of the array substrate and supporting structure. If the silicon solar cells are changed out for multi-junction solar cells, an additional 45 kilograms of science above the silicon base line can be launched and serviced at a price of approximately $58 thousand per kilogram. The trade shows that even if the multi-junction arrays are priced over ten times that of silicon cells, a price that is much higher than projected, that the additional 45 kilograms of science are launched and serviced at $182 thousand per kilogram. This is still much less than original $552 thousand per kilogram to launch and service the science. Data and qualitative factors are presented to show that these figures are subject to a great deal of uncertainty. Nonetheless, the benefit of the higher efficiency solar cells for TRMM is far greater than the uncertainties in the analysis.

The automated array assembly task of the low-cost silicon solar array project, phase 2

NASA Technical Reports Server (NTRS)

Coleman, M. G.; Pryor, R. A.; Sparks, T. G.; Legge, R.; Saltzman, D. L.

1980-01-01

Several specific processing steps as part of a total process sequence for manufacturing silicon solar cells were studied. Ion implantation was identified as the preferred process step for impurity doping. Unanalyzed beam ion implantation was shown to have major cost advantages over analyzed beam implantation. Further, high quality cells were fabricated using a high current unanalyzed beam. Mechanically masked plasma patterning of silicon nitride was shown to be capable of forming fine lines on silicon surfaces with spacings between mask and substrate as great as 250 micrometers. Extensive work was performed on advances in plated metallization. The need for the thick electroless palladium layer was eliminated. Further, copper was successfully utilized as a conductor layer utilizing nickel as a barrier to copper diffusion into the silicon. Plasma etching of silicon for texturing and saw damage removal was shown technically feasible but not cost effective compared to wet chemical etching techniques.

Investigation of test methods, material properties, and processes for solar cell encapsulants. Fourteenth quarterly progress report, August 12, 1978-November 12, 1979. [EVA, EPDM, aliphatic urethane, PVC plastisol, and butyl acrylate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Willis, P. B.; Baum, B.; Schnitzer, H. S.

1979-12-01

Springborn Laboratories is engaged in a study of evaluating potentially useful encapsulating materials for Task 3 of the Low-Cost Silicon Solar Array project (LSA) funded by DOE. The goal of this program is to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. This report presents the results of a cost analysis of candidate potting compounds for long life solar module encapsulation. Additionally, the two major encapsulation processes, sheet lamination and liquid casting, are costed on the basis of a large scale production facility. Potting compounds studied include EVA, sheet, clear; EVA,more » sheet, pigmented; EPDM, sheet, clear; Aliphatic urethane, syrup; PVC Plastisol; Butyl acrylate, syrup; and Butyl acrylate, sheet.« less

The Lightweight Integrated Solar Array and anTenna (LISA-T) Big Power for Small Spacecraft

NASA Technical Reports Server (NTRS)

Johnson, Les; Carr, John A.; Boyd, Darren

2017-01-01

NASA is developing a space power system using lightweight, flexible photovoltaic devices originally developed for use here on Earth to provide low cost power for spacecraft. The Lightweight Integrated Solar Array and anTenna (LISA-T) is a launch stowed, orbit deployed array on which thin-film photovoltaic and antenna elements are embedded. The LISA-T system is deployable, building upon NASA's expertise in developing thin-film deployable solar sails such the one being developed for the Near Earth Asteroid Scout project which will fly in 2018. One of the biggest challenges for the NEA Scout, and most other spacecraft, is power. There simply isn't enough of it available, thus limiting the range of operation of the spacecraft from the Sun (due to the small surface area available for using solar cells), the range of operation from the Earth (low available power with inherently small antenna sizes tightly constrain the bandwidth for communication), and the science (you can only power so many instruments with limited power). The LISA-T has the potential to mitigate each of these limitations, especially for small spacecraft. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between their need for power and robust communications with the requirements of the science or engineering payload they are developed to fly. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft and CubeSats. The problem is that these CubeSats can usually only generate between 7W and 50W of power. The power that can be generated by the LISA-T ranges from tens of watts to several hundred watts, at a much higher mass and stowage efficiency. A matrix of options are in development, including planar (pointed) and omnidirectional (non-pointed) arrays. The former is seeking the highest performance possible while the latter is seeking GN&C simplicity. Options for leveraging both high performance, 'typical cost' triple junction thin-film solar cells as well as moderate performance, low cost cells are being developed. Alongside, UHF (ultrahigh frequency), S-band, and X-band antennas are being integrated into the array to move their space claim away from the spacecraft and open the door for more capable multi-element antenna designs such as those needed for spherical coverage and electronically steered phase arrays.

The Lightweight Integrated Solar Array and anTenna (LISA-T) - Big Power for Small Spacecraft

NASA Technical Reports Server (NTRS)

Johnson, Les; Carr, John; Boyd, Darren

2017-01-01

NASA is developing a space power system using lightweight, flexible photovoltaic devices originally developed for use here on Earth to provide low cost power for spacecraft. The Lightweight Integrated Solar Array and anTenna (LISA-T) is a launch-stowed, orbit-deployed array on which thin-film photovoltaic and antenna elements are embedded. The LISA-T system is deployable, building upon NASA's expertise in developing thin-film deployable solar sails such the one being developed for the Near Earth Asteroid Scout project which will fly in 2018. One of the biggest challenges for the NEA Scout, and most other spacecraft, is power. There simply isn't enough of it available, thus limiting the range of operation of the spacecraft from the Sun (due to the small surface area available for using solar cells), the range of operation from the Earth (low available power with inherently small antenna sizes tightly constrain the bandwidth for communication), and the science (you can only power so many instruments with limited power). The LISA-T has the potential to mitigate each of these limitations. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between their need for power and robust communications with the requirements of the science or engineering payload they are developed to fly. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft and CubeSats. The problem is that these CubeSats can usually only generate between 7 watts and 50 watts of power. The power that can be generated by the LISA-T ranges from tens of watts to several hundred watts. A matrix of options are in development, including planar (pointed) and omnidirectional (non-pointed) arrays. The former is seeking the highest performance possible while the latter is seeking GN&C (Guidance, Navigation and Control) simplicity. In both cases, power generation ranges from tens of watts to several hundred with an expected specific power greater than 250 watts per kilogram and a stowed power density greater than 200 kilowatts per cubic meter. Options for leveraging both high performance, 'typical cost' triple junction thin-film solar cells as well as moderate performance, low cost cells are being developed. Alongside, both UHF (ultra high frequency) and S-band antennas are being integrated into the array to move their space claim away from the spacecraft and open the door for omnidirectional communications and electronically steered phase arrays.

Analysis and evalaution in the production process and equipment area of the low-cost solar array project. [including modifying gaseous diffusion and using ion implantation

NASA Technical Reports Server (NTRS)

Goldman, H.; Wolf, M.

1979-01-01

The manufacturing methods for photovoltaic solar energy utilization are assessed. Economic and technical data on the current front junction formation processes of gaseous diffusion and ion implantation are presented. Future proposals, including modifying gaseous diffusion and using ion implantation, to decrease the cost of junction formation are studied. Technology developments in current processes and an economic evaluation of the processes are included.

Automated array assembly task development of low-cost polysilicon solar cells

NASA Technical Reports Server (NTRS)

Jones, G. T.

1980-01-01

Development of low cost, large area polysilicon solar cells was conducted in this program. Three types of polysilicon materialk were investigated. A theoretical and experimenal comparison between single crystal silicon and polysilicon solar cell efficiency was performed. Significant electrical performance differences were observed between types of wafer material, i.e. fine grain and coarse grain polysilicon and single crystal silicon. Efficiency degradation due to grain boundaries in fin grain and coarse grain polysilicon was shown to be small. It was demonstrated that 10 percent efficient polysilicon solar cells can be produced with spray on n+ dopants. This result fulfills an important goal of this project, which is the production of batch quantity of 10 percent efficient polysilicon solar cells.

Accelerated/abbreviated test methods, study 4 of task 3 (encapsulation) of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Kolyer, J. M.; Mann, N. R.

1978-01-01

Inherent weatherability is controlled by the three weather factors common to all exposure sites: insolation, temperature, and humidity. Emphasis was focused on the transparent encapsulant portion of miniature solar cell arrays by eliminating weathering effects on the substrate and circuitry (which are also parts of the encapsulant system). The most extensive data were for yellowing, which were measured conveniently and precisely. Considerable data also were obtained on tensile strength. Changes in these two properties after outdoor exposure were predicted very well from accelerated exposure data.

Solar Electric Propulsion Concepts for Human Space Exploration

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Mcguire, Melissa L.; Oleson, Steven R.; Barrett, Michael J.

2016-01-01

Advances in solar array and electric thruster technologies now offer the promise of new, very capable space transportation systems that will allow us to cost effectively explore the solar system. NASA has developed numerous solar electric propulsion spacecraft concepts with power levels ranging from tens to hundreds of kilowatts for robotic and piloted missions to asteroids and Mars. This paper describes nine electric and hybrid solar electric/chemical propulsion concepts developed over the last 5 years and discusses how they might be used for human exploration of the inner solar system.

Solar Electric Propulsion Concepts for Human Space Exploration

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; McGuire, Melissa L.; Oleson, Steven R.; Barrett, Michael J.

2015-01-01

Advances in solar array and electric thruster technologies now offer the promise of new, very capable space transportation systems that will allow us to cost effectively explore the solar system. NASA has developed numerous solar electric propulsion spacecraft concepts with power levels ranging from tens to hundreds of kilowatts for robotic and piloted missions to asteroids and Mars. This paper describes nine electric and hybrid solar electric/chemical propulsion concepts developed over the last 5 years and discusses how they might be used for human exploration of the inner solar system.

Silicon web process development. [for low cost solar cells

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Hopkins, R. H.; Seidensticker, R. G.; Mchugh, J. P.; Hill, F. E.; Heimlich, M. E.; Driggers, J. M.

1979-01-01

Silicon dendritic web, a single crystal ribbon shaped during growth by crystallographic forces and surface tension (rather than dies), is a highly promising base material for efficient low cost solar cells. The form of the product smooth, flexible strips 100 to 200 microns thick, conserves expensive silicon and facilitates automation of crystal growth and the subsequent manufacturing of solar cells. These characteristics, coupled with the highest demonstrated ribbon solar cell efficiency-15.5%-make silicon web a leading candidate to achieve, or better, the 1986 Low Cost Solar Array (LSA) Project cost objective of 50 cents per peak watt of photovoltaic output power. The main objective of the Web Program, technology development to significantly increase web output rate, and to show the feasibility for simultaneous melt replenishment and growth, have largely been accomplished. Recently, web output rates of 23.6 sq cm/min, nearly three times the 8 sq cm/min maximum rate of a year ago, were achieved. Webs 4 cm wide or greater were grown on a number of occassions.

The 40 KW of Solar Cell Modules for the Large Scale Production Task a Low Cost Silicon Solar Array Project

NASA Technical Reports Server (NTRS)

Jones, G. T.

1977-01-01

Forty kilowatts of solar cell modules was produced in this program. This is equivalent to 4123 modules. The average power output per module was 9.7 watts at 16.5 volts, 60 C and 100 mW/sq cm. The peak production rate was 200 modules per week which is equal to 1.9 kW per week. This rate was sustained for over four and one-half months and is equivalent to 100 kW per year. This final report covers the solar cell module design, electrical and power performance, module preproduction environmental test results, production and shipping schedule, program summary, and delivery. A cost analysis section is written. Particular emphasis on the percentage of labor and material utilized in constructing a solar cell module is presented. Also included are cost reduction recommendations.

ZnO nanosheet arrays constructed on weaved titanium wire for CdS-sensitized solar cells

PubMed Central

2014-01-01

Ordered ZnO nanosheet arrays were grown on weaved titanium wires by a low-temperature hydrothermal method. CdS nanoparticles were deposited onto the ZnO nanosheet arrays using the successive ionic layer adsorption and reaction method to make a photoanode. Nanoparticle-sensitized solar cells were assembled using these CdS/ZnO nanostructured photoanodes, and their photovoltaic performance was studied systematically. The best light-to-electricity conversion efficiency was obtained to be 2.17% under 100 mW/cm2 illumination, and a remarkable short-circuit photocurrent density of approximately 20.1 mA/cm2 was recorded, which could attribute to the relatively direct pathways for transportation of electrons provided by ZnO nanosheet arrays as well as the direct contact between ZnO and weaved titanium wires. These results indicate that CdS/ZnO nanostructures on weaved titanium wires would open a novel possibility for applications of low-cost solar cells. PMID:24618047

Photovoltaic power system for a lunar base

NASA Astrophysics Data System (ADS)

Karia, Kris

An assessment is provided of the viability of using photovoltaic power technology for lunar base application during the initial phase of the mission. The initial user power demands were assumed to be 25 kW (daytime) and 12.5 kW (night time). The effect of lunar adverse environmental conditions were also considered in deriving the photovoltaic power system concept. The solar cell array was found to impose no more design constraints than those solar arrays currently being designed for spacecraft and the Space Station Freedom. The long lunar night and the need to store sufficient energy to sustain a lunar facility during this period was found to be a major design driver. A photovoltaic power system concept was derived using high efficiency thin GaAs solar cells on a deployable flexible Kapton blanket. The solar array design was sized to generate sufficient power for daytime use and for a regenerative fuel cell (RFC) energy storage system to provide power during the night. Solar array sun-tracking is also proposed to maximize the array power output capability. The system launch mass was estimated to be approximately 10 metric tons. For mission application of photovoltaic technology other issues have to be addressed including the constraints imposed by launch vehicle, safety, and cost. For the initial phase of the mission a photovoltaic power system offers a safe option.

Automated array assembly task, phase 1

NASA Technical Reports Server (NTRS)

Carbajal, B. G.

1977-01-01

State-of-the-art technologies applicable to silicon solar cell and solar cell module fabrication were assessed. The assessment consisted of a technical feasibility evaluation and a cost projection for high volume production of solar cell modules. Design equations based on minimum power loss were used as a tool in the evaluation of metallization technologies. A solar cell process sensitivity study using models, computer calculations, and experimental data was used to identify process step variation and cell output variation correlations.

Photovoltaic power for Space Station Freedom

NASA Technical Reports Server (NTRS)

Baraona, Cosmo R.

1990-01-01

Space Station Freedom is described with special attention given to its electric power system. The photovoltaic arrays, the battery energy storage system, and the power management, and distribution system are also discussed. The current design of Freedom's power system and the system requirements, trade studies, and competing factors which lead to system selections are referenced. This will be the largest power system ever flown in space. This system represents the culmination of many developments that have improved system performance, reduced cost, and improved reliability. Key developments and their evolution into the current space station solar array design are briefly described. The features of the solar cell and the array including the development, design, test, and flight hardware production status are given.

Photovoltaic power for Space Station Freedom

NASA Technical Reports Server (NTRS)

Baraona, Cosmo R.

1990-01-01

Space Station Freedom is described with special attention to its electric power system. The photovoltaic arrays, the battery energy storage system, and the power management and distribution system are also discussed. The current design of Freedom's power system and the system requirements, trade studies, and competing factors which lead to system selections are referenced. This will be the largest power system ever flown in space. This system represents the culmination of many developments that have improved system performance, reduced cost, and improved reliability. Key developments and their evolution into the current space station solar array design are briefly described. The features of the solar cell and the array including the development, design, test, and flight hardware production status are given.

The economic payoff for a state-of-the-art high-efficiency flat-plate crystalline silicon solar cell technology

NASA Technical Reports Server (NTRS)

Bickler, Donald B.; Callaghan, W. T.

1987-01-01

In 1986 during the flat-plate solar array project, silicon solar cells 4.0 sq cm in area were fabricated at the Jet Propulsion Laboratory (JPL) with a conversion efficiency of 20.1 percent (AM1.5-global). Sixteen cells were processed with efficiencies measuring 19.5 percent (AM1.5 global) or better. These cells were produced using refined versions of conventional processing methods, aside from certain advanced techniques that bring about a significant reduction in a major mechanism (surface recombination) that limits cell efficiency. Wacker Siltronic p-type float-zone 0.18-ohm-cm wafers were used. Conversion efficiencies in this range have previously been reported by other researchers, but generally on much smaller (0.5 vs. 4.0 cm) devices which have undergone sophisticated and costly processing steps. An economic analysis is presented of the potential payoffs for this approach, using the Solar Array Manufacturing Industry Costing Standards (SAMICS) methodology. The process sequence used and the assumptions made for capturing the economies of scale are presented.

Flight Test of a Technology Transparent Light Concentration Panel on SMEX/WIRE

NASA Technical Reports Server (NTRS)

Stern, Theodore G.; Lyons, John

2000-01-01

A flight experiment has demonstrated a modular solar concentrator that can be used as a direct substitute replacement for planar photovoltaic panels in spacecraft solar arrays. The Light Concentrating Panel (LCP) uses an orthogrid arrangement of composite mirror strips to form an array of rectangular mirror troughs that reflect light onto standard, high-efficiency solar cells at a concentration ratio of approximately 3:1. The panel area, mass, thickness, and pointing tolerance has been shown to be similar to a planar array using the same cells. Concentration reduces the panel's cell area by 2/3, which significantly reduces the cost of the panel. An opportunity for a flight experiment module arose on NASA's Small Explorer / Wide-Field Infrared Explorer (SMEX/WIRE) spacecraft, which uses modular solar panel modules integrated into a solar panel frame structure. The design and analysis that supported implementation of the LCP as a flight experiment module is described. Easy integration into the existing SMEX-LITE wing demonstrated the benefits of technology transparency. Flight data shows the stability of the LCP module after nearly one year in Low Earth Orbit.

Efficient Cells Cut the Cost of Solar Power

NASA Technical Reports Server (NTRS)

2013-01-01

If you visit Glenn Research Center, you might encounter a photovoltaic (PV) array that looks unlike anything you've ever seen. In fact, what one would normally identify as the panel is actually a series of curved mirrors called solar concentrators, engineered to reflect sunlight rather than absorb it. These concentrators gather, intensify, and focus sun beams upward, aiming at a fixture containing specialized silicon concentrated PV chips the actual solar cells. If you stay by the array for a while, you'll notice that the solar concentrators follow the path of the sun throughout the day, changing position to best capture and utilize the sunlight. The specialized chips that make the technology possible are the brainchild of Bernard Sater, an engineer who had worked at Glenn since the early 1960s before retiring to pursue his unique ideas for harnessing solar power. Sater contributed to multiple PV projects in the latter part of his career at the Center, including research and development on the International Space Station s solar arrays. In his spare time, he enjoyed tinkering with new approaches to solar power, experiments that resulted in the system installed at Glenn today. Sater s basic idea had two components. First, he wanted to create a silicon cell that was smaller, more efficient, and much lower cost than those available at the time. To ensure that the potential of such a chip could be realized, he also planned on pairing it with a system that could concentrate sunlight and focus it directly on the cell. When he retired from Glenn in 1994 to focus on researching and developing the technology full time, Sater found that NASA was interested in the concept and ready to provide funding, facilities, and expertise in order to assist in its development.

Recent developments in the economic modeling of photovoltaic module manufacturing

NASA Technical Reports Server (NTRS)

Chamberlain, R. G.

1979-01-01

Recent developments in the solar array manufacturing industry costing standards (SAMICS) are described. Consideration is given to the added capability to handle arbitrary operating schedules and the revised procedure for calculation of one-time costs. The results of an extensive validation study are summarized.

Analysis and evaluation of processes and equipment in tasks 2 and 4 of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Goldman, H.; Wolf, M.

1978-01-01

Several experimental and projected Czochralski crystal growing process methods were studied and compared to available operations and cost-data of recent production Cz-pulling, in order to elucidate the role of the dominant cost contributing factors. From this analysis, it becomes apparent that the specific add-on costs of the Cz-process can be expected to be reduced by about a factor of three by 1982, and about a factor of five by 1986. A format to guide in the accumulation of the data needed for thorough techno-economic analysis of solar cell production processes was developed.

Evaluation of solar cells for potential space satellite power applications

NASA Technical Reports Server (NTRS)

1977-01-01

The evaluation focused on the following subjects: (1) the relative merits of alternative solar cell materials, based on performance and availability, (2) the best manufacturing methods for various solar cell options and the effects of extremely large production volumes on their ultimate costs and operational characteristics, (3) the areas of uncertainty in achieving large solar cell production volumes, (4) the effects of concentration ratios on solar array mass and system performance, (5) the factors influencing solar cell life in the radiation environment during transport to and in geosynchronous orbit, and (6) the merits of conducting solar cell manufacturing operations in space.

Silicon material task. Part 3: Low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Roques, R. A.; Coldwell, D. M.

1977-01-01

The feasibility of a process for carbon reduction of low impurity silica in a plasma heat source was investigated to produce low-cost solar-grade silicon. Theoretical aspects of the reaction chemistry were studied with the aid of a computer program using iterative free energy minimization. These calculations indicate a threshold temperature exists at 2400 K below which no silicon is formed. The computer simulation technique of molecular dynamics was used to study the quenching of product species.

Low cost solar array project. Experimental process system development unit for producing semiconductor-grade silicon using the silane-to-silicon process

NASA Technical Reports Server (NTRS)

1980-01-01

Technical activities are reported in the design of process, facilities, and equipment for producing silicon at a rate and price comensurate with production goals for low cost solar cell modules. The silane-silicone process has potential for providing high purity poly-silicon on a commercial scale at a price of fourteen dollars per kilogram by 1986, (1980 dollars). Commercial process, economic analysis, process support research and development, and quality control are discussed.

Thermal design of spacecraft solar arrays using a polyimide foam

NASA Astrophysics Data System (ADS)

Bianco, N.; Iasiello, M.; Naso, V.

2015-11-01

The design of the Thermal Control System (TCS) of spacecraft solar arrays plays a fundamental role. Indeed, the spacecraft components must operate within a certain range of temperature. If this doesn't occur, their performance is reduced and they may even break. Solar arrays, which are employed to recharge batteries, are directly exposed to the solar heat flux, and they need to be insulated from the earth's surface irradiation. Insulation is currently provided either with a white paint coating or with a Multi Layer Insulation (MLI) system [1]. A configuration based on an open-cell polyimide foam has also been recently proposed [2]. Using polyimide foams in TCSs looks very attractive in terms of costs, weight and assembling. An innovative thermal analysis of the above cited TCS configurations is carried out in this paper, by solving the porous media energy equation, under the assumption of Local Thermal Equilibrium (LTE) between the two phases. Radiation effects through the solar array are also considered by using the Rosseland approximation. Under a stationary daylight condition, temperature profiles are obtained by means of the finite-element based code COMSOL Multiphysics®. Finally, since the weight plays an important role in aerospace applications, weights of the three TCS configurations are compared.

Flat-plate solar array project. Volume 4: High-efficiency solar cells

NASA Technical Reports Server (NTRS)

Leipold, M.; Cheng, L.; Daud, T.; Mokashi, A.; Burger, D.; Christensen, E. (Editor); Murry, J. (Editor); Bengelsdorf, I. (Editor)

1986-01-01

The High Efficiency Solar Cell Task was assigned the objective of understanding and developing high efficiency solar cell devices that would meet the cost and performance goals of the Flat Plate Solar Array (FSA) Project. The need for research dealing with high efficiency devices was considered important because of the role efficiency plays in reducing price per watt of generated energy. The R&D efforts conducted during the 1982 to 1986 period are summarized to provide understanding and control of energy conversion losses associated with crystalline silicon solar cells. New levels of conversion efficiency were demonstrated. Major contributions were made both to the understanding and reduction of bulk and surface losses in solar cells. For example, oxides, nitrides, and polysilicon were all shown to be potentially useful surface passivants. Improvements in measurement techniques were made and Auger coefficients and spectral absorption data were obtained for unique types of silicon sheets. New modelling software was developed including a program to optimize a device design based on input characteristics of a cell.

Modeling energy production of solar thermal systems and wind turbines for installation at corn ethanol plants

NASA Astrophysics Data System (ADS)

Ehrke, Elizabeth

Nearly every aspect of human existence relies on energy in some way. Most of this energy is currently derived from fossil fuel resources. Increasing energy demands coupled with environmental and national security concerns have facilitated the move towards renewable energy sources. Biofuels like corn ethanol are one of the ways the U.S. has significantly reduced petroleum consumption. However, the large energy requirement of corn ethanol limits the net benefit of the fuel. Using renewable energy sources to produce ethanol can greatly improve its economic and environmental benefits. The main purpose of this study was to model the useful energy received from a solar thermal array and a wind turbine at various locations to determine the feasibility of applying these technologies at ethanol plants around the country. The model calculates thermal energy received from a solar collector array and electricity generated by a wind turbine utilizing various input data to characterize the equipment. Project cost and energy rate inputs are used to evaluate the profitability of the solar array or wind turbine. The current state of the wind and solar markets were examined to give an accurate representation of the economics of each industry. Eighteen ethanol plant locations were evaluated for the viability of a solar thermal array and/or wind turbine. All ethanol plant locations have long payback periods for solar thermal arrays, but high natural gas prices significantly reduce this timeframe. Government incentives will be necessary for the economic feasibility of solar thermal arrays. Wind turbines can be very profitable for ethanol plants in the Midwest due to large wind resources. The profitability of wind power is sensitive to regional energy prices. However, government incentives for wind power do not significantly change the economic feasibility of a wind turbine. This model can be used by current or future ethanol facilities to investigate or begin the planning process for a solar thermal array or wind turbine. The model is meant to aide in the planning stages of a renewable energy project, and advanced investigation will be needed to move forward with that project.

Low-cost solar array progress and plans

NASA Astrophysics Data System (ADS)

Callaghan, W. T.

It is pointed out that significant redirection has occurred in the U.S. Department of Energy (DOE) Photovoltaics Program, and thus in the Flat-Plate Solar Array Project (FSA), since the 3rd European Communities Conference. The Silicon Materials Task has now the objective to sponsor theoretical and experimental research on silicon material refinement technology suitable for photovoltaic flat-plate solar arrays. With respect to the hydrochlorination reaction, a process proof of concept was completed through definition of reaction kinetics, catalyst, and reaction characteristics. In connection with the dichlorosilane chemical vapor desposition process, a preliminary design was completed of an experimental process system development unit with a capacity of 100 to 200 MT/yr of Si.Attention is also given to the silicon-sheet formation research area, environmental isolation research, the cell and module formation task, the engineering sciences area, and the module performance and failure analysis area.

The Energetic Transient Array ETA - A network of 'space buoys' in solar orbit for observations of gamma-ray bursts

NASA Technical Reports Server (NTRS)

Ricker, George R.

1990-01-01

The Energetic Transient Array (ETA) is a concept for a dedicated interplanetary network of about 40 microsatellites ('space buoys') deployed in an about 1 AU radius solar orbit for the observation of cosmic gamma ray bursts (GRBs). Such a network is essential for the determination of highly accurate (about 0.1 arcsec) error boxes for GRBs. For each of about 100 bursts which would be detectable per year of observation by such a network, high resolution spectra could be obtained through the use of passively-cooled Ge gamma-ray detectors. Stabilization of each microsatellite would be achieved by a novel technique based on the radiation pressure exerted on 'featherable' solar paddles. It should be possible to have a fully functional array of satellites in place before the end of the decade for a total cost of about $20M, exclusive of launcher fees.

Influence of mass moment of inertia on normal modes of preloaded solar array mast

NASA Technical Reports Server (NTRS)

Armand, Sasan C.; Lin, Paul

1992-01-01

Earth-orbiting spacecraft often contain solar arrays or antennas supported by a preloaded mast. Because of weight and cost considerations, the structures supporting the spacecraft appendages are extremely light and flexible; therefore, it is vital to investigate the influence of all physical and structural parameters that may influence the dynamic behavior of the overall structure. The study primarily focuses on the mast for the space station solar arrays, but the formulations and the techniques developed in this study apply to any large and flexible mast in zero gravity. Furthermore, to determine the influence on the circular frequencies, the mass moment of inertia of the mast was incorporated into the governing equation of motion for bending. A finite element technique (MSC/NASTRAN) was used to verify the formulation. Results indicate that when the mast is relatively flexible and long, the mass moment inertia influences the circular frequencies.

Recent developments in photovoltaic energy by ERDA/NASA-LeRC

NASA Technical Reports Server (NTRS)

Deyo, J. N.

1977-01-01

Application development activities were designed to stimulate the market for photovoltaics so that as costs are reduced there will be an increasing market demand to encourage the expansion of industrial solar array production capacity. Supporting these application development activities are tasks concerned with: (1) establishing standards and methodology for terrestrial solar cell calibration; (2) conducting standard and diagnostic measurements on solar cells and modules; and (3) conducting real time and accelerated testing of solar cell modules and materials of construction under outdoor sunlight conditions.

Advanced Solar Cell and Array Technology for NASA Deep Space Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael; Benson, Scott; Scheiman, David; Finacannon, Homer; Oleson, Steve; Landis, Geoffrey

2008-01-01

A recent study by the NASA Glenn Research Center assessed the feasibility of using photovoltaics (PV) to power spacecraft for outer planetary, deep space missions. While the majority of spacecraft have relied on photovoltaics for primary power, the drastic reduction in solar intensity as the spacecraft moves farther from the sun has either limited the power available (severely curtailing scientific operations) or necessitated the use of nuclear systems. A desire by NASA and the scientific community to explore various bodies in the outer solar system and conduct "long-term" operations using using smaller, "lower-cost" spacecraft has renewed interest in exploring the feasibility of using photovoltaics for to Jupiter, Saturn and beyond. With recent advances in solar cell performance and continuing development in lightweight, high power solar array technology, the study determined that photovoltaics is indeed a viable option for many of these missions.

Proceedings of the Flat-Plate Solar Array Project Workshop on Crystal Gowth for High-Efficiency Silicon Solar Cells

NASA Technical Reports Server (NTRS)

Dumas, K. A. (Editor)

1985-01-01

A Workshop on Crystal Growth for High-Efficiency Silicon Solar Cells was held December 3 and 4, 1984, in San Diego, California. The Workshop offered a day and a half of technical presentations and discussions and an afternoon session that involved a panel discussion and general discussion of areas of research that are necessary to the development of materials for high-efficiency solar cells. Topics included the theoretical and experimental aspects of growing high-quality silicon crystals, the effects of growth-process-related defects on photovoltaic devices, and the suitability of various growth technologies as cost-effective processes. Fifteen invited papers were presented, with a discussion period following each presentation. The meeting was organized by the Flat-Plate Solar Array Project of the Jet Propulsion Laboratory. These Proceedings are a record of the presentations and discussions, edited for clarity and continuity.

Concept, Design, and Prototyping of XSAS: A High Power Extendable Solar Array for CubeSat Applications

NASA Technical Reports Server (NTRS)

Senatore, Patrick; Klesh, Andrew; Zurbuchen, Thomas H.; McKague, Darren; Cutler, James

2010-01-01

CubeSats have proven themselves as a reliable and cost-effective method to perform experiments in space, but they are highly constrained by their specifications and size. One such constraint is the average continuous power, about 5 W, which is available to the typical CubeSat. To improve this constraint, we have developed the eXtendable Solar Array System (XSAS), a deployable solar array prototype in a CubeSat package, which can provide an average 23 W of continuous power. The prototype served as a technology demonstrator for the high risk mechanisms needed to release, deploy, and control the solar array. Aside from this drastic power increase, it is in the integration of each mechanism, their application within the small CubeSat form-factor, and the inherent passive control benefit of the deployed geometry that make XSAS a novel design. In this paper, we discuss the requirements and design process for the XSAS system and mechanical prototype, and provide qualitative and quantitative results from numerical simulations and prototype tests. We also discuss future work, including an upcoming NASA zero-gravity flight campaign, to further improve on XSAS and prepare it for future launch opportunities.

Development of a solar array drive mechanism for micro-satellite platforms

NASA Astrophysics Data System (ADS)

Galatis, Giorgos; Guo, Jian; Buursink, Jeroen

2017-10-01

Photovoltaic solar array (PVSA) systems are the most widely used method for spacecraft power generation. However, in many satellite missions, the optimum orientation of the PVSA system is not always compatible with that of the payload orientation. Many methods, have been examined in the past to overcome this problem. Up to date, the most widely used active method for large costly satellites is the Solar Array Drive Mechanism (SADM). The SADM serves as the interface between the satellite body and the PVSA subsystem, enabling the decoupling of their spatial orientation. Nonetheless, there exists a research and development gap for such systems regarding low cost micro-satellites. During the literature study of this paper, individual orbital parameters of various micro-satellites have been extracted and compared to the rotational freedom of the corresponding SADMs used. The findings demonstrated that the implemented SADMs are over designed. It is therefore concluded that these components are not tailored made for each spacecraft mission individually, but rather, exhibit a generic design to full fill a majority of mission profiles and requirements. Motivated by the above analysis, the cardinal objective of the current research is to develop a low cost mechanism that will be precisely tailored for the use of a low Earth orbit (LEO) micro-satellite platform orbiting in altitudes of 500 - 1000km . The design of the mechanism may vary from the existing miniaturized SADMs. For example, the preliminary analysis of the current research suggests, that the conventional use of the slip ring system as the electronic transfer unit can be replaced by a seMI Orientation Unit (MIOU). Systems engineering tools for concept generation and selection have been used. In addition, simulation and mathematical modelling have been implemented on component and system level, to accurately predict the behaviour of the system under various modes of operation. The production and system testing of the prototype has taken place and it has verified that the development of such a system, will aid the power generation of the solar arrays, while having a positive impact on the cost reduction of such satellites.

Planetary and Deep Space Requirements for Photovoltaic Solar Arrays

NASA Technical Reports Server (NTRS)

Bankston, C. P.; Bennett, R. B.; Stella, P. M.

1995-01-01

In the past 25 years, the majority of interplanetary spacecraft have been powered by nuclear sources. However, as the emphasis on smaller, low cost missions gains momentum, more deep space missions now being planned have baselined photovoltaic solar arrays due to the low power requirements (usually significantly less than 100 W) needed for engineering and science payloads. This will present challenges to the solar array builders, inasmuch as planetary requirements usually differ from earth orbital requirements. In addition, these requirements often differ greatly, depending on the specific mission; for example, inner planets vs. outer planets, orbiters vs. flybys, spacecraft vs. landers, and so on. Also, the likelihood of electric propulsion missions will influence the requirements placed on solar array developers. This paper will discuss representative requirements for a range of planetary and deep space science missions now in the planning stages. We have divided the requirements into three categories: Inner planets and the sun; outer planets (greater than 3 AU); and Mars, cometary, and asteroid landers and probes. Requirements for Mercury and Ganymede landers will be covered in the Inner and Outer Planets sections with their respective orbiters. We will also discuss special requirements associated with solar electric propulsion (SEP). New technology developments will be needed to meet the demanding environments presented by these future applications as many of the technologies envisioned have not yet been demonstrated. In addition, new technologies that will be needed reside not only in the photovoltaic solar array, but also in other spacecraft systems that are key to operating the spacecraft reliably with the photovoltaics.

Spectrophotovoltaic orbital power generation

NASA Technical Reports Server (NTRS)

Onffroy, J. R.

1980-01-01

The feasibilty of a spectrophotovoltaic orbital power generation system that optically concentrates solar energy is demonstrated. A dichroic beam-splitting mirror is used to divide the solar spectrum into two wavebands. Absorption of these wavebands by GaAs and Si solar cell arrays with matched energy bandgaps increases the cell efficiency while decreasing the amount of heat that must be rejected. The projected cost per peak watt if this system is $2.50/W sub p.

Power Converters Maximize Outputs Of Solar Cell Strings

NASA Technical Reports Server (NTRS)

Frederick, Martin E.; Jermakian, Joel B.

1993-01-01

Microprocessor-controlled dc-to-dc power converters devised to maximize power transferred from solar photovoltaic strings to storage batteries and other electrical loads. Converters help in utilizing large solar photovoltaic arrays most effectively with respect to cost, size, and weight. Main points of invention are: single controller used to control and optimize any number of "dumb" tracker units and strings independently; power maximized out of converters; and controller in system is microprocessor.

High temperature, high intensity solar array. [for Venus Radar Mapper mission

NASA Technical Reports Server (NTRS)

Smith, B. S.; Brooks, G. R.; Pinkerton, R.

1985-01-01

The solar array for the Venus Radar Mapper mission will operate in the high temperature, high intensity conditions of a low Venus orbit environment. To fulfill the performance requirements in this environment at minimum cost and mass while maximizing power density and packing factor on the panel surface, several features were introduced into the design. These features included the use of optical surface reflectors (OSR's) to reduce the operating temperature; new adhesives for conductive bonding of OSR's to avoid electrostatic discharges; custom-designed large area cells and novel shunt diode circuit and panel power harness configurations.

SERT D spacecraft study. [project planning and objectives

NASA Technical Reports Server (NTRS)

1974-01-01

The SERT D (Space Electric Rocket Test - D) study defines a possible spacecraft project that would demonstrate the use of electric ion thrusters for long-term (5 yr) station keeping and attitude control of a synchronous orbit satellite. Other mission objectives included in the study were: station walking to satellite rendezvous and inspection, use of low cost attitude sensing system, use of an advanced solar array orientation and slip ring system, and an ion thruster integrated directly with a solar array power source. The SERT D spacecraft, if launched, will become SERT 3 the third space electric thruster test.

Phase 2: Array automated assembly task low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Jones, G. T.

1979-01-01

Several microwave systems for use in solar cell fabrication were developed and experimentally tested. The first system used a standing wave rectangular waveguide horn applicator. Satisfactory results were achieved with this system for impedance matching and wafer surface heating uniformity. The second system utilized a resonant TM sub 011 mode cylindrical cavity but could not be employed due to its poor energy coupling efficiency. The third and fourth microwave systems utilized a circular waveguide operating in the TM sub 01 and TM sub 11 but had problems with impedance matching, efficiency, and field uniformity.

Photovoltaic applications of Compound Parabolic Concentrator (CPC)

NASA Technical Reports Server (NTRS)

Winston, R.

1975-01-01

The use of a compound parabolic concentrator as field collector, in conjunction with a primary focusing concentrator for photovoltaic applications is studied. The primary focusing concentrator can be a parabolic reflector, an array of Fresnel mirrors, a Fresnel lens or some other lens. Silicon solar cell grid structures are proposed that increase efficiency with concentration up to 10 suns. A ray tracing program has been developed to determine energy distribution at the exit of a compound parabolic concentrator. Projected total cost of a CPC/solar cell system will be between 4 and 5 times lower than for flat plate silicon cell arrays.

Low cost solar array project silicon materials task. Development of a process for high capacity arc heater production of silicon for solar arrays

NASA Technical Reports Server (NTRS)

Reed, W. H.

1978-01-01

Silicon tetrachloride and a reductant (sodium) will be injected into an arc heated mixture of hydrogen and argon, yielding silicon and gaseous sodium chloride. Detailed characterization of the Sonicore sodium injection nozzle, using water as the test fluid was completed. Results indicated that flow rates of 45 gph sodium and 50 scfm argon should produce sufficiently small droplet sizes. The design effort was also completed for the test system preparation which was divided into two categories: (1) system components and (2) test system-laboratory integration.

LSA: Low-cost Solar Array project

NASA Technical Reports Server (NTRS)

1978-01-01

Topics discussed include silicon material processing; large-area silicon sheet development; encapsulation materials testing and development; project engineering and operations activities, and manufacturing techniques. The steps taken to integrate these efforts, are described.

Multi-100 kW: Planar low cost solar array development

NASA Technical Reports Server (NTRS)

1982-01-01

The applicability of selected low cost options to solar array blanket design was studied by fabricating representative modules and submitting them to thermal cycle environment. Large area (5.9 x 5.9 cm) solar cells of 3 varieties were purchased: (1) Standard wraparound, (2) Copper contacts substituted for the conventional Titanium-Palladium-Silver, and (3) Standard wraparound except with gridded back contact instead of continuous metallization. The baseline cell was purchased to compare fabrication cost and to serve as a control cell during test evaluation of the other two cells. All cells were assembled into either substrate modules where the cell is individually filtered and welded to an integrated Kapton-copper circuit or into a superstrate configuration with 4 cells jointly adhered to a single sheet of microsheet and then welded to the integrated Kapton-copper circuit. Cell quality, particularly in the metallization of contacts, was less than desired. Problems were encountered with copper metallization in laying down a barrier metal which would ohmically bond to the silicon. The cells received were shunted (sintered) or with low contact pull strength (non-sintered), thus leading to the decision to solder rather than weld the copper cells to the Kapton substrate.

Laser-zone growth in a Ribbon-To-Ribbon, RTR, process silicon sheet growth development for the large area silicon sheet task of the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Gurtler, R. W.; Baghdadi, A.

1977-01-01

A ribbon-to-ribbon process was used for routine growth of samples for analysis and fabrication into solar cells. One lot of solar cells was completely evaluated: ribbon solar cell efficiencies averaged 9.23% with a highest efficiency of 11.7%. Spherical reflectors have demonstrated significant improvements in laser silicon coupling efficiencies. Material analyses were performed including silicon photovoltage and open circuit photovoltage diffusion length measurements, crystal morphology studies, modulus of rupture measurements, and annealing/gettering studies. An initial economic analysis was performed indicating that ribbon-to-ribbon add-on costs of $.10/watt might be expected in the early 1980's.

Advances in Radiation-Tolerant Solar Arrays for SEP Missions

NASA Technical Reports Server (NTRS)

O'Neill, Mark J.; Eskenazi, Michael I.; Ferguson, Dale C.

2007-01-01

As the power levels of commercial communications satellites reach the 20 kWe and higher, new options begin to emerge for transferring the satellite from LEO to GEO. In the past electric propulsion has been demonstrated successfully for this mission - albeit under unfortunate circumstances when the kick motor failed. The unexpected use of propellant for the electric propulsion (EP) system compromised the life of that vehicle, but did demonstrate the viability of such an approach. Replacing the kick motor on a satellite and replacing that mass by additional propellant for the EP system as well as mass for additional revenue-producing transponders should lead to major benefits for the provider. Of course this approach requires that the loss in solar array power during transit of the Van Allen radiation belts is not excessive and still enables the 15 to 20 year mission life. In addition, SEP missions to Jupiter, with its exceptional radiation belts, would mandate a radiation-resistant solar array to compete with a radioisotope alternative. Several critical issues emerge as potential barriers to this approach: reducing solar array radiation damage, operating the array at high voltage (>300 V) for extended times for Hall or ion thrusters, designing an array that will be resistant to micrometeoroid impacts and the differing environmental conditions as the vehicle travels from LEO to GEO (or at Jupiter), producing an array that is light weight to preserve payload mass fraction - and to do this at a cost that is lower than today's arrays. This paper will describe progress made to date on achieving an array that meets all these requirements and is also useful for deep space electric propulsion missions.

Toward optimized light utilization in nanowire arrays using scalable nanosphere lithography and selected area growth.

PubMed

Madaria, Anuj R; Yao, Maoqing; Chi, Chunyung; Huang, Ningfeng; Lin, Chenxi; Li, Ruijuan; Povinelli, Michelle L; Dapkus, P Daniel; Zhou, Chongwu

2012-06-13

Vertically aligned, catalyst-free semiconducting nanowires hold great potential for photovoltaic applications, in which achieving scalable synthesis and optimized optical absorption simultaneously is critical. Here, we report combining nanosphere lithography (NSL) and selected area metal-organic chemical vapor deposition (SA-MOCVD) for the first time for scalable synthesis of vertically aligned gallium arsenide nanowire arrays, and surprisingly, we show that such nanowire arrays with patterning defects due to NSL can be as good as highly ordered nanowire arrays in terms of optical absorption and reflection. Wafer-scale patterning for nanowire synthesis was done using a polystyrene nanosphere template as a mask. Nanowires grown from substrates patterned by NSL show similar structural features to those patterned using electron beam lithography (EBL). Reflection of photons from the NSL-patterned nanowire array was used as a measure of the effect of defects present in the structure. Experimentally, we show that GaAs nanowires as short as 130 nm show reflection of <10% over the visible range of the solar spectrum. Our results indicate that a highly ordered nanowire structure is not necessary: despite the "defects" present in NSL-patterned nanowire arrays, their optical performance is similar to "defect-free" structures patterned by more costly, time-consuming EBL methods. Our scalable approach for synthesis of vertical semiconducting nanowires can have application in high-throughput and low-cost optoelectronic devices, including solar cells.

Development of processes for the production of low cost silicon dendritic web for solar cells

NASA Technical Reports Server (NTRS)

Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Hopkins, R. H.; Skutch, M. E.; Driggers, J. M.; Hill, F. E.

1980-01-01

High area output rates and continuous, automated growth are two key technical requirements for the growth of low-cost silicon ribbons for solar cells. By means of computer-aided furnace design, silicon dendritic web output rates as high as 27 sq cm/min have been achieved, a value in excess of that projected to meet a $0.50 per peak watt solar array manufacturing cost. The feasibility of simultaneous web growth while the melt is replenished with pelletized silicon has also been demonstrated. This step is an important precursor to the development of an automated growth system. Solar cells made on the replenished material were just as efficient as devices fabricated on typical webs grown without replenishment. Moreover, web cells made on a less-refined, pelletized polycrystalline silicon synthesized by the Battelle process yielded efficiencies up to 13% (AM1).

Rooftops of San Fernando

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, G.

1978-06-01

A review of the Jet Propulsion Laboratory study of the possibilities of using solar cell arrays on rooftops in the San Fernando Valley is given. Some cost and performance goals developed in this study are described. (MOW)

Analysis and Evaluation of Processes and Equipment in Tasks 2 and 4 of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Wolf, M.

1979-01-01

To facilitate the task of objectively comparing competing process options, a methodology was needed for the quantitative evaluation of their relative cost effectiveness. Such a methodology was developed and is described, together with three examples for its application. The criterion for the evaluation is the cost of the energy produced by the system. The method permits the evaluation of competing design options for subsystems, based on the differences in cost and efficiency of the subsystems, assuming comparable reliability and service life, or of competing manufacturing process options for such subsystems, which include solar cells or modules. This process option analysis is based on differences in cost, yield, and conversion efficiency contribution of the process steps considered.

Low-cost solar array project progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.

1981-01-01

The considered project is part of the DOE Photovoltaic Technology and Market Development Program. This program is concerned with the development and the utilization of cost-competitive photovoltaic systems. The project has the objective to develop, by 1986, the national capability to manufacture low-cost, long-life photovoltaic arrays at production rates that will realize economies of scale, and at a price of less than $0.70/watt. The array performance objectives include an efficiency greater than 10% and an operating lifetime longer than 20 years. The objective of the silicon material task is to establish the practicality of processes for producing silicon suitable for terrestrial photovoltaic applications at a price of $14/kg. The large-area sheet task is concerned with the development of process technology for sheet formation. Low-cost encapsulation material systems are being developed in connection with the encapsulation task. Another project goal is related to the development of economical process sequences.

Phase 2 of the Array Automated Assembly Task for the Low Cost Solar Array Project

NASA Technical Reports Server (NTRS)

Campbell, R. B.; Rai-Choundhury, P.; Seman, E. J.; Rohatgi, A.; Davis, J. R.; Ostroski, J. W.; Stapleton, R. E.

1979-01-01

Two process specifications supplied by contractors were tested. The aluminum silk screening process resulted in cells comparable to those from sputtered Al. The electroless plating of contacts specification could be used only with extensive modification. Several experiments suggest that there is some degradation of the front junction during the Al back surface field (BSF) fabrication. A revised process sequence was defined which incorporates Al BSF formation. A cost analysis of this process yielded a selling price of $0.75/watt peak in 1980.

Automated Array Assembly, Phase 2

NASA Technical Reports Server (NTRS)

Daiello, R. V.

1978-01-01

The purpose of the overall program is to establish technological readiness and provide verification for the elements of a manufacturing sequence which would ultimately be suitable for the large-scale production of silicon solar-array modules at a selling price of less than $500/kW. A program and process plan for accomplishing this objective was developed and put into operation. Three junction-formation processes are shown; since cost analysis shows that they do not differ greatly in cost, each should be considered for technical merits and possible future cost reduction. The progress made in the various process steps of the plan is described, and conclusions are presented.

High-power, ultralow-mass solar arrays: FY-77 solar arrays technology readiness assessment report, volume 2

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Young, L. E.; Brandhorst, H. W., Jr.

1978-01-01

Development efforts are reported in detail for: (1) a lightweight solar array system for solar electric propulsion; (2) a high efficiency thin silicon solar cell; (3) conceptual design of 200 W/kg solar arrays; (4) fluorocarbon encapsulation for silicon solar cell array; and (5) technology assessment of concentrator solar arrays.

The energetic transient array-ETA-A network of ``space buoys'' in solar orbit for observations of gamma-ray bursts

NASA Astrophysics Data System (ADS)

Ricker, George R.

1990-08-01

The Energetic Transient Array (ETA) is a concept for a dedicated interplanetary network of ~40 microsatellites (``space buoys'') deployed in an ~1 AU radius solar orbit for the observation of cosmic gamma ray bursts (GRBs). Such a network is essential for the determination of highly accurate (~0.1 arc sec) error boxes for GRBs. For each of ~100 bursts which would be detectable per year of observation by such a network, high resolution (ΔE/E ~0.2% at 1 MeV) spectra could be obtained through the use of passively-cooled Ge gamma-ray detectors. Stabilization of each microsatellite would be achieved by a novel technique based on the radiation pressure exerted on ``featherable'' solar paddles. Because of the simplicity of the microsats, as well as the economics of mass production and the failure tolerance of such a network of independent satellites, a unit cost of ~$250 K per microsat can be anticipated. Should such a project be undertaken in the mid 1990's, possibly as an International mission, it should be possible to have a fully functional array of satellites in place before the end of the decade for a total cost of ~$20M, exclusive of launcher fees.

Space Science

NASA Image and Video Library

1999-04-20

NASA's Space Optics Manufacturing Technology Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century, including the long-term goal of imaging Earth-like planets in distant solar systems. A segmented array of mirrors was designed by the Space Optics Manufacturing Technology Center for the solar concentrator test stand at the Marshall Space Flight Center (MSFC) for powering solar thermal propulsion engines. Each hexagon mirror has a spherical surface to approximate a parabolic concentrator when combined into the entire 18-foot diameter array. The aluminum mirrors were polished with a diamond turning machine that creates a glass-like reflective finish on metal. The precision fabrication machinery at the Space Optics Manufacturing Technology Center at MSFC can polish specialized optical elements to a world class quality of smoothness. This image shows optics physicist, Vince Huegele, examining one of the 144-segment hexagonal mirrors of the 18-foot diameter array at the MSFC solar concentrator test stand.

Space Science

NASA Image and Video Library

1999-04-20

NASA's Space Optics Manufacturing Technology Center has been working to expand our view of the universe via sophisticated new telescopes. The Optics Center's goal is to develop low-cost, advanced space optics technologies for the NASA program in the 21st century, including the long-term goal of imaging Earth-like planets in distant solar systems. A segmented array of mirrors was designed by the Space Optics Manufacturing Technology Center for solar the concentrator test stand at the Marshall Space Flight Center (MSFC) for powering solar thermal propulsion engines. Each hexagon mirror has a spherical surface to approximate a parabolic concentrator when combined into the entire 18-foot diameter array. The aluminum mirrors were polished with a diamond turning machine, that creates a glass-like reflective finish on metal. The precision fabrication machinery at the Space Optics Manufacturing Technology Center at MSFC can polish specialized optical elements to a world class quality of smoothness. This image shows optics physicist, Vince Huegele, examining one of the 144-segment hexagonal mirrors of the 18-foot diameter array at the MSFC solar concentrator test stand.

Silicon on ceramic process. Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Zook, J. D.; Heaps, J. D.; Maciolek, R. B.; Koepke, B. G.; Butter, C. D.; Schuldt, S. B.

1977-01-01

The technical and economic feasibility of producing solar-cell-quality sheet silicon was investigated. The sheets were made by coating one surface of carbonized ceramic substrates with a thin layer of large-grain polycrystalline silicon from the melt. Significant progress was made in all areas of the program.

Measurement Techniques and Instruments Suitable for Life-prediction Testing of Photovoltaic Arrays

NASA Technical Reports Server (NTRS)

Noel, G. T.; Wood, V. E.; Mcginniss, V. D.; Hassell, J. A.; Richard, N. A.; Gaines, G. B.; Carmichael, D. C.

1979-01-01

The validation of a 20-year service life for low-cost photovoltaic arrays is a critical requirement in the Low-Cost Solar Array (LSA) Project. The validation is accomplished through accelerated life-prediction tests. A two-phase study was conducted to address the needs before such tests are carried out. The results and recommended techniques from the Phase 1 investigation are summarized in the appendix. Phase 2 of the study is covered in this report and consisted of experimental evaluations of three techniques selected from these recommended as a results of the Phase 1 findings. The three techniques evaluated were specular and nonspecular optical reflectometry, chemiluminescence measurements, and electric current noise measurements.

Environmental testing of block 2 solar cell modules

NASA Technical Reports Server (NTRS)

Griffith, J. S.

1979-01-01

The testing procedures and results of samples of the LSA Project Block 2 procurement of silicon solar cell modules are described. Block 2 was the second large scale procurement of silicon solar cell modules made by the JPL Low-cost Solar Array Project with deliveries in 1977 and early 1978. The results showed that the Block 2 modules were greatly improved over Block 1 modules. In several cases it was shown that design improvements were needed to reduce environmental test degradation. These improvements were incorporated during this production run.

Cost Trade Between Multi-Junction, Gallium Arsenide, and Silicon Solar Cells

NASA Technical Reports Server (NTRS)

Gaddy, Edward M.

1995-01-01

Multi-junction (MJ), gallium arsenide (GaAs), and silicon (Si) solar cells have respective test efficiencies of approximately 24%, 18.5% and 14.8%. Multi-junction and gallium arsenide solar cells weigh more than silicon solar 2 cells and cost approximately five times as much per unit power at the cell level. A trade is performed for the TRMM spacecraft to determine which of these cell types would have offered an overall performance and price advantage to the spacecraft. A trade is also performed for the multi-junction cells under the assumption that they will cost over ten times that of silicon cells at the cell level. The trade shows that the TRMM project, less the cost of the instrument, ground systems and mission operations, would spend approximately $552,000 dollars per kilogram to launch and suppon3science in the case of the spacecraft equipped with silicon solar cells. If these cells are changed out for gallium arsenide solar cells, an additional 31 kilograms of science can be launched and serviced at a price of approximately $90 thousand per kilogram. The weight reduction is shown to derive from the smaller area of the array and hence reductions in the weight of the array substrate and supporting structure. ff the silicon solar cells are changed out for multi-junction solar cells, an additional 45 kilograms of science above the silicon base line can be launched and supported at a price of approximately $58,000 per kilogram. The trade shows that even if the multi-junction cells are priced over ten times that of silicon cells, a price that is much higher than projected, that the additional 45 kilograms of science are launched and serviced at $180,000 per kilogram. This is still much less than the original $552,000 per kilogram to launch and service the science. Data and qualitative factors are presented to show that these figures are subject to a great deal of uncertainty. Nonetheless, the benefit of the higher efficiency solar cells for TRMM is far greater than the uncertainties in the analysis.

Proceedings of the 16th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1980-01-01

The principal achievement of the Low Cost Solar Array Project in 1980 was the attainment of $2.80/Wp Technical Readiness, and that processes and equipment now commercially available can make possible a deliverable product in 1982. A prototype array for intermediate load applications was demonstrated using frameless modules. It was proof tested to 40 lb/sq ft loading, and priced at $24/sq m, including array fabrication, module installation, shipping to the site and site installation for quantities of 20 MW.

Tandem Solar Cells Using GaAs Nanowires on Si: Design, Fabrication, and Observation of Voltage Addition.

PubMed

Yao, Maoqing; Cong, Sen; Arab, Shermin; Huang, Ningfeng; Povinelli, Michelle L; Cronin, Stephen B; Dapkus, P Daniel; Zhou, Chongwu

2015-11-11

Multijunction solar cells provide us a viable approach to achieve efficiencies higher than the Shockley-Queisser limit. Due to their unique optical, electrical, and crystallographic features, semiconductor nanowires are good candidates to achieve monolithic integration of solar cell materials that are not lattice-matched. Here, we report the first realization of nanowire-on-Si tandem cells with the observation of voltage addition of the GaAs nanowire top cell and the Si bottom cell with an open circuit voltage of 0.956 V and an efficiency of 11.4%. Our simulation showed that the current-matching condition plays an important role in the overall efficiency. Furthermore, we characterized GaAs nanowire arrays grown on lattice-mismatched Si substrates and estimated the carrier density using photoluminescence. A low-resistance connecting junction was obtained using n(+)-GaAs/p(+)-Si heterojunction. Finally, we demonstrated tandem solar cells based on top GaAs nanowire array solar cells grown on bottom planar Si solar cells. The reported nanowire-on-Si tandem cell opens up great opportunities for high-efficiency, low-cost multijunction solar cells.

Solar power from satellites

NASA Technical Reports Server (NTRS)

Glaser, P. E.

1977-01-01

Microwave beaming of satellite-collected solar energy to earth for conversion to useful industrial power is evaluated for feasibility, with attention given to system efficiencies and costs, ecological impact, hardware to be employed, available options for energy conversion and transmission, and orbiting and assembly. Advantages of such a power generation and conversion system are listed, plausible techniques for conversion of solar energy (thermionic, thermal electric, photovoltaic) and transmission to earth (lasers, arrays of mirrors, microwave beams) are compared. Structural fatigue likely to result from brief daily eclipses, 55% system efficiency at the present state of the art, present projections of system costs, and projected economic implications of the technology are assessed. Two-stage orbiting and assembly plans are described.

Production technology for high efficiency ion implanted solar cells

NASA Technical Reports Server (NTRS)

Kirkpatrick, A. R.; Minnucci, J. A.; Greenwald, A. C.; Josephs, R. H.

1978-01-01

Ion implantation is being developed for high volume automated production of silicon solar cells. An implanter designed for solar cell processing and able to properly implant up to 300 4-inch wafers per hour is now operational. A machine to implant 180 sq m/hr of solar cell material has been designed. Implanted silicon solar cells with efficiencies exceeding 16% AM1 are now being produced and higher efficiencies are expected. Ion implantation and transient processing by pulsed electron beams are being integrated with electrostatic bonding to accomplish a simple method for large scale, low cost production of high efficiency solar cell arrays.

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photo-voltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic control system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Dynamic analysis of space-related linear and non-linear structures

NASA Technical Reports Server (NTRS)

Bosela, Paul A.; Shaker, Francis J.; Fertis, Demeter G.

1990-01-01

In order to be cost effective, space structures must be extremely light weight, and subsequently, very flexible structures. The power system for Space Station Freedom is such a structure. Each array consists of a deployable truss mast and a split blanket of photovoltaic solar collectors. The solar arrays are deployed in orbit, and the blanket is stretched into position as the mast is extended. Geometric stiffness due to the preload make this an interesting non-linear problem. The space station will be subjected to various dynamic loads, during shuttle docking, solar tracking, attitude adjustment, etc. Accurate prediction of the natural frequencies and mode shapes of the space station components, including the solar arrays, is critical for determining the structural adequacy of the components, and for designing a dynamic controls system. The process used in developing and verifying the finite element dynamic model of the photo-voltaic arrays is documented. Various problems were identified, such as grounding effects due to geometric stiffness, large displacement effects, and pseudo-stiffness (grounding) due to lack of required rigid body modes. Analysis techniques, such as development of rigorous solutions using continuum mechanics, finite element solution sequence altering, equivalent systems using a curvature basis, Craig-Bampton superelement approach, and modal ordering schemes were utilized. The grounding problems associated with the geometric stiffness are emphasized.

Final Technical Report, City of Brockton Solar Brightfield: Deploying a Solar Array on a Brockton Brownfield

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ribeiro, Lori

The City of Brockton, Massachusetts sought to install New England’s largest solar array at a remediated brownfield site on Grove Street. The 425-kilowatt solar photovoltaic array – or “Brightfield” – was installed in an urban park setting along with interpretive displays to maximize the educational opportunities. The “Brightfield” project included 1,395 310-Watt solar panels connected in “strings” that span the otherwise unusable 3.7-acre site. The project demonstrated that it is both technically and economically feasible to install utility scale solar photovoltaics on a capped landfill site. The US Department of Energy conceived the Brightfields program in 2000, and Brockton’s Brightfieldmore » is the largest such installation nationwide. Brockton’s project demonstrated that while it was both technically and economically feasible to perform such a project, the implementation was extremely challenging due to the state policy barriers, difficulty obtaining grant funding, and level of sophistication required to perform the financing and secure required state approvals. This demonstration project can be used as a model for other communities that wish to implement “Brownfields to Brightfields” projects; 2) implementing utility scale solar creates economies of scale that can help to decrease costs of photovoltaics; 3) the project is an aesthetic, environmental, educational and economic asset for the City of Brockton.« less

On-Orbit Reconfigurable Solar Array

NASA Technical Reports Server (NTRS)

Levy, Robert K. (Inventor)

2017-01-01

In one or more embodiments, the present disclosure teaches a method for reconfiguring a solar array. The method involves providing, for the solar array, at least one string of solar cells. The method further involves deactivating at least a portion of at least one of the strings of solar cells of the solar array when power produced by the solar array reaches a maximum power allowance threshold. In addition, the method involves activating at least a portion of at least one of the strings of the solar cells in the solar array when the power produced by the solar array reaches a minimum power allowance threshold.

Outer Planet Science Missions enabled by Solar Power

NASA Astrophysics Data System (ADS)

Kaplan, M.; Klaus, K.; Smith, D. B.

2009-12-01

Our studies demonstrate that New Frontiers-class science missions to the Jupiter and Saturn systems are possible with commercial solar powered space craft. These spacecraft are flight proven with more than 60 years of in-space operation and are equipped with highly efficient solar arrays capable of up to 25kW in low earth orbit. Such a vehicle could generate nearly 1kW in the Jovian System. Our analysis shows substantially greater power at the end of mission with this solar array system than the system that is planned for use in the Europa Jupiter System Flagship mission study. In the next few years, a new solar array technology will be developed and demonstrated by DARPA that will provide even higher power. DARPA’s Fast Access Space Testbed (FAST) program objective is to develop a revolutionary approach to spacecraft high power generation. This high power generation Subsystem, when combined with electric propulsion, will form the technological basis for a light weight, high power, highly mobile spacecraft platform. The FAST program will demonstrate the implementation of solar concentrators and high flux solar cells in conjunction with high specific impulse electric propulsion, to produce a high performance, lightweight power and propulsion system. A basic FAST spacecraft design provides about 60 kW in LEO, which scales to > 2 kW at 5 AU, or a little less than 1 kW at 10 AU. In principle, higher power levels (120 kW or even 180kW at 1 AU) could be accommodated with this technology. We envision missions using this FAST array and NASA’s NEXT engines for solar electric propulsion (SEP) Jovian and Saturn system maneuvers. We envision FAST arrays to cost in the tens of millions, making this an affordable, plutonium-free way to do outer planets science. Continued funding will mean flight experiments conducted in the 2012 timeframe that could make this technology flight proven for the New Frontiers 4 opportunity.

High Aspect Ratio Semiconductor Heterojunction Solar Cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Redwing, Joan; Mallouk, Tom; Mayer, Theresa

2013-05-17

The project focused on the development of high aspect ratio silicon heterojunction (HARSH) solar cells. The solar cells developed in this study consisted of high density vertical arrays of radial junction silicon microwires/pillars formed on Si substrates. Prior studies have demonstrated that vertical Si wire/pillar arrays enable reduced reflectivity and improved light trapping characteristics compared to planar solar cells. In addition, the radial junction structure offers the possibility of increased carrier collection in solar cells fabricated using material with short carrier diffusion lengths. However, the high junction and surface area of radial junction Si wire/pillar array devices can be problematicmore » and lead to increased diode leakage and enhanced surface recombination. This study investigated the use of amorphous hydrogenated Si in the form of a heterojunction-intrinsic-thin layer (HIT) structure as a junction formation method for these devices. The HIT layer structure has widely been employed to reduce surface recombination in planar crystalline Si solar cells. Consequently, it was anticipated that it would also provide significant benefits to the performance of radial junction Si wire/pillar array devices. The overall goals of the project were to demonstrate a HARSH cell with a HIT-type structure in the radial junction Si wire/pillar array configuration and to develop potentially low cost pathways to fabricate these devices. Our studies demonstrated that the HIT structure lead to significant improvements in the open circuit voltage (V oc>0.5) of radial junction Si pillar array devices compared to devices fabricated using junctions formed by thermal diffusion or low pressure chemical vapor deposition (LPCVD). In addition, our work experimentally demonstrated that the radial junction structure lead to improvements in efficiency compared to comparable planar devices for devices fabricated using heavily doped Si that had reduced carrier diffusion lengths. Furthermore, we made significant advances in employing the bottom-up vapor-liquid-solid (VLS) growth technique for the fabrication of the Si wire arrays. Our work elucidated the effects of growth conditions and substrate pattern geometry on the growth of large area Si microwire arrays grown with SiCl4. In addition, we also developed a process to grow p-type Si nanowire arrays using aluminum as the catalyst metal instead of gold. Finally, our work demonstrated the feasibility of growing vertical arrays of Si wires on non-crystalline glass substrates using polycrystalline Si template layers. The accomplishments demonstrated in this project will pave the way for future advances in radial junction wire array solar cells.« less

Phase 2 of the array automated assembly task for the low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Petersen, R. C.

1980-01-01

Studies were conducted on several fundamental aspects of electroless nickel/solder metallization for silicon solar cells. A process, which precedes the electroless nickel plating with several steps of palladium plating and heat treatment, was compared directly with single step electroless nickel plating. Work was directed toward answering specific questions concerning the effect of silicon surface oxide on nickel plating, effects of thermal stresses on the metallization, sintering of nickel plated on silicon, and effects of exposure to the plating solution on solar cell characteristics. The process was found to be extremely lengthy and cumbersome, and was also found to produce a product virtually identical to that produced by single step electroless nickel plating, as shown by adhesion tests and electrical characteristics of cells under illumination.

UNISAT-3 Power System

NASA Astrophysics Data System (ADS)

Santoni, Fabio; Piergentili, Fabrizio; Bulgarelli, Fabio; Graziani, Filippo

2005-05-01

An overview of the UNISAT-3 microsatellite power subsystem is given. This is an educational, low weight and low cost microsatellite designed, built, launched and operated in space by students and professors of Scuola di Ingegneria Aerospaziale, at University of Rome "La Sapienza". The satellite power system is based on terrestrial technology solar arrays and NiCd batteries. The microsatellite hosts other solar arrays, including multi-junction solar cells and mono- crystalline silicon high efficiency solar cells, in order to compare their behaviour in orbit. Moreover a MPPT (Maximum Power Point Tracking ) system has been designed and tested, and it is a technological payload of UNISAT-3. The MPPT design follows the studies performed in the field of solar powered racing cars, with modifications to make the system suitable for use in space. The system design, numerical simulation and hardware ground testing are described in the paper. The experiment and the performance evaluation criterion are described, together with the preliminary results of the first eight months of operation in orbit.

Develop Silicone Encapsulation Systems for Terrestrial Silicon Solar Arrays

NASA Technical Reports Server (NTRS)

1979-01-01

A cost effective encapsulant system was identified and a silicone acrylic cover material containing a durable ultraviolet screening agent was prepared. The effectiveness of the cover material in protecting photo-oxidatively sensitive polymers was demonstrated.

Flat-plate solar array progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.; Henry, P. K.

1984-01-01

The Flat-Plate Solar Array Project (FSA), sponsored by the U.S. Department of Energy (DOE) and managed by the Jet Propulsion Laboratory (JPL), has achieved progress in a broad range of technical activities since that reported at the Fourth European Communities Conference. A particularly important analysis has been completed recently which confirms the adoption into practice by the U.S. Photovoltaic (PV Industry, of all the low-cost module technology elements proposed at the 16th Project Integration Meeting for a $2.80/Wp (1980 U.S. Dollars) design approach in the fall of 1980. This work presents along with a projection, using the same techniques, for what is believed to be a very credible ribbon-based module design for less that $0.55/Wp (1980 U.S. Dollars). Other areas to be reported upon include low-cost Si feedstock refinement; ribbon growth; process sequence development for cells; environmental isolation; engineering science investigations; and module testing progress.

A 100 kW-Class Technology Demonstrator for Space Solar Power

NASA Technical Reports Server (NTRS)

Carrington, Connie; Howell, Joe; Day, Greg

2004-01-01

A first step in the development of solar power from space is the flight demonstration of critical technologies. These fundamental technologies include efficient solar power collection and generation, power management and distribution, and thermal management. In addition, the integration and utilization of these technologies into a viable satellite bus could provide an energy-rich platform for a portfolio of payload experiments such as wireless power transmission (WPT). This paper presents the preliminary design of a concept for a 100 kW-class fiee-flying platform suitable for flight demonstration of technology experiments. Recent space solar power (SSP) studies by NASA have taken a stepping stones approach that lead to the gigawatt systems necessary to cost-effectively deliver power from space. These steps start with a 100 kW-class satellite, leading to a 500 kW and then a 1 MW-class platform. Later steps develop a 100 M W bus that could eventually lead to a 1-2 GW pilot plant for SSP. Our studies have shown that a modular approach is cost effective. Modular designs include individual laser-power-beaming satellites that fly in constellations or that are autonomously assembled into larger structures at geosynchronous orbit (GEO). Microwave power-beamed approaches are also modularized into large numbers of identical units of solar arrays, power converters, or supporting structures for arrays and microwave transmitting antennas. A cost-effective approach to launching these modular units is to use existing Earth-to-orbit (ETO) launch systems, in which the modules are dropped into low Earth orbit (LEO) and then the modules perform their own orbit transfer to GEO using expendable solar arrays to power solar electric thrusters. At GEO, the modules either rendezvous and are assembled robotically into larger platforms, or are deployed into constellations of identical laser power-beaming satellites. Since solar electric propulsion by the modules is cost-effective for both self-transport of the modules from LEO to GEO, and for on-orbit stationkeeping and repositioning capability during the satellite's lifetime, this technology is also critical in technology development for SSP. The 100 kW-class technology demonstrator will utilize advanced solar power collection and generation technologies, power management and distribution, advanced thermal management, and solar electric propulsion. State-of-the-art solar concentrators, highly efficient multi-junction solar cells, integrated thermal management on the arrays, and innovative deployable structure design and packaging make the 100 kW satellite feasible for launch on one existing launch vehicle. Early SSP studies showed that a major percentage of the on-orbit mass for power-beaming satellites was from massive power converters at the solar arrays, at the bus, at the power transmitter, or at combinations of these locations. Higher voltage mays and power management and distribution (PMAD) systems reduce or eliminate the need for many of these massive power converters, and could enable direct-drive of high-voltage solar electric thrusters. Lightweight, highly efficient thermal management systems are a critical technology that must be developed and flown for SSP feasibility. Large amounts of power on satellites imply that large amounts of waste heat will need to be managed. In addition, several of the more innovative lightweight configurations proposed for SSP satellites take advantage of solar concentrators that are intractable without advanced thermal management technologies for the solar arrays. These thermal management systems include efficient interfaces with the WPT systems or other high-power technology experiments, lightweight deployable radiators that can be easily integrated into satellite buses, and efficient reliable thermal distribution systems that can pipe heat from the technology experiments to the radiators. In addition to demonstrating the integration and use of these mission-ctical technologies, the 100 kw-class satellite will provide a large experiment deck for a portfolio of technology experiments. Current plans for this technology demonstrator allow 2000 kg of payload capability and up to 100 kW of power. The technology experiments could include one or more wireless power transmission demonstrations, either to the Earth s surface or to a suitable space-based receiver. Technology experiments to quantify the on-orbit performance of critical technologies for SSP or space exploration are welcomed. In addition, the technology experiments provide an opportunity for international cooperation, to advance technology readiness levels of SSP technologies that require flight demonstration. This paper will present the preliminary design for a 100 kW solar-powered satellite and a variety of technology experiments that may be suitable for flight demonstration. In addition, a space-to-Earth-surface WPT experiment will be discussed.

Cloud Forecasting and 3-D Radiative Transfer Model Validation using Citizen-Sourced Imagery

NASA Astrophysics Data System (ADS)

Gasiewski, A. J.; Heymsfield, A.; Newman Frey, K.; Davis, R.; Rapp, J.; Bansemer, A.; Coon, T.; Folsom, R.; Pfeufer, N.; Kalloor, J.

2017-12-01

Cloud radiative feedback mechanisms are one of the largest sources of uncertainty in global climate models. Variations in local 3D cloud structure impact the interpretation of NASA CERES and MODIS data for top-of-atmosphere radiation studies over clouds. Much of this uncertainty results from lack of knowledge of cloud vertical and horizontal structure. Surface-based data on 3-D cloud structure from a multi-sensor array of low-latency ground-based cameras can be used to intercompare radiative transfer models based on MODIS and other satellite data with CERES data to improve the 3-D cloud parameterizations. Closely related, forecasting of solar insolation and associated cloud cover on time scales out to 1 hour and with spatial resolution of 100 meters is valuable for stabilizing power grids with high solar photovoltaic penetrations. Data for cloud-advection based solar insolation forecasting with requisite spatial resolution and latency needed to predict high ramp rate events obtained from a bottom-up perspective is strongly correlated with cloud-induced fluctuations. The development of grid management practices for improved integration of renewable solar energy thus also benefits from a multi-sensor camera array. The data needs for both 3D cloud radiation modelling and solar forecasting are being addressed using a network of low-cost upward-looking visible light CCD sky cameras positioned at 2 km spacing over an area of 30-60 km in size acquiring imagery on 30 second intervals. Such cameras can be manufactured in quantity and deployed by citizen volunteers at a marginal cost of 200-400 and operated unattended using existing communications infrastructure. A trial phase to understand the potential utility of up-looking multi-sensor visible imagery is underway within this NASA Citizen Science project. To develop the initial data sets necessary to optimally design a multi-sensor cloud camera array a team of 100 citizen scientists using self-owned PDA cameras is being organized to collect distributed cloud data sets suitable for MODIS-CERES cloud radiation science and solar forecasting algorithm development. A low-cost and robust sensor design suitable for large scale fabrication and long term deployment has been developed during the project prototyping phase.

NREL Center for Photovoltaics

ScienceCinema

None

2017-12-09

Solar cells, also called photovoltaics (PV) by solar cell scientists, convert sunlight directly into electricity. Solar cells are often used to power calculators and watches. The performance of a solar cell is measured in terms of its efficiency at turning sunlight into electricity. Only sunlight of certain energies will work efficiently to create electricity, and much of it is reflected or absorbed by the material that make up the cell. Because of this, a typical commercial solar cell has an efficiency of 15%—about one-sixth of the sunlight striking the cell generates electricity. Low efficiencies mean that larger arrays are needed, and that means higher cost. Improving solar cell efficiencies while holding down the cost per cell is an important goal of the PV industry, researchers at the National Renewable Energy Laboratory (NREL) and other U.S. Department of Energy (DOE) laboratories, and they have made significant progress. The first solar cells, built in the 1950s, had efficiencies of less than 4%.

The Stretched Lens Array SquareRigger (SLASR) for Space Power

NASA Technical Reports Server (NTRS)

Piszczor, Michael F.; O'Neill, Mark J.; Eskenazi, Michael I.; Brandhorst, Henry W.

2006-01-01

For the past three years, our team has been developing, refining, and maturing a unique solar array technology known as Stretched Lens Array SquareRigger (SLASR). SLASR offers an unprecedented portfolio of state-of-the-art performance metrics, including areal power density, specific power, stowed power density, high-voltage capability, radiation hardness, modularity, scalability, mass-producibility, and cost-effectiveness. SLASR is particularly well suited to high-power space missions, including solar electric propulsion (SEP) space tugs, major exploration missions to the Moon and Mars, and power-intensive military spacecraft. SLASR is also very well suited to high-radiation missions, since the cell shielding mass penalty is 85% less for the SLASR concentrator array than for one-sun planar arrays. The paper describes SLASR technology and presents significant results of developments to date in a number of key areas, from advances in the key components to full-scale array hardware fabrication and evaluation. A summary of SLASR s unprecedented performance metrics, both near-term and longer term, will be presented. Plans for future SLASR developments and near-term space applications will also be outlined.

Solar array technology evaluation program for SEPS (Solar Electrical Propulsion Stage)

NASA Technical Reports Server (NTRS)

1974-01-01

An evaluation of the technology and the development of a preliminary design for a 25 kilowatt solar array system for solar electric propulsion are discussed. The solar array has a power to weight ratio of 65 watts per kilogram. The solar array system is composed of two wings. Each wing consists of a solar array blanket, a blanket launch storage container, an extension/retraction mast assembly, a blanket tensioning system, an array electrical harness, and hardware for supporting the system for launch and in the operating position. The technology evaluation was performed to assess the applicable solar array state-of-the-art and to define supporting research necessary to achieve technology readiness for meeting the solar electric propulsion system solar array design requirements.

Silicon materials task of the Low Cost Solar Array Project: Effect of impurities and processing on silicon solar cells

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Davis, J. R.; Rohatgi, A.; Hanes, M. H.; Rai-Choudhury, P.; Mollenkopf, H. C.

1982-01-01

The effects of impurities and processing on the characteristics of silicon and terrestrial silicon solar cells were defined in order to develop cost benefit relationships for the use of cheaper, less pure solar grades of silicon. The amount of concentrations of commonly encountered impurities that can be tolerated in typical p or n base solar cells was established, then a preliminary analytical model from which the cell performance could be projected depending on the kinds and amounts of contaminants in the silicon base material was developed. The impurity data base was expanded to include construction materials, and the impurity performace model was refined to account for additional effects such as base resistivity, grain boundary interactions, thermal processing, synergic behavior, and nonuniform impurity distributions. A preliminary assessment of long term (aging) behavior of impurities was also undertaken.

The use of solar energy - photovoltaic - in hydrogen production and arid zones like Saudi Arabia

NASA Astrophysics Data System (ADS)

Sayigh, A. A. M.

This paper deals with the use of photovoltaic technology for the production of hydrogen from water by electrolysis. First of all the amount of electricity needed for this process was assessed, then various types of solar cell systems to generate the electricity needed were discussed and the best system was established. Some of the investigations involved testing of solar cells with concentrators and with fixed tilt or tracking devices. Several small panels of solar cells were used in testing the effect of local dust and sand as well as the fixed tilt in the area of Riyadh. The cost of producing hydrogen by electrolysis using electricity from a conventional grid was calculated. This cost was compared with the cost of production of hydrogen if a solar cell array was used. The paper outlines the continuous price increase of oil to produce electricity and the rapid decrease in price of solar cells. Both these advances will lead to a cheaper way of producing hydrogen by solar energy. In addition it is shown that technology is almost trouble free and requires very little know-how as far as operation is concerned.

Deployable Propulsion and Power Systems for Solar System Exploration

NASA Technical Reports Server (NTRS)

Johnson, Les; Carr, John

2017-01-01

NASA is developing thin-film based, deployable propulsion, power and communication systems for small spacecraft that could provide a revolutionary new capability allowing small spacecraft exploration of the solar system. The Near Earth Asteroid (NEA) Scout reconnaissance mission will demonstrate solar sail propulsion on a 6U CubeSat interplanetary spacecraft and lay the groundwork for their future use in deep space science and exploration missions. Solar sails use sunlight to propel vehicles through space by reflecting solar photons from a large, mirror-like sail made of a lightweight, highly reflective material. This continuous photon pressure provides propellantless thrust, allowing for very high delta V maneuvers on long-duration, deep space exploration. Since reflected light produces thrust, solar sails require no onboard propellant. The Lightweight Integrated Solar Array and Transceiver (LISA-T) is a launch stowed, orbit deployed array on which thin-film photovoltaic and antenna elements are embedded. Inherently, small satellites are limited in surface area, volume, and mass allocation; driving competition between power, communications, and GN&C (guidance navigation and control) subsystems. This restricts payload capability and limits the value of these low-cost satellites. LISA-T is addressing this issue, deploying large-area arrays from a reduced volume and mass envelope - greatly enhancing power generation and communications capabilities of small spacecraft. The NEA Scout mission, funded by NASA's Advanced Exploration Systems Program and managed by NASA MSFC, will use the solar sail as its primary propulsion system, allowing it to survey and image one or more NEA's of interest for possible future human exploration. NEA Scout uses a 6U cubesat (to be provided by NASA's Jet Propulsion Laboratory), an 86 sq m solar sail and will weigh less than 12 kilograms. NEA Scout will be launched on the first flight of the Space Launch System in 2018. Similar in concept to the NEA Scout solar sail, the LISA-T array is designed to fit into a very small volume and provide abundant power and omnidirectional communications in just about any deployment configuration. The technology is being proposed for flight validation as early as 2019 in a low earth orbit demonstration using a 3U cubesat, of which less than 1U will be devoted to the LISA-T power and propulsion system. By leveraging recent advancements in thin films, photovoltaics and miniaturized electronics, new mission-level capabilities will be enabled aboard lower-cost small spacecraft instead of their more expensive, traditional counterparts, enabling a new generation of frequent, inexpensive deep space missions.

Three-dimensional electrodes for dye-sensitized solar cells: synthesis of indium-tin-oxide nanowire arrays and ITO/TiO2 core-shell nanowire arrays by electrophoretic deposition

NASA Astrophysics Data System (ADS)

Wang, Hong-Wen; Ting, Chi-Feng; Hung, Miao-Ken; Chiou, Chwei-Huann; Liu, Ying-Ling; Liu, Zongwen; Ratinac, Kyle R.; Ringer, Simon P.

2009-02-01

Dye-sensitized solar cells (DSSCs) show promise as a cheaper alternative to silicon-based photovoltaics for specialized applications, provided conversion efficiency can be maximized and production costs minimized. This study demonstrates that arrays of nanowires can be formed by wet-chemical methods for use as three-dimensional (3D) electrodes in DSSCs, thereby improving photoelectric conversion efficiency. Two approaches were employed to create the arrays of ITO (indium-tin-oxide) nanowires or arrays of ITO/TiO2 core-shell nanowires; both methods were based on electrophoretic deposition (EPD) within a polycarbonate template. The 3D electrodes for solar cells were constructed by using a doctor-blade for coating TiO2 layers onto the ITO or ITO/TiO2 nanowire arrays. A photoelectric conversion efficiency as high as 4.3% was achieved in the DSSCs made from ITO nanowires; this performance was better than that of ITO/TiO2 core-shell nanowires or pristine TiO2 films. Cyclic voltammetry confirmed that the reaction current was significantly enhanced when a 3D ITO-nanowire electrode was used. Better separation of charge carriers and improved charge transport, due to the enlarged interfacial area, are thought to be the major advantages of using 3D nanowire electrodes for the optimization of DSSCs.

A Module Experimental Process System Development Unit (MEPSDU). [flat plate solar arrays

NASA Technical Reports Server (NTRS)

1981-01-01

The development of a cost effective process sequence that has the potential for the production of flat plate photovoltaic modules which meet the price goal in 1986 of 70 cents or less per Watt peak is described. The major accomplishments include (1) an improved AR coating technique; (2) the use of sand blast back clean-up to reduce clean up costs and to allow much of the Al paste to serve as a back conductor; and (3) the development of wave soldering for use with solar cells. Cells were processed to evaluate different process steps, a cell and minimodule test plan was prepared and data were collected for preliminary Samics cost analysis.

International ultraviolet explorer solar array power degradation

NASA Technical Reports Server (NTRS)

Day, J. H., Jr.

1983-01-01

The characteristic electrical performance of each International Ultraviolet Explorer (IUE) solar array panel is evaluated as a function of several prevailing variables (namely, solar illumination, array temperature and solar cell radiation damage). Based on degradation in the current-voltage characteristics of the array due to solar cell damage accumulated over time by space charged particle radiations, the available IUE solar array power is determined for life goals up to 10 years. Best and worst case calculations are normalized to actual IUE flight data (available solar array power versus observatory position) to accurately predict the future IUE solar array output. It is shown that the IUE solar array can continue to produce more power than is required at most observatory positions for at least 5 more years.

Solar Power Satellites: Reconsideration as Renewable Energy Source Based on Novel Approaches

NASA Astrophysics Data System (ADS)

Ellery, Alex

2017-04-01

Solar power satellites (SPS) are a solar energy generation mechanism that captures solar energy in space and converts this energy into microwave for transmission to Earth-based rectenna arrays. They offer a constant, high integrated energy density of 200 W/m2 compared to <10 W/m2 for other renewable energy sources. Despite this promise as a clean energy source, SPS have been relegated out of consideration due to their enormous cost and technological challenge. It has been suggested that for solar power satellites to become economically feasible, launch costs must decrease from their current 20,000/kg to <200/kg. Even with the advent of single-stage-to-orbit launchers which propose launch costs dropping to 2,000/kg, this will not be realized. Yet, the advantages of solar power satellites are many including the provision of stable baseload power. Here, I present a novel approach to reduce the specific cost of solar power satellites to 1/kg by leveraging two enabling technologies - in-situ resource utilization of lunar material and 3D printing of this material. Specifically, we demonstrate that electric motors may be constructed from lunar material through 3D printing representing a major step towards the development of self-replicating machines. Such machines have the capacity to build solar power satellites on the Moon, thereby bypassing the launch cost problem. The productive capacity of self-replicating machines favours the adoption of large constellations of small solar power satellites. This opens up additional clean energy options for combating climate change by meeting the demands for future global energy.

Advanced solar panel designs

NASA Technical Reports Server (NTRS)

Ralph, E. L.; Linder, E.

1995-01-01

This paper describes solar cell panel designs that utilize new hgih efficiency solar cells along with lightweight rigid panel technology. The resulting designs push the W/kg and W/sq m parameters to new high levels. These new designs are well suited to meet the demand for higher performance small satellites. This paper reports on progress made on two SBIR Phase 1 contracts. One panel design involved the use of large area (5.5 cm x 6.5 cm) GaAs/Ge solar cells of 19% efficiency combined with a lightweight rigid graphite fiber epoxy isogrid substrate configuration. A coupon (38 cm x 38 cm) was fabricated and tested which demonstrated an array specific power level of 60 W/kg with a potential of reaching 80 W/kg. The second panel design involved the use of newly developed high efficiency (22%) dual junction GaInP2/GaAs/Ge solar cells combined with an advanced lightweight rigid substrate using aluminum honeycomb core with high strength graphite fiber mesh facesheets. A coupon (38 cm x 38 cm) was fabricated and tested which demonstrated an array specific power of 105 W/kg and 230 W/sq m. This paper will address the construction details of the panels and an a analysis of the component weights. A strawman array design suitable for a typical small-sat mission is described for each of the two panel design technologies being studied. Benefits in respect to weight reduction, area reduction, and system cost reduction are analyzed and compared to conventional arrays.

ISRU Reactant, Fuel Cell Based Power Plant for Robotic and Human Mobile Exploration Applications

NASA Technical Reports Server (NTRS)

Baird, Russell S.; Sanders, Gerald; Simon, Thomas; McCurdy, Kerri

2003-01-01

Three basic power generation system concepts are generally considered for lander, rover, and Extra-Vehicular Activity (EVA) assistant applications for robotic and human Moon and Mars exploration missions. The most common power system considered is the solar array and battery system. While relatively simple and successful, solar array/battery systems have some serious limitations for mobile applications. For typical rover applications, these limitations include relatively low total energy storage capabilities, daylight only operating times (6 to 8 hours on Mars), relatively short operating lives depending on the operating environment, and rover/lander size and surface use constraints. Radioisotope power systems are being reconsidered for long-range science missions. Unfortunately, the high cost, political controversy, and launch difficulties that are associated with nuclear-based power systems suggests that the use of radioisotope powered landers, rovers, and EVA assistants will be limited. The third power system concept now being considered are fuel cell based systems. Fuel cell power systems overcome many of the performance and surface exploration limitations of solar array/battery power systems and the prohibitive cost and other difficulties associated with nuclear power systems for mobile applications. In an effort to better understand the capabilities and limitations of fuel cell power systems for Moon and Mars exploration applications, NASA is investigating the use of in-Situ Resource Utilization (ISRU) produced reactant, fuel cell based power plants to power robotic outpost rovers, science equipment, and future human spacecraft, surface-excursion rovers, and EVA assistant rovers. This paper will briefly compare the capabilities and limitations of fuel cell power systems relative to solar array/battery and nuclear systems, discuss the unique and enhanced missions that fuel cell power systems enable, and discuss the common technology and system attributes possible for robotic and human exploration to maximize scientific return and minimize cost and risk to both. Progress made to date at the Johnson Space Center on an ISRU producible reactant, Proton Exchange Membrane (PEM) fuel cell based power plant project to demonstrate the concept in conjunction with rover applications will be presented in detail.

ISRU Reactant, Fuel Cell Based Power Plant for Robotic and Human Mobile Exploration Applications

NASA Astrophysics Data System (ADS)

Baird, Russell S.; Sanders, Gerald; Simon, Thomas; McCurdy, Kerri

2003-01-01

Three basic power generation system concepts are generally considered for lander, rover, and Extra-Vehicular Activity (EVA) assistant applications for robotic and human Moon and Mars exploration missions. The most common power system considered is the solar array and battery system. While relatively simple and successful, solar array/battery systems have some serious limitations for mobile applications. For typical rover applications, these limitations include relatively low total energy storage capabilities, daylight only operating times (6 to 8 hours on Mars), relatively short operating lives depending on the operating environment, and rover/lander size and surface use constraints. Radioisotope power systems are being reconsidered for long-range science missions. Unfortunately, the high cost, political controversy, and launch difficulties that are associated with nuclear-based power systems suggests that the use of radioisotope powered landers, rovers, and EVA assistants will be limited. The third power system concept now being considered are fuel cell based systems. Fuel cell power systems overcome many of the performance and surface exploration limitations of solar array/battery power systems and the prohibitive cost and other difficulties associated with nuclear power systems for mobile applications. In an effort to better understand the capabilities and limitations of fuel cell power systems for Moon and Mars exploration applications. NASA is investigating the use of In-Situ Resource Utilization (ISRU) produced reactant, fuel cell based power plants to power robotic outpost rovers, science equipment, and future human spacecraft, surface-excursion rovers, and EVA assistant rovers. This paper will briefly compare the capabilities and limitations of fuel cell power systems relative to solar array/battery and nuclear systems, discuss the unique and enhanced missions that fuel cell power systems enable, and discuss the common technology and system attributes possible for robotic and human exploration to maximize scientific return and minimize cost and risk to both. Progress made to date at the Johnson Space Center on an ISRU producible reactant. Proton Exchange Membrane (PEM) fuel cell based power plant project for use in the first demonstration of this concept in conjunction with rover applications will be presented in detail.

Can Integrated Micro-Optical Concentrator Technology Revolutionize Flat-Plate Photovoltaic Solar Energy Harvesting?

NASA Astrophysics Data System (ADS)

Haney, Michael W.

2015-12-01

The economies-of-scale and enhanced performance of integrated micro-technologies have repeatedly delivered disruptive market impact. Examples range from microelectronics to displays to lighting. However, integrated micro-scale technologies have yet to be applied in a transformational way to solar photovoltaic panels. The recently announced Micro-scale Optimized Solar-cell Arrays with Integrated Concentration (MOSAIC) program aims to create a new paradigm in solar photovoltaic panel technology based on the incorporation of micro-concentrating photo-voltaic (μ-CPV) cells. As depicted in Figure 1, MOSAIC will integrate arrays of micro-optical concentrating elements and micro-scale PV elements to achieve the same aggregated collection area and high conversion efficiency of a conventional (i.e., macro-scale) CPV approach, but with the low profile and mass, and hopefully cost, of a conventional non-concentrated PV panel. The reduced size and weight, and enhanced wiring complexity, of the MOSAIC approach provide the opportunity to access the high-performance/low-cost region between the conventional CPV and flat-plate (1-sun) PV domains shown in Figure 2. Accessing this portion of the graph in Figure 2 will expand the geographic and market reach of flat-plate PV. This talk reviews the motivation and goals for the MOSAIC program. The diversity of the technical approaches to micro-concentration, embedded solar tracking, and hybrid direct/diffuse solar resource collection found in the MOSAIC portfolio of projects will also be highlighted.

Development of large-area monolithically integrated silicon-film photovoltaic modules

NASA Astrophysics Data System (ADS)

Rand, J. A.; Cotter, J. E.; Ingram, A. E.; Ruffins, T. R.; Shreve, K. P.; Hall, R. B.; Barnett, A. M.

1993-06-01

This report describes work to develop Silicon-Film (trademark) Product 3 into a low-cost, stable solar cell for large-scale terrestrial power applications. The Product 3 structure is a thin (less than 100 micron) polycrystalline layer of silicon on a durable, insulating, ceramic substrate. The insulating substrate allows the silicon layer to be isolated and metallized to form a monolithically interconnected array of solar cells. High efficiency is achievable with the use of light trapping and a passivated back surface. The long-term goal for the product is a 1200 sq cm, 18%-efficient, monolithic array. The short-term objectives are to improve material quality and to fabricate 100 sq cm monolithically interconnected solar cell arrays. Low minority-carrier diffusion length in the silicon film and series resistance in the interconnected device structure are presently limiting device performance. Material quality is continually improving through reduced impurity contamination. Metallization schemes, such as a solder-dipped interconnection process, have been developed that will allow low-cost production processing and minimize R(sub s) effects. Test data for a nine-cell device (16 sq cm) indicated a V(sub oc) of 3.72 V. These first-reported monolithically interconnected multicrystalline silicon-on-ceramic devices show low shunt conductance (less than 0.1 mA/sq cm) due to limited conduction through the ceramic and no process-related metallization shunts.

The role of radiation hard solar cells in minimizing the costs of global satellite communications systems

NASA Technical Reports Server (NTRS)

Summers, Geoffrey P.; Walters, Robert J.; Messenger, Scott R.; Burke, Edward A.

1995-01-01

An analysis embodied in a PC computer program is presented which quantitatively demonstrates how the availability of radiation hard solar cells can minimize the cost of a global satellite communication system. The chief distinction between the currently proposed systems, such as Iridium Odyssey and Ellipsat, is the number of satellites employed and their operating altitudes. Analysis of the major costs associated with implementing these systems shows that operation within the earth's radiation belts can reduce the total system cost by as much as a factor of two, so long as radiation hard components including solar cells, can be used. A detailed evaluation of several types of planar solar cells is given, including commercially available Si and GaAs/Ge cells, and InP/Si cells which are under development. The computer program calculates the end of life (EOL) power density of solar arrays taking into account the cell geometry, coverglass thickness, support frame, electrical interconnects, etc. The EOL power density can be determined for any altitude from low earth orbit (LEO) to geosynchronous (GEO) and for equatorial to polar planes of inclination. The mission duration can be varied over the entire range planned for the proposed satellite systems. An algorithm is included in the program for determining the degradation of cell efficiency for different cell technologies due to proton and electron irradiation. The program can be used to determine the optimum configuration for any cell technology for a particular orbit and for a specified mission life. Several examples of applying the program are presented, in which it is shown that the EOL power density of different technologies can vary by an order of magnitude for certain missions. Therefore, although a relatively radiation soft technology can be made to provide the required EOL power by simply increasing the size of the array, the impact on the total system budget could be unacceptable, due to increased launch and hardware costs. In aggregate these factors can account for more than a 10% increase in the total system cost. Since the estimated total costs of proposed global coverage systems range from $1 Billion to $9 Billion, the availability of radiation hard solar cells could make a decisive difference in the selection of a particular constellation architecture.

The Use, Evolution and Lessons Learnt of Deployable Static Solar Array Mechanisms

NASA Technical Reports Server (NTRS)

Ferris, Mark; Haslehurst, Andrew

2014-01-01

This paper focuses on the mechanisms incorporated into SSTL's static deployable arrays; namely the sprung-hinges and hold down and release mechanism (HDRM). Combined, the HDRM and hinges form the hold down release system (HDRS). The deployable static solar array HDRS has been successfully used on several missions, first launched upon the DMC-CFESAT spacecraft in 2007 for a U.S. customer (Figure 1), and later used on DMC-UK2 and EXACTVIEW-1 launched in 2009 and 2012, respectively. The simple, robust and low-cost solution HDRS has been evident in allowing missions to satisfy an ever increasing power demand, allowing the solar arrays to increase in size and have a preferable sun angle for increased cell efficiency. The system is now being employed on the first mission out of SSTL's U.S. office (SST-US) on the Orbital Test Bed platform. This paper shall cover details of the original design and development program, problems incurred on latter missions, and evolution of the HDRS for the present Orbital Test Bed mission. Both the original development and recent evolutions have taken place in rapid timescales, to satisfy the high-turnaround of SSTL missions.

Effects of Solar Photovoltaic Panels on Roof Heat Transfer

NASA Technical Reports Server (NTRS)

Dominguez, A.; Klessl, J.; Samady, M.; Luvall, J. C.

2010-01-01

Building Heating, Ventilation and Air Conditioning (HVAC) is a major contributor to urban energy use. In single story buildings with large surface area such as warehouses most of the heat enters through the roof. A rooftop modification that has not been examined experimentally is solar photovoltaic (PV) arrays. In California alone, several GW in residential and commercial rooftop PV are approved or in the planning stages. With the PV solar conversion efficiency ranging from 5-20% and a typical installed PV solar reflectance of 16-27%, 53-79% of the solar energy heats the panel. Most of this heat is then either transferred to the atmosphere or the building underneath. Consequently solar PV has indirect effects on roof heat transfer. The effect of rooftop PV systems on the building roof and indoor energy balance as well as their economic impacts on building HVAC costs have not been investigated. Roof calculator models currently do not account for rooftop modifications such as PV arrays. In this study, we report extensive measurements of a building containing a flush mount and a tilted solar PV array as well as exposed reference roof. Exterior air and surface temperature, wind speed, and solar radiation were measured and thermal infrared (TIR) images of the interior ceiling were taken. We found that in daytime the ceiling surface temperature under the PV arrays was significantly cooler than under the exposed roof. The maximum difference of 2.5 C was observed at around 1800h, close to typical time of peak energy demand. Conversely at night, the ceiling temperature under the PV arrays was warmer, especially for the array mounted flat onto the roof. A one dimensional conductive heat flux model was used to calculate the temperature profile through the roof. The heat flux into the bottom layer was used as an estimate of the heat flux into the building. The mean daytime heat flux (1200-2000 PST) under the exposed roof in the model was 14.0 Watts per square meter larger than under the tilted PV array. The maximum downward heat flux was 18.7 Watts per square meters for the exposed roof and 7.0 Watts per square meters under the tilted PV array, a 63% reduction due to the PV array. This study is unique as the impact of tilted and flush PV arrays could be compared against a typical exposed roof at the same roof for a commercial uninhabited building with exposed ceiling and consisting only of the building envelope. Our results indicate a more comfortable indoor environment in PV covered buildings without HVAC both in hotter and cooler seasons.

Results of module electrical measurement of the DOE 46-kilowatt procurement

NASA Technical Reports Server (NTRS)

Curtis, H. B.

1978-01-01

Current-voltage measurements have been made on terrestrial solar cell modules of the DOE/JPL Low Cost Silicon Solar Array procurement. Data on short circuit current, open circuit voltage, and maximum power for the four types of modules are presented in normalized form, showing distribution of the measured values. Standard deviations from the mean values are also given. Tests of the statistical significance of the data are discussed.

Ion-plating of solar cell arrays encapsulation task: LSA project 32

NASA Technical Reports Server (NTRS)

Volkers, J. C.

1983-01-01

An ion plating process by which solar cells can be metallized and AR coated, yielding efficiencies equal to or better than state-of-the-art cells, was developed. It was demonstrated that ion plated AR films may be used as an effective encapsulant, offering primary protection for the metallization. It was also shown that ion plated metallization and AR coatings can be consistent with the project cost goals.

FDTD modeling of solar energy absorption in silicon branched nanowires.

PubMed

Lundgren, Christin; Lopez, Rene; Redwing, Joan; Melde, Kathleen

2013-05-06

Thin film nanostructured photovoltaic cells are increasing in efficiency and decreasing the cost of solar energy. FDTD modeling of branched nanowire 'forests' are shown to have improved optical absorption in the visible and near-IR spectra over nanowire arrays alone, with a factor of 5 enhancement available at 1000 nm. Alternate BNW tree configurations are presented, achieving a maximum absorption of over 95% at 500 nm.

Inorganic Photovoltaics Materials and Devices: Past, Present, and Future

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Bailey, Sheila G.; Rafaelle, Ryne P.

2005-01-01

This report describes recent aspects of advanced inorganic materials for photovoltaics or solar cell applications. Specific materials examined will be high-efficiency silicon, gallium arsenide and related materials, and thin-film materials, particularly amorphous silicon and (polycrystalline) copper indium selenide. Some of the advanced concepts discussed include multi-junction III-V (and thin-film) devices, utilization of nanotechnology, specifically quantum dots, low-temperature chemical processing, polymer substrates for lightweight and low-cost solar arrays, concentrator cells, and integrated power devices. While many of these technologies will eventually be used for utility and consumer applications, their genesis can be traced back to challenging problems related to power generation for aerospace and defense. Because this overview of inorganic materials is included in a monogram focused on organic photovoltaics, fundamental issues and metrics common to all solar cell devices (and arrays) will be addressed.

Automated Array Assembly, Phase 2

NASA Technical Reports Server (NTRS)

Carbajal, B. G.

1979-01-01

The Automated Array Assembly Task, Phase 2 of the Low Cost Silicon Solar Array Project is a process development task. The contract provides for the fabrication of modules from large area tandem junction cells (TJC). During this quarter, effort was focused on the design of a large area, approximately 36 sq cm, TJC and process verification runs. The large area TJC design was optimized for minimum I squared R power losses. In the TJM activity, the cell-module interfaces were defined, module substrates were formed and heat treated and clad metal interconnect strips were fabricated.

SOLINS- SOLAR INSOLATION MODEL FOR COMPUTING AVAILABLE SOLAR ENERGY TO A SURFACE OF ARBITRARY ORIENTATION

NASA Technical Reports Server (NTRS)

Smith, J. H.

1994-01-01

This computer program, SOLINS, was developed to aid engineers and solar system designers in the accurate modeling of the average hourly solar insolation on a surface of arbitrary orientation. The program can be used to study insolation problems specific to residential and commercial applications where the amount of space available for solar collectors is limited by shadowing problems, energy output requirements, and costs. For tandem rack arrays, SOLINS will accommodate the use of augmentation reflectors built into the support structure to increase insolation values at the collector surface. As the use of flat plate solar collectors becomes more prevalent in the building industry, the engineer and designer must have the capability to conduct extensive sensitivity analyses on the orientation and location of solar collectors. SOLINS should prove to be a valuable aid in this area of engineering. SOLINS uses a modified version of the National Bureau of Standards model to calculate the direct, diffuse, and reflected components of total insolation on a tilted surface with a given azimuthal orientation. The model is based on the work of Liu and Jordan with corrections by Kusuda and Ishii to account for early morning and late afternoon errors. The model uses a parametric description of the average day solar climate to generate monthly average day profiles by hour of the insolation level on the collector surface. The model includes accommodation of user specified ground and landscape reflectivities at the collector site. For roof or ground mounted, tilted arrays, SOLINS will calculate insolation including the effects of shadowing and augmentation reflectors. The user provides SOLINS with data describing the array design, array orientation, the month, the solar climate parameter, the ground reflectance, and printout control specifications. For the specified array and environmental conditions, SOLINS outputs the hourly insolation the array will receive during an average day during the month specified, along with the total insolation the collector surface will receive over an average 24-hour period. This program is written in FORTRAN IV for batch execution and has been implemented on an IBM 370 computer with a central memory requirement of approximately 46K of 8 bit bytes. The SOLINS routines were developed in 1979.

Innovative Ballasted Flat Roof Solar PV Racking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peek, Richard T.

2014-12-15

The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction ofmore » the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.« less

New Voltage and Current Thresholds Determined for Sustained Space Plasma Arcing

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.; Galofaro, Joel T.; Vayner, Boris V.

2003-01-01

It has been known for many years, based partly on NASA Glenn Research Center testing, that high-voltage solar arrays arc into the space plasma environment. Solar arrays are composed of solar cells in series with each other (a string), and the strings may be connected in parallel to produce the entire solar array power. Arcs on solar arrays can damage or destroy solar cells, and in the extreme case of sustained arcing, entire solar array strings, in a flash. In the case of sustained arcing (discovered at Glenn and applied to the design and construction of solar arrays on Space Systems/Loral (SS/Loral, Palo Alto, CA) satellites, Deep-Space 1, and Terra), an arc on one solar array string can couple to an adjacent string and continue to be powered by the solar array output until a permanent electrical short is produced. In other words, sustained arcs produced by arcs into the plasma (so-called trigger arcs) may turn into disastrous sustained arcs by involving other array strings.

Investigation of test methods, material properties and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.; Baum, B.

1977-01-01

The potentially useful encapsulating materials for Task 3 of the Low-Cost Silicon Solar Array project were studied to identify, evaluate, and recommend encapsulant materials and processes for the production of cost-effective, long-life solar cell modules. Materials for study were chosen on the basis of existing knowledge of generic chemical types having high resistance to environmental weathering. The materials varied from rubbers to thermoplastics and presented a broad range of mechanical properties and processing requirements. Basic physical and optical properties were measured on the polymers and were redetermined after exposure to indoor artificial accelerated aging conditions covering four time periods. Strengths and weaknesses of the various materials were revealed and data was accumulated for the development of predictive methodologies. To date, silicone rubbers, fluorocarbons, and acrylic polymers appear to have the most promising combination of characteristics. The fluorocarbons may be used only as films, however, because of their high cost.

Silicon materials task of the low-cost solar array project. Phase 4: Effects of impurities and processing on silicon solar cells

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Hanes, M. H.; Davis, J. R.; Rohatgi, A.; Raichoudhury, P.; Mollenkopf, H. C.

1981-01-01

The results of the study form a basis for silicon producers, wafer manufacturers, and cell fabricators to develop appropriate cost-benefit relationships for the use of less pure, less costly solar grade silicon. Cr is highly mobile in silicon even at temperatures as low as 600 C. Contrasting with earlier data for Mo, Ti, and V, Cr concentrations vary from place to place in polycrystalline silicon wafers and the electrically-active Cr concentration in the polysilicon is more than an order of magnitude smaller than would be projected from single crystal impurity data. We hypothesize that Cr diffuses during ingot cooldown after growth, preferentially segregates to grain and becomes electrically deactivated. Accelerated aging data from Ni-contaminated silicon imply that no significant impurity-induced cell performance reduction should be expected over a twenty year device lifetime.

Polycrystalline silicon material availability and market pricing outlook study for 1980 to 88: January 1983 update

NASA Technical Reports Server (NTRS)

Costogue, E.; Pellin, R.

1983-01-01

Photovoltaic solar cell arrays which convert solar energy into electrical energy can become a cost effective, alternative energy source provided that an adequate supply of low priced materials and automated fabrication techniques are available. Presently, silicon is the most promising cell material for achieving the near term cost goals of the Photovoltaics Program. Electronic grade silicon is produced primarily for the semiconductor industry with the photovoltaic industry using, in most cases, the production rejects of slightly lower grade material. Therefore, the future availability of adequate supplies of low cost silicon is one of the major concerns of the Photovoltaic Program. The supply outlook for silicon with emphasis on pricing is updated and is based primarily on an industry survey conducted by a JPL consultant. This survey included interviews with polycrystalline silicon manufacturers, a large cross section of silicon users and silicon solar cell manufacturers.

(abstract) Scaling Nominal Solar Cell Impedances for Array Design

NASA Technical Reports Server (NTRS)

Mueller, Robert L; Wallace, Matthew T.; Iles, Peter

1994-01-01

This paper discusses a task the objective of which is to characterize solar cell array AC impedance and develop scaling rules for impedance characterization of large arrays by testing single solar cells and small arrays. This effort is aimed at formulating a methodology for estimating the AC impedance of the Mars Pathfinder (MPF) cruise and lander solar arrays based upon testing single cells and small solar cell arrays and to create a basis for design of a single shunt limiter for MPF power control of flight solar arrays having very different inpedances.

Energy conversion system

DOEpatents

Murphy, Lawrence M.

1987-01-01

The energy conversion system includes a photo-voltaic array for receiving solar radiation and converting such radiation to electrical energy. The photo-voltaic array is mounted on a stretched membrane that is held by a frame. Tracking means for orienting the photo-voltaic array in predetermined positions that provide optimal exposure to solar radiation cooperate with the frame. An enclosure formed of a radiation transmissible material includes an inside containment space that accommodates the photo-voltaic array on the stretched membrane, the frame and the tracking means, and forms a protective shield for all such components. The enclosure is preferably formed of a flexible inflatable material and maintains its preferred form, such as a dome, under the influence of a low air pressure furnished to the dome. Under this arrangement the energy conversion system is streamlined for minimizing wind resistance, sufficiently weatherproof for providing protection against weather hazards such as hail, capable of using diffused light, lightweight for low-cost construction, and operational with a minimal power draw.

Energy conversion system

DOEpatents

Murphy, L.M.

1985-09-16

The energy conversion system includes a photo-voltaic array for receiving solar radiation and converting such radiation to electrical energy. The photo-voltaic array is mounted on a stretched membrane that is held by a frame. Tracking means for orienting the photo-voltaic array in predetermined positions that provide optimal exposure to solar radiation cooperate with the frame. An enclosure formed of a radiation transmissible material includes an inside containment space that accommodates the photo-voltaic array on the stretched membrane, the frame and the tracking means, and forms a protective shield for all such components. The enclosure is preferably formed of a flexible inflatable material and maintains its preferred form, such as a dome, under the influence of a low air pressure furnished to the dome. Under this arrangement the energy conversion system is streamlined for minimizing wind resistance, sufficiently weathproof for providing protection against weather hazards such as hail, capable of using diffused light, lightweight for low-cost construction and operational with a minimal power draw.

Solar Electric Propulsion Technology Development for Electric Propulsion

NASA Technical Reports Server (NTRS)

Mercer, Carolyn R.; Kerslake, Thomas W.; Scheidegger, Robert J.; Woodworth, Andrew A.; Lauenstein, Jean-Marie

2015-01-01

NASA is developing technologies to prepare for human exploration missions to Mars. Solar electric propulsion (SEP) systems are expected to enable a new cost effective means to deliver cargo to the Mars surface. Nearer term missions to Mars moons or near-Earth asteroids can be used to both develop and demonstrate the needed technology for these future Mars missions while demonstrating new capabilities in their own right. This presentation discusses recent technology development accomplishments for high power, high voltage solar arrays and power management that enable a new class of SEP missions.

Integrated thin film cadmium sulfide solar cell module

NASA Technical Reports Server (NTRS)

Mickelsen, R. A.; Abbott, D. D.

1971-01-01

The design, development, fabrication and tests of flexible integrated thin-film cadmium sulfide solar cells and modules are discussed. The development of low cost and high production rate methods for interconnecting cells into large solar arrays is described. Chromium thin films were applied extensively in the deposited cell structures as a means to: (1) achieve high adherence between the cadmium sulfide films and the vacuum-metallized copper substrates, (2) obtain an ohmic contact to the cadmium sulfide films, and (3) improve the adherence of gold films as grids or contact areas.

Accelerated/abbreviated test methods of the low-cost silicon solar array project. Study 4, task 3: Encapsulation

NASA Technical Reports Server (NTRS)

Kolyer, J. M.; Mann, N. R.

1977-01-01

Methods of accelerated and abbreviated testing were developed and applied to solar cell encapsulants. These encapsulants must provide protection for as long as 20 years outdoors at different locations within the United States. Consequently, encapsulants were exposed for increasing periods of time to the inherent climatic variables of temperature, humidity, and solar flux. Property changes in the encapsulants were observed. The goal was to predict long term behavior of encapsulants based upon experimental data obtained over relatively short test periods.

Array automated assembly task, phase 2. Low cost silicon solar array project

NASA Technical Reports Server (NTRS)

Rhee, S. S.; Jones, G. T.; Allison, K. T.

1978-01-01

Several modifications instituted in the wafer surface preparation process served to significantly reduce the process cost to 1.55 cents per peak watt in 1975 cents. Performance verification tests of a laser scanning system showed a limited capability to detect hidden cracks or defects, but with potential equipment modifications this cost effective system could be rendered suitable for applications. Installation of electroless nickel plating system was completed along with an optimization of the wafer plating process. The solder coating and flux removal process verification test was completed. An optimum temperature range of 500-550 C was found to produce uniform solder coating with the restriction that a modified dipping procedure is utilized. Finally, the construction of the spray-on dopant equipment was completed.

Solar cell array design handbook - The principles and technology of photovoltaic energy conversion

NASA Technical Reports Server (NTRS)

Rauschenbach, H. S.

1980-01-01

Photovoltaic solar cell array design and technology for ground-based and space applications are discussed from the user's point of view. Solar array systems are described, with attention given to array concepts, historical development, applications and performance, and the analysis of array characteristics, circuits, components, performance and reliability is examined. Aspects of solar cell array design considered include the design process, photovoltaic system and detailed array design, and the design of array thermal, radiation shielding and electromagnetic components. Attention is then given to the characteristics and design of the separate components of solar arrays, including the solar cells, optical elements and mechanical elements, and the fabrication, testing, environmental conditions and effects and material properties of arrays and their components are discussed.

Bi-Axial Solar Array Drive Mechanism: Design, Build and Environmental Testing

NASA Technical Reports Server (NTRS)

Scheidegger, Noemy; Ferris, Mark; Phillips, Nigel

2014-01-01

The development of the Bi-Axial Solar Array Drive Mechanism (BSADM) presented in this paper is a demonstration of SSTL's unique space manufacturing approach that enables performing rapid development cycles for cost-effective products that meet ever-challenging mission requirements: The BSADM is designed to orient a solar array wing towards the sun, using its first rotation axis to track the sun, and its second rotation axis to compensate for the satellite orbit and attitude changes needed for a successful payload operation. The tight development schedule, with manufacture of 7 Flight Models within 1.5 year after kick-off, is offset by the risk-reduction of using qualified key component-families from other proven SSTL mechanisms. This allowed focusing the BSADM design activities on the mechanism features that are unique to the BSADM, and having an Engineering Qualification Model (EQM) built 8 months after kick-off. The EQM is currently undergoing a full environmental qualification test campaign. This paper presents the BSADM design approach that enabled meeting such a challenging schedule, its design particularities, and the ongoing verification activities.

Evaluation of selected chemical processes for production of low-cost silicon phase 2. silicon material task, low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Blocher, J. M., Jr.; Browning, M. F.; Rose, E. E.; Thompson, W. B.; Schmitt, W. A.; Fippin, J. S.; Kidd, R. W.; Liu, C. Y.; Kerbler, P. S.; Ackley, W. R.

1978-01-01

Progress from October 1, 1977, through December 31, 1977, is reported in the design of the 50 MT/year experimental facility for the preparation of high purity silicon by the zinc vapor reduction of silicon tetrachloride in a fluidized bed of seed particles to form a free flowing granular product.

Initial technical environmental, and economic evaluation of space solar power concepts. Volume 2: Detailed report

NASA Technical Reports Server (NTRS)

1976-01-01

The SPS concepts which appear to be technically feasible are discussed in terms of the economic viability and competitive costs with other energy sources. The concepts discussed include: power station, microwave reception and conversion, space construction and maintenance, space transportation, and program costs and analysis. The conclusions presented include: (1) The maximum output of an individual microwave transmission link to earth is about 5 GW. (2) The mass of 10 GW SPS is between 47,000,000 and 124,000,00 kg. (3) The silicon solar cell arrays make up well over half the weight and cost of the satellite. (4) The SPS in equatorial orbit will be eclipsed by the earth and by other satellites.

Amorphous silicon thin films: The ultimate lightweight space solar cell

NASA Technical Reports Server (NTRS)

Vendura, G. J., Jr.; Kruer, M. A.; Schurig, H. H.; Bianchi, M. A.; Roth, J. A.

1994-01-01

Progress is reported with respect to the development of thin film amorphous (alpha-Si) terrestrial solar cells for space applications. Such devices promise to result in very lightweight, low cost, flexible arrays with superior end of life (EOL) performance. Each alpha-Si cell consists of a tandem arrangement of three very thin p-i-n junctions vapor deposited between film electrodes. The thickness of this entire stack is approximately 2.0 microns, resulting in a device of negligible weight, but one that must be mechanically supported for handling and fabrication into arrays. The stack is therefore presently deposited onto a large area (12 by 13 in), rigid, glass superstrate, 40 mil thick, and preliminary space qualification testing of modules so configured is underway. At the same time, a more advanced version is under development in which the thin film stack is transferred from the glass onto a thin (2.0 mil) polymer substrate to create large arrays that are truly flexible and significantly lighter than either the glassed alpha-Si version or present conventional crystalline technologies. In this paper the key processes for such effective transfer are described. In addition, both glassed (rigid) and unglassed (flexible) alpha-Si cells are studied when integrated with various advanced structures to form lightweight systems. EOL predictions are generated for the case of a 1000 W array in a standard, 10 year geosynchronous (GEO) orbit. Specific powers (W/kg), power densities (W/sq m) and total array costs ($/sq ft) are compared.

Solar Array Power Conditioning for a Spinning Satellite

NASA Astrophysics Data System (ADS)

De Luca, Antonio; Chirulli, Giovanni

2008-09-01

The conditioning of the output power from a solar array can mainly be achieved by the adoption of DET or MPPT based architecture. There are several factors that can orientate the choice of the system designer towards one solution or the other; some of them maybe inherent to the mission derived requirements (Illumination levels, EMC cleanliness, etc.), others come directly from a careful assessment of performances and losses of both power conditioner and solar array.Definition of the criteria on which basis the final choice is justified is important as they have to guarantee a clear determination of the available versus the required power in all those mission conditions identifiable as design drivers for the overall satellite system both in terms of mass and costs.Such criteria cannot just be simple theoretical enunciations of principles; nor the meticulous definition of them on a case by case basis for different types of missions as neither option gives a guarantee of being conclusive.The aim of this paper is then to suggest assessment steps and guidelines that can be considered generically valid for any mission case, starting from the exposition of the trade off activity performed in order to choose the power conditioning solution for a spinning satellite having unregulated power bus architecture. Calculations and numerical simulations have been made in order to establish the needed solar array surface in case of adoption of a DET or MPPT solution, taking into account temperature and illumination levels on the solar cells, as well as power losses and inefficiencies from the solar generator to the main power bus, in different mission phases. Particular attention has been taken in order to correctly evaluate the thermal effects on the rest of the spacecraft as function of the adopted power system regulation.

Solar cell array design handbook, volume 1

NASA Technical Reports Server (NTRS)

Rauschenbach, H. S.

1976-01-01

Twelve chapters discuss the following: historical developments, the environment and its effects, solar cells, solar cell filters and covers, solar cell and other electrical interconnections, blocking and shunt diodes, substrates and deployment mechanisms, material properties, design synthesis and optimization, design analysis, procurement, production and cost aspects, evaluation and test, orbital performance, and illustrative design examples. A comprehensive index permits rapid locating of desired topics. The handbook consists of two volumes: Volume 1 is of an expository nature while Volume 2 contains detailed design data in an appendix-like fashion. Volume 2 includes solar cell performance data, applicable unit conversion factors and physical constants, and mechanical, electrical, thermal optical, magnetic, and outgassing material properties. Extensive references are provided.

Planar waveguide concentrator used with a seasonal tracker.

PubMed

Bouchard, Sébastien; Thibault, Simon

2012-10-01

Solar concentrators offer good promise for reducing the cost of solar power. Planar waveguides equipped with a microlens slab have already been proposed as an excellent approach to produce medium to high concentration levels. Instead, we suggest the use of a cylindrical microlens array to get useful concentration without tracking during the day. To use only a seasonal tracking system and get the highest possible concentration, cylindrical microlenses are placed in the east-west orientation. Our new design has an acceptance angle in the north-south direction of ±9° and ±54° in the east-west axis. Simulation of our optimized system achieves a 4.6× average concentration level from 8:30 to 16:30 with a maximum of 8.1× and 80% optical efficiency. The low-cost advantage of waveguide-based solar concentrators could support their use in roof-mounted solar panels and eliminate the need for an expensive and heavy active tracker.

Low cost solar array project. Task 1: Silicon material, gaseous melt replenishment system

NASA Technical Reports Server (NTRS)

Jewett, D. N.; Bates, H. E.; Hill, D. M.

1979-01-01

A system to combine silicon formation, by hydrogen reduction of trichlorosilane, with the capability to replenish a crystal growth system is described. A variety of process parameters to allow sizing and specification of gas handling system components was estimated.

Low-cost Solar Array Project. Feasibility of the Silane Process for Producing Semiconductor-grade Silicon

NASA Technical Reports Server (NTRS)

1979-01-01

The feasibility of Union Carbide's silane process for commercial application was established. An integrated process design for an experimental process system development unit and a commercial facility were developed. The corresponding commercial plant economic performance was then estimated.

Advanced Thin Film Solar Arrays for Space: The Terrestrial Legacy

NASA Technical Reports Server (NTRS)

Bailey, Sheila; Hepp, Aloysius; Raffaelle, Ryne; Flood, Dennis

2001-01-01

As in the case for single crystal solar cells, the first serious thin film solar cells were developed for space applications with the promise of better power to weight ratios and lower cost. Future science, military, and commercial space missions are incredibly diverse. Military and commercial missions encompass both hundreds of kilowatt arrays to tens of watt arrays in various earth orbits. While science missions also have small to very large power needs there are additional unique requirements to provide power for near sun missions and planetary exploration including orbiters, landers, and rovers both to the inner planets and the outer planets with a major emphasis in the near term on Mars. High power missions are particularly attractive for thin film utilization. These missions are generally those involving solar electric propulsion, surface power systems to sustain an outpost or a permanent colony on the surface of the Moon or Mars, space based lasers or radar, or large Earth orbiting power stations which can serve as central utilities for other orbiting spacecraft, or potentially beaming power to the Earth itself. This paper will discuss the current state of the art of thin film solar cells and the synergy with terrestrial thin film photovoltaic evolution. It will also address some of the technology development issues required to make thin film photovoltaics a viable choice for future space power systems.

Assessment of the biophysical impacts of utility-scale photovoltaics through observations and modelling

NASA Astrophysics Data System (ADS)

Broadbent, A. M.; Georgescu, M.; Krayenhoff, E. S.; Sailor, D.

2017-12-01

Utility-scale solar power plants are a rapidly growing component of the solar energy sector. Utility-scale photovoltaic (PV) solar power generation in the United States has increased by 867% since 2012 (EIA, 2016). This expansion is likely to continue as the cost PV technologies decrease. While most agree that solar power can decrease greenhouse gas emissions, the biophysical effects of PV systems on surface energy balance (SEB), and implications for surface climate, are not well understood. To our knowledge, there has never been a detailed observational study of SEB at a utility-scale solar array. This study presents data from an eddy covariance observational tower, temporarily placed above a utility-scale PV array in Southern Arizona. Comparison of PV SEB with a reference (unmodified) site, shows that solar panels can alter the SEB and near surface climate. SEB observations are used to develop and validate a new and more complete SEB PV model. In addition, the PV model is compared to simpler PV modelling methods. The simpler PV models produce differing results to our newly developed model and cannot capture the more complex processes that influence PV SEB. Finally, hypothetical scenarios of PV expansion across the continental United States (CONUS) were developed using various spatial mapping criteria. CONUS simulations of PV expansion reveal regional variability in biophysical effects of PV expansion. The study presents the first rigorous and validated simulations of the biophysical effects of utility-scale PV arrays.

Analysis and evaluation of process and equipment in tasks 2 and 4 of the Low Cost Solar Array project

NASA Technical Reports Server (NTRS)

Goldman, H.; Wolf, M.

1978-01-01

Several experimental and projected Czochralski crystal growing process methods were studied and compared to available operations and cost-data of recent production Cz-pulling, in order to elucidate the role of the dominant cost contributing factors. From this analysis, it becomes apparent that substantial cost reductions can be realized from technical advancements which fall into four categories: an increase in furnace productivity; the reduction of crucible cost through use of the crucible for the equivalent of multiple state-of-the-art crystals; the combined effect of several smaller technical improvements; and a carry over effect of the expected availability of semiconductor grade polysilicon at greatly reduced prices. A format for techno-economic analysis of solar cell production processes was developed, called the University of Pennsylvania Process Characterization (UPPC) format. The accumulated Cz process data are presented.

Operational considerations to reduce solar array loads

NASA Technical Reports Server (NTRS)

Gerstenmaier, W.

1992-01-01

The key parameters associated with solar array plume loads are examined, and operational considerations aimed at minimizing the effect of the Shuttle plumes on the Space Station solar arrays are discussed. These include solar array pointing to reduce loads and restrictions on Shuttle piloting. Particular attention is given to the method used to obtain the forcing functions (thruster time firing histories) for solar array plume calculation.

Wind loading on solar concentrators: some general considerations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roschke, E. J.

A survey has been completed to examine the problems and complications arising from wind loading on solar concentrators. Wind loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of solar collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. Wind characteristics are discussed from a general point of view; current methods for determining design wind speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. Wind tunnel testing is discussed, and environmental wind tunnels are reviewed; recent results onmore » heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly. Wind loads, i.e., forces and moments, are proportional to the square of the mean wind velocity. Forces are proportional to the square of concentrator diameter, and moments are proportional to the cube of diameter. Thus, wind loads have an important bearing on size selection from both cost and performance standpoints. It is concluded that sufficient information exists so that reasonably accurate predictions of wind loading are possible for a given paraboloidal concentrator configuration, provided that reliable and relevant wind conditions are specified. Such predictions will be useful to the design engineer and to the systems engineer as well. Information is lacking, however, on wind effects in field arrays of paraboloidal concentrators. Wind tunnel tests have been performed on model heliostat arrays, but there are important aerodynamic differences between heliostats and paraboloidal dishes.« less

Control Algorithms Charge Batteries Faster

NASA Technical Reports Server (NTRS)

2012-01-01

On March 29, 2011, NASA s Mercury Surface, Space Environment, Geochemistry and Ranging (MESSENGER) spacecraft beamed a milestone image to Earth: the first photo of Mercury taken from orbit around the solar system s innermost planet. (MESSENGER is also the first spacecraft to orbit Mercury.) Like most of NASA s deep space probes, MESSENGER is enabled by a complex power system that allows its science instruments and communications to function continuously as it travels millions of miles from Earth. "Typically, there isn't one particular power source that can support the entire mission," says Linda Taylor, electrical engineer in Glenn Research Center s Power Systems Analysis Branch. "If you have solar arrays and you are in orbit, at some point you re going to be in eclipse." Because of this, Taylor explains, spacecraft like MESSENGER feature hybrid power systems. MESSENGER is powered by a two-panel solar array coupled with a nickel hydrogen battery. The solar arrays provide energy to the probe and charge the battery; when the spacecraft s orbit carries it behind Mercury and out of the Sun s light, the spacecraft switches to battery power to continue operations. Typically, hybrid systems with multiple power inputs and a battery acting alternately as storage and a power source require multiple converters to handle the power flow between the devices, Taylor says. (Power converters change the qualities of electrical energy, such as from alternating current to direct current, or between different levels of voltage or frequency.) This contributes to a pair of major concerns for spacecraft design. "Weight and size are big drivers for any space application," Taylor says, noting that every pound added to a space vehicle incurs significant costs. For an innovative solution to managing power flows in a lightweight, cost-effective manner, NASA turned to a private industry partner.

Technology developments toward 30-year-life of photovoltaic modules

NASA Technical Reports Server (NTRS)

Ross, R. G., Jr.

1984-01-01

As part of the United States National Photovoltaics Program, the Jet Propulsion Laboratory's Flat-Plate Solar Array Project (FSA) has maintained a comprehensive reliability and engineering sciences activity addressed toward understanding the reliability attributes of terrestrial flat-plate photovoltaic arrays and to deriving analysis and design tools necessary to achieve module designs with a 30-year useful life. The considerable progress to date stemming from the ongoing reliability research is discussed, and the major areas requiring continued research are highlighted. The result is an overview of the total array reliability problem and of available means of achieving high reliability at minimum cost.

Fort Yukon, Alaska DOE Implementation Grant Gwich'in Solar and Energy Efficiency in the Arctic Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cadzow, Janet; Messier, Dave

Gwichyaa Zhee Gwich’in Tribal Government (GZGTG) applied for funding in 2014 under the U.S. Department of Energy Office of Indian Energy Deployment of Clean Energy on Tribal Lands funding opportunity. They were awarded 50% of the project costs for the construction of an 18kW, grid-tied solar PV array on the fort Yukon Tribal Hall, the construction of a 3kW solar PV array on the tribally owned greenhouse, the replacement of inefficient florescent lighting fixtures in the tribal hall to higher efficiency LED lights and the addition of blow in cellulose insulation to the attic of the tribal hall to assistmore » with heat retention. Total DOE Funding for the project was $124,735. Total GZGTG funding for the project was $133,321 for a total project cost of $258,056. The Project was completed with 100% local labor on the tribal hall solar PV installation, the LED lighting retrofit and the insulation on the tribal hall. Based on the results at the tribal hall/office, the tribe also used their own tribal funding to retrofit the lighting in the community hall from florescent to LED lights. The resulting project was completed by the end of Sept 2016 and results have shown a decrease in fuel used at the tribal hall/office of 35% and a decrease in electric costs at the tribal hall of 68%. The total energy costs before the project were approximately $28,000 a year and the energy equivalent of 385 MMBTU/yr. After the project the total energy costs decreased to $11,200/yr. and an energy equivalent of only 242 MMBTU. This represents an overall decrease in energy use of 38%. All in all the tribe and the community regard this project as a huge success!« less

Investigation of Proposed Process Sequence for the Array Automated Assembly Task, Phase 2. [low cost silicon solar array fabrication

NASA Technical Reports Server (NTRS)

Mardesich, N.; Garcia, A.; Bunyan, S.; Pepe, A.

1979-01-01

The technological readiness of the proposed process sequence was reviewed. Process steps evaluated include: (1) plasma etching to establish a standard surface; (2) forming junctions by diffusion from an N-type polymeric spray-on source; (3) forming a p+ back contact by firing a screen printed aluminum paste; (4) forming screen printed front contacts after cleaning the back aluminum and removing the diffusion oxide; (5) cleaning the junction by a laser scribe operation; (6) forming an antireflection coating by baking a polymeric spray-on film; (7) ultrasonically tin padding the cells; and (8) assembling cell strings into solar circuits using ethylene vinyl acetate as an encapsulant and laminating medium.

Integrated propulsion for near-Earth space missions. Volume 2: Technical

NASA Technical Reports Server (NTRS)

Dailey, C. L.; Meissinger, H. F.; Lovberg, R. H.; Zafran, S.

1981-01-01

The calculation approach is described for parametric analysis of candidate electric propulsion systems employed in LEO to GEO missions. Occultation relations, atmospheric density effects, and natural radiation effects are presented. A solar cell cover glass tradeoff is performed to determine optimum glass thickness. Solar array and spacecraft pointing strategies are described for low altitude flight and for optimum array illumination during ascent. Mass ratio tradeoffs versus transfer time provide direction for thruster technology improvements. Integrated electric propulsion analysis is performed for orbit boosting, inclination change, attitude control, stationkeeping, repositioning, and disposal functions as well as power sharing with payload on orbit. Comparison with chemical auxiliary propulsion is made to quantify the advantages of integrated propulsion in terms of weight savings and concomittant launch cost savings.

Torsional Buckling Tests of a Simulated Solar Array

NASA Technical Reports Server (NTRS)

Thornton, E. A.

1996-01-01

Spacecraft solar arrays are typically large structures supported by long, thin deployable booms. As such, they may be particularly susceptible to abnormal structural behavior induced by mechanical and thermal loading. One example is the Hubble Space Telescope solar arrays which consist of two split tubes fit one inside the other called BiSTEMs. The original solar arrays on the Hubble Space Telescope were found to be severely twisted following deployment and later telemetry data showed the arrays were vibrating during daylight to night and night to daylight transition. The solar array twist however can force the BiSTEM booms to change in cross-section and cause tile solar arrays to react unpredictably to future loading. The solar arrays were redesigned to correct for tile vibration, however, upon redeployment they again twisted. To assess the influence of boom cross-sectional configuration, experiments were conducted on two types of booms, (1)booms with closed cross-sections, and (2) booms with open cross-sections. Both models were subjected to compressive loading and imposed tip deflections. An existing analytical model by Chung and Thornton was used to define the individual load ranges for each model solar array configuration. The load range for the model solar array using closed cross-section booms was 0-120 Newtons and 0-160 Newtons for the model solar array using open cross-section booms. The results indicate the model solar array with closed cross-section booms buckled only in flexure. However, the results of the experiment with open cross-section booms indicate the model solar array buckled only in torsion and with imposed tip deflections the cross section can degrade by rotation of the inner relative to the outer STEM. For tile Hubble Space Telescope solar arrays the results of these experiments indicate the twisting resulted from the initial mechanical loading of the open cross-section booms.

Advanced photovoltaic solar array design assessment

NASA Technical Reports Server (NTRS)

Stella, Paul; Scott-Monck, John

1987-01-01

The Advanced Photovoltaic Solar Array (APSA) program seeks to bring to flight readiness a solar array that effectively doubles the specific power of the Solar Array Flight Experiment/Solar Electric Propulsion (SAFE/SEP) design that was successfully demonstrated during the Shuttle 41-D mission. APSA is a critical intermediate milestone in the effort to demonstrate solar array technologies capable of 300 W/kg and 300 W/square m at beginning of life (BOL). It is not unreasonable to anticipate the development of solar array designs capable of 300 W/kg at BOL for operational power levels approx. greater than 25 kW sub e. It is also quite reasonable to expect that high performance solar arrays capable of providing at least 200 W/kg at end of life for most orbits now being considered by mission planners will be realized in the next decade.

Novel duplex vapor electrochemical method for silicon solar cells

NASA Technical Reports Server (NTRS)

Kapur, V.; Sancier, K. M.; Sanjurjo, A.; Leach, S.; Westphal, S.; Bartlett, R.; Nanis, L.

1978-01-01

Progress in the development of low-cost solar arrays is reported. Topics covered include: (1) development of a simplified feed system for the Na used in the Na-SiF4 reactor; (2) production of high purity silicon through the reduction of sodium fluosilicate with sodium metal; (3) the leaching process for recovering silicon from the reaction products of the SiF4-Na reaction; and (4) silicon separation by the melting of the reaction product.

Analysis and Evaluation of Processes and Equipment in Tasks 2 and 4 of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Goldman, H.; Wolf, M.

1978-01-01

The significant economic data for the current production multiblade wafering and inner diameter slicing processes were tabulated and compared to data on the experimental and projected multiblade slurry, STC ID diamond coated blade, multiwire slurry and crystal systems fixed abrasive multiwire slicing methods. Cost calculations were performed for current production processes and for 1982 and 1986 projected wafering techniques.

Low cost solar array project: Cell and module formation research area. Process research of non-CZ silicon material

NASA Technical Reports Server (NTRS)

1983-01-01

Meniscus coates tests, back junction formation using a new boron containing liquid, tests of various SiO2 and boron containing liquids, pelletized silicon for replenishment during web growth, and ion implantation compatibility/feasibility study are discussed.

Solar array study for solar electric propulsion spacecraft for the Encke rendezvous mission

NASA Technical Reports Server (NTRS)

Sequeira, E. A.; Patterson, R. E.

1974-01-01

The work is described which was performed on the design, analysis and performance of a 20 kW rollup solar array capable of meeting the design requirements of a solar electric spacecraft for the 1980 Encke rendezvous mission. To meet the high power requirements of the proposed electric propulsion mission, solar arrays on the order of 186.6 sq m were defined. Because of the large weights involved with arrays of this size, consideration of array configurations is limited to lightweight, large area concepts with maximum power-to-weight ratios. Items covered include solar array requirements and constraints, array concept selection and rationale, structural and electrical design considerations, and reliability considerations.

Electromagnetically Clean Solar Arrays

NASA Technical Reports Server (NTRS)

Stem, Theodore G.; Kenniston, Anthony E.

2008-01-01

The term 'electromagnetically clean solar array' ('EMCSA') refers to a panel that contains a planar array of solar photovoltaic cells and that, in comparison with a functionally equivalent solar-array panel of a type heretofore used on spacecraft, (1) exhibits less electromagnetic interferences to and from other nearby electrical and electronic equipment and (2) can be manufactured at lower cost. The reduction of electromagnetic interferences is effected through a combination of (1) electrically conductive, electrically grounded shielding and (2) reduction of areas of current loops (in order to reduce magnetic moments). The reduction of cost is effected by designing the array to be fabricated as a more nearly unitary structure, using fewer components and fewer process steps. Although EMCSAs were conceived primarily for use on spacecraft they are also potentially advantageous for terrestrial applications in which there are requirements to limit electromagnetic interference. In a conventional solar panel of the type meant to be supplanted by an EMCSA panel, the wiring is normally located on the back side, separated from the cells, thereby giving rise to current loops having significant areas and, consequently, significant magnetic moments. Current-loop geometries are chosen in an effort to balance opposing magnetic moments to limit far-0field magnetic interactions, but the relatively large distances separating current loops makes full cancellation of magnetic fields problematic. The panel is assembled from bare photovoltaic cells by means of multiple sensitive process steps that contribute significantly to cost, especially if electomagnetic cleanliness is desired. The steps include applying a cover glass and electrical-interconnect-cell (CIC) sub-assemble, connecting the CIC subassemblies into strings of series-connected cells, laying down and adhesively bonding the strings onto a panel structure that has been made in a separate multi-step process, and mounting the wiring on the back of the panel. Each step increases the potential for occurrence of latent defects, loss of process control, and attrition of components. An EMCSA panel includes an integral cover made from a transparent material. The silicone cover supplants the individual cover glasses on the cells and serves as an additional unitary structural support that offers the advantage, relative to glass, of the robust, forgiving nature of the silcone material. The cover contains pockets that hold the solar cells in place during the lamination process. The cover is coated with indium tin oxide to make its surface electrically conductive, so that it serves as a contiguous, electrically grounded shield over the entire panel surface. The cells are mounted in proximity to metallic printed wiring. The painted-wiring layer comprises metal-film traces on a sheet of Kapton (or equivalent) polyimide. The traces include contact pads on one side of the sheet for interconnecting the cells. Return leads are on the opposite side of the sheet, positioned to form the return currents substantially as mirror images of, and in proximity to, the cell sheet currents, thereby minimizing magnetic moments. The printed-wiring arrangement mimics the back-wiring arrangement of conventional solar arrays, but the current-loop areas and the resulting magnetic moments are much smaller because the return-current paths are much closer to the solar-cell sheet currents. The contact pads are prepared with solder fo electrical and mechanical bonding to the cells. The pocketed cover/shield, the solar cells, the printed-wiring layer, an electrical bonding agent, a mechanical-bonding agent, a composite structural front-side face sheet, an aluminum honeycomb core, and a composite back-side face sheet are all assembled, then contact pads are soldered to the cells and the agents are cured in a single lamination process.

Seven-panel solar wing deployment and on-orbit maneuvering analyses

NASA Astrophysics Data System (ADS)

Hwang, Earl

2005-05-01

BSS developed a new generation high power (~20kW) solar array to meet the customer demands. The high power solar array had the north and south solar wings of which designs were identical. Each side of the solar wing consists of three main conventional solar panels and the four-side panel swing-out new design. The fully deployed solar array surface area is 966 ft2. It was a quite challenging task to define the solar array's optimum design parameters and deployment scheme for such a huge solar array's successful deployment and on-orbit maneuvering. Hence, a deployable seven-flex-panel solar wing nonlinear math model and a fully deployed solar array/bus-payload math model were developed with the Dynamic Analysis and Design System (DADS) program codes utilizing the inherited and empirical data. Performing extensive parametric analyses with the math model, the optimum design parameters and the orbit maneuvering /deployment schemes were determined to meet all the design requirements, and for the successful solar wing deployment on-orbit.

The U.S. and Japanese amorphous silicon technology programs A comparison

NASA Technical Reports Server (NTRS)

Shimada, K.

1984-01-01

The U.S. Department of Energy/Solar Energy Research Institute Amorphous Silicon (a-Si) Solar Cell Program performs R&D on thin-film hydrogenated amorphous silicon for eventual development of stable amorphous silicon cells with 12 percent efficiency by 1988. The Amorphous Silicon Solar Cell Program in Japan is sponsored by the Sunshine Project to develop an alternate energy technology. While the objectives of both programs are to eventually develop a-Si photovoltaic modules and arrays that would produce electricity to compete with utility electricity cost, the U.S. program approach is research oriented and the Japanese is development oriented.

Simulation and optimum design of hybrid solar-wind and solar-wind-diesel power generation systems

NASA Astrophysics Data System (ADS)

Zhou, Wei

Solar and wind energy systems are considered as promising power generating sources due to its availability and topological advantages in local power generations. However, a drawback, common to solar and wind options, is their unpredictable nature and dependence on weather changes, both of these energy systems would have to be oversized to make them completely reliable. Fortunately, the problems caused by variable nature of these resources can be partially overcome by integrating these two resources in a proper combination to form a hybrid system. However, with the increased complexity in comparison with single energy systems, optimum design of hybrid system becomes more complicated. In order to efficiently and economically utilize the renewable energy resources, one optimal sizing method is necessary. This thesis developed an optimal sizing method to find the global optimum configuration of stand-alone hybrid (both solar-wind and solar-wind-diesel) power generation systems. By using Genetic Algorithm (GA), the optimal sizing method was developed to calculate the system optimum configuration which offers to guarantee the lowest investment with full use of the PV array, wind turbine and battery bank. For the hybrid solar-wind system, the optimal sizing method is developed based on the Loss of Power Supply Probability (LPSP) and the Annualized Cost of System (ACS) concepts. The optimization procedure aims to find the configuration that yields the best compromise between the two considered objectives: LPSP and ACS. The decision variables, which need to be optimized in the optimization process, are the PV module capacity, wind turbine capacity, battery capacity, PV module slope angle and wind turbine installation height. For the hybrid solar-wind-diesel system, minimization of the system cost is achieved not only by selecting an appropriate system configuration, but also by finding a suitable control strategy (starting and stopping point) of the diesel generator. The optimal sizing method was developed to find the system optimum configuration and settings that can achieve the custom-required Renewable Energy Fraction (fRE) of the system with minimum Annualized Cost of System (ACS). Du to the need for optimum design of the hybrid systems, an analysis of local weather conditions (solar radiation and wind speed) was carried out for the potential installation site, and mathematical simulation of the hybrid systems' components was also carried out including PV array, wind turbine and battery bank. By statistically analyzing the long-term hourly solar and wind speed data, Hong Kong area is found to have favorite solar and wind power resources compared with other areas, which validates the practical applications in Hong Kong and Guangdong area. Simulation of PV array performance includes three main parts: modeling of the maximum power output of the PV array, calculation of the total solar radiation on any tilted surface with any orientations, and PV module temperature predictions. Five parameters are introduced to account for the complex dependence of PV array performance upon solar radiation intensities and PV module temperatures. The developed simulation model was validated by using the field-measured data from one existing building-integrated photovoltaic system (BIPV) in Hong Kong, and good simulation performance of the model was achieved. Lead-acid batteries used in hybrid systems operate under very specific conditions, which often cause difficulties to predict when energy will be extracted from or supplied to the battery. In this thesis, the lead-acid battery performance is simulated by three different characteristics: battery state of charge (SOC), battery floating charge voltage and the expected battery lifetime. Good agreements were found between the predicted values and the field-measured data of a hybrid solar-wind project. At last, one 19.8kW hybrid solar-wind power generation project, designed by the optimal sizing method and set up to supply power for a telecommunication relay station on a remote island of Guangdong province, was studied. Simulation and experimental results about the operating performances and characteristics of the hybrid solar-wind project have demonstrated the feasibility and accuracy of the recommended optimal sizing method developed in this thesis.

Low Cost Solar Array Project. Feasibility of the silane process for producing semiconductor-grade silicon. Final report, October 1975-March 1979

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1979-06-01

The commercial production of low-cost semiconductor-grade silicon is an essential requirement of the JPL/DOE (Department of Energy) Low-Cost Solar Array (LSA) Project. A 1000-metric-ton-per-year commercial facility using the Union Carbide Silane Process will produce molten silicon for an estimated price of $7.56/kg (1975 dollars, private financing), meeting the DOE goal of less than $10/kg. Conclusions and technology status are reported for both contract phases, which had the following objectives: (1) establish the feasibility of Union Carbide's Silane Process for commercial application, and (2) develop an integrated process design for an Experimental Process System Development Unit (EPSDU) and a commercial facility,more » and estimate the corresponding commercial plant economic performance. To assemble the facility design, the following work was performed: (a) collection of Union Carbide's applicable background technology; (b) design, assembly, and operation of a small integrated silane-producing Process Development Unit (PDU); (c) analysis, testing, and comparison of two high-temperature methods for converting pure silane to silicon metal; and (d) determination of chemical reaction equilibria and kinetics, and vapor-liquid equilibria for chlorosilanes.« less

Thermal/Dynamic Characterization Test of the Solar Array Panel for Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Jenkins, Kathleen; Hershfeld, Donald J.

1999-01-01

The Hubble Space Telescope has experienced a problem maintaining pointing accuracy during emergence of the spacecraft from the Earth's shadow. The problem has been attributed to the rapid thermal gradient that develops when the heat from the Sun strikes the cold solar arrays. The thermal gradient causes the solar arrays to deflect or bend and this motion is sufficient to disturb the pointing control system. In order to alleviate this problem, a new design for the solar arrays has been fabricated. These new solar arrays will replace the current solar arrays during a future Hubble servicing mission. The new solar arrays have been designed so that the effective net motion of the center of mass of each panel is essentially zero. Although the solar array thermal deflection problem has been studied extensively over a period of years, a full scale test of the actual flight panels was required in order to establish confidence in the analyses. This test was conducted in the JPL Solar Simulation Facility in April, 1999. This presentation will discuss the objectives and methods of the test and present some typical test data.

Wafer-scale high-throughput ordered arrays of Si and coaxial Si/Si(1-x)Ge(x) wires: fabrication, characterization, and photovoltaic application.

PubMed

Pan, Caofeng; Luo, Zhixiang; Xu, Chen; Luo, Jun; Liang, Renrong; Zhu, Guang; Wu, Wenzhuo; Guo, Wenxi; Yan, Xingxu; Xu, Jun; Wang, Zhong Lin; Zhu, Jing

2011-08-23

We have developed a method combining lithography and catalytic etching to fabricate large-area (uniform coverage over an entire 5-in. wafer) arrays of vertically aligned single-crystal Si nanowires with high throughput. Coaxial n-Si/p-SiGe wire arrays are also fabricated by further coating single-crystal epitaxial SiGe layers on the Si wires using ultrahigh vacuum chemical vapor deposition (UHVCVD). This method allows precise control over the diameter, length, density, spacing, orientation, shape, pattern and location of the Si and Si/SiGe nanowire arrays, making it possible to fabricate an array of devices based on rationally designed nanowire arrays. A proposed fabrication mechanism of the etching process is presented. Inspired by the excellent antireflection properties of the Si/SiGe wire arrays, we built solar cells based on the arrays of these wires containing radial junctions, an example of which exhibits an open circuit voltage (V(oc)) of 650 mV, a short-circuit current density (J(sc)) of 8.38 mA/cm(2), a fill factor of 0.60, and an energy conversion efficiency (η) of 3.26%. Such a p-n radial structure will have a great potential application for cost-efficient photovoltaic (PV) solar energy conversion. © 2011 American Chemical Society

Developing an Inflatable Solar Array

NASA Technical Reports Server (NTRS)

Malone, Patrick K.; Jankowski, Francis J.; Williams, Geoffery T.; Vendura, George J., Jr.

1992-01-01

Viewgraphs describing the development of an inflatable solar array as part of the Inflatable Torus Solar Array Technology (ITSAT) program are presented. Program phases, overall and subsystem designs, and array deployment are addressed.

Goddard Space Flight Center solar array missions, requirements and directions

NASA Technical Reports Server (NTRS)

Gaddy, Edward; Day, John

1994-01-01

The Goddard Space Flight Center (GSFC) develops and operates a wide variety of spacecraft for conducting NASA's communications, space science, and earth science missions. Some are 'in house' spacecraft for which the GSFC builds the spacecraft and performs all solar array design, analysis, integration, and test. Others are 'out of house' spacecraft for which an aerospace contractor builds the spacecraft and develops the solar array under direction from GSFC. The experience of developing flight solar arrays for numerous GSFC 'in house' and 'out of house' spacecraft has resulted in an understanding of solar array requirements for many different applications. This presentation will review those solar array requirements that are common to most GSFC spacecraft. Solar array technologies will be discussed that are currently under development and that could be useful to future GSFC spacecraft.

Photovoltaic test and demonstration project for the National Photovoltaic Conversion program

NASA Technical Reports Server (NTRS)

Deyo, J. N.

1975-01-01

Proposed are photovoltaic system tests and demonstrations covering a wide range of applications in order to develop low cost photovoltaic cells suitable for terrestrial applications. Program objectives are: (1) tests and model system demonstrations; (2) device performance and diagnostics; and (3) endurance of solar cell modules and arrays.

Quantitative analysis of defects in silicon: Silicon sheet growth development for the large area silicon sheet task of the low cost solar array project

NASA Technical Reports Server (NTRS)

Natesh, R.; Smith, J. M.; Qidwai, H. A.

1978-01-01

The various steps involved in the chemical polishing and etching of silicon samples are described and the data on twins, grain boundaries and dislocation pits from fifty-three (53) samples are discussed.

Naval Postgraduate School Solar Cell Array Tester

DTIC Science & Technology

2010-12-01

PROGRAM MANAGEMENT ................................45 1. SCHEDULE .....................................47 B. BUDGET...budget and schedule from December 2009 to September 2010. In addition, a total development cost estimate, including labor, equipment, and testing... scheduler becomes active, all tasks become eligible to run, and normal operations begin. Figure 21 shows a diagram of the startup actions [32

A review of the silicon material task

NASA Technical Reports Server (NTRS)

Lutwack, R.

1984-01-01

The Silicon Material Task of the Flat-Plate Solar Array Project was assigned the objective of developing the technology for low-cost processes for producing polysilicon suitable for terrestrial solar-cell applications. The Task program comprised sections for process developments for semiconductor-grade and solar-cell-grade products. To provide information for deciding upon process designs, extensive investigations of the effects of impurities on material properties and the performance of cells were conducted. The silane process of the Union Carbide Corporation was carried through several stages of technical and engineering development; a pilot plant was the culmination of this effort. The work to establish silane fluidized-bed technology for a low-cost process is continuing. The advantages of the use of dichlorosilane is a siemens-type were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

A review of the silicon material task

NASA Astrophysics Data System (ADS)

Lutwack, R.

1984-02-01

The Silicon Material Task of the Flat-Plate Solar Array Project was assigned the objective of developing the technology for low-cost processes for producing polysilicon suitable for terrestrial solar-cell applications. The Task program comprised sections for process developments for semiconductor-grade and solar-cell-grade products. To provide information for deciding upon process designs, extensive investigations of the effects of impurities on material properties and the performance of cells were conducted. The silane process of the Union Carbide Corporation was carried through several stages of technical and engineering development; a pilot plant was the culmination of this effort. The work to establish silane fluidized-bed technology for a low-cost process is continuing. The advantages of the use of dichlorosilane is a siemens-type were shown by Hemlock Semiconductor Corporation. The development of other processes is described.

Electrochemical wastewater treatment directly powered by photovoltaic panels: electrooxidation of a dye-containing wastewater.

PubMed

Valero, David; Ortiz, Juan M; Expósito, Eduardo; Montiel, Vicente; Aldaz, Antonio

2010-07-01

Electrochemical technologies have proved to be useful for the treatment of wastewater, but to enhance their green characteristics it seems interesting to use a green electric energy such as that provided by photovoltaic (PV) cells, which are actually under active research to decrease the economic cost of solar kW. The aim of this work is to demonstrate the feasibility and utility of using an electrooxidation system directly powered by a photovoltaic array for the treatment of a wastewater. The experimental system used was an industrial electrochemical filter press reactor and a 40-module PV array. The influence on the degradation of a dye-containing solution (Remazol RB 133) of different experimental parameters such as the PV array and electrochemical reactor configurations has been studied. It has been demonstrated that the electrical configuration of the PV array has a strong influence on the optimal use of the electric energy generated. The optimum PV array configuration changes with the intensity of the solar irradiation, the conductivity of the solution, and the concentration of pollutant in the wastewater. A useful and effective methodology to adjust the EO-PV system operation conditions to the wastewater treatment is proposed.

Effects of silicon nanowire morphology on optical properties and hybrid solar cell performance

NASA Astrophysics Data System (ADS)

Syu, Hong-Jhang; Shiu, Shu-Chia; Hung, Yung-Jr; Lee, San-Liang; Lin, Ching-Fuh

2012-10-01

Silicon nanowire (SiNW) arrays are widespread applied on hybrid photovoltaic devices because SiNW arrays can substitute the pyramid texture and anti-reflection coating due to its strong light trapping. Also, SiNWs can be prepared through a cost-efficient process of metal-assisted chemical etching. However, though longer SiNW arrays have lower reflectance, the top of long SiNWs aggregate together to make junction synthesis difficult for SiNW/organic hybrid solar cell. To control and analyze the effect of SiNW array morphology on hybrid solar cells, here we change the metal deposition condition for metal-assisted chemical etching to obtain different SiNW array morphologies. The experiment was separated to two groups, by depositing metal, say, Ag, before etching (BE) or during etching (DE). For group BE, Ag was deposited on n-type Si (n-Si) wafers by thermal evaporation; then etched by H2O2 and HF. For group DE, n-Si was etched by Ag+ and HF directly. Ag was deposited on n-Si during etching process. Afterwards, residual Ag and SiO2 were removed by HNO3 and buffered HF, successively; then Ti and Ag were evaporated on the bottom of Si to be a cathode. Finally, SiNWs were stuck on the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) that was spincoated on the ITO coated glass to form SiNW/organic heterojunction. The results show that group BE has reflectance lower than that in group DE in solar spectrum. However, group BE has smaller power conversion efficiency (PCE) of 8.65% and short-circuit current density (Jsc) of 24.94 mA/cm2 than group DE of PCE of 9.47% and Jsc of 26.81 mA/cm2.

The ARA Mark 3 solar array design and development

NASA Technical Reports Server (NTRS)

vanHassel, Rob H. A.

1996-01-01

The ARA (Advanced Rigid Array) Mark3 solar array of Fokker Space BV is currently in its final stages of qualification (wing tests to be completed in March, 1996; unit/part tests in April, 1996). With regard to its predecessor, the ARA Mark2, the design has not only been improved in terms of mechanical and electrical performance, but also with regard to production cost and throughput time. This 'state of the art' array is designed to fit the needs of a wide variety of geostationary telecommunications satellites and is qualified for launch on the complete range of medium/large size commercial launchers (Ariane IV & V, Atlas, Delta, Proton, Long March, H2). The first mission to fly the new ARA Mk3 array is Hot Bird 2 (customer: Eutelsat, prime contractor: Matra Marconi Space; launch: mid-1996). In this configuration, its end of life (EOL) power-to-mass ratio is 42 W/kg, with an operational life of more than 12 years. The main mechanisms on a solar array are typically found in the deployment system and in the hold down and release system. During the design and development phase of these mechanisms, extensive engineering and qualification tests have been performed. This paper presents the key design features of these mechanisms and the improvements that were made with regard to their predecessors. It also describes the qualification philosophy on unit/part and wing level. Finally, some of the development items that turned out to be critical, as well as the lessons learned from them, are discussed.

Atomic Oxygen Durability Testing of an International Space Station Solar Array Validation Coupon

NASA Technical Reports Server (NTRS)

Forkapa, Mark J.; Stidham, Curtis; Banks, Bruce A.; Rutledge, Sharon K.; Ma, David H.; Sechkar, Edward A.

1996-01-01

An International Space Station solar array validation coupon was exposed in a directed atomic oxygen beam for space environment durability testing at the NASA Lewis Research Center. Exposure to atomic oxygen and intermittent tensioning of the solar array were conducted to verify the solar array#s durability to low Earth orbital atomic oxygen and to the docking threat of plume loading both of which are anticipated over its expected mission life of fifteen years. The validation coupon was mounted on a specially designed rotisserie. The rotisserie mounting enabled the solar and anti-solar facing side of the array to be exposed to directed atomic oxygen in a sweeping arrival process replicating space exposure. The rotisserie mounting also enabled tensioning, in order to examine the durability of the array and its hinge to simulated plume loads. Flash testing to verify electrical performance of the solar array was performed with a solar simulator before and after the exposure to atomic oxygen and tensile loading. Results of the flash testing indicated little or no degradation in the solar array#s performance. Photographs were also taken of the array before and after the durability testing and are included along with comparisons and discussions in this report. The amount of atomic oxygen damage appeared minor with the exception of a very few isolated defects. There were also no indications that the simulated plume loadings had weakened or damaged the array, even though there was some erosion of Kapton due to atomic oxygen attack. Based on the results of this testing, it is apparent that the International Space Station#s solar arrays should survive the low Earth orbital atomic oxygen environment and docking threats which are anticipated over its expected mission life.

Electric Propulsion Upper-Stage for Launch Vehicle Capability Enhancement

NASA Technical Reports Server (NTRS)

Kemp, Gregory E.; Dankanich, John W.; Woodcock, Gordon R.; Wingo, Dennis R.

2007-01-01

The NASA In-Space Propulsion Technology Project Office initiated a preliminary study to evaluate the performance benefits of a solar electric propulsion (SEP) upper-stage with existing and near-term small launch vehicles. The analysis included circular and elliptical Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO) transfers, and LEO to Low Lunar Orbit (LLO) applications. SEP subsystem options included state-of-the-art and near-term solar arrays and electric thrusters. In-depth evaluations of the Aerojet BPT-4000 Hall thruster and NEXT gridded ion engine were conducted to compare performance, cost and revenue potential. Preliminary results indicate that Hall thruster technology is favored for low-cost, low power SEP stages, while gridded-ion engines are favored for higher power SEP systems unfettered by transfer time constraints. A low-cost point design is presented that details one possible stage configuration and outlines system limitations, in particular fairing volume constraints. The results demonstrate mission enhancements to large and medium class launch vehicles, and mission enabling performance when SEP system upper stages are mounted to low-cost launchers such as the Minotaur and Falcon 1. Study results indicate the potential use of SEP upper stages to double GEO payload mass capability and to possibly enable launch on demand capability for GEO assets. Transition from government to commercial applications, with associated cost/benefit analysis, has also been assessed. The sensitivity of system performance to specific impulse, array power, thruster size, and component costs are also discussed.

Analysis and evaluation in the production process and equipment area of the low-cost solar array project

NASA Technical Reports Server (NTRS)

Wolf, M.; Goldman, H.

1981-01-01

The attributes of the various metallization processes were investigated. It is shown that several metallization process sequences will lead to adequate metallization for large area, high performance solar cells at a metallization add on price in the range of $6. to 12. m squared, or 4 to $.8/W(peak), assuming 15% efficiency. Conduction layer formation by thick film silver or by tin or tin/lead solder leads to metallization add-on prices significantly above the $6. to 12/m squared range c.) The wet chemical processes of electroless and electrolytic plating for strike/barrier layer and conduction layer formation, respectively, seem to be most cost effective.

SAVANT: Solar Array Verification and Analysis Tool Demonstrated

NASA Technical Reports Server (NTRS)

Chock, Ricaurte

2000-01-01

The photovoltaics (PV) industry is now being held to strict specifications, such as end-oflife power requirements, that force them to overengineer their products to avoid contractual penalties. Such overengineering has been the only reliable way to meet such specifications. Unfortunately, it also results in a more costly process than is probably necessary. In our conversations with the PV industry, the issue of cost has been raised again and again. Consequently, the Photovoltaics and Space Environment Effects branch at the NASA Glenn Research Center at Lewis Field has been developing a software tool to address this problem. SAVANT, Glenn's tool for solar array verification and analysis is in the technology demonstration phase. Ongoing work has proven that more efficient and less costly PV designs should be possible by using SAVANT to predict the on-orbit life-cycle performance. The ultimate goal of the SAVANT project is to provide a user-friendly computer tool to predict PV on-orbit life-cycle performance. This should greatly simplify the tasks of scaling and designing the PV power component of any given flight or mission. By being able to predict how a particular PV article will perform, designers will be able to balance mission power requirements (both beginning-of-life and end-of-life) with survivability concerns such as power degradation due to radiation and/or contamination. Recent comparisons with actual flight data from the Photovoltaic Array Space Power Plus Diagnostics (PASP Plus) mission validate this approach.

The Implementation of Advanced Solar Array Technology in Future NASA Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael F.; Kerslake, Thomas W.; Hoffman, David J.; White, Steve; Douglas, Mark; Spence, Brian; Jones, P. Alan

2003-01-01

Advanced solar array technology is expected to be critical in achieving the mission goals on many future NASA space flight programs. Current PV cell development programs offer significant potential and performance improvements. However, in order to achieve the performance improvements promised by these devices, new solar array structures must be designed and developed to accommodate these new PV cell technologies. This paper will address the use of advanced solar array technology in future NASA space missions and specifically look at how newer solar cell technologies impact solar array designs and overall power system performance.

Flat-plate solar array project. Volume 2: Silicon material

NASA Technical Reports Server (NTRS)

Lutwack, R.

1986-01-01

The goal of the Silicon Material Task, a part of the Flat Plate Solar Array (FSA) Project, was to develop and demonstate the technology for the low cost production of silicon of suitable purity to be used as the basic material for the manufacture of terrestrial photovoltaic solar cells. Summarized are 11 different processes for the production of silicon that were investigated and developed to varying extent by industrial, university, and Government researchers. The silane production section of the Union Carbide Corp. (UCC) silane process was developed completely in this program. Coupled with Siemens-type chemical vapor deposition reactors, the process was carried through the pilot stage. The overall UCC process involves the conversion of metallurgical-grade silicon to silane followed by decomposition of the silane to purified silicon. The other process developments are described to varying extents. Studies are reported on the effects of impurities in silicon on both silicon-material properties and on solar cell performance. These studies on the effects of impurities yielded extensive information and models for relating specific elemental concentrations to levels of deleterious effects.

Flat-plate solar array project. Volume 2: Silicon material

NASA Astrophysics Data System (ADS)

Lutwack, R.

1986-10-01

The goal of the Silicon Material Task, a part of the Flat Plate Solar Array (FSA) Project, was to develop and demonstate the technology for the low cost production of silicon of suitable purity to be used as the basic material for the manufacture of terrestrial photovoltaic solar cells. Summarized are 11 different processes for the production of silicon that were investigated and developed to varying extent by industrial, university, and Government researchers. The silane production section of the Union Carbide Corp. (UCC) silane process was developed completely in this program. Coupled with Siemens-type chemical vapor deposition reactors, the process was carried through the pilot stage. The overall UCC process involves the conversion of metallurgical-grade silicon to silane followed by decomposition of the silane to purified silicon. The other process developments are described to varying extents. Studies are reported on the effects of impurities in silicon on both silicon-material properties and on solar cell performance. These studies on the effects of impurities yielded extensive information and models for relating specific elemental concentrations to levels of deleterious effects.

The New NASA-STD-4005 and NASA-HDBK-4006, Essentials for Direct-Drive Solar Electric Propulsion

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.

2007-01-01

High voltage solar arrays are necessary for direct-drive solar electric propulsion, which has many advantages, including simplicity and high efficiency. Even when direct-drive is not used, the use of high voltage solar arrays leads to power transmission and conversion efficiencies in electric propulsion Power Management and Distribution. Nevertheless, high voltage solar arrays may lead to temporary power disruptions, through the so-called primary electrostatic discharges, and may permanently damage arrays, through the so-called permanent sustained discharges between array strings. Design guidance is needed to prevent these solar array discharges, and to prevent high power drains through coupling between the electric propulsion devices and the high voltage solar arrays. While most electric propulsion systems may operate outside of Low Earth Orbit, the plasmas produced by their thrusters may interact with the high voltage solar arrays in many ways similarly to Low Earth Orbit plasmas. A brief description of previous experiences with high voltage electric propulsion systems will be given in this paper. There are two new official NASA documents available free through the NASA Standards website to help in designing and testing high voltage solar arrays for electric propulsion. They are NASA-STD-4005, the Low Earth Orbit Spacecraft Charging Design Standard, and NASA-HDBK-4006, the Low Earth Orbit Spacecraft Charging Design Handbook. Taken together, they can both educate the high voltage array designer in the engineering and science of spacecraft charging in the presence of dense plasmas and provide techniques for designing and testing high voltage solar arrays to prevent electrical discharges and power drains.

KSC-00pp1212

NASA Image and Video Library

2000-08-30

Workers rise to the occasion on accordion lifts as they oversee the movement of solar array in front of them. The solar array will be installed onto the Integrated Equipment Assembly (IEA). A component of the International Space Station, the solar array is the second one being installed on the IEA. The arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1213

NASA Image and Video Library

2000-08-30

An overhead crane in the Space Station Processing Facility lifts a solar array as workers stand by to help guide it. The solar array will be installed onto the Integrated Equipment Assembly (IEA). A component of the International Space Station, the solar array is the second one being installed on the IEA. The arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

Lightweight, Flexible Solar Cells on Stainless Steel Foil and Polymer for Space and Stratospheric Applications

NASA Technical Reports Server (NTRS)

Beernink, Kevin; Guha, Subhendu; Yang, Jeff; Banerjee, Arindam; Lord, Ken; DeMaggio, Greg; Liu, Frank; Pietka, Ginger; Johnson, Todd; Reinhout, Melanie;

Skylab

NASA Image and Video Library

1970-01-01

This is a photograph of a technician checking on a solar array wing for the Orbital Workshop as it is deployed. A solar array, consisting of two wings covered on one side with solar cells, was mounted outside the workshop to generate electrical power to augment the power generated by another solar array mounted on the solar observatory.

Utilizing Solar Power Technologies for On-Orbit Propellant Production

NASA Technical Reports Server (NTRS)

Fikes, John C.; Howell, Joe T.; Henley, Mark W.

2006-01-01

The cost of access to space beyond low Earth orbit may be reduced if vehicles can refuel in orbit. The cost of access to low Earth orbit may also be reduced by launching oxygen and hydrogen propellants in the form of water. To achieve this reduction in costs of access to low Earth orbit and beyond, a propellant depot is considered that electrolyzes water in orbit, then condenses and stores cryogenic oxygen and hydrogen. Power requirements for such a depot require Solar Power Satellite technologies. A propellant depot utilizing solar power technologies is discussed in this paper. The depot will be deployed in a 400 km circular equatorial orbit. It receives tanks of water launched into a lower orbit from Earth, converts the water to liquid hydrogen and oxygen, and stores up to 500 metric tons of cryogenic propellants. This requires a power system that is comparable to a large Solar Power Satellite capable of several 100 kW of energy. Power is supplied by a pair of solar arrays mounted perpendicular to the orbital plane, which rotates once per orbit to track the Sun. The majority of the power is used to run the electrolysis system. Thermal control is maintained by body-mounted radiators; these also provide some shielding against orbital debris. The propellant stored in the depot can support transportation from low Earth orbit to geostationary Earth orbit, the Moon, LaGrange points, Mars, etc. Emphasis is placed on the Water-Ice to Cryogen propellant production facility. A very high power system is required for cracking (electrolyzing) the water and condensing and refrigerating the resulting oxygen and hydrogen. For a propellant production rate of 500 metric tons (1,100,000 pounds) per year, an average electrical power supply of 100 s of kW is required. To make the most efficient use of space solar power, electrolysis is performed only during the portion of the orbit that the Depot is in sunlight, so roughly twice this power level is needed for operations in sunlight (slightly over half of the time). This power level mandates large solar arrays, using advanced Space Solar Power technology. A significant amount of the power has to be dissipated as heat, through large radiators. This paper briefly describes the propellant production facility and the requirements for a high power system capability. The Solar Power technologies required for such an endeavor are discussed.

The revised solar array synthesis computer program

NASA Technical Reports Server (NTRS)

1970-01-01

The Revised Solar Array Synthesis Computer Program is described. It is a general-purpose program which computes solar array output characteristics while accounting for the effects of temperature, incidence angle, charged-particle irradiation, and other degradation effects on various solar array configurations in either circular or elliptical orbits. Array configurations may consist of up to 75 solar cell panels arranged in any series-parallel combination not exceeding three series-connected panels in a parallel string and no more than 25 parallel strings in an array. Up to 100 separate solar array current-voltage characteristics, corresponding to 100 equal-time increments during the sunlight illuminated portion of an orbit or any 100 user-specified combinations of incidence angle and temperature, can be computed and printed out during one complete computer execution. Individual panel incidence angles may be computed and printed out at the user's option.

Extremely Cost-Effective and Efficient Solar Vapor Generation under Nonconcentrated Illumination Using Thermally Isolated Black Paper.

PubMed

Liu, Zhejun; Song, Haomin; Ji, Dengxin; Li, Chenyu; Cheney, Alec; Liu, Youhai; Zhang, Nan; Zeng, Xie; Chen, Borui; Gao, Jun; Li, Yuesheng; Liu, Xiang; Aga, Diana; Jiang, Suhua; Yu, Zongfu; Gan, Qiaoqiang

2017-02-27

Passive solar vapor generation represents a promising and environmentally benign method of water purification/desalination. However, conventional solar steam generation techniques usually rely on costly and cumbersome optical concentration systems and have relatively low efficiency due to bulk heating of the entire liquid volume. Here, an efficient strategy using extremely low-cost materials, i.e., carbon black (powder), hydrophilic porous paper, and expanded polystyrene foam is reported. Due to the excellent thermal insulation between the surface liquid and the bulk volume of the water and the suppressed radiative and convective losses from the absorber surface to the adjacent heated vapor, a record thermal efficiency of ≈88% is obtained under 1 sun without concentration, corresponding to the evaporation rate of 1.28 kg (m 2 h) -1 . When scaled up to a 100 cm 2 array in a portable solar water still system and placed in an outdoor environment, the freshwater generation rate is 2.4 times of that of a leading commercial product. By simultaneously addressing both the need for high-efficiency operation as well as production cost limitations, this system can provide an approach for individuals to purify water for personal needs, which is particularly suitable for undeveloped regions with limited/no access to electricity.

Single Source Precursors for Thin Film Solar Cells

NASA Technical Reports Server (NTRS)

Banger, Kulbinder K.; Hollingsworth, Jennifer A.; Harris, Jerry D.; Cowen, Jonathan; Buhro, William E.; Hepp, Aloysius F.

2002-01-01

The development of thin film solar cells on flexible, lightweight, space-qualified substrates provides an attractive cost solution to fabricating solar arrays with high specific power, (W/kg). The use of a polycrystalline chalcopyrite absorber layer for thin film solar cells is considered as the next generation photovoltaic devices. At NASA GRC we have focused on the development of new single source precursors (SSP) and their utility to deposit the chalcopyrite semi-conducting layer (CIS) onto flexible substrates for solar cell fabrication. The syntheses and thermal modulation of SSPs via molecular engineering is described. Thin-film fabrication studies demonstrate the SSPs can be used in a spray CVD (chemical vapor deposition) process, for depositing CIS at reduced temperatures, which display good electrical properties, suitable for PV (photovoltaic) devices.

Workshop on Heteroepitaxial InP Solar Cells

NASA Technical Reports Server (NTRS)

Weinberg, I.; Walters, R. W.

1993-01-01

In a generic sense, the justification for any sort of InP solar cell research applies, i.e. to take advantage of the inherently high radiation resistance and efficiency of InP solar cells. To be more specific, the approach is justified by its potential for significant cost reduction and the availability of greatly increased cell area afforded by substrates such as Si and Ge. The use of substrates, such as the latter two, would result in increased ruggedness, ease of handling, and improved manufacturability. The use of more rugged substrates would lead to a greatly increased capability for cell thinning leading to the desirable feature of reduced array weight.

Study of Automated Module Fabrication for Lightweight Solar Blanket Utilization

NASA Technical Reports Server (NTRS)

Gibson, C. E.

1979-01-01

Cost-effective automated techniques for accomplishing the titled purpose; based on existing in-house capability are described. As a measure of the considered automation, the production of a 50 kilowatt solar array blanket, exclusive of support and deployment structure, within an eight-month fabrication period was used. Solar cells considered for this blanket were 2 x 4 x .02 cm wrap-around cells, 2 x 2 x .005 cm and 3 x 3 x .005 cm standard bar contact thin cells, all welded contacts. Existing fabrication processes are described, the rationale for each process is discussed, and the capability for further automation is discussed.

Satellite Power Study (SPS) concept definition study (Exhibit D). Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Hanley, G. M.

1981-01-01

Efforts concentrated on updating of the Rockwell reference concept, definition of new system options, studies of special emphasis topics, further definition of the transportation system, and further program definition. The Rockwell reference satellite concept has a gallium arsenide (GaAs) solar cell array having flat concentrators with an effective concentration ratio of 1.83at end of life. Alternatives to this concept includes solid state power amplifiers or magnetrons for dc/RF conversion and multibandgap solar cells for solar to dc energy conversion. Two solid state concepts were studied. It was determined that the magnetron approach was the lowest mass and cost system.

Progress Report 18 for the Period February to July 1981 and Proceeidngs of the 18th Project Integration Meeting

NASA Technical Reports Server (NTRS)

1981-01-01

Progress in the low cost solar array project during the period February to July 1981 is reported. Included are: (1) project analysis and integration; (2) technology development in silicon material, large area silicon sheer and encapsulation; (3) process development; (4) engineering, and operations.

Low-cost solar array project and Proceedings of the 14th Project Integration Meeting

NASA Technical Reports Server (NTRS)

Mcdonald, R. R.

1980-01-01

Activities are reported on the following areas: project analysis and integration; technology development in silicon material, large area sheet silicon, and encapsulation; production process and equipment development; and engineering and operations, and the steps taken to integrate these efforts. Visual materials presented at the project Integration Meeting are included.

Silicon sheet growth development for the large area silicon sheet task of the low cost solar array project. Quantitative analysis of defects in silicon

NASA Technical Reports Server (NTRS)

Natesh, R.

1978-01-01

The various steps involved in obtaining quantitative information of structural defects in crystalline silicon samples are described. Procedures discussed include: (1) chemical polishing; (2) chemical etching; and (3) automated image analysis of samples on the QTM 720 System.

MILSTAR's flexible substrate solar array: Lessons learned, addendum

NASA Technical Reports Server (NTRS)

Gibb, John

1990-01-01

MILSTAR's Flexible Substrate Solar Array (FSSA) is an evolutionary development of the lightweight, flexible substrate design pioneered at Lockheed during the seventies. Many of the features of the design are related to the Solar Array Flight Experiment (SAFE), flown on STS-41D in 1984. FSSA development has created a substantial technology base for future flexible substrate solar arrays such as the array for the Space Station Freedom. Lessons learned during the development of the FSSA can and should be applied to the Freedom array and other future flexible substrate designs.

Solar power satellites - Technical, social and political implications

NASA Astrophysics Data System (ADS)

Knelman, F. H.

Solar power satellite systems (SPS) are examined, together with their environmental and social impacts and the energy policies necessary for their construction. The energy source, the sun, is acceptable to advocates of decentralized technologies, while the conversion system is fitted to large institutions. However, large-scale power plants are subject to persistent malfunctions, and the approximately 50 sq km SPS solar array is projected to suffer from at least recurring cell contact failures. The power could also be generated by heat engines for transmission by either laser or microwaves. Numerous feasibility and cost-benefit studies are still required, including defining the transmission beam's effects on the atmosphere, ionosphere, and human health. Furthermore, the resource allocations, capital costs, insurance, and institutional problems still need clarification, as do the design, logistics, and development of an entire new, much larger launch system based on Shuttle technology. Finally, the military defensibility of the SPS power station is questioned.

Economic evaluation of a solar hot-water-system

NASA Technical Reports Server (NTRS)

1981-01-01

Analysis shows economic benefits at six representative sites using actual data from Tempe, Arizona and San Diego, California installations. Model is two-tank cascade water heater with flat-plate collector array for single-family residences. Performances are forecast for Albuquerque, New Mexico; Fort Worth, Texas; Madison, Wisconsin; and Washington, D.C. Costs are compared to net energy savings using variables for each site's environmental conditions, loads, fuel costs, and other economic factors; uncertainty analysis is included.

An IBM PC-based math model for space station solar array simulation

NASA Technical Reports Server (NTRS)

Emanuel, E. M.

1986-01-01

This report discusses and documents the design, development, and verification of a microcomputer-based solar cell math model for simulating the Space Station's solar array Initial Operational Capability (IOC) reference configuration. The array model is developed utilizing a linear solar cell dc math model requiring only five input parameters: short circuit current, open circuit voltage, maximum power voltage, maximum power current, and orbit inclination. The accuracy of this model is investigated using actual solar array on orbit electrical data derived from the Solar Array Flight Experiment/Dynamic Augmentation Experiment (SAFE/DAE), conducted during the STS-41D mission. This simulator provides real-time simulated performance data during the steady state portion of the Space Station orbit (i.e., array fully exposed to sunlight). Eclipse to sunlight transients and shadowing effects are not included in the analysis, but are discussed briefly. Integrating the Solar Array Simulator (SAS) into the Power Management and Distribution (PMAD) subsystem is also discussed.

Solar maximum: Solar array degradation

NASA Technical Reports Server (NTRS)

Miller, T.

1985-01-01

The 5-year in-orbit power degradation of the silicon solar array aboard the Solar Maximum Satellite was evaluated. This was the first spacecraft to use Teflon R FEP as a coverglass adhesive, thus avoiding the necessity of an ultraviolet filter. The peak power tracking mode of the power regulator unit was employed to ensure consistent maximum power comparisons. Telemetry was normalized to account for the effects of illumination intensity, charged particle irradiation dosage, and solar array temperature. Reference conditions of 1.0 solar constant at air mass zero and 301 K (28 C) were used as a basis for normalization. Beginning-of-life array power was 2230 watts. Currently, the array output is 1830 watts. This corresponds to a 16 percent loss in array performance over 5 years. Comparison of Solar Maximum Telemetry and predicted power levels indicate that array output is 2 percent less than predictions based on an annual 1.0 MeV equivalent election fluence of 2.34 x ten to the 13th power square centimeters space environment.

Space Plasma Shown to Make Satellite Solar Arrays Fail

NASA Technical Reports Server (NTRS)

Ferguson, Dale C.

1999-01-01

In 1997, scientists and engineers of the Photovoltaic and Space Environments Branch of the NASA Lewis Research Center, Maxwell Technologies, and Space Systems/Loral discovered a new failure mechanism for solar arrays on communications satellites in orbit. Sustained electrical arcs, initiated by the space plasma and powered by the solar arrays themselves, were found to have destroyed solar array substrates on some Space Systems/Loral satellites, leading to array failure. The mechanism was tested at Lewis, and mitigation strategies were developed to prevent such disastrous occurrences on-orbit in the future. Deep Space 1 is a solar-electric-powered space mission to a comet, launched on October 24, 1998. Early in 1998, scientists at Lewis and Ballistic Missile Defense Organization (BMDO) realized that some aspects of the Deep Space 1 solar arrays were nearly identical to those that had led to the failure of solar arrays on Space Systems/Loral satellites. They decided to modify the Deep Space 1 arrays to prevent catastrophic failure in space. The arrays were suitably modified and are now performing optimally in outer space. Finally, the Earth Observing System (EOS) AM1, scheduled for launch in mid-1999, is a NASA mission managed by the Goddard Space Flight Center. Realizing the importance of Lewis testing on the Loral arrays, EOS-AM1 management asked Lewis scientists to test their solar arrays to show that they would not fail in the same way. The first phase of plasma testing showed that sustained arcing would occur on the unmodified EOS-AM1 arrays, so the arrays were removed from the spacecraft and fixed. Now, Lewis scientists have finished plasma testing of the modified array configuration to ensure that EOS-AM1 will have no sustained arcing problems on-orbit.

Photogrammetric Assessment of the Hubble Space Telescope Solar Arrays During the Second Servicing Mission

NASA Technical Reports Server (NTRS)

Sapp, C. A.; Dragg, J. L.; Snyder, M. W.; Gaunce, M. T.; Decker, J. E.

1998-01-01

This report documents the photogrammetric assessment of the Hubble Space Telescope (HST) solar arrays conducted by the NASA c Center Image Science and Analysis Group during Second Servicing Mission 2 (SM-2) on STS-82 in February 1997. Two type solar array analyses were conducted during the mission using Space Shuttle payload bay video: (1) measurement of solar array motion due to induced loads, and (2) measurement of the solar array static or geometric twist caused by the cumulative array loading. The report describes pre-mission planning and analysis technique development activities conducted to acquire and analyze solar array imagery data during SM-2. This includes analysis of array motion obtained during SM-1 as a proof-of-concept of the SM-2 measurement techniques. The report documents the results of real-time analysis conducted during the mission and subsequent analysis conducted post-flight. This report also provides a summary of lessons learned on solar array imagery analysis from SM-2 and recommendations for future on-orbit measurements applicable to HST SM-3 and to the International Space Station. This work was performed under the direction of the Goddard Space Flight Center HST Flight Systems and Servicing Project.

Review of biased solar arraay. Plasma interaction studies

NASA Technical Reports Server (NTRS)

Stevens, N. J.

1981-01-01

The Solar Electric Propulsion System (SEPS) is proposed for a variety of space missions. Power for operating SEPS is obtained from large solar array wings capable of generating tens of kilowatts of power. To minimize resistive losses in the solar array bus lines, the array is designed to operate at voltages up to 400 volts. This use of high voltage can increase interactions between the biased solar cell interconnects and plasma environments. With thrusters operating, the system ground is maintained at space plasma potential which exposes large areas of the arrays at the operating voltages. This can increase interactions with both the natural and enhanced charged particle environments. Available data on interactions between biased solar array surfaces and plasma environments are summarized. The apparent relationship between collection phenomena and solar cell size and effects of array size on interactions are discussed. The impact of these interactions on SEPS performance is presented.

Reinventing the Solar Power Satellite

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.

2004-01-01

The selling price of electrical power varies with time. The economic viability of space solar power is maximum if the power can be sold at peak power rates, instead of baseline rate. Price and demand of electricity was examined from spot-market data from four example markets: New England, New York City, suburban New York, and California. The data was averaged to show the average price and demand for power as a function of time of day and time of year. Demand varies roughly by a factor of two between the early-morning minimum demand, and the afternoon maximum; both the amount of peak power, and the location of the peak, depends significantly on the location and the weather. The demand curves were compared to the availability curves for solar energy and for tracking and non-tracking satellite solar power systems in order to compare the market value of terrestrial and solar electrical power. In part 2, new designs for a space solar power (SSP) system were analyzed to provide electrical power to Earth for economically competitive rates. The approach was to look at innovative power architectures to more practical approaches to space solar power. A significant barrier is the initial investment required before the first power is returned. Three new concepts for solar power satellites were invented and analyzed: a solar power satellite in the Earth-Sun L2 point, a geosynchronous no-moving parts solar power satellite, and a nontracking geosynchronous solar power satellite with integral phased array. The integral-array satellite had several advantages, including an initial investment cost approximately eight times lower than the conventional design.

Design of a 7kW power transfer solar array drive mechanism

NASA Technical Reports Server (NTRS)

Sheppard, J. G.

1982-01-01

With the availability of the Shuttle and the European launcher, Ariane, there will be a continuing trend towards large payload satellite missions requiring high-power, high-inertia, flexible solar arrays. The need arises for a solar array drive with a large power transfer capability which can rotate these solar arrays without disturbing the satellite body pointing. The modular design of such a Solar Array Drive Mechanism (SADM) which is capable of transferring 7kW of power or more is described. Total design flexibility has been achieved, enabling different spacecraft power requirements to be accommodated within the SADM design.

The Solar Anomalous and Magnetospheric Particle Explorer (SAMPEX) yo-yo despin and solar array deployment mechanism

NASA Technical Reports Server (NTRS)

Kellogg, James W.

1993-01-01

The SAMPEX spacecraft, successfully launched in July 1992, carried a yo-yo despin system and deployable solar arrays. The despin and solar array mechanisms formed an integral system as the yo-yo cables held the solar array release mechanism in place. The SAMPEX design philosophy was to minimize size and weight through the use of a predominantly single string system. The design challenge was to build a system in a limited space, which was reliable with minimal redundancy. This paper covers the design and development of the SAMPEX yo-yo despin and solar array deployment mechanisms. The problems encountered during development and testing will also be discussed.

The Upper Atmosphere Research Satellite In-Flight Dynamics

NASA Technical Reports Server (NTRS)

Woodard, Stanley E.

1997-01-01

Upper Atmosphere Research Satellite flight data from the first 737 days after launch (September 1991) was used to investigate spacecraft disturbances and responses. The investigation included two in-flight dynamics experiments (approximately three orbits each). Orbital and configuration influences on spacecraft dynamic response were also examined. Orbital influences were due to temperature variation from crossing the Earth's terminator and variation of the solar incident energy as the orbit precessed. During the terminator crossing, the rapid ambient temperature change caused the spacecraft's two flexible appendages to experience thermal elastic bending (thermal snap). The resulting response was dependent upon the orientation of the solar array and the solar incident energy. Orbital influences were also caused by on-board and environmental disturbances and spacecraft configuration changes resulting in dynamic responses which were repeated each orbit. Configuration influences were due to solar array rotation changing spacecraft modal properties. The investigation quantified the spacecraft dynamic response produced by the solar array and high gain antenna harmonic drive disturbances. The solar array's harmonic drive output resonated two solar array modes. Friction in the solar array gear drive provided sufficient energy dissipation which prevented the solar panels from resonating catastrophically; however, the solar array vibration amplitude was excessively large. The resulting vibration had a latitude-specific pattern.

Economic analysis of the unified heliostat array. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1981-01-31

The Unified Heliostat Array (UHA) was investigated as to cost and optical performance. Two heliostats, the Veda Industrial Heliostat (VIH) and the Repowering Heliostat were investigated in conjunction with the UHA. The UHA was found to be a viable candidate for solar thermal central receiver applications. The UHA-VIH combination was shown to provide very high flux densities and to be suitable for high temperature applications in the 1000/sup 0/K to 2000/sup 0/K range. These temperatures were shown to be achievable even with very small (1 MWt) collector fields.

Large-Format AlGaN PIN Photodiode Arrays for UV Images

NASA Technical Reports Server (NTRS)

Aslam, Shahid; Franz, David

2010-01-01

A large-format hybridized AlGaN photodiode array with an adjustable bandwidth features stray-light control, ultralow dark-current noise to reduce cooling requirements, and much higher radiation tolerance than previous technologies. This technology reduces the size, mass, power, and cost of future ultraviolet (UV) detection instruments by using lightweight, low-voltage AlGaN detectors in a hybrid detector/multiplexer configuration. The solar-blind feature eliminates the need for additional visible light rejection and reduces the sensitivity of the system to stray light that can contaminate observations.

KSC-00pp1219

NASA Image and Video Library

2000-08-30

A solar array is nearly in place on the Integrated Equipment Assembly, next to Solar Array Wing-3, which is already installed. Components of the International Space Station, the arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

The Long Wavelength Array (LWA): A Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar

DTIC Science & Technology

2010-09-01

adds an extra dimension to both IPS and other observations. The polarization of the CME synchrotron emission observed by [3] will be of great...base funding. 8. REFERENCES 1. Kassim et al., The 74 MHz System on the Very Large Array, The Astrophysical Journal Supplement Series, Vol. 172...The Long Wavelength Array (LWA): A Large HF/VHF Array for Solar Physics, Ionospheric Science, and Solar Radar Namir E. Kassim Naval Research

EVA 2 - old solar array installed in payload bay

NASA Image and Video Library

2002-03-05

STS109-326-008 (5 March 2002) --- Astronaut Michael J. Massimino, mission specialist, works at the stowage area for the Hubble Space Telescope's port side solar array. Astronauts Massimino and James H. Newman removed the old port solar array and stowed it in Columbia’s payload bay for a return to Earth. They then went on to install a third-generation solar array and its associated electrical components. Two crew mates had accomplished the same feat with the starboard array on the previous day.

Mars Solar Power

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A.; Kerslake, Thomas W.; Jenkins, Phillip P.; Scheiman, David A.

2004-01-01

NASA missions to Mars, both robotic and human, rely on solar arrays for the primary power system. Mars presents a number of challenges for solar power system operation, including a dusty atmosphere which modifies the spectrum and intensity of the incident solar illumination as a function of time of day, degradation of the array performance by dust deposition, and low temperature operation. The environmental challenges to Mars solar array operation will be discussed and test results of solar cell technology operating under Mars conditions will be presented, along with modeling of solar cell performance under Mars conditions. The design implications for advanced solar arrays for future Mars missions is discussed, and an example case, a Martian polar rover, are analyzed.

Solar electric propulsion thruster interactions with solar arrays

NASA Technical Reports Server (NTRS)

Parks, D. E.; Katz, I.

1977-01-01

The effect of interactions of spacecraft-generated and naturally occurring plasmas with high voltage solar array components on an advanced solar electric propulsion system proposed for the Halley's Comet rendezvous mission was investigated. The spacecraft-generated plasma consists of mercury ions and neutralizing electrons resulting from the operation of ion thrusters (the charge-exchange plasma) and associated hollow cathode neutralizers. Quantitative results are given for the parasitic currents and power coupled into solar arrays with voltage fixed as a function of position on the array.

Space Station Freedom Solar Array design development

NASA Astrophysics Data System (ADS)

Winslow, Cindy

The SSF program's Electrical Power System supports a high-power bus with six solar-array wings in LEO; each solar array generates 30.8 kW at 161.1 V dc, with a deployed natural frequency of 0.1 Hz. Design challenges to the solar array, which must survive exposure for 15 years of operating life, include atomic oxygen, the thermal environment, and spacecraft propulsion plume-impingement loads. Tests thus far completed address cell UV-exposure effects, thermal cycling, and solar-cell deflection.

A Parametric Assessment of the Mission Applicability of Thin-film Solar Arrays

NASA Technical Reports Server (NTRS)

Hoffman, David J.

2002-01-01

Results are presented from a parametric assessment of the applicability and spacecraft-level impacts of very lightweight thin-film solar arrays with relatively large deployed areas for representative space missions. The most and least attractive features of thin-film solar arrays are briefly discussed. A calculation is then presented illustrating that from a solar array alone mass perspective, larger arrays with less efficient but lighter thin-film solar cells can weigh less than smaller arrays with more efficient but heavier crystalline cells. However, a spacecraft-level systems assessment must take into account the additional mass associated with solar array deployed area: the propellant needed to desaturate the momentum accumulated from area-related disturbance torques and to perform aerodynamic drag makeup reboost. The results for such an assessment are presented for a representative low Earth orbit (LEO) mission, as a function of altitude and mission life, and a geostationary Earth orbit (GEO) mission. Discussion of the results includes a list of specific mission types most likely to benefit from using thin-film arrays. The presentation concludes with a list of issues to be addressed prior to use of thin-film solar arrays in space and the observation that with their unique characteristics, very lightweight arrays using efficient, thin film cells on flexible substrates may become the best array option for a subset of Earth orbiting and deep space missions.

Computer Modelling and Simulation of Solar PV Array Characteristics

NASA Astrophysics Data System (ADS)

Gautam, Nalin Kumar

2003-02-01

The main objective of my PhD research work was to study the behaviour of inter-connected solar photovoltaic (PV) arrays. The approach involved the construction of mathematical models to investigate different types of research problems related to the energy yield, fault tolerance, efficiency and optimal sizing of inter-connected solar PV array systems. My research work can be divided into four different types of research problems: 1. Modeling of inter-connected solar PV array systems to investigate their electrical behavior, 2. Modeling of different inter-connected solar PV array networks to predict their expected operational lifetimes, 3. Modeling solar radiation estimation and its variability, and 4. Modeling of a coupled system to estimate the size of PV array and battery-bank in the stand-alone inter-connected solar PV system where the solar PV system depends on a system providing solar radiant energy. The successful application of mathematics to the above-m entioned problems entailed three phases: 1. The formulation of the problem in a mathematical form using numerical, optimization, probabilistic and statistical methods / techniques, 2. The translation of mathematical models using C++ to simulate them on a computer, and 3. The interpretation of the results to see how closely they correlated with the real data. Array is the most cost-intensive component of the solar PV system. Since the electrical performances as well as life properties of an array are highly sensitive to field conditions, different characteristics of the arrays, such as energy yield, operational lifetime, collector orientation, and optimal sizing were investigated in order to improve their efficiency, fault-tolerance and reliability. Three solar cell interconnection configurations in the array - series-parallel, total-cross-tied, and bridge-linked, were considered. The electrical characteristics of these configurations were investigated to find out one that is comparatively less susceptible to the mismatches due to manufacturer's tolerances in cell characteristics, shadowing, soiling and aging of solar cells. The current-voltage curves and the values of energy yield characterized by maximum-power points and fill factors for these arrays were also obtained. Two different mathematical models, one for smaller size arrays and the other for the larger size arrays, were developed. The first model takes account of the partial differential equations with boundary value conditions, whereas the second one involves the simple linear programming concept. Based on the initial information on the values of short-circuit current and open-circuit voltage of thirty-six single-crystalline silicon solar cells provided by a manufacturer, the values of these parameters for up to 14,400 solar cells were generated randomly. Thus, the investigations were done for three different cases of array sizes, i.e., (6 x 6), (36 x 8) and (720 x 20), for each configuration. The operational lifetimes of different interconnected solar PV arrays and the improvement in their life properties through different interconnection and modularized configurations were investigated using a reliability-index model. Under normal conditions, the efficiency of a solar cell degrades in an exponential manner, and its operational life above a lowest admissible efficiency may be considered as the upper bound of its lifetime. Under field conditions, the solar cell may fail any time due to environmental stresses, or it may function up to the end of its expected lifetime. In view of this, the lifetime of a solar cell in an array was represented by an exponentially distributed random variable. At any instant of time t, this random variable was considered to have two states: (i) the cell functioned till time t, or (ii) the cell failed within time t. It was considered that the functioning of the solar cell included its operation at an efficiency decaying with time under normal conditions. It was assumed that the lifetime of a solar cell had lack of memory or aging property, which meant that no matter how long (say, t) the cell had been operational, the probability that it would last an additional time ?t was independent of t. The operational life of the solar cell above a lowest admissible efficiency was considered as the upper bound of its expected lifetime. The value of the upper bound on the expected life of solar cell was evaluated using the information provided by the manufacturers of the single-crystalline silicon solar cells. Then on the basis of these lifetimes, the expected operational lifetimes of the array systems were obtained. Since the investigations of the effects of collector orientation on the performance of an array require the continuous values of global solar radiation on a surface, a method to estimate the global solar radiation on a surface (horizontal or tilted) was also proposed. The cloudiness index was defined as the fraction of extraterrestrial radiation that reached the earth's surface when the sky above the location of interest was obscured by the cloud cover. The cloud cover at the location of interest during any time interval of a day was assumed to follow the fuzzy random phenomenon. The cloudiness index, therefore, was considered as a fuzzy random variable that accounted for the cloud cover at the location of interest during any time interval of a day. This variable was assumed to depend on four other fuzzy random variables that, respectively, accounted for the cloud cover corresponding to the 1) type of cloud group, 2) climatic region, 3) season with most of the precipitation, and 4) type of precipitation at the location of interest during any time interval. All possible types of cloud covers were categorized into five types of cloud groups. Each cloud group was considered to be a fuzzy subset. In this model, the cloud cover at the location of interest during a time interval was considered to be the clouds that obscure the sky above the location. The cloud covers, with all possible types of clouds having transmissivities corresponding to values in the membership range of a fuzzy subset (i.e., a type of cloud group), were considered to be the membership elements of that fuzzy subset. The transmissivities of different types of cloud covers in a cloud group corresponded to the values in the membership range of that cloud group. Predicate logic (i.e., if---then---, else---, conditions) was used to set the relationship between all the fuzzy random variables. The values of the above-mentioned fuzzy random variables were evaluated to provide the value of cloudiness index for each time interval at the location of interest. For each case of the fuzzy random variable, heuristic approach was used to identify subjectively the range ([a, b], where a and b were real numbers with in [0, 1] such that a

Theoretical models of Kapton heating in solar array geometries

NASA Technical Reports Server (NTRS)

Morton, Thomas L.

1992-01-01

In an effort to understand pyrolysis of Kapton in solar arrays, a computational heat transfer program was developed. This model allows for the different materials and widely divergent length scales of the problem. The present status of the calculation indicates that thin copper traces surrounded by Kapton and carrying large currents can show large temperature increases, but the other configurations seen on solar arrays have adequate heat sinks to prevent substantial heating of the Kapton. Electron currents from the ambient plasma can also contribute to heating of thin traces. Since Kapton is stable at temperatures as high as 600 C, this indicates that it should be suitable for solar array applications. There are indications that the adhesive sued in solar arrays may be a strong contributor to the pyrolysis problem seen in solar array vacuum chamber tests.

PEP solar array definition study

NASA Technical Reports Server (NTRS)

1979-01-01

The conceptual design of a large, flexible, lightweight solar array is presented focusing on a solar array overview assessment, solar array blanket definition, structural-mechanical systems definition, and launch/reentry blanket protection features. The overview assessment includes a requirements and constraints review, the thermal environment assessment on the design selection, an evaluation of blanket integration sequence, a conceptual blanket/harness design, and a hot spot analysis considering the effects of shadowing and cell failures on overall array reliability. The solar array blanket definition includes the substrate design, hinge designs and blanket/harness flexibility assessment. The structural/mechanical systems definition includes an overall loads and deflection assessment, a frequency analysis of the deployed assembly, a components weights estimate, design of the blanket housing and tensioning mechanism. The launch/reentry blanket protection task includes assessment of solar cell/cover glass cushioning concepts during ascent and reentry flight condition.

KSC-00pp1214

NASA Image and Video Library

2000-08-30

The overhead crane carrying a solar array turns on its axis to move the array to the Integrated Equipment Assembly (IEA) for installation. A component of the International Space Station, the solar array is the second one being installed on the IEA. The arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

Wafer-Scale Integration of Inverted Nanopyramid Arrays for Advanced Light Trapping in Crystalline Silicon Thin Film Solar Cells.

PubMed

Zhou, Suqiong; Yang, Zhenhai; Gao, Pingqi; Li, Xiaofeng; Yang, Xi; Wang, Dan; He, Jian; Ying, Zhiqin; Ye, Jichun

2016-12-01

Crystalline silicon thin film (c-Si TF) solar cells with an active layer thickness of a few micrometers may provide a viable pathway for further sustainable development of photovoltaic technology, because of its potentials in cost reduction and high efficiency. However, the performance of such cells is largely constrained by the deteriorated light absorption of the ultrathin photoactive material. Here, we report an efficient light-trapping strategy in c-Si TFs (~20 μm in thickness) that utilizes two-dimensional (2D) arrays of inverted nanopyramid (INP) as surface texturing. Three types of INP arrays with typical periodicities of 300, 670, and 1400 nm, either on front, rear, or both surfaces of the c-Si TFs, are fabricated by scalable colloidal lithography and anisotropic wet etch technique. With the extra aid of antireflection coating, the sufficient optical absorption of 20-μm-thick c-Si with a double-sided 1400-nm INP arrays yields a photocurrent density of 39.86 mA/cm(2), which is about 76 % higher than the flat counterpart (22.63 mA/cm(2)) and is only 3 % lower than the value of Lambertian limit (41.10 mA/cm(2)). The novel surface texturing scheme with 2D INP arrays has the advantages of excellent antireflection and light-trapping capabilities, an inherent low parasitic surface area, a negligible surface damage, and a good compatibility for subsequent process steps, making it a good alternative for high-performance c-Si TF solar cells.

Photovoltaic devices based on quantum dot functionalized nanowire arrays embedded in an organic matrix

NASA Astrophysics Data System (ADS)

Kung, Patrick; Harris, Nicholas; Shen, Gang; Wilbert, David S.; Baughman, William; Balci, Soner; Dawahre, Nabil; Butler, Lee; Rivera, Elmer; Nikles, David; Kim, Seongsin M.

2012-01-01

Quantum dot (QD) functionalized nanowire arrays are attractive structures for low cost high efficiency solar cells. QDs have the potential for higher quantum efficiency, increased stability and lifetime compared to traditional dyes, as well as the potential for multiple electron generation per photon. Nanowire array scaffolds constitute efficient, low resistance electron transport pathways which minimize the hopping mechanism in the charge transport process of quantum dot solar cells. However, the use of liquid electrolytes as a hole transport medium within such scaffold device structures have led to significant degradation of the QDs. In this work, we first present the synthesis uniform single crystalline ZnO nanowire arrays and their functionalization with InP/ZnS core-shell quantum dots. The structures are characterized using electron microscopy, optical absorption, photoluminescence and Raman spectroscopy. Complementing photoluminescence, transmission electron microanalysis is used to reveal the successful QD attachment process and the atomistic interface between the ZnO and the QD. Energy dispersive spectroscopy reveals the co-localized presence of indium, phosphorus, and sulphur, suggestive of the core-shell nature of the QDs. The functionalized nanowire arrays are subsequently embedded in a poly-3(hexylthiophene) hole transport matrix with a high degree of polymer infiltration to complete the device structure prior to measurement.

Dense-array concentrator photovoltaic system using non-imaging dish concentrator and crossed compound parabolic concentrator

NASA Astrophysics Data System (ADS)

Chong, Kok-Keong; Yew, Tiong-Keat; Wong, Chee-Woon; Tan, Ming-Hui; Tan, Woei-Chong; Lai, An-Chow; Lim, Boon-Han; Lau, Sing-Liong; Rahman, Faidz Abdul

2015-04-01

Solar concentrating device plays an important role by making use of optical technology in the design, which can be either reflector or lens to deliver high flux of sunlight onto the Concentrator Photovoltaic (CPV) module receiver ranging from hundreds to thousand suns. To be more competitive compared with fossil fuel, the current CPV systems using Fresnel lens and Parabolic dish as solar concentrator that are widely deployed in United States, Australia and Europe are facing great challenge to produce uniformly focused sunlight on the solar cells as to reduce the cost of electrical power generation. The concept of non-imaging optics is not new, but it has not fully explored by the researchers over the world especially in solving the problem of high concentration solar energy, which application is only limited to be a secondary focusing device or low concentration device using Compound Parabolic Concentrator. With the current advancement in the computer processing power, we has successfully invented the non-imaging dish concentrator (NIDC) using numerical simulation method to replace the current parabolic dish as primary focusing device with high solar concentration ratio (more than 400 suns) and large collective area (from 25 to 125 m2). In this paper, we disclose our research and development on dense array CPV system based on non-imaging optics. The geometry of the NIDC is determined using a special computational method. In addition, an array of secondary concentrators, namely crossed compound parabolic concentrators, is also proposed to further focus the concentrated sunlight by the NIDC onto active area of solar cells of the concentrator photovoltaic receiver. The invention maximizes the absorption of concentrated sunlight for the electric power generation system.

Status of the use of microwave power transmission technology in the solar power satellite

NASA Technical Reports Server (NTRS)

Brown, W. C.

1985-01-01

Attention is given to recent advances in the technologies needed to build and transport a Solar Power satellite. Among the areas of NASA sponsored SPS research are: the application of ground-based, electronically steerable arrays to the SPS space-based microwave transmitting antenna; and the application of microwave transmission technology to a low-cost LEO-to-GEO transportation system to build the SPS. A photograph of a thin-film etched circuit rectenna for powering the LEO-to-GEO transportation system is provided.

A lightweight solar array study

NASA Technical Reports Server (NTRS)

Josephs, R. H.

1977-01-01

A sample module was assembled to model a portion of a flexible extendable solar array, a type that promises to become the next generation of solar array design. The resulting study of this module is intended to provide technical support to the array designer for lightweight component selection, specifications, and tests. Selected from available lightweight components were 127-micron-thick wrap-around contacted solar cells, 34- micron-thick sputtered glass covers, and as a substrate a 13-micron-thick polyimide film clad with a copper printed circuit. Each component displayed weaknesses. The thin solar cells had excessive breakage losses. Sputtered glass cover adhesion was poor, and the covered cell was weaker than the cell uncovered. Thermal stresses caused some cell delamination from the model solar array substrate.

Integrated Power Source Grant

NASA Technical Reports Server (NTRS)

2001-01-01

Traditional spacecraft power systems incorporate a solar array energy source, an energy storage element (battery), and battery charge control and bus voltage regulation electronics to provide continuous electrical power for spacecraft systems and instruments. Dedicated power conditioning components provide limited fault isolation between systems and instruments, while a centralized power-switching unit provides spacecraft load control. Battery undervoltage conditions are detected by the spacecraft processor, which removes fault conditions and non-critical loads before permanent battery damage can occur. Cost effective operation of a micro-sat constellation requires a fault tolerant spacecraft architecture that minimizes on-orbit operational costs by permitting autonomous reconfiguration in response to unexpected fault conditions. A new micro-sat power system architecture that enhances spacecraft fault tolerance and improves power system survivability by continuously managing the battery charge and discharge processes on a cell-by-cell basis has been developed. This architecture is based on the Integrated Power Source (US patent 5644207), which integrates dual junction solar cells, Lithium Ion battery cells, and processor based charge control electronics into a structural panel that can be deployed or used to form a portion of the outer shell of a micro-spacecraft. The first generation Integrated Power Source is configured as a one inch thick panel in which prismatic Lithium Ion battery cells are arranged in a 3x7 matrix (26VDC) and a 3x1 matrix (3.7VDC) to provide the required output voltages and load currents. A multi-layer structure holds the battery cells, as well as the thermal insulators that are necessary to protect the Lithium Ion battery cells from the extreme temperatures of the solar cell layer. Independent thermal radiators, located on the back of the panel, are dedicated to the solar cell array, the electronics, and the battery cell array. In deployed panel applications, these radiators maintain the battery cells in an appropriate operational temperature range.

Process Development of Gallium Nitride Phosphide Core-Shell Nanowire Array Solar Cell

NASA Astrophysics Data System (ADS)

Chuang, Chen

Dilute Nitride GaNP is a promising materials for opto-electronic applications due to its band gap tunability. The efficiency of GaNxP1-x /GaNyP1-y core-shell nanowire solar cell (NWSC) is expected to reach as high as 44% by 1% N and 9% N in the core and shell, respectively. By developing such high efficiency NWSCs on silicon substrate, a further reduction of the cost of solar photovoltaic can be further reduced to 61$/MWh, which is competitive to levelized cost of electricity (LCOE) of fossil fuels. Therefore, a suitable NWSC structure and fabrication process need to be developed to achieve this promising NWSC. This thesis is devoted to the study on the development of fabrication process of GaNxP 1-x/GaNyP1-y core-shell Nanowire solar cell. The thesis is divided into two major parts. In the first parts, previously grown GaP/GaNyP1-y core-shell nanowire samples are used to develop the fabrication process of Gallium Nitride Phosphide nanowire solar cell. The design for nanowire arrays, passivation layer, polymeric filler spacer, transparent col- lecting layer and metal contact are discussed and fabricated. The property of these NWSCs are also characterized to point out the future development of Gal- lium Nitride Phosphide NWSC. In the second part, a nano-hole template made by nanosphere lithography is studied for selective area growth of nanowires to improve the structure of core-shell NWSC. The fabrication process of nano-hole templates and the results are presented. To have a consistent features of nano-hole tem- plate, the Taguchi Method is used to optimize the fabrication process of nano-hole templates.

KSC-00pp1217

NASA Image and Video Library

2000-08-30

In the Space Station Processing Facility, workers help guide a solar array into position for installation on the Integrated Equipment Assembly. Solar Array Wing-3 is already in place. Components of the International Space Station, the arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1215

NASA Image and Video Library

2000-08-30

In the Space Station Processing Facility, the overhead crane carrying a solar array arrives at the Integrated Equipment Assembly (IEA) on which it will be installed. Solar Array Wing-3 is already in place. Components of the International Space Station, the arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1218

NASA Image and Video Library

2000-08-30

Workers in the Space Station Processing Facility give close attention to the placement of a solar array on the Integrated Equipment Assembly. Solar Array Wing-3 is already in place. Components of the International Space Station, the arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

An Analytic Approach for Optimal Geometrical Design of GaAs Nanowires for Maximal Light Harvesting in Photovoltaic Cells

PubMed Central

Wu, Dan; Tang, Xiaohong; Wang, Kai; Li, Xianqiang

2017-01-01

Semiconductor nanowires(NWs) with subwavelength scale diameters have demonstrated superior light trapping features, which unravel a new pathway for low cost and high efficiency future generation solar cells. Unlike other published work, a fully analytic design is for the first time proposed for optimal geometrical parameters of vertically-aligned GaAs NW arrays for maximal energy harvesting. Using photocurrent density as the light absorbing evaluation standard, 2 μm length NW arrays whose multiple diameters and periodicity are quantitatively identified achieving the maximal value of 29.88 mA/cm2 under solar illumination. It also turns out that our method has wide suitability for single, double and four different diameters of NW arrays for highest photon energy harvesting. To validate this analytical method, intensive numerical three-dimensional finite-difference time-domain simulations of the NWs’ light harvesting are also carried out. Compared with the simulation results, the predicted maximal photocurrent densities lie within 1.5% tolerance for all cases. Along with the high accuracy, through directly disclosing the exact geometrical dimensions of NW arrays, this method provides an effective and efficient route for high performance photovoltaic design. PMID:28425488

Tungsten trioxide nanoplate array supported platinum as a highly efficient counter electrode for dye-sensitized solar cells.

PubMed

Song, Dandan; Cui, Peng; Zhao, Xing; Li, Meicheng; Chu, Lihua; Wang, Tianyue; Jiang, Bing

2015-03-19

A tungsten trioxide (WO₃) nanoplate array is fabricated directly on the FTO/glass substrate and used as a platinum (Pt) nanoscale supporter for a highly efficient and low Pt-consumption counter electrode (CE) in dye-sensitized solar cells (DSCs). A Pt/WO₃ composite structure, with Pt nanoparticles having a diameter of 2-3 nm, increases the electrochemical catalytic activity in catalyzing the reduction of triiodide. Accordingly, the power conversion efficiency is increased from less than 1% for WO₃ CE and 8.1% for Pt CE, respectively, to 8.9% for Pt/WO₃ CE. Moreover, the use of Pt/WO₃ CE can dramatically reduce the consumption of scarce Pt material, with a relatively low Pt-loading of ∼2 μg cm(-2), while maintaining a much better performance. The excellent performance of Pt/WO₃ CE is attributed to the efficient electron injection and transport via WO₃ supporters, as well as the nanostructure array morphology of WO₃ for deposition of fine Pt nanoparticles. This work provides an approach for developing highly catalytic and low-cost Pt based CEs, which also has implications for the development of Pt/WO₃ nanoplate arrays for other applications.

Reliability analysis method of a solar array by using fault tree analysis and fuzzy reasoning Petri net

NASA Astrophysics Data System (ADS)

Wu, Jianing; Yan, Shaoze; Xie, Liyang

2011-12-01

To address the impact of solar array anomalies, it is important to perform analysis of the solar array reliability. This paper establishes the fault tree analysis (FTA) and fuzzy reasoning Petri net (FRPN) models of a solar array mechanical system and analyzes reliability to find mechanisms of the solar array fault. The index final truth degree (FTD) and cosine matching function (CMF) are employed to resolve the issue of how to evaluate the importance and influence of different faults. So an improvement reliability analysis method is developed by means of the sorting of FTD and CMF. An example is analyzed using the proposed method. The analysis results show that harsh thermal environment and impact caused by particles in space are the most vital causes of the solar array fault. Furthermore, other fault modes and the corresponding improvement methods are discussed. The results reported in this paper could be useful for the spacecraft designers, particularly, in the process of redesigning the solar array and scheduling its reliability growth plan.

Microprocessor control of multiple peak power tracking DC/DC converters for use with solar cell arrays

NASA Technical Reports Server (NTRS)

Frederick, Martin E. (Inventor); Jermakian, Joel (Inventor)

1991-01-01

A method and an apparatus is provided for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained. The system is totally modular and additional solar array strings may be added to the system simply by adding converter boards to the system and changing some constants in the controller's control routines.

Automated Array Assembly Task In-depth Study of Silicon Wafer Surface Texturizing

NASA Technical Reports Server (NTRS)

Jones, G. T.; Chitre, S.; Rhee, S. S.; Allison, K. L.

1979-01-01

A low cost wafer surface texturizing process was studied. An investigation of low cost cleaning operations to clean residual wax and organics from the surface of silicon wafers was made. The feasibility of replacing dry nitrogen with clean dry air for drying silicon wafers was examined. The two stage texturizing process was studied for the purpose of characterizing relevant parameters in large volume applications. The effect of gettering solar cells on photovoltaic energy conversion efficiency is described.

Low cost solar array project: Experimental process system development unit for producing semiconductor-grade silicon using silane-to-silicon process

NASA Technical Reports Server (NTRS)

1980-01-01

The design, fabrication, and installation of an experimental process system development unit (EPSDU) were analyzed. Supporting research and development were performed to provide an information data base usable for the EPSDU and for technological design and economical analysis for potential scale-up of the process. Iterative economic analyses were conducted for the estimated product cost for the production of semiconductor grade silicon in a facility capable of producing 1000-MT/Yr.

NASA-OAST program in photovoltaic energy conversion

NASA Technical Reports Server (NTRS)

Mullin, J. P.; Flood, D. J.

1982-01-01

The NASA program in photovoltaic energy conversion includes research and technology development efforts on solar cells, blankets, and arrays. The overall objectives are to increase conversion efficiency, reduce mass, reduce cost, and increase operating life. The potential growth of space power requirements in the future presents a major challenge to the current state of technology in space photovoltaic systems.

Self-Powered Solar-Blind Photodetector with Fast Response Based on Au/β-Ga2O3 Nanowires Array Film Schottky Junction.

PubMed

Chen, Xing; Liu, Kewei; Zhang, Zhenzhong; Wang, Chunrui; Li, Binghui; Zhao, Haifeng; Zhao, Dongxu; Shen, Dezhen

2016-02-17

Because of the direct band gap of 4.9 eV, β-Ga2O3 has been considered as an ideal material for solar-blind photodetection without any bandgap tuning. Practical applications of the photodetectors require fast response speed, high signal-to-noise ratio, low energy consumption and low fabrication cost. Unfortunately, most reported β-Ga2O3-based photodetectors usually possess a relatively long response time. In addition, the β-Ga2O3 photodetectors based on bulk, the individual 1D nanostructure, and the film often suffer from the high cost, the low repeatability, and the relatively large dark current, respectively. In this paper, a Au/β-Ga2O3 nanowires array film vertical Schottky photodiode is successfully fabricated by a simple thermal partial oxidation process. The device exhibits a very low dark current of 10 pA at -30 V with a sharp cutoff at 270 nm. More interestingly, the 90-10% decay time of our device is only around 64 μs, which is much quicker than any other previously reported β-Ga2O3-based photodetectors. Besides, the self-powering, the excellent stability and the good reproducibility of Au/β-Ga2O3 nanowires array film photodetector are helpful to its commercialization and practical applications.

Simulated Space Environmental Effects on Thin Film Solar Array Components

NASA Technical Reports Server (NTRS)

Finckenor, Miria; Carr, John; SanSoucie, Michael; Boyd, Darren; Phillips, Brandon

2017-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection typically afforded by thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 100, 500, and 700 keV energy protons, and a fourth set were exposed to >2,000 hours of near ultraviolet (NUV) radiation. A final set was rapidly thermal cycled between -55 and +125 C. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed.

Simulated Space Environmental Effects on Thin Film Solar Array Components

NASA Technical Reports Server (NTRS)

Finckenor, Miria; Carr, John; SanSoucie, Michael; Boyd, Darren; Phillips, Brandon

2017-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection typically afforded by thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 100, 500, and 700 keV energy protons, and a fourth set were exposed to >2,000 hours of near ultraviolet (NUV) radiation. A final set was rapidly thermal cycled between -55 and +125degC. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed.

Simulated Space Environmental Effects on Thin Film Solar Array Components

NASA Technical Reports Server (NTRS)

Finckenor, Miria; Carr, John; SanSoucie, Michael; Boyd, Darren; Phillips, Brandon

2017-01-01

The Lightweight Integrated Solar Array and Transceiver (LISA-T) experiment consists of thin-film, low mass, low volume solar panels. Given the variety of thin solar cells and cover materials and the lack of environmental protection afforded by typical thick coverglasses, a series of tests were conducted in Marshall Space Flight Center's Space Environmental Effects Facility to evaluate the performance of these materials. Candidate thin polymeric films and nitinol wires used for deployment were also exposed. Simulated space environment exposures were selected based on SSP 30425 rev. B, "Space Station Program Natural Environment Definition for Design" or AIAA Standard S-111A-2014, "Qualification and Quality Requirements for Space Solar Cells." One set of candidate materials were exposed to 5 eV atomic oxygen and concurrent vacuum ultraviolet (VUV) radiation for low Earth orbit simulation. A second set of materials were exposed to 1 MeV electrons. A third set of samples were exposed to 50, 500, and 750 keV energy protons, and a fourth set were exposed to >2,000 hours of ultraviolet radiation. A final set was rapidly thermal cycled between -50 and +120 C. This test series provides data on enhanced power generation, particularly for small satellites with reduced mass and volume resources. Performance versus mass and cost per Watt is discussed.

Dip coating process: Silicon sheet growth development for the large-area silicon sheet task of the low-cost silicon solar array project

NASA Technical Reports Server (NTRS)

Heaps, J. D.; Maciolek, R. B.; Zook, J. D.; Harrison, W. B.; Scott, M. W.; Hendrickson, G.; Wolner, H. A.; Nelson, L. D.; Schuller, T. L.; Peterson, A. A.

1976-01-01

The technical and economic feasibility of producing solar cell quality sheet silicon by dip-coating one surface of carbonized ceramic substrates with a thin layer of large grain polycrystalline silicon was investigated. The dip-coating methods studied were directed toward a minimum cost process with the ultimate objective of producing solar cells with a conversion efficiency of 10% or greater. The technique shows excellent promise for low cost, labor-saving, scale-up potentialities and would provide an end product of sheet silicon with a rigid and strong supportive backing. An experimental dip-coating facility was designed and constructed, several substrates were successfully dip-coated with areas as large as 25 sq cm and thicknesses of 12 micron to 250 micron. There appears to be no serious limitation on the area of a substrate that could be coated. Of the various substrate materials dip-coated, mullite appears to best satisfy the requirement of the program. An inexpensive process was developed for producing mullite in the desired geometry.

POwer WithOut Wire (POWOW): A SEP Concept for Space Exploration

NASA Technical Reports Server (NTRS)

Brandhorst, Henry W., Jr.; ONeill, Mark

2000-01-01

Electric propulsion has emerged as a cost-effective solution to a wide range of satellite applications. Deep Space 1 demonstrated electric propulsion as a primary propulsion source for a spacecraft. The POwer WithOut Wires (POWOW) concept has been developed as a solar electric propelled spacecraft that would travel to Mars, for example, enter selenosynchronous orbit and then use lasers to beam power to surface installations. This concept has been developed with industrial expertise in high efficiency solar cells, advanced concentrator modules, innovative arrays, and high power electric propulsion systems. The paper will present the latest version of the spacecraft, the technologies involved, possible missions and trip times to Mars and laser beaming options. The POWOW spacecraft is a general purpose solar electric propulsion system that includes technologies that are directly applicable to commercial and government spacecraft with power levels ranging from 4 kW in Low Earth Orbits (LEO) to about 1 MW. The system is modular and expandable. Learning curve costing methodologies are used to demonstrate cost effectiveness of a modular system.

The interactions of solar arrays with electric thrusters

NASA Technical Reports Server (NTRS)

Kaufman, H. R.; Isaacson, G. C.; Domitz, S.

1976-01-01

The generation of a charge-exchange plasma by a thruster, the transport of this plasma to the solar array, and the interaction of the solar array with the plasma after it arrives are all described. The generation of this plasma can be described accurately from thruster geometry and operating conditions. The transport of the charge-exchange plasma was studied experimentally with a 15 cm thruster. A model was developed for simple thruster-array configurations. A variety of experiments were surveyed for the interaction of the plasma at the solar array.

Silicon materials task of the low cost solar array project. Phase 3: Effect of impurities and processing on silicon solar cells

NASA Technical Reports Server (NTRS)

Hopkins, R. H.; Davis, J. R.; Blais, P. D.; Rohatgi, A.; Campbell, R. B.; Rai-Choudhury, P.; Mollenkopf, H. C.; Mccormick, J. R.

1979-01-01

The 13th quarterly report of a study entitled an Investigation of the Effects of Impurities and Processing on Silicon Solar Cells is given. The objective of the program is to define the effects of impurities, various thermochemical processes and any impurity-process interactions on the performance of terrestrial silicon solar cells. The Phase 3 program effort falls in five areas: (1) cell processing studies; (2) completion of the data base and impurity-performance modeling for n-base cells; (3) extension of p-base studies to include contaminants likely to be introduced during silicon production, refining or crystal growth; (4) anisotropy effects; and (5) a preliminary study of the permanence of impurity effects in silicon solar cells. The quarterly activities for this report focus on tasks (1), (3) and (4).

Flat-plate solar array project process development area: Process research of non-CZ silicon material

NASA Technical Reports Server (NTRS)

Campbell, R. B.

1986-01-01

Several different techniques to simultaneously diffuse the front and back junctions in dendritic web silicon were investigated. A successful simultaneous diffusion reduces the cost of the solar cell by reducing the number of processing steps, the amount of capital equipment, and the labor cost. The three techniques studied were: (1) simultaneous diffusion at standard temperatures and times using a tube type diffusion furnace or a belt furnace; (2) diffusion using excimer laser drive-in; and (3) simultaneous diffusion at high temperature and short times using a pulse of high intensity light as the heat source. The use of an excimer laser and high temperature short time diffusion experiment were both more successful than the diffusion at standard temperature and times. The three techniques are described in detail and a cost analysis of the more successful techniques is provided.

Flat-plate solar array progress and plans

NASA Technical Reports Server (NTRS)

Callaghan, W. T.

1984-01-01

The results of research into the technology of flat-plate solar arrays undertaken in the Flat-Plate Solar Array Project under the sponsorship of the U.S. Department of Energy are surveyed. Topics examined include Si refinement, ribbon-sheet substrate formation, module process sequences, environmental isolation, module engineering and testing, and photovoltaic-array economics.

Measurement of high-voltage and radiation-damage limitations to advanced solar array performance

NASA Technical Reports Server (NTRS)

Guidice, D. A.; Severance, P. S.; Keinhardt, K. C.

1991-01-01

A description is given of the reconfigured Photovoltaic Array Space Power (PASP) Plus experiment: its objectives, solar-array complement, and diagnostic sensors. Results from a successful spaceflight will lead to a better understanding of high-voltage and radiation-damage limitations in the operation of new-technology solar arrays.

Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures.

PubMed

Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, SenPo; Xiu, Fei; Ho, Johnny C

2016-09-27

Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices.

Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

PubMed Central

Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, SenPo; Xiu, Fei; Ho, Johnny C.

2016-01-01

Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices. PMID:27671709

Lightweight Solar Power for Small Satellites

NASA Technical Reports Server (NTRS)

Nabors, Sammy A.

2015-01-01

The innovation targets small satellites or CubeSats for which conventional deployable arrays are not feasible due to their size, weight and complexity. This novel solar cell array includes a thin and flexible photovoltaic cell applied to an inflatable structure to create a high surface area array for collecting solar energy in a lightweight, simple and deployable structure. The inflatable array, with its high functional surface area, eliminates the need and the mechanisms required to point the system toward the sun. The power density achievable in these small arrays is similar to that of conventional high-power deployable/pointable arrays used on large satellites or space vehicles. Although inflatable solar arrays have been previously considered by others, the arrays involved the use of traditional rigid solar cells. Researchers are currently working with thin film photovoltaics from various suppliers so that the NASA innovation is not limited to any particular solar cell technology. NASA has built prototypes and tested functionality before and after inflation. As shown in the current-voltage currents below, deployment does not damage the cell performance.

P6 Truss, Photovoltaic (PV) Solar Array Wing (SAW)

NASA Image and Video Library

2000-12-07

STS097-376-019 (7 December 2000) --- A close-up view of the P6 solar array on the International Space Station (ISS), backdropped against the blackness of space and the Earth’s horizon. The P6 solar array is the first of eight sets of solar arrays that at the completion of the space station construction in 2006, will comprise the station’s electrical power system, converting sunlight to electricity.

P6 Truss, Photovoltaic (PV) Solar Array Wing (SAW)

NASA Image and Video Library

2000-12-07

STS097-376-006 (7 Dec 2000) --- A close-up view of the P6 solar array on the International Space Station (ISS), backdropped against the blackness of space and the Earth?s horizon. The P6 solar array is the first of eight sets of solar arrays that at the completion of the space station construction in 2006, will comprise the station?s electrical power system, converting sunlight to electricity.

Deployment dynamics and control of large-scale flexible solar array system with deployable mast

NASA Astrophysics Data System (ADS)

Li, Hai-Quan; Liu, Xiao-Feng; Guo, Shao-Jing; Cai, Guo-Ping

2016-10-01

In this paper, deployment dynamics and control of large-scale flexible solar array system with deployable mast are investigated. The adopted solar array system is introduced firstly, including system configuration, deployable mast and solar arrays with several mechanisms. Then dynamic equation of the solar array system is established by the Jourdain velocity variation principle and a method for dynamics with topology changes is introduced. In addition, a PD controller with disturbance estimation is designed to eliminate the drift of spacecraft mainbody. Finally the validity of the dynamic model is verified through a comparison with ADAMS software and the deployment process and dynamic behavior of the system are studied in detail. Simulation results indicate that the proposed model is effective to describe the deployment dynamics of the large-scale flexible solar arrays and the proposed controller is practical to eliminate the drift of spacecraft mainbody.

Options Studied for Managing Space Station Solar Array Electrical Hazards for Sequential Shunt Unit Replacement

NASA Technical Reports Server (NTRS)

Delleur, Ann M.; Kerslake, Thomas W.; Levy, Robert K.

2004-01-01

The U.S. solar array strings on the International Space Station are connected to a sequential shunt unit (SSU). The job of the SSU is to shunt, or short, the excess current from the solar array, such that just enough current is provided downstream to maintain the 160-V bus voltage while meeting the power load demand and recharging the batteries. Should an SSU fail on-orbit, it would be removed and replaced with the on-orbit spare during an astronaut space walk or extravehicular activity (EVA) (see the photograph). However, removing an SSU during an orbit Sun period with input solar array power connectors fully energized could result in substantial hardware damage and/or safety risk to the EVA astronaut. The open-circuit voltage of cold solar-array strings can exceed 320 V, and warm solar-array strings could feed a short circuit with a total current level exceeding 240 A.

Daytime Solar Heating of Photovoltaic Arrays in Low Density Plasmas

NASA Technical Reports Server (NTRS)

Galofaro, J.; Vayner, B.; Ferguson, D.

2003-01-01

The purpose of the current work is to determine the out-gassing rate of H2O molecules for a solar array placed under daytime solar heating (full sunlight) conditions typically encountered in a Low Earth Orbital (LEO) environment. Arc rates are established for individual arrays held at 14 C and are used as a baseline for future comparisons. Radiated thermal solar flux incident to the array is simulated by mounting a stainless steel panel equipped with resistive heating elements several centimeters behind the array. A thermal plot of the heater plate temperature and the array temperature as a function of heating time is then obtained. A mass spectrometer is used to record the levels of partial pressure of water vapor in the test chamber after each of the 5 heating/cooling cycles. Each of the heating cycles was set to time duration of 40 minutes to simulate the daytime solar heat flux to the array over a single orbit. Finally the array is cooled back to ambient temperature after 5 complete cycles and the arc rates of the solar arrays is retested. A comparison of the various data is presented with rather some unexpected results.

Mariner 9 Solar Array Design, Manufacture, and Performance

NASA Technical Reports Server (NTRS)

Sequeira, E. A.

1973-01-01

The mission of Mariner 9, the first spacecraft to orbit another planet, was to make scientific observations of the surface of Mars. Throughout this unique mission, the Mariner 9 solar array successfully supported the power requirements of the spacecraft without experiencing anomalies. Basically, the design of the solar array was similar to those of Mariners 6 and 7; however, Mariner 9 had the additional flight operational requirement to perform in a Mars orbit environment mode. The array special tests provided information on the current-voltage characteristics and array space degradation. Tests indicated that total solar array current degradation was 3.5 percent, which could probably be attributed to the gradual degradation of the cover glass and/or the RTV 602 adhesive employed to cement the cover glass to the solar cell.

KSC-00pp1194

NASA Image and Video Library

2000-08-18

In the Space Station Processing Facility, Solar Array Wing-3, an element of the International Space Station, is lifted from a work stand to move it to the Integrated Electronic Assembly for testing. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1199

NASA Image and Video Library

2000-08-18

In the Space Station Processing Facility, Solar Array Wing-3, a component of the International Space Station, is installed in the Integrated Electronic Assembly where it will be tested. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1193

NASA Image and Video Library

2000-08-18

Workers in the Space Station Processing Facility get ready to move Solar Array Wing-3, a component of the International Space Station, for installation onto the Integrated Electronic Assembly. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1198

NASA Image and Video Library

2000-08-18

In the Space Station Processing Facility, Solar Array Wing-3, a component of the International Space Station, is installed in the Integrated Electronic Assembly where it will be tested. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1195

NASA Image and Video Library

2000-08-18

In the Space Station Processing Facility, Solar Array Wing-3 (at top), a component of the International Space Station, hovers above the Integrated Electronic Assembly where it will be installed for testing. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

Weight optimization of ultra large space structures

NASA Technical Reports Server (NTRS)

Reinert, R. P.

1979-01-01

The paper describes the optimization of a solar power satellite structure for minimum mass and system cost. The solar power satellite is an ultra large low frequency and lightly damped space structure; derivation of its structural design requirements required accommodation of gravity gradient torques which impose primary loads, life up to 100 years in the rigorous geosynchronous orbit radiation environment, and prevention of continuous wave motion in a solar array blanket suspended from a huge, lightly damped structure subject to periodic excitations. The satellite structural design required a parametric study of structural configurations and consideration of the fabrication and assembly techniques, which resulted in a final structure which met all requirements at a structural mass fraction of 10%.

Wind loading on solar concentrators: Some general considerations

NASA Technical Reports Server (NTRS)

Roschke, E. J.

1984-01-01

A survey was completed to examine the problems and complications arising from wind loading on solar concentrators. Wind loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of solar collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. Wind characteristics are discussed from a general point of view. Current methods for determining design wind speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. Wind tunnel testing is discussed, and environmental wind tunnels are reviewed. Recent results on heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly.

The effect of atmospheric drag on the design of solar-cell power systems for low Earth orbit

NASA Technical Reports Server (NTRS)

Kyser, A. C.

1983-01-01

The feasibility of reducing the atmospheric drag of low orbit solar powered satellites by operating the solar-cell array in a minimum-drag attitude, rather than in the conventional Sun pointing attitude was determined. The weights of the solar array, the energy storage batteries, and the fuel required to overcome the drag of the solar array for a range of design life times in orbit were considered. The drag of the array was estimated by free molecule flow theory, and the system weights were calculated from unit weight estimates for 1990 technology. The trailing, minimum drag system was found to require 80% more solar array area, and 30% more battery capacity, the system weights for reasonable life times were dominated by the thruster fuel requirements.

KSC-00pp1210

NASA Image and Video Library

2000-08-30

Workers in the Space Station Processing Facility help guide an overhead crane toward a workstand containing a solar array in order to move it for installation onto the Integrated Equipment Assembly (IEA). A component of the International Space Station, the solar array is the second one being installed on the IEA. The arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1216

NASA Image and Video Library

2000-08-30

In the Space Station Processing Facility, the overhead crane carrying a solar array maneuvers its cargo into position on the Integrated Equipment Assembly on which it will be installed. Solar Array Wing-3 is already in place. Components of the International Space Station, the arrays are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

Feasibility study of a 200 watt per kilogram lightweight solar array system. [for interplanetary spacecraft

NASA Technical Reports Server (NTRS)

Stanhouse, R.; Cokonis, J.; Rayl, G.

1976-01-01

Progress in an investigation of the feasibility of designing a lightweight solar array with a power-to-weight ratio of 200 watts per kilogram is described. This solar array will produce 10,000 watts of electrical power at 1 A.U. at its beginning of life (BOL), and degrade less than 20% over a three year period in interplanetary flight. A review of existing lightweight solar array system concepts is presented along with discussion pertaining to their applicable technology as it relates to a 200 watt/kilogram array. Also presented is a discussion of the candidate development solar cells being considered, and various deployable boom concepts under investigation.

Solid state laser applications in photovoltaics manufacturing

NASA Astrophysics Data System (ADS)

Dunsky, Corey; Colville, Finlay

2008-02-01

Photovoltaic energy conversion devices are on a rapidly accelerating growth path driven by increasing government and societal pressure to use renewable energy as part of an overall strategy to address global warming attributed to greenhouse gas emissions. Initially supported in several countries by generous tax subsidies, solar cell manufacturers are relentlessly pushing the performance/cost ratio of these devices in a quest to reach true cost parity with grid electricity. Clearly this eventual goal will result in further acceleration in the overall market growth. Silicon wafer based solar cells are currently the mainstay of solar end-user installations with a cost up to three times grid electricity. But next-generation technology in the form of thin-film devices promises streamlined, high-volume manufacturing and greatly reduced silicon consumption, resulting in dramatically lower per unit fabrication costs. Notwithstanding the modest conversion efficiency of thin-film devices compared to wafered silicon products (around 6-10% versus 15-20%), this cost reduction is driving existing and start-up solar manufacturers to switch to thin-film production. A key aspect of these devices is patterning large panels to create a monolithic array of series-interconnected cells to form a low current, high voltage module. This patterning is accomplished in three critical scribing processes called P1, P2, and P3. Lasers are the technology of choice for these processes, delivering the desired combination of high throughput and narrow, clean scribes. This paper examines these processes and discusses the optimization of industrial lasers to meet their specific needs.

Using the sun analog sensor (SAS) data to investigate solar array yoke motion on the GOES-8 and -9 spacecraft

NASA Astrophysics Data System (ADS)

Phenneger, Milton; Knack, Jennifer L.

1996-10-01

The GOES-8 and -9 Sun analog sensor (SAS) flight data is analyzed to evaluate the attitude motion environment of payloads mounted on the solar array. The work was performed in part to extend analysis in progress to support the solar x-ray imager to be flown on the GOES-M. The SAS is a two axis sensor mounted on the x-ray sensor pointing (XRP) module to measure the east/west error angle between the SUn and the solar array normal and to provide a north south error angle for automatic solar pointing of the x-ray sensor by the XRP. The goal was to search for evidence of solar array vibrational modes in the 2 Hz and 0.5 Hz range and to test the predicted amplitudes. The results show that the solar array rotates at the rate of the mean Sun with unexpected oscillation periods of 5.6 minutes, 90 minutes, and 1440 minutes originating from the two 16.1 gear drive train stages between the solar array drive stepper motor and the solar array yoke. The higher frequency oscillations are detected as random noise at the 1/16 Hz telemetry sampling rate of the SAS. This supports the preflight predictions for the high frequency modes but provide s no detailed measurement of the frequency as expected for this data period. In addition to this the data indicates that the solar array is responding unexpectedly to GOES imager instrument blackbody calibration events.

Solar array maximum power tracking with closed-loop control of a 30-centimeter ion thruster

NASA Technical Reports Server (NTRS)

Gruber, R. P.

1977-01-01

A new solar array/ion thruster system control concept has been developed and demonstrated. An ion thruster beam load is used to automatically and continuously operate an unregulated solar array at its maximum power point independent of variations in solar array voltage and current. Preliminary tests were run which verified that this method of control can be implemented with a few, physically small, signal level components dissipating less than two watts.

Boeing's High Voltage Solar Tile Test Results

NASA Astrophysics Data System (ADS)

Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

2002-10-01

Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

Boeing's High Voltage Solar Tile Test Results

NASA Technical Reports Server (NTRS)

Reed, Brian J.; Harden, David E.; Ferguson, Dale C.; Snyder, David B.

2002-01-01

Real concerns of spacecraft charging and experience with solar array augmented electrostatic discharge arcs on spacecraft have minimized the use of high voltages on large solar arrays despite numerous vehicle system mass and efficiency advantages. Boeing's solar tile (patent pending) allows high voltage to be generated at the array without the mass and efficiency losses of electronic conversion. Direct drive electric propulsion and higher power payloads (lower spacecraft weight) will benefit from this design. As future power demand grows, spacecraft designers must use higher voltage to minimize transmission loss and power cable mass for very large area arrays. This paper will describe the design and discuss the successful test of Boeing's 500-Volt Solar Tile in NASA Glenn's Tenney chamber in the Space Plasma Interaction Facility. The work was sponsored by NASA's Space Solar Power Exploratory Research and Technology (SERT) Program and will result in updated high voltage solar array design guidelines being published.

Quality assessment of solar UV irradiance measured with array spectroradiometers

NASA Astrophysics Data System (ADS)

Egli, Luca; Gröbner, Julian; Hülsen, Gregor; Bachmann, Luciano; Blumthaler, Mario; Dubard, Jimmy; Khazova, Marina; Kift, Richard; Hoogendijk, Kees; Serrano, Antonio; Smedley, Andrew; Vilaplana, José-Manuel

2016-04-01

The reliable quantification of ultraviolet (UV) radiation at the earth's surface requires accurate measurements of spectral global solar UV irradiance in order to determine the UV exposure to human skin and to understand long-term trends in this parameter. Array spectroradiometers (ASRMs) are small, light, robust and cost-effective instruments, and are increasingly used for spectral irradiance measurements. Within the European EMRP ENV03 project "Solar UV", new devices, guidelines and characterization methods have been developed to improve solar UV measurements with ASRMs, and support to the end user community has been provided. In order to assess the quality of 14 end user ASRMs, a solar UV intercomparison was held on the measurement platform of the World Radiation Center (PMOD/WRC) in Davos, Switzerland, from 10 to 17 July 2014. The results of the blind intercomparison revealed that ASRMs, currently used for solar UV measurements, show a large variation in the quality of their solar UV measurements. Most of the instruments overestimate the erythema-weighted UV index - in particular at large solar zenith angles - due to stray light contribution in the UV-B range. The spectral analysis of global solar UV irradiance further supported the finding that the uncertainties in the UV-B range are very large due to stray light contribution in this wavelength range. In summary, the UV index may be detected by some commercially available ASRMs within 5 % compared to the world reference spectroradiometer, if well characterized and calibrated, but only for a limited range of solar zenith angles. Generally, the tested instruments are not yet suitable for solar UV measurements for the entire range between 290 and 400 nm under all atmospheric conditions.

Chemical vapor deposition growth

NASA Technical Reports Server (NTRS)

Ruth, R. P.; Manasevit, H. M.; Kenty, J. L.; Moudy, L. A.; Simpson, W. I.; Yang, J. J.

1976-01-01

The chemical vapor deposition (CVD) method for the growth of Si sheet on inexpensive substrate materials is investigated. The objective is to develop CVD techniques for producing large areas of Si sheet on inexpensive substrate materials, with sheet properties suitable for fabricating solar cells meeting the technical goals of the Low Cost Silicon Solar Array Project. Specific areas covered include: (1) modification and test of existing CVD reactor system; (2) identification and/or development of suitable inexpensive substrate materials; (3) experimental investigation of CVD process parameters using various candidate substrate materials; (4) preparation of Si sheet samples for various special studies, including solar cell fabrication; (5) evaluation of the properties of the Si sheet material produced by the CVD process; and (6) fabrication and evaluation of experimental solar cell structures, using standard and near-standard processing techniques.

Tandem concentrator photovoltaic array applied to Space Station Freedom evolutionary power requirements

NASA Technical Reports Server (NTRS)

Fisher, Edward M., Jr.

1991-01-01

Additional power is required to support Space Station Freedom (SSF) evolution. Boeing Defense and Space Group, LeRC, and Entech Corporation have participated in the development of efficiency gallium arsenide and gallium antimonide solar cells make up the solar array tandem cell stacks. Entech's Mini-Dome Fresnel Lens Concentrators focus solar energy onto the active area of the solar cells at 50 times one solar energy flux. Development testing for a flight array, to be launched in Nov. 1992 is under way with support from LeRC. The tandem cells, interconnect wiring, concentrator lenses, and structure were integrated into arrays subjected to environmental testing. A tandem concentrator array can provide high mass and area specific power and can provide equal power with significantly less array area and weight than the baseline array design. Alternatively, for SSF growth, an array of twice the baseline power can be designed which still has a smaller drag area than the baseline.

Evaluation of space station solar array technology

NASA Technical Reports Server (NTRS)

1972-01-01

The research concerning lightweight solar array assemblies since 1970 is reported. A bibliography of abstracts of documents used for reference during this period is included along with an evaluation of available solar array technology. A list of recommended technology programs is presented.

Hubble Space Telescope solar cell module thermal cycle test

NASA Technical Reports Server (NTRS)

Douglas, Alexander; Edge, Ted; Willowby, Douglas; Gerlach, Lothar

1992-01-01

The Hubble Space Telescope (HST) solar array consists of two identical double roll-out wings designed after the Hughes flexible roll-up solar array (FRUSA) and was developed by the European Space Agency (ESA) to meet specified HST power output requirements at the end of 2 years, with a functional lifetime of 5 years. The requirement that the HST solar array remain functional both mechanically and electrically during its 5-year lifetime meant that the array must withstand 30,000 low Earth orbit (LEO) thermal cycles between approximately +100 and -100 C. In order to evaluate the ability of the array to meet this requirement, an accelerated thermal cycle test in vacuum was conducted at NASA's Marshall Space Flight Center (MSFC), using two 128-cell solar array modules which duplicated the flight HST solar array. Several other tests were performed on the modules. The thermal cycle test was interrupted after 2,577 cycles, and a 'cold-roll' test was performed on one of the modules in order to evaluate the ability of the flight array to survive an emergency deployment during the dark (cold) portion of an orbit. A posttest static shadow test was performed on one of the modules in order to analyze temperature gradients across the module. Finally, current in-flight electrical performance data from the actual HST flight solar array will be tested.

Solar Cell and Array Technology Development for NASA Solar Electric Propulsion Missions

NASA Technical Reports Server (NTRS)

Piszczor, Michael; McNatt, Jeremiah; Mercer, Carolyn; Kerslake, Tom; Pappa, Richard

2012-01-01

NASA is currently developing advanced solar cell and solar array technologies to support future exploration activities. These advanced photovoltaic technology development efforts are needed to enable very large (multi-hundred kilowatt) power systems that must be compatible with solar electric propulsion (SEP) missions. The technology being developed must address a wide variety of requirements and cover the necessary advances in solar cell, blanket integration, and large solar array structures that are needed for this class of missions. Th is paper will summarize NASA's plans for high power SEP missions, initi al mission studies and power system requirements, plans for advanced photovoltaic technology development, and the status of specific cell and array technology development and testing that have already been conducted.

Extremely Black Vertically Aligned Carbon Nanotube Arrays for Solar Steam Generation.

PubMed

Yin, Zhe; Wang, Huimin; Jian, Muqiang; Li, Yanshen; Xia, Kailun; Zhang, Mingchao; Wang, Chunya; Wang, Qi; Ma, Ming; Zheng, Quan-Shui; Zhang, Yingying

2017-08-30

The unique structure of a vertically aligned carbon nanotube (VACNT) array makes it behave most similarly to a blackbody. It is reported that the optical absorptivity of an extremely black VACNT array is about 0.98-0.99 over a large spectral range of 200 nm-200 μm, inspiring us to explore the performance of VACNT arrays in solar energy harvesting. In this work, we report the highly efficient steam generation simply by laminating a layer of VACNT array on the surface of water to harvest solar energy. It is found that under solar illumination the temperature of upper water can significantly increase with obvious water steam generated, indicating the efficient solar energy harvesting and local temperature rise by the thin layer of VACNTs. We found that the evaporation rate of water assisted by VACNT arrays is 10 times that of bare water, which is the highest ratio for solar-thermal-steam generation ever reported. Remarkably, the solar thermal conversion efficiency reached 90%. The excellent performance could be ascribed to the strong optical absorption and local temperature rise induced by the VACNT layer, as well as the ultrafast water transport through the VACNT layer due to the frictionless wall of CNTs. Based on the above, we further demonstrated the application of VACNT arrays in solar-driven desalination.

Interaction of a solar array with an ion thruster due to the charge-exchange plasma

NASA Technical Reports Server (NTRS)

Kaufman, H. R.

1976-01-01

The generation of a charge exchange plasma by a thruster, the transport of this plasma to the solar array, and the interaction of the solar array with the plasma after it arrives are all described. The generation of this plasma is described accurately from thruster geometry and operating conditions. The transport of the charge exchange plasma was studied experimentally with a 15 cm thruster. A model was developed for simple thruster array configurations. A variety of experiments were surveyed for the interaction of the plasma at the solar array.

Thin-Film Solar Array Earth Orbit Mission Applicability Assessment

NASA Technical Reports Server (NTRS)

Hoffman, David J.; Kerslake, Thomas W.; Hepp, Aloysius F.; Raffaelle, Ryne P.

2002-01-01

This is a preliminary assessment of the applicability and spacecraft-level impact of using very lightweight thin-film solar arrays with relatively large deployed areas for representative Earth orbiting missions. The most and least attractive features of thin-film solar arrays are briefly discussed. A simple calculation is then presented illustrating that from a solar array alone mass perspective, larger arrays with less efficient but lighter thin-film solar cells can weigh less than smaller arrays with more efficient but heavier crystalline cells. However, a proper spacecraft-level systems assessment must take into account the additional mass associated with solar array deployed area: the propellant needed to desaturate the momentum accumulated from area-related disturbance torques and to perform aerodynamic drag makeup reboost. The results for such an assessment are presented for a representative low Earth orbit (LEO) mission, as a function of altitude and mission life, and a geostationary Earth orbit (GEO) mission. Discussion of the results includes a list of specific mission types most likely to benefit from using thin-film arrays. NASA Glenn's low-temperature approach to depositing thin-film cells on lightweight, flexible plastic substrates is also briefly discussed to provide a perspective on one approach to achieving this enabling technology. The paper concludes with a list of issues to be addressed prior to use of thin-film solar arrays in space and the observation that with their unique characteristics, very lightweight arrays using efficient, thin-film cells on flexible substrates may become the best array option for a subset of Earth orbiting missions.

Plasma Interactions with High Voltage Solar Arrays for a Direct Drive Hall Effect Thruster System

NASA Technical Reports Server (NTRS)

Schneider, T.; Horvater, M. A.; Vaughn, J.; Carruth, M. R.; Jongeward, G. A.; Mikellides, I. G.

2003-01-01

The Environmental Effects Group of NASA s Marshall Space Flight Center (MSFC) is conducting research into the effects of plasma interaction with high voltage solar arrays. These high voltage solar arrays are being developed for a direct drive Hall Effect Thruster propulsion system. A direct drive system configuration will reduce power system mass by eliminating a conventional power-processing unit. The Environmental Effects Group has configured two large vacuum chambers to test different high-voltage array concepts in a plasma environment. Three types of solar arrays have so far been tested, an International Space Station (ISS) planar array, a Tecstar planar array, and a Tecstar solar concentrator array. The plasma environment was generated using a hollow cathode plasma source, which yielded densities between 10(exp 6) - 10(exp 7) per cubic centimeter and electron temperatures of 0.5-1 eV. Each array was positioned in this plasma and biased in the -500 to + 500 volt range. The current collection was monitored continuously. In addition, the characteristics of arcing, snap over, and other features, were recorded. Analysis of the array performance indicates a time dependence associated with the current collection as well as a tendency for "conditioning" over a large number of runs. Mitigation strategies, to reduce parasitic current collection, as well as arcing, include changing cover-glass geometry and layout as well as shielding the solar cell edges. High voltage performance data for each of the solar array types tested will be presented. In addition, data will be provided to indicate the effectiveness of the mitigation techniques.

Preliminary space station solar array structural design study

NASA Technical Reports Server (NTRS)

Dorsey, J. T.; Bush, H. G.; Mikulas, M. M., Jr.

1984-01-01

Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.

Preliminary space station solar array structural design study

NASA Astrophysics Data System (ADS)

Dorsey, J. T.; Bush, H. G.; Mikulas, M. M., Jr.

Structurally efficient ways to support the large solar arrays (3,716 square meters which are currently considered for space station use) are examined. An erectable truss concept is presented for the on orbit construction of winged solar arrays. The means for future growth, maintenance, and repair are integrally designed into this concept. Results from parametric studies, which highlight the physical and structural differences between various configuration options are presented. Consideration is given to both solar blanket and hard panel arrays.

Development of the solar array deployment and drive system for the XTE spacecraft

NASA Technical Reports Server (NTRS)

Farley, Rodger; Ngo, Son

1995-01-01

The X-ray Timing Explorer (XTE) spacecraft is a NASA science low-earth orbit explorer-class satellite to be launched in 1995, and is an in-house Goddard Space Flight Center (GSFC) project. It has two deployable aluminum honeycomb solar array wings with each wing being articulated by a single axis solar array drive assembly. This paper will address the design, the qualification testing, and the development problems as they surfaced of the Solar Array Deployment and Drive System.

KSC-00pp1196

NASA Image and Video Library

2000-08-18

Workers in the Space Station Processing Facility watch closely as Solar Array Wing-3, a component of the International Space Station, is lowered toward the Integrated Electronic Assembly where it will be installed for testing. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1209

NASA Image and Video Library

2000-08-30

Workers in the Space Station Processing Facility prepare an overhead crane they will use to move a solar array, a component of the International Space Station, for installation onto the Integrated Equipment Assembly. The solar array is the second one being installed. They are scheduled to be launched on mission STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

KSC-00pp1197

NASA Image and Video Library

2000-08-18

Workers in the Space Station Processing Facility watch closely as Solar Array Wing-3, a component of the International Space Station, is moved toward the Integrated Electronic Assembly where it will be installed for testing. The solar array is scheduled to be launched on STS-97 in late November along with the P6 truss. The Station’s electrical power system (EPS) will use eight photovoltaic solar arrays to convert sunlight to electricity. Each of the eight solar arrays will be 112 feet long by 39 feet wide. The solar arrays are mounted on a “blanket” that can be folded like an accordion for delivery. Once in orbit, astronauts will deploy the blankets to their full size. Gimbals will be used to rotate the arrays so that they will face the Sun to provide maximum power to the Space Station

Thermal cycle testing of Space Station Freedom solar array blanket coupons

NASA Technical Reports Server (NTRS)

Scheiman, David A.; Schieman, David A.

1991-01-01

Lewis Research Center is presently conducting thermal cycle testing of solar array blanket coupons that represent the baseline design for Space Station Freedom. Four coupons were fabricated as part of the Photovoltaic Array Environment Protection (PAEP) Program, NAS 3-25079, at Lockheed Missile and Space Company. The objective of the testing is to demonstrate the durability or operational lifetime of the solar array welded interconnect design within the durability or operational lifetime of the solar array welded interconnect design within a low earth orbit (LEO) thermal cycling environment. Secondary objectives include the observation and identification of potential failure modes and effects that may occur within the solar array blanket coupons as a result of thermal cycling. The objectives, test articles, test chamber, performance evaluation, test requirements, and test results are presented for the successful completion of 60,000 thermal cycles.

Core-shell silicon nanowire solar cells

PubMed Central

Adachi, M. M.; Anantram, M. P.; Karim, K. S.

2013-01-01

Silicon nanowires can enhance broadband optical absorption and reduce radial carrier collection distances in solar cell devices. Arrays of disordered nanowires grown by vapor-liquid-solid method are attractive because they can be grown on low-cost substrates such as glass, and are large area compatible. Here, we experimentally demonstrate that an array of disordered silicon nanowires surrounded by a thin transparent conductive oxide has both low diffuse and specular reflection with total values as low as < 4% over a broad wavelength range of 400 nm < λ < 650 nm. These anti-reflective properties together with enhanced infrared absorption in the core-shell nanowire facilitates enhancement in external quantum efficiency using two different active shell materials: amorphous silicon and nanocrystalline silicon. As a result, the core-shell nanowire device exhibits a short-circuit current enhancement of 15% with an amorphous Si shell and 26% with a nanocrystalline Si shell compared to their corresponding planar devices. PMID:23529071

Lightweight, low-cost solar energy collector

NASA Technical Reports Server (NTRS)

Hochberg, Eric B. (Inventor); Costen, Michael K. (Inventor)

2006-01-01

A lightweight solar concentrator of the reflecting parabolic or trough type is realized via a thin reflecting film, an inflatable structural housing and tensioned fibers. The reflector element itself is a thin, flexible, specularly-reflecting sheet or film. The film is maintained in the parabolic trough shape by means of a plurality of identical tensioned fibers arranged to be parallel to the longitudinal axis of the parabola. Fiber ends are terminated in two identical spaced anchorplates, each containing a plurality of holes which lie on the desired parabolic contour. In a preferred embodiment, these fibers are arrayed in pairs with one fiber contacting the front side of the reflecting film and the other contacting the back side of the reflecting film. The reflective surface is thereby slidably captured between arrays of fibers which control the shape and position of the reflective film. Gas pressure in the inflatable housing generates fiber tension to achieve a truer parabolic shape.

Low cost solar array project silicon materials task. Development of a process for high capacity arc heater production of silicon for solar arrays

NASA Technical Reports Server (NTRS)

Fey, M. G.

1981-01-01

The experimental verification system for the production of silicon via the arc heater-sodium reduction of SiCl4 was designed, fabricated, installed, and operated. Each of the attendant subsystems was checked out and operated to insure performance requirements. These subsystems included: the arc heaters/reactor, cooling water system, gas system, power system, Control & Instrumentation system, Na injection system, SiCl4 injection system, effluent disposal system and gas burnoff system. Prior to introducing the reactants (Na and SiCl4) to the arc heater/reactor, a series of gas only-power tests was conducted to establish the operating parameters of the three arc heaters of the system. Following the successful completion of the gas only-power tests and the readiness tests of the sodium and SiCl4 injection systems, a shakedown test of the complete experimental verification system was conducted.

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1985-01-01

This is a view of a solar cell blanket deployed on a water table during the Solar Array deployment test. The Hubble Space Telescope (HST) Solar Arrays provide power to the spacecraft. The arrays are mounted on opposite sides of the HST, on the forward shell of the Support Systems Module. Each array stands on a 4-foot mast that supports a retractable wing of solar panels 40-feet (12.1-meters) long and 8.2-feet (2.5-meters) wide, in full extension. The arrays rotate so that the solar cells face the Sun as much as possible to harness the Sun's energy. The Space Telescope Operations Control Center at the Goddard Space Center operates the array, extending the panels and maneuvering the spacecraft to focus maximum sunlight on the arrays. The purpose of the HST, the most complex and sensitive optical telescope ever made, is to study the cosmos from a low-Earth orbit. By placing the telescope in space, astronomers are able to collect data that is free of the Earth's atmosphere. The HST Solar Array was designed by the European Space Agency and built by British Aerospace. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST.

Extremely Cost‐Effective and Efficient Solar Vapor Generation under Nonconcentrated Illumination Using Thermally Isolated Black Paper

PubMed Central

Liu, Zhejun; Song, Haomin; Ji, Dengxin; Li, Chenyu; Cheney, Alec; Liu, Youhai; Zhang, Nan; Zeng, Xie; Chen, Borui; Gao, Jun; Li, Yuesheng; Liu, Xiang; Aga, Diana; Jiang, Suhua; Yu, Zongfu

2017-01-01

Passive solar vapor generation represents a promising and environmentally benign method of water purification/desalination. However, conventional solar steam generation techniques usually rely on costly and cumbersome optical concentration systems and have relatively low efficiency due to bulk heating of the entire liquid volume. Here, an efficient strategy using extremely low‐cost materials, i.e., carbon black (powder), hydrophilic porous paper, and expanded polystyrene foam is reported. Due to the excellent thermal insulation between the surface liquid and the bulk volume of the water and the suppressed radiative and convective losses from the absorber surface to the adjacent heated vapor, a record thermal efficiency of ≈88% is obtained under 1 sun without concentration, corresponding to the evaporation rate of 1.28 kg (m2 h)−1. When scaled up to a 100 cm2 array in a portable solar water still system and placed in an outdoor environment, the freshwater generation rate is 2.4 times of that of a leading commercial product. By simultaneously addressing both the need for high‐efficiency operation as well as production cost limitations, this system can provide an approach for individuals to purify water for personal needs, which is particularly suitable for undeveloped regions with limited/no access to electricity. PMID:28616256

Photovoltaic module hot spot durability design and test methods

NASA Technical Reports Server (NTRS)

Arnett, J. C.; Gonzalez, C. C.

1981-01-01

As part of the Jet Propulsion Laboratory's Low-Cost Solar Array Project, the susceptibility of fat-plate modules to hot-spot problems is investigated. Hot-spot problems arise in modules when the cells become back-biased and operate in the negative-voltage quadrant, as a result of short-circuit current mismatch, cell cracking or shadowing. The details of a qualification test for determining the capability of modules of surviving field hot-spot problems and typical results of this test are presented. In addition, recommended circuit-design techniques for improving the module and array reliability with respect to hot-spot problems are presented.

SPS silicon reference system

NASA Technical Reports Server (NTRS)

Woodcock, G. R.

1980-01-01

The design analysis of a silicon power conversion system for the solar power satellite (SPS) is summarized. The solar array, consisting of glass encapsulated 50 micrometer silicon solar cells, is described. The general scheme for power distribution to the array/antenna interface is described. Degradation by proton irradiation is considered. The interface between the solar array and the klystron equipped power transmitter is described.

Versatile control of metal-assisted chemical etching for vertical silicon microwire arrays and their photovoltaic applications

PubMed Central

Um, Han-Don; Kim, Namwoo; Lee, Kangmin; Hwang, Inchan; Hoon Seo, Ji; Yu, Young J.; Duane, Peter; Wober, Munib; Seo, Kwanyong

2015-01-01

A systematic study was conducted into the use of metal-assisted chemical etching (MacEtch) to fabricate vertical Si microwire arrays, with several models being studied for the efficient redox reaction of reactants with silicon through a metal catalyst by varying such parameters as the thickness and morphology of the metal film. By optimizing the MacEtch conditions, high-quality vertical Si microwires were successfully fabricated with lengths of up to 23.2 μm, which, when applied in a solar cell, achieved a conversion efficiency of up to 13.0%. These solar cells also exhibited an open-circuit voltage of 547.7 mV, a short-circuit current density of 33.2 mA/cm2, and a fill factor of 71.3% by virtue of the enhanced light absorption and effective carrier collection provided by the Si microwires. The use of MacEtch to fabricate high-quality Si microwires therefore presents a unique opportunity to develop cost-effective and highly efficient solar cells. PMID:26060095

Low cost solar array project: Experimental process system development unit for producing semiconductor-grade silicon using the silane-to-silicon process

NASA Technical Reports Server (NTRS)

1981-01-01

The results of the free space reactor experimental work are summarized. Overall, the objectives were achieved and the unit can be confidently scaled to the EPSDU size based on the experimental work and supporting theoretical analyses. The piping and instrumentation of the fluidized bed reactor was completed.

Quantitative Analysis of Defects in Silicon. Silicon Sheet Growth Development for the Large Area Silicon Sheet Task of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Natesh, R.; Smith, J. M.; Qidwai, H. A.

1979-01-01

The various steps involved in the chemical polishing and etching of silicon samples are described. Data on twins, dislocation pits, and grain boundaries from thirty-one (31) silicon sample are also discussed. A brief review of the changes made to upgrade the image analysis system is included.

Comparison of candidate solar array maximum power utilization approaches. [for spacecraft propulsion

NASA Technical Reports Server (NTRS)

Costogue, E. N.; Lindena, S.

1976-01-01

A study was made of five potential approaches that can be utilized to detect the maximum power point of a solar array while sustaining operations at or near maximum power and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

A Practical Guide To Solar Array Simulation And PCDU Test

NASA Astrophysics Data System (ADS)

Schmitz, Noah; Carroll, Greg; Clegg, Russell

2011-10-01

Solar arrays consisting of multiple photovoltaic segments provide power to satellites and charge internal batteries for use during eclipse. Solar arrays have unique I-V characteristics and output power which vary with environmental and operational conditions such as temperature, irradiance, spin, and eclipse. Therefore, specialty power solutions are needed to properly test the satellite on the ground, especially the Power Control and Distribution Unit (PCDU) and the Array Power Regulator (APR.) This paper explores some practical and theoretical considerations that should be taken into account when choosing a commercial, off-the-shelf solar array simulator (SAS) for verification of the satellite PCDU. An SAS is a unique power supply with I-V output characteristics that emulate the solar arrays used to power a satellite. It is important to think about the strengths and the limitations of this emulation capability, how closely the SAS approximates a real solar panel, and how best to design a system using SAS as components.

Simulation of a solar-assisted absorption air conditioning system for applications in Puerto Rico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khan, A.Y.; Hernandez, H.R.; Gonzalez, J.E.

1995-11-01

Regions without conventional fuel sources have felt the need for the development of new technologies for air conditioning applications as cost of electrical energy production has continually risen the cost of air conditioning by conventional means. This paper deals with the simulation of a solar-assisted absorption system for air conditioning application in Puerto Rico. A simple thermodynamic model for the solar assisted absorption system has been developed. A solar energy based thermal storage system along with an auxiliary heater is used to provide the required energy in the generator of this absorption system. Results from a parametric analysis to studymore » the influence of the absorber, generator, condenser and evaporator temperatures, on the COP of the system are presented in this paper. The influence of two different refrigerant/absorbent pairs, water/lithium bromide and water/lithium-chloride have also been studied. A sub-system consisting of an array of flat plate solar collectors along with a hot water storage is modeled and verified with the data from an already existing system operating in Sacramento. Finally, off-design performance of a 35 kW solar-assisted absorption system is simulated to report the auxiliary heating requirement for a typical summer day operation in southern Puerto Rico.« less

Will we exceed 50% efficiency in photovoltaics?

NASA Astrophysics Data System (ADS)

Luque, Antonio

2011-08-01

Solar energy is the most abundant and reliable source of energy we have to provide for the multi-terawatt challenge we are facing. Although huge, this resource is relatively dispersed. High conversion efficiency is probably necessary for cost effectiveness. Solar cell efficiencies above 40% have been achieved with multijunction (MJ) solar cells. These achievements are here described. Possible paths for improvement are hinted at including third generation photovoltaics concepts. It is concluded that it is very likely that the target of 50% will eventually be achieved. This high efficiency requires operating under concentrated sunlight, partly because concentration helps increase the efficiency but mainly because the cost of the sophisticated cells needed can only be paid by extracting as much electric power form each cell as possible. The optical challenges associated with the concentrator optics and the tools for overcoming them, in particular non-imaging optics, are briefly discussed and the results and trends are described. It is probable that optical efficiency over 90% will be possible in the future. This would lead to a module efficiency of 45%. The manufacturing of a concentrator has to be addressed at three levels of integration: module, array, and photovoltaic (PV) subfield. The PV plant as a whole is very similar than a flat module PV plant with two-axes tracking. At the module level, the development of tools for easy manufacturing and quality control is an important topic. Furthermore, they can accommodate in different position cells with different spectral sensitivities so complementing the effort in manufacturing MJ cells. At the array level, a proper definition of the nameplate watts, since the diffuse light is not used, is under discussion. The cost of installation of arrays in the field can be very much reduced by self aligning tracking control strategies. At the subfield level, aspects such as the self shadowing of arrays causes the CPV subfields to be sparsely packed leading to a ground efficiency, in the range of 10%, that in some cases will be below that of fixed modules of much lower cell efficiency. All this taken into account, High Concentration PV (HCPV) has the opportunity to become the cheapest of the PV technologies and beat the prevalent electricity generation technologies. Of course the way will be paved with challenges, and success is not guaranteed.

Power and Propulsion System Design for Near-Earth Object Robotic Exploration

NASA Technical Reports Server (NTRS)

Snyder, John Steven; Randolph, Thomas M.; Landau, Damon F.; Bury, Kristen M.; Malone, Shane P.; Hickman, Tyler A.

2011-01-01

Near-Earth Objects (NEOs) are exciting targets for exploration; they are relatively easy to reach but relatively little is known about them. With solar electric propulsion, a vast number of interesting NEOs can be reached within a few years and with extensive flexibility in launch date. An additional advantage of electric propulsion for these missions is that a spacecraft can be small, enabling a fleet of explorers launched on a single vehicle or as secondary payloads. Commercial, flight-proven Hall thruster systems have great appeal based on their performance and low cost risk, but one issue with these systems is that the power processing units (PPUs) are designed for regulated spacecraft power architectures which are not attractive for small NEO missions. In this study we consider the integrated design of power and propulsion systems that utilize the capabilities of existing PPUs in an unregulated power architecture. Models for solar array and engine performance are combined with low-thrust trajectory analyses to bound spacecraft design parameters for a large class of NEO missions, then detailed array performance models are used to examine the array output voltage and current over a bounded mission set. Operational relationships between the power and electric propulsion systems are discussed, and it is shown that both the SPT-100 and BPT-4000 PPUs can perform missions over a solar range of 0.7 AU to 1.5 AU - encompassing NEOs, Venus, and Mars - within their operable input voltage ranges. A number of design trades to control the array voltage are available, including cell string layout, array offpointing during mission operations, and power draw by the Hall thruster system.