Energy

Method and Circuit for In-Situ Health Monitoring of Solar Cells in Space

Potential applications include use in diagnostics for terrestrial solar power generation systems. John H. Glenn Research Center, Cleveland, Ohio NASA’s Glenn Research Center has developed a method and apparatus for in-situ health monitoring of solar cells. The innovation is a novel approach to solar cell monitoring, as it is radiation- hard, consumes few system resources, and uses commercially available components. The system operates at temperatures from –55 to 225 °C, allowing it to reside close to the array in direct sunlight. The circuitry measures solar cell current versus voltage (I-V) curves using relatively inexpensive electronics, a single switchable +28 V power bus, and two analog-to-digital (A/D) converter channels. A single transistor is used as a variable resistive load across the cell, rather than the large resistor arrays or active current sources normally used to characterize cells. Originally developed for space, the technology can be adapted for use in terrestrial solar power generation systems.

Posted in: Briefs, Energy, Solar Power

Read More >>

Foldable and Deployable Power Collection System

The lightweight solar power array can be used in electric vehicles, portable and field-deployable power systems, and power for emergency response operations. Marshall Space Flight Center, Alabama NASA’s Marshall Space Flight Center is developing a lightweight space-based solar power array with a high power-to-stowed-volume and weight ratio. The system provides power to small satellites and CubeSats that are power starved, operating on extremely limited power because of the size restrictions for housing onboard power sources. The beauty of NASA’s new solar unit is in its simplicity and packaged power density. Small satellites cannot take advantage of deployable high-efficiency solar cell arrays due to their complexity and mechanical needs; the weight and volume requirements exceed what is available in small satellites and CubeSats. The new system, for example, is compact enough to provide a 3U CubeSat with ~200 Watts, or a 6U with 500 Watts of power. NASA is developing the technology and is looking for partners to license and commercialize it.

Posted in: Briefs, Energy, Solar Power

Read More >>

Solid-State Ultracapacitor

Marshall Space Flight Center, Alabama NASA’s Marshall Space Flight Center has developed a solid-state ultracapacitor utilizing a novel nanocomposite dielectric material. The material’s design is based on the internal barrier layer capacitance (IBLC) concept, and it uses novel dielectric and metallic conductive ink formulations.

Posted in: Briefs, Energy

Read More >>

Double-acting Extremely Light Thermo-Acoustic (DELTA) Converter

This technology enables a new class of lightweight power systems for small aircraft, camping, or micro-cogeneration that is small, quiet, efficient, and essentially maintenance-free. John H. Glenn Research Center, Cleveland, Ohio Power generation from an external or internal heat source using thermal energy conversion technologies such as solid-state thermionics and thermoelectrics or dynamic conversion with Otto, Stirling, Brayton, or Rankine technologies is fundamentally limited in maximum specific power due to either low efficiency and/or operating frequency. These solid-state technologies are low voltage and hence produce a high DC current that restricts their minimum geometry to approximately 4 A/mm2 to avoid overheating. High-power implementations of this technology class are inefficient, large, and heavy.

Posted in: Briefs, Energy

Read More >>

Chassis Short Mitigation and Characterization Technique for the Multi-Mission Radioisotope Thermoelectric Generator

NASA’s Jet Propulsion Laboratory, Pasadena, California The radioisotope thermoelectric generator (RTG) is a flight-proven, capable source of power that reliably converts heat into electricity. NASA and the Department of Energy (DoE) have developed a new generation of such power systems that could be used for a variety of space missions. The newest RTG, called a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), has been designed to operate on Mars and in the vacuum of space. However, shorts between the internal electrical power circuit and chassis frame of the MMRTG have been observed in the engineering unit, qualification unit, and flight unit. The internal shorts seemed to appear and sometimes clear spontaneously. A root cause has not been determined for these internal shorts, and their resistance, power rating, and energy rating are largely unknown. A mitigation and measurement technique is needed.

Posted in: Briefs, Energy

Read More >>

White, Electrically Conductive, Radiation-Stable, Thermal Control Coating

Goddard Space Flight Center, Greenbelt, Maryland A highly reflective, white conductive coating system was developed using a layered approach with a combination of commercially available white conductive pigments within a conductive binder system. The top coating is a space-stable, radiation-resistant, highly reflective coating that has been tailored to provide optimum reflectance properties and meet vacuum thermal surface resistivities. The combined layer is a mixture of a highly reflective, electrically dissipative coating and a moderately reflective but highly conductive pigment in a conductive binder. A second, underlying layer of conductive white coating offers optimum adhesion to metal substrates and the topcoat. The system vacuum resistivity at room temperature is approximately 1 × 109 ohms/sq, and has a solar absorptance of less than 0.13 as measured on a Cary 5000 spectrophotometer.

Posted in: Briefs, TSP, Thermoelectrics, Coatings & Adhesives, Materials

Read More >>

Piezoelectric Actuated Inchworm Motor (PAIM)

This linear piezoelectric actuator can operate at temperatures of 77 K or below. NASA’s Jet Propulsion Laboratory, Pasadena, California Conventional piezoelectric materials, such as PZTs, have reasonably high electromechanical coupling over 70%, and excellent performance at room temperature. However, their coupling factor (converting electrical to mechanical energy and vice versa) drops substantially at cryogenic temperatures, as the extrinsic contributions (domain wall motions) are almost frozen out below 130 K.

Posted in: Briefs, TSP, Energy, Fluid Handling, Motors & Drives

Read More >>

The U.S. Government does not endorse any commercial product, process, or activity identified on this web site.