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

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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Advanced photovoltaic solar array design assessment

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.

Stella, Paul↗
NASA NTRS1976

System tests with electric thruster beam and accelerator directly powered from laboratory solar arrays

Laboratory high voltage solar arrays were operated directly connected to power the beam and accelerator loads of an 8-centimeter ion thruster. The beam array comprised conventional 2 by 2 centimeter solar cells; the accelerator array comprised multiple junction edge-illuminated solar cells. Conventional laboratory power supplies powered the thruster's other loads. Tests were made to evaluate thruster performance and to investigate possible electrical interactions between the solar arrays and the thruster. Thruster performance was the same as with conventional laboratory beam and accelerator power supplies. Most of the thruster beam short circuits that occurred during solar array operation were cleared spontaneously without automatic or manual intervention. No spontaneous clearing occurred during conventional power supply operation.

Stover, J. B.↗
NASA NTRS1980

Design and flight performance of the Pioneer Venus Multiprobe and Orbiter solar arrays

The designs of the solar arrays for the Pioneer Venus Orbiter and Multiprobe spacecraft are described, and the power output predicted for these arrays is compared with the in-space performance. The Orbiter solar array was designed to produce a minimum of 329 W at 28 V after 243 days in Venus orbit, except during eclipses and periapsis phases, when battery power was to be used. After 492 days in orbit, this solar array was producing 365.3 W at 29.6 V, exceeding its design objectives. The Multiprobe solar array produced sufficient power at low sun angles to effect the release of the large probe and the three small probes and to power the scientific instruments onboard the spacecraft during its approach and destructive entry into the Venusian atmosphere.

Goldhammer, L. J.↗
NASA NTRS2019

Photogrammetry-Based Analysis of the On-Orbit Structural Dynamics of the Roll-Out Solar Array

The Roll-Out Solar Array (ROSA) flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017. ROSA is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors. This paper will discuss the results of various structural dynamics experiments conducted on the ISS during the weeks following launch. Data gathered from instrumentation on the solar array wing during the experiments was previously compared with pre-flight predictions from two different Finite Element Modeling (FEM) efforts. In this paper, data generated from photogrammetry is compared with accelerometer data and used to extend previous conclusions. Whereas previous analyses were only able to track the accelerations of six discrete points on the structure and photovoltaic (PV) blanket of ROSA, the photogrammetry analysis makes available displacements for dozens of points distributed throughout the array. This larger data set makes it possible to compare higher-order PV blanket modes with FEM predictions, in addition to verifying conclusions reached using accelerometer data. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays.

Chamberlain, Matthew K.↗
NASA NTRS2017

On-Orbit Structural Dynamics Performance of the Roll-Out Solar Array

The Roll-Out Solar Array (ROSA) flight experiment was launched to the International Space Station (ISS) on June 3rd, 2017. ROSA is an innovative, lightweight solar array with a flexible substrate that makes use of the stored strain energy in its composite structural members to provide deployment without the use of motors. This paper will discuss the results of various structural dynamics experiments conducted on the ISS during the weeks following launch. Data gathered from instrumentation on the solar array wing during the experiments are compared with pre-flight predictions from two different finite element modeling efforts. Two distinct methods were used to reconstruct the modal characteristics of ROSA from the data collected on orbit. Of particular interest in this effort are the first few system modes and mode shapes of the array, the amount of structural damping present, and degree of structural thermal interaction seen during eclipse exit. Discrepancies between the behavior predicted by the models and that observed on orbit are identified and discussed. The goal in this effort was to better understand the performance of ROSA and to improve modeling efforts for future designs of similar solar arrays.

Chamberlain, Matthew K.↗
NASA NTRS2005

Promising Results from Three NASA SBIR Solar Array Technology Development Programs

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.

Eskenazi, Mike↗
NASA NTRS1978

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

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.

Reed, W. H.↗
NASA NTRS1981

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

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.

Fey, M. G.↗
NASA NTRS1982

Solar Array Flight Experiment (SAFE)

The solar arrays flight experiment consists of four experiments on two different flights. The first experiment, termed the baseline, has a basic purpose to demonstrate the flight readiness of lightweight solar array technology for solar electric propulsion and other payload power applications. The early availability of this experiment and its basic large space structure characteristics make it a logical candidate to demonstrate other disciplines critical to large space structures. These demonstrations form the basis for three other solar array experiments, two in remote sensing and one in control. All of these experiments are briefly reviewed in this paper.

Schock, R. W.↗
NASA NTRSDate not supplied

Space Technology Mission Directorate - Game Changing Development Program - Vertical Solar Array Technology Project

The Vertical Solar Array Technology (VSAT) project is focused on the development of solar array technologies necessary for sustained presence on the lunar surface circa 2028. Existing solar array structures and deployment system technologies are designed for either zero-g or horizontal surface deployment. VSAT will explore vertical array deployment on extension masts of up to 10m in length in order to capture near continuous sun light at the lunar south pole.

GCD↗
NASA NTRS1993

Enhanced plasma current collection from weakly conducting solar array blankets

Among the solar cell technologies to be tested in space as part of the Solar Array Module Plasma Interactions Experiment (SAMPIE) will be the Advanced Photovoltaic Solar Array (APSA). Several prototype twelve cell coupons were built for NASA using different blanket materials and mounting techniques. The first conforms to the baseline design for APSA which calls for the cells to be mounted on a carbon loaded Kapton blanket to control charging in GEO. When deployed, this design has a flexible blanket supported around the edges. A second coupon was built with the cells mounted on Kapton-H, which was in turn cemented to a solid aluminum substrate. A final coupon was identical to the latter but used germanium coated Kapton to control atomic oxygen attack in LEO. Ground testing of these coupons in a plasma chamber showed considerable differences in plasma current collection. The Kapton-H coupon demonstrated current collection consistent with exposed interconnects and some degree of cell snapover. The other two coupons experienced anomalously large collection currents. This behavior is believed to be a consequence of enhanced plasma sheaths supported by the weakly conducting carbon and germanium used in these coupons. The results reported here are the first experimental evidence that the use of such materials can result in power losses to high voltage space power systems.

Hillard, G. Barry↗
NASA NTRS1997

Pre-Flight Dark Forward Electrical Testing of the Mir Cooperative Solar Array

The Mir Cooperative Solar Array (MCSA) was developed jointly by the United States (US) and Russia to provide approximately 6 kW of photovoltaic power to the Russian space station Mir. After final assembly in Russia, the MCSA was shipped to the NASA Kennedy Space Center (KSC) in the summer of 1995 and launched to Mir in November 1995. Program managers were concerned of the potential for MCSA damage during the transatlantic shipment and the associated handling operations. To address this concern, NASA Lewis Research Center (LERC) developed an innovative dark-forward electrical test program to assess the gross electrical condition of each generator following shipment from Russia. The use of dark test techniques, which allow the array to remain in the stowed configuration, greatly simplifies the checkout of large area solar arrays. MCSA dark electrical testing was successfully performed at KSC in July 1995 following transatlantic shipment. Data from this testing enabled engineers to quantify the effects of potential MCSA physical damage that would degrade on-orbit electrical performance. In this paper, an overview of the principles and heritage of photovoltaic array dark testing is given. The specific MCSA dark test program is also described including the hardware, software, testing procedures and test results. The current-voltage (4) response of both solar cell circuitry and by-pass diode circuitry was obtained. To guide the development of dark test hardware, software and procedures, a dedicated FORTRAN computer code was developed to predict the dark 4 responses of generators with a variety of feasible damage modes. By comparing the actual test data with the predictions, the physical condition of the generator could be inferred. Based on this data analysis, no electrical short-circuits or open-circuits were detected. This suggested the MCSA did not sustain physical damage that affected electrical performance during handling and shipment from Russia to the US. Good agreement between the test data and computational predictions indicated MCSA electrical performance was amenable to accurate analysis and was well understood.

Kerslake, Thomas W.↗
NASA NTRS1996

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

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.

Forkapa, Mark J.↗
NASA NTRS1975

SEPS solar array design and technology evaluation

The solar array system considered 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, and an array electrical harness. A technology evaluation is performed to assess the applicable solar array state-of-the-art and to define the supporting effort necessary to achieve technology readiness for meeting the Solar Electric Propulsion Stage (SEPS) solar array design requirements. Details of mechanical design are discussed along with questions of electrical design, operational reliability advantages, and array assembly advantages.

Elms, R. V., Jr.↗
NASA NTRS1979

Effect of parasitic plasma currents on solar-array power output

Solar-array voltage-current curves are calculated by assuming the existence of parasitic loads that consist of local currents of charged particles collected by the array. Three cases of interest are calculated to demonstrate how the distribution and magnitude of parasitic currents affect output. Solar array performance degradation became significant when the total parasitic current plus the load current exceeded the short-circuit current. Approximate graphical methods were useful for many applications. Power loss, which was calculated by summing the product of parasitic current and the local potential, underestimated the loss in maximum power.

Domitz, S.↗
NASA NTRS1970

The revised solar array synthesis computer program

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.

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