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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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This presentation gives an overview of recent research activities at NASA Glenn Research Center (GRC). The presentation covers research associated with materials for high voltage aerospace applications such electric propulsion systems, planetary exploration.
This presentation provides the background information on NASA-GRC high voltage (HV) materials team research efforts towards electrified propulsion systems since 2016 . Additionally, it covers polymer and ceramic filler materials development for HV electrical insulation composites, copper/ carbon nanotube hybrid conductors, modeling efforts, HV test capabilities, and future material processing capabilities.
During an investigation of anomalous voltages during a NASA scientific mission, a NASA Engineering and Safety Center (NESC) team discovered that the design of NiH 2 CPV batteries may be susceptible to a unique electrolyte bridging between the two internal cells resulting in undesired ionic current flow. This condition can lead to depletion of the capacity within one of the two cells.
Most commercial cylindrical 18650 Lithium-Ion (Li-Ion) cells have two internal protective devices: the Positive Temperature Coefficient (PTC) and the Current Interrupt Device (CID). The PTC protects the cells under external short conditions and the CID protects the cells under overcharge conditions. While proven to be effective at the single cell and small-size battery levels, these devices do not always offer protection when used in high-voltage and high-capacity battery designs.
Very lossy powdered iron material, in the lining of a polyester resin, replaces the dielectric material in the short coaxial transmission line of a simple filter. The lossy material absorbs microwave signals along high voltage power supply leads.
A liquid switch which does not depend on any mechanical, gravitational, or inertial actuation is developed for use in space environments. It may be remotely operated on low dc voltage.
A voltage-tuned oscillator circuit is described which sweeps the output signal frequency linearly exponentially varying with time.
Function generator utilizing parallel impedance networks with zener diodes produces functions which are discontinuous in slope. The function generated appears at the output of the parallel network in the form of a voltage varying in time.
Using a zener diode as the reference element, a simple transistorized circuit provides a stable variable reference voltage.
Transistorized clamping circuit clamps either of two voltage levels to input of digital-to-analog resistive matrix with 0.1 percent error. Clamping circuit technique has analog, digital, and hybrid circuit applications.
Self-oscillating dc to ac converter with transistor switching to produce a square wave output is used for low and high voltage power sources. The converter has a high efficiency throughout a wide range of loads.
Two or more series RLC circuits are used with a negative feedback amplifier to make a voltage variable oscillator. This combination results in high phase stability and optimum frequency modulation.
Voltage Controlled Oscillator /VCO/, represented by an equivalent RF circuit, is easily adjusted for optimum performance by varying the circuit parameter. It contains a crystal drive level which is also easily adjusted to obtain minimum phase noise.
Tri-electrode cold cathode X-ray impulse tube of simple construction and low operating voltage
High voltage pulse generator with solid state components - transistor circuits
High voltage power supply design for lunar X-ray diffractometer
Monolithic silicon integrated differential amplifier circuit developed with single ended output and feedback controlled voltage gain
Time-base encoder using sinusoidal reference voltage which does not produce undesirable switching transients resulting from abrupt variation