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

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NASA NTRS1977

Design of space-type electronic power transformers

Both open and encapsulated varieties of high reliability, low weight, and high efficiency moderate and high voltage transformers were investigated to determine the advantages and limitations of their construction in the ranges of power and voltage required for operation in the hard vacuum environment of space. Topics covered include: (1) selection of the core material; (2) preliminary calculation of core dimensions; (3) selection of insulating materials including magnet wire insulation, coil forms, and layer and interwinding insulation; (4) coil design; (5) calculation of copper losses, core losses and efficiency; (6) calculation of temperature rise; and (7) optimization of design with changes in core selection or coil design as required to meet specifications.

Ahearn, J. F.↗

NASA NTRSDate not supplied

Reliable Power Hibernation and Recovery for Solar Powered Lunar Missions

NASA Glenn Research Center has been working on a solution to surviving the lunar night based on the discovery that Li-Ion cells can survive the freeze/thaw process. This implies that a lunar surface spacecraft could hibernate through the coldest portions of the night and recover at lunar dawn. Survival and recovery also depend on power electronics capable of tolerating the cold and reliably starting at lunar dawn based on solar array output alone. GRC is working with STMD Space Technology Research Grant investigators to characterize Li-ion cells through the freeze-thaw process and fully understand the electro-chemical and thermal-mechanical processes to assure reliable cell hibernation and recovery. Further, we are working with investigators to determine what power semiconductor material, transistor technology, and power architecture is best suited for reliable cold start at lunar dawn and methodically restoring the power system to full operation for the next lunar cycle.

Spacecraft Power↗

NASA NTRS1979

Preliminary study, analysis and design for a power switch for digital engine actuators

Innovative control configurations using high temperature switches to operate actuator driving solenoids were studied. The impact on engine control system life cycle costs and reliability of electronic control and (ECU) heat dissipation due to power conditioning and interface drivers were addressed. Various power supply and actuation schemes were investigated, including optical signal transmission and electronics on the actuator, engine driven alternator, and inside the ECU. The use of a switching shunt power conditioner results in the most significant decrease in heat dissipation within the ECU. No overall control system reliability improvement is projected by the use of remote high temperature switches for solenoid drivers.

Beattie, E. C.↗

NASA NTRS2000

Wide-Temperature Electronics for Thermal Control of Nanosats

This document represents a presentation which examines the wide and low-temperature electronics required for NanoSatellites. In the past, larger spacecraft used Radioisotope Heating Units (RHU's). The advantage of the use of these electronics is that they could eliminate or reduce the requirement for RHU's, reduce system weight and simplify spacecraft design by eliminating containment/support structures for RHU's. The Glenn Research Center's Wide/Low Temperature Power Electronics Program supports the development of power systems capable of reliable, efficient operation over wide and low temperature ranges. Included charts review the successes and failures of various electronic devices, the IRF541 HEXFET, The NE76118n-Channel GaAS MESFET, the Lithium Carbon Monofluoride Primary Battery, and a COTS DC-DC converter. The preliminary result of wide/low temperature testing of CTS and custom parts and power circuit indicate that through careful selection of components and technologies it is possible to design and build power circuits which operate from room temperature to near 100K.

Dickman, John Ellis↗

NASA NTRS1994

Advanced technology for a satellite multichannel demultiplexer/demodulator

Satellite on-board processing is needed to efficiently service multiple users while at the same time minimizing earth station complexity. The processing satellite receives a wideband uplink at 30 GHz and down-converts it to a suitable intermediate frequency. A multichannel demultiplexer then separates the composite signal into discrete channels. Each channel is then demodulated by bulk demodulators, with the baseband signals routed to the downlink processor for retransmission to the receiving earth stations. This type of processing circumvents many of the difficulties associated with traditional bent-pipe repeater satellites. Uplink signal distortion and interference are not retransmitted on the downlink. Downlink power can be allocated in accordance with user needs, independent of uplink transmissions. This allows the uplink users to employ different data rates as well as different modulation and coding schemes. In addition, all downlink users have a common frequency standard and symbol clock on the satellite, which is useful for network synchronization in time division multiple access schemes. The purpose of this program is to demonstrate the concept of an optically implemented multichannel demultiplexer (MCD). A proof-of-concept (POC) model has been developed which has the ability to receive a 40 MHz wide composite signal consisting of up to 1000 40 kHz QPSK modulated channels and perform the demultiplexing process. In addition a set of special test equipment (STE) has been configured to evaluate the performance of the POC model. The optical MCD is realized as an acousto-optic spectrum analyzer utilizing the capability of Bragg cells to perform the required channelization. These Bragg cells receive an optical input from a laser source and an RF input (the signal). The Bragg interaction causes optical output diffractions at angles proportional to the RF input frequency. These discrete diffractions are optically detected and output to individual demodulators for baseband conversion. Optimization of the MCD design was conducted in order to achieve a compromise between two opposing sources of signal degradation: adjacent channel interference and intersymbol interference. The system was also optimized to allow simple, inexpensive ground stations communications with the MCD. These design goals led to the realization of a POC MCD which demonstrates the demultiplexing function with minimal signal degradation. Performance evaluation results using the STE equipment indicate that the dynamic range of the demultiplexer in the presence of adjacent and multiple channel loading is 40 - 50 dB. Measured bit error rate (BER) probabilities varied from the predicted theoretical results by one dB or less. The performance of the proof-of-concept model indicate that the development of a space qualified optically implemented MCD are feasible. The advantages to such an implementation include reduced size, weight and power and increased reliability when compared with electronic approaches. All of these factors are critical to on-board satellite processors. Further optimization can be conducted which trade ground station complexity and MCD performance to achieve desired system results.

Abramovitz, Irwin J.↗

NASA NTRS2016

Conceive, Believe and Achieve; A Path to Miniaturization, COTS Infusion, and Size Weight and Power Realization for Flight

JPL along with other aerospace agencies such as the US Air Force Space Pro-grams and a packaging technology innovator, i3 Electronics, Inc., are evaluating the use of state-of-the-art (SOA) commercial off-the-shelf (COTS) and alternative packaging technologies for future high performance and high reliability space applications. Utilization of SOA COTS technologies have resulted in large scale reduction in electronics volume, weight, power, cost and schedule with outstanding electrical performance and high reliability. We will share JPL’s joint design, architectural approach, alternative substrate materials selection, associated processes, and mission assurance role in identifying reliability and qualification risks, as part of the three year Heterogeneous Packaging/Device Integration effort under the guidance and leadership of JPL’s Mission Assurance Directorate.

Hunter, Don J.↗

NASA NTRS2007

Diaphragm Pump With Resonant Piezoelectric Drive

A diaphragm pump driven by a piezoelectric actuator is undergoing development. This pump is intended to be a prototype of lightweight, highly reliable pumps for circulating cooling liquids in protective garments and high-power electronic circuits, and perhaps for some medical applications. The pump would be highly reliable because it would contain no sliding seals or bearings that could wear, the only parts subject to wear would be two check valves, and the diaphragm and other flexing parts could be designed, by use of proven methods, for extremely long life. Because the pump would be capable of a large volumetric flow rate and would have only a small dead volume, its operation would not be disrupted by ingestion of gas, and it could be started reliably under all conditions. The prior art includes a number piezoelectrically actuated diaphragm pumps. Because of the smallness of the motions of piezoelectric actuators (typical maximum strains only about 0.001), the volumetric flow rates of those pumps are much too small for typical cooling applications. In the pump now undergoing development, mechanical resonance would be utilized to amplify the motion generated by the piezoelectric actuator and thereby multiply the volumetric flow rate. The prime mover in this pump would be a stack of piezoelectric ceramic actuators, one end of which would be connected to a spring that would be part of a spring-and-mass resonator structure. The mass part of the resonator structure would include the pump diaphragm (see Figure 1). Contraction of the spring would draw the diaphragm to the left, causing the volume of the fluid chamber to increase and thereby causing fluid to flow into the chamber. Subsequent expansion of the spring would push the diaphragm to the right, causing the volume of the fluid chamber to decrease, and thereby expelling fluid from the chamber. The fluid would enter and leave the chamber through check valves. The piezoelectric stack would be driven electrically to make it oscillate at the resonance frequency of the spring and- mass structure. This frequency could be made high enough (of the order of 400 Hz) that the masses of all components could be made conveniently small. The resonance would amplify the relatively small motion of the piezoelectric stack (a stroke of the order of 10 m) to a diaphragm stroke of the order of 0.5 mm. The exact amplification factor would depend on the rate of damping of oscillations; this, in turn, would depend on details of design and operation, including (but not limited to) the desired pressure rise and volumetric flow rate. In order to obtain resonance with large displacement, the damping rate must be low enough that the energy imparted to the pumped fluid on each stroke is much less than the kinetic and potential energy exchanged between the mass and spring during each cycle of oscillation. To minimize the power demand of the pump, a highly efficient drive circuit would be used to excite the piezoelectric stack. This circuit (see Figure 2) would amount to a special-purpose regenerative, switching power supply that would operate in a power-source mode during the part of an oscillation cycle when the excitation waveform was positive and in a power-recovery mode during the part of the cycle when the excitation waveform was negative. The circuit would include a voltage-boosting dc-to-dc converter that would convert between a supply potential of 24 Vdc and the high voltage needed to drive the piezoelectric stack. Because of the power-recovery feature, the circuit would consume little power. It should be possible to build the circuit as a compact unit, using readily available components.

Izenson, Michael G.↗

NASA NTRS2024

Extended Investigation into Fault-Tolerant Integrated Motor Drive for a Quadrotor Urban Air Mobility (UAM) Aircraft

Electric propulsor machines and their associated power electronics have been identified in past studies as low-reliability components in emerging Urban Air Mobility (UAM) Vertical Takeoff and Landing (VTOL) vehicles that raise their predicted catastrophic failure rates. This research effort extends previously presented work investigating the use of fault-tolerant (FT) motor drives in quadrotor aircraft as a promising approach to significantly increase their mean-time-to-failure (MTTF). In particular, fault-tolerant modular motor drives (FT-MMDs) are identified as strong candidates for closing the electric propulsor reliability gap. These FT-MMDs divide a machine drive into multiple redundant modules, each consisting of three phase stator windings and power electronics units, enabling continued machine operation after a module failure. Achieving the highest possible isolation between modules (physical, magnetic, thermal, electrical) is critically important in FT-MMDs to prevent the propagation of any failure between modules. Key additional requirements for achieving the highest possible reliability characteristics with FT-MMDs are high repair rates and aggressive suppression of all single-point failures.

quadrotor↗

NASA NTRS1983

Research on spacecraft electrical power conversion

The history of spacecraft electrical power conversion in literature, research and practice is reviewed. It is noted that the design techniques, analyses and understanding which were developed make today's contribution to power computers and communication installations. New applications which require more power, improved dynamic response, greater reliability, and lower cost are outlined. The switching mode approach in electronic power conditioning is discussed. Technical aspects of the research are summarized.

Wilson, T. G.↗

NASA NTRS1997

High-Temperature Passive Power Electronics

In many future NASA missions - such as deep-space exploration, the National AeroSpace Plane, minisatellites, integrated engine electronics, and ion or arcjet thrusters - high-power electrical components and systems must operate reliably and efficiently in high-temperature environments. The high-temperature power electronics program at the NASA Lewis Research Center focuses on dielectric and insulating material research, the development and characterization of high-temperature components, and the integration of the developed components into a demonstrable 200 C power system - such as an inverter. NASA Lewis has developed high-temperature power components through collaborative efforts with the Air Force Wright Laboratory, Northrop Grumman, and the University of Wisconsin. Ceramic and film capacitors, molypermalloy powder inductors, and a coaxially wound transformer were designed, developed, and evaluated for high-temperature operation.

Source record↗

NASA NTRS1980

Modified reference SPS with solid state transmitting antenna

The motivations for considering solid state microwave power amplifiers for the solar power satellite transmitting antenna are the possibilities of greatly increased system reliability due to elimination of electron tube cathodes, a lower mass per unit power and transmitting array area due to the high power densities obtainable in semiconductors, and, probably, cost savings due to development of small hardware items that can be handled by individuals instead of organizations. In order to provide a fair assessment where we stand today with regard to solid state SPS technology, the design described here is close to that of the NASA/DOE reference and is implemented using today's solid state technology with only a small "push". The small push is raising the efficiency of DC-RF conversion from the .68 obtained by RCA in 1975 to somewhat over .8 of the solid state SPS. This is generally considered feasible by semiconductor industry representatives. Other solid state SPS configurations can yield somewhat better performance. However, these generally do not provide as fair a vehicle for comparison with the reference and usually also incorporate somewhat more advanced technologies.

Woodcock, G. R.↗

NASA NTRS1975

Power processing for electric propulsion

The potential of achieving up to 30 per cent more spacecraft payload or 50 per cent more useful operating life by the use of electric propulsion in place of conventional cold gas or hydrazine systems in science, communications, and earth applications spacecraft is a compelling reason to consider the inclusion of electric thruster systems in new spacecraft design. The propulsion requirements of such spacecraft dictate a wide range of thruster power levels and operational lifetimes, which must be matched by lightweight, efficient, and reliable thruster power processing systems. This paper will present electron bombardment ion thruster requirements; review the performance characteristics of present power processing systems; discuss design philosophies and alternatives in areas such as inverter type, arc protection, and control methods; and project future performance potentials for meeting goals in the areas of power processor weight (10 kg/kW), efficiency (approaching 92 per cent), reliability (0.96 for 15,000 hr), and thermal control capability (0.3 to 5 AU).

Finke, R. C.↗

NASA NTRS2009

Effect of Electrostatic Discharge on Electrical Characteristics of Discrete Electronic Components

This article reports on preliminary results of a study conducted to examine how temporary electrical overstress seed fault conditions in discrete power electronic components that cannot be detected with reliability tests but impact longevity of the device. These defects do not result in formal parametric failures per datasheet specifications, but result in substantial change in the electrical characteristics when compared with pristine device parameters. Tests were carried out on commercially available 600V IGBT devices using transmission line pulse (TLP) and system level ESD stress. It was hypothesized that the ESD causes local damage during the ESD discharge which may greatly accelerate degradation mechanisms and thus reduce the life of the components. This hypothesis was explored in simulation studies where different types of damage were imposed to different parts of the device. Experimental results agree qualitatively with the simulation for a number of tests which will motivate more in-depth modeling of the damage.

Wysocki, Phil↗

NASA NTRS1971

The electrical power subsystem of the Pioneer F/G spacecraft.

The Pioneer F/G spacecraft is the first to use radioisotope thermoelectric generators (RTG's) for a long duration interplanetary mission. This paper describes the design of the spacecraft power subsystem which meets the unique requirements of such a mission. The primary power source consists of four SNAP 19 RTG's. The 4.2 volt dc outputs of the RTG's are inverted to higher voltage ac by four inverters which are connected in parallel at their outputs. A power control unit (PCU) regulates the ac output of the inverters such that the RTG's are operated at near maximum power voltage throughout the mission. The PCU also contains charge and discharge controls for a silver cadmium battery which supplements the RTG's if load requirements temporarily exceed RTG power output. Battery reliability is enhanced by overcharge and cell reversal protection electronics which are provided for each cell. Multiple, low voltage, regulated dc outputs which supply power to the spacecraft subsystems are provided by a central transformer-rectifier-filter unit (CTRF). The CTRF operates directly from the regulated ac bus.

Reppucci, G. M.↗

NASA NTRS2001

Electronics for Extreme Environments

Most of the NASA missions involve extreme environments comprising radiation and low or high temperatures. Current practice of providing friendly ambient operating environment to electronics costs considerable power and mass (for shielding). Immediate missions such as the Europa orbiter and lander and Mars landers require the electronics to perform reliably in extreme conditions during the most critical part of the mission. Some other missions planned in the future also involve substantial surface activity in terms of measurements, sample collection, penetration through ice and crust and the analysis of samples. Thus it is extremely critical to develop electronics that could reliably operate under extreme space environments. Silicon On Insulator (SOI) technology is an extremely attractive candidate for NASA's future low power and high speed electronic systems because it offers increased transconductance, decreased sub-threshold slope, reduced short channel effects, elimination of kink effect, enhanced low field mobility, and immunity from radiation induced latch-up. A common belief that semiconductor devices function better at low temperatures is generally true for bulk devices but it does not hold true for deep sub-micron SOI CMOS devices with microscopic device features of 0.25 micrometers and smaller. Various temperature sensitive device parameters and device characteristics have recently been reported in the literature. Behavior of state of the art technology devices under such conditions needs to be evaluated in order to determine possible modifications in the device design for better performance and survivability under extreme environments. Here, we present a unique approach of developing electronics for extreme environments to benefit future NASA missions as described above. This will also benefit other long transit/life time missions such as the solar sail and planetary outposts in which electronics is out open in the unshielded space at the ambient space temperatures and always exposed to radiation. Additional information is contained in the original extended abstract.

Patel, J. U.↗

NASA NTRS1977

Advanced combined iodine dispenser and detector

A total weight of 1.23 kg (2.7 lb), a total volume of 1213 cu m (74 cu in), and an average power consumption of 5.5W was achieved in the advanced combined iodine dispenser/detector by integrating the detector with the iodine source, arranging all iodinator components within a compact package and lowering the parasitic power to the detector and electronics circuits. These achievements surpassed the design goals of 1.36 kg (3.0 lb), 1671 cu m (102 cu in) and 8W. The reliability and maintainability were improved by reducing the detector lamp power, using an interchangeable lamp concept, making the electronic circuit boards easily accessible, providing redundant water seals and improving the accessibility to the iodine accumulator for refilling. The system was designed to iodinate (to 5 ppm iodine) the fuel cell water generated during 27 seven-day orbiter missions (equivalent to 18,500 kg (40,700 lb) of water) before the unit must be recharged with iodine crystals.

Lantz, J. B.↗

NASA NTRSDate not supplied

Assessment of Cryogenic Analog Electronics for Lunar Environment

Assessment of Analog Electronics for Lunar Power Hibernation Non-nuclear robotic spacecraft on the Moon may not reliably operate past the first lunar day due to the subsequent long lunar night with an extreme low temperature range of 50K-100K. To address this concern, the NASA Glenn Research Center is developing a lunar power hibernation protocol that could enable spacecraft to passively survive the lunar night without any additional heating source and then reactivate at lunar dawn. Low cost lunar robotic missions could extend their mission lifetime from a single lunar cycle to potentially many months, thus greatly extending science data gathering and return on investment for commercial missions. This approach centers on evidence that lithium-ion battery cells can recover to full operation after being subjected to cryogenic temperatures. Exploiting this battery capability requires that all spacecraft electronics, including power system and avionics, passively tolerate the extreme cold without degradation. Key elements in the power system will also need to be capable of actively operating in the extreme cold to perform the functions required to restore the system to full operation after solar power returns at lunar dawn. This presentation provides an assessment of extreme-cold tolerance and operational capability of analog electronics where choices in semiconductor material, device type, and circuit fabrication technology has a dramatic impact on circuit behavior and reliability at low temperatures.

Lunar↗

NASA NTRS2015

High-Temperature, Wirebondless, Ultracompact Wide Bandgap Power Semiconductor Modules

Silicon carbide (SiC) and other wide bandgap semiconductors offer great promise of high power rating, high operating temperature, simple thermal management, and ultrahigh power density for both space and commercial power electronic systems. However, this great potential is seriously limited by the lack of reliable high-temperature device packaging technology. This Phase II project developed an ultracompact hybrid power module packaging technology based on the use of double lead frames and direct lead frame-to-chip transient liquid phase (TLP) bonding that allows device operation up to 450 degC. The new power module will have a very small form factor with 3-5X reduction in size and weight from the prior art, and it will be capable of operating from 450 degC to -125 degC. This technology will have a profound impact on power electronics and energy conversion technologies and help to conserve energy and the environment as well as reduce the nation's dependence on fossil fuels.

Elmes, John↗