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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 1,405 records · Page 78

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NASA NTRSDate not supplied

Modeling Spacecraft Power Systems Using the SPACE Code

The NASA Glenn Research Center’s Power Architecture and Analysis Branch performs spacecraft electrical power system (EPS) performance analysis using the System Power Analysis for Capability Evaluation (SPACE) model. Accurately predicting EPS performance requires a wide range of inputs, including the spacecraft’s position, attitude, solar array temperature, load demand, and data on the EPS itself. By operating as a combined analysis tool with integrated orbit mechanics, attitude, shadowing, thermal, solar array, battery, and electrical component models, SPACE provides flexibility for the analyst to examine various scenarios without a time-consuming iterative process involving separate analysis tools and groups. SPACE also achieves short run times by tailoring the complexity of the included models, providing enough fidelity to ensure accurate EPS performance predictions without being bogged down by unnecessary detail. These advantages that SPACE has over similar power system models has contributed to its successful use on a variety of human spaceflight programs for over three decades, and makes it applicable across the development cycle from early conceptual design up through on-orbit operations.

Electrical Power System↗

NASA NTRS2013

Revolutionary Aeropropulsion Concept for Sustainable Aviation: Turboelectric Distributed Propulsion

In response to growing aviation demands and concerns about the environment and energy usage, a team at NASA proposed and examined a revolutionary aeropropulsion concept, a turboelectric distributed propulsion system, which employs multiple electric motor-driven propulsors that are distributed on a large transport vehicle. The power to drive these electric propulsors is generated by separately located gas-turbine-driven electric generators on the airframe. This arrangement enables the use of many small-distributed propulsors, allowing a very high effective bypass ratio, while retaining the superior efficiency of large core engines, which are physically separated but connected to the propulsors through electric power lines. Because of the physical separation of propulsors from power generating devices, a new class of vehicles with unprecedented performance employing such revolutionary propulsion system is possible in vehicle design. One such vehicle currently being investigated by NASA is called the "N3-X" that uses a hybrid-wing-body for an airframe and superconducting generators, motors, and transmission lines for its propulsion system. On the N3-X these new degrees of design freedom are used (1) to place two large turboshaft engines driving generators in freestream conditions to minimize total pressure losses and (2) to embed a broad continuous array of 14 motor-driven fans on the upper surface of the aircraft near the trailing edge of the hybrid-wing-body airframe to maximize propulsive efficiency by ingesting thick airframe boundary layer flow. Through a system analysis in engine cycle and weight estimation, it was determined that the N3-X would be able to achieve a reduction of 70% or 72% (depending on the cooling system) in energy usage relative to the reference aircraft, a Boeing 777-200LR. Since the high-power electric system is used in its propulsion system, a study of the electric power distribution system was performed to identify critical dynamic and safety issues. This paper presents some of the features and issues associated with the turboelectric distributed propulsion system and summarizes the recent study results, including the high electric power distribution, in the analysis of the N3-X vehicle.

Kim, Hyun Dae↗

NASA NTRS1976

A comparison of GaAs and Si hybrid solar power systems

An analytical comparison of energy output from various silicon and gallium arsenide hybrid solar power systems, producing electric power and also thermal power for heating or cooling, is made. System performance indices in terms of capital cost, peak power, total power output, and electric power were evaluated. Limiting values for annual energy production from GaAs and Si solar concentrator systems were estimated to be 2 cents and 6.8 cents per kWh for GaAs concentrator systems and between 2.5 cents and 11 cents per kWh for Si concentrator systems.

Heinbockel, J. H.↗

NASA NTRS1980

Development of Automated Power Systems Management for planetary spacecraft

Automated Power Systems Management is a technology being developed at JPL to provide the capability for onboard monitoring, computation, and control of planetary-spacecraft electrical power systems without the need for ground intervention. The technology uses microcomputers to provide the control and flexibility necessary to achieve rapid and decisive control of power system functions in the event of electrical power failures or unplanned events requiring power system responses. The current program at JPL includes the design, fabrication, test, and evaluation of a breadboard spacecraft power system, modified to incorporate automated power system functions which are implemented by means of a distributed microcomputer system.

Bridgeforth, A. O.↗

NASA NTRS1975

A Thruster Sub-System Module (TSSM) for solar electric propulsion

Solar Electric Propulsion (SEP) is currently being studied for possible use in a number of near-earth and planetary missions. Thruster systems for these missions could be integrated directly into a spacecraft or modularized into a Thruster Sub-System Module (TSSM). A TSSM for electric propulsion missions would consist of a 30-cm ion thruster, thruster gimbal system, propellant storage and feed system, associated Power Processing Unit (PPU), thermal control system and complete supporting structure. The TSSM would be wholly self-contained and be essentially a plug-in or strap-on electric stage with simple mechanical, thermal, electrical and propellant interfaces. The TSSM described in this report is designed for a broad range of missions requiring from two to ten TSSM's mounted in a 2 by x configuration. The thermal control system is designed to accommodate waste heat from the power processor based on realistic efficiencies when the TSSM is operating from 0.7 to 3.5 AU's. The modules are 0.61 M (2 ft) wide by 2.29 M (7.5 ft) long and have a dry weight including propellant tank of 54.4 kg (120 lb). The propellant tank will hold 145.1 kg (320 lb) of mercury.

Sharp, G. R.↗

NASA NTRS2018

Solid State Ephemeral Electric Potential and Electric Field Sensor

Systems, methods, and devices of the various embodiments provide a field effect transistor (FET) that controls equilibrium by reversing the effects of leakage currents affecting the gate response of the FET by using an equilibrium pump electrode. The equilibrium reversing gate FETs (ergFETs) of the various embodiments, may include an equilibrium pump electrode located within a non-conducting gap. The ergFETs of the various embodiments may provide solid state ephemeral electric potential and electric field sensor systems and methods for measuring ephemeral electric potentials and electric fields.

Generazio, Edward R.↗

NASA NTRS2016

International Space Station Lithium-Ion Battery

The International Space Station (ISS) Electric Power System (EPS) currently uses Nickel-Hydrogen (Ni-H2) batteries to store electrical energy. The batteries are charged during insolation and discharged during eclipse. The Ni-H2 batteries are designed to operate at a 35 depth of discharge (DOD) maximum during normal operation in a Low Earth Orbit. Since the oldest of the 48 Ni-H2 battery Orbital Replacement Units (ORUs) has been cycling since September 2006, these batteries are now approaching their end of useful life. In 2010, the ISS Program began the development of Lithium-Ion (Li-ion) batteries to replace the Ni-H2 batteries and concurrently funded a Li-ion cell life testing project. This paper will include an overview of the ISS Li-Ion battery system architecture and the progress of the Li-ion battery design and development.

Battery↗

NASA NTRS2009

Simplified Ion Thruster Xenon Feed System for NASA Science Missions

The successful implementation of ion thruster technology on the Deep Space 1 technology demonstration mission paved the way for its first use on the Dawn science mission, which launched in September 2007. Both Deep Space 1 and Dawn used a "bang-bang" xenon feed system which has proven to be highly successful. This type of feed system, however, is complex with many parts and requires a significant amount of engineering work for architecture changes. A simplified feed system, with fewer parts and less engineering work for architecture changes, is desirable to reduce the feed system cost to future missions. An attractive new path for ion thruster feed systems is based on new components developed by industry in support of commercial applications of electric propulsion systems. For example, since the launch of Deep Space 1 tens of mechanical xenon pressure regulators have successfully flown on commercial spacecraft using electric propulsion. In addition, active proportional flow controllers have flown on the Hall-thruster-equipped Tacsat-2, are flying on the ion thruster GOCE mission, and will fly next year on the Advanced EHF spacecraft. This present paper briefly reviews the Dawn xenon feed system and those implemented on other xenon electric propulsion flight missions. A simplified feed system architecture is presented that is based on assembling flight-qualified components in a manner that will reduce non-recurring engineering associated with propulsion system architecture changes, and is compared to the NASA Dawn standard. The simplified feed system includes, compared to Dawn, passive high-pressure regulation, a reduced part count, reduced complexity due to cross-strapping, and reduced non-recurring engineering work required for feed system changes. A demonstration feed system was assembled using flight-like components and used to operate a laboratory NSTAR-class ion engine. Feed system components integrated into a single-string architecture successfully operated the engine over the entire NSTAR throttle range over a series of tests. Flow rates were very stable with variations of at most 0.2%, and transition times between throttle levels were typically 90 seconds or less with a maximum of 200 seconds, both significant improvements over the Dawn bang-bang feed system.

Snyder, John Steven↗

NASA NTRS1993

Stirling Converters For Solar Power

Two designs expected to meet long-term goals for performance and cost. Proposed for advanced systems to convert solar thermal power to electrical power. Each system, designed to operate with 11-m-diameter paraboloidal reflector, includes solar-energy receiver, liquid-metal heat-transport subsystem, free-piston Stirling engine, cooling subsystem, alternator or generator coupled directly or indirectly to commercial electric-power system, and control and power-conditioning circuitry. System converts approximately 75 kW of input solar thermal power falling on collector to about 25 kW of output electrical power.

Shaltens, Richard K.↗

NASA NTRS2012

Spacecraft Conceptual Design for Returning Entire Near-Earth Asteroids

In situ resource utilization (ISRU) in general, and asteroid mining in particular are ideas that have been around for a long time, and for good reason. It is clear that ultimately human exploration beyond low-Earth orbit will have to utilize the material resources available in space. Historically, the lack of sufficiently capable in-space transportation has been one of the key impediments to the harvesting of near-Earth asteroid resources. With the advent of high-power (or order 40 kW) solar electric propulsion systems, that impediment is being removed. High-power solar electric propulsion (SEP) would be enabling for the exploitation of asteroid resources. The design of a 40-kW end-of-life SEP system is presented that could rendezvous with, capture, and subsequently transport a 1,000-metric-ton near-Earth asteroid back to cislunar space. The conceptual spacecraft design was developed by the Collaborative Modeling for Parametric Assessment of Space Systems (COMPASS) team at the Glenn Research Center in collaboration with the Keck Institute for Space Studies (KISS) team assembled to investigate the feasibility of an asteroid retrieval mission. Returning such an object to cislunar space would enable astronaut crews to inspect, sample, dissect, and ultimately determine how to extract the desired materials from the asteroid. This process could jump-start the entire ISRU industry.

asteroid retrieval↗

NASA NTRS2019

Feasibility of Electrified Propulsion for Ultra-Efficient Commercial Aircraft Final Report

MIT, Aurora Flight Sciences, and USC have collaborated to assess the feasibility of electric, hybridelectric, and turbo-electric propulsion for ultra-efficient commercial transportation. The work has drawn on the team expertise in disciplines related to aircraft design, propulsion-airframe integration, electric machines and systems, engineering system design, and optimization. A parametric trade space analysis has been carried out to assess vehicle performance across a range of transport missions and propulsion architectures to establish how electrified propulsion systems scale. An optimization approach to vehicle conceptual design modeling was taken to enable rapid multidisciplinary design space exploration and sensitivity analysis. The results of the analysis indicate vehicle aero-propulsive integration benefits enabled by electrification are required to offset the increased weight and loss associated with the electric system and achieve enhanced performance; the report describes the conceptual configurations than can offer such enhancements. The main contribution of the present work is the definition of electric vehicle design attributes for potential efficiency improvements at different scales. Based on these results, key areas for future research are identified, and extensions to the trade space analysis suitable for higher fidelity electrified commercial aircraft design and analysis have been developed.

Hall, D.K.↗

NASA NTRS1980

Thermal energy storage effort at JPL

The technical, operational, and economic readiness of parabolic dish systems for electric and thermal applications was investigated. A parabolic dish system was then developed to the point at which subsequent commercialization activities can lead to successful market penetration. The immediate possible applications of the dish system to thermal energy storage are discussed.

Young, D. L.↗

NASA NTRS1980

Monitoring and control requirement definition study for Dispersed Storage and Generation (DSG), volume 1

Twenty-four functional requirements were prepared under six categories and serve to indicate how to integrate dispersed storage generation (DSG) systems with the distribution and other portions of the electric utility system. Results indicate that there are no fundamental technical obstacles to prevent the connection of dispersed storage and generation to the distribution system. However, a communication system of some sophistication is required to integrate the distribution system and the dispersed generation sources for effective control. The large-size span of generators from 10 KW to 30 MW means that a variety of remote monitoring and control may be required. Increased effort is required to develop demonstration equipment to perform the DSG monitoring and control functions and to acquire experience with this equipment in the utility distribution environment.

Source record↗

NASA NTRS1981

Integrated propulsion for near-Earth space missions. Volume 1: Executive summary

Tradeoffs between electric propulsion system mass ratio and transfer time from LEO to GEO were conducted parametrically for various thruster efficiency, specific impulse, and other propulsion parameters. A computer model was developed for performing orbit transfer calculations which included the effects of aerodynamic drag, radiation degradation, and occultation. The tradeoff results showed that thruster technology areas for integrated propulsion should be directed towards improving primary thruster efficiency in the range from 1500 to 2500 seconds, and be continued towards reducing specific mass. Comparison of auxiliary propulsion systems showed large total propellant mass savings with integrated electric auxiliary propulsion. Stationkeeping is the most demanding on orbit propulsion requirement. At area densities above 0.5 sq m/kg, East-West stationkeeping requirements from solar pressure exceed North-South stationkeeping requirements from gravitational forces. A solar array pointing strategy was developed to minimize the effects of atmospheric drag at low altitude, enabling electric propulsion to initiate orbit transfer at Shuttle's maximum cargo carrying altitude. Gravity gradient torques are used during ascent to sustain the spacecraft roll motion required for optimum solar array illumination. A near optimum cover glass thickness of 6 mils was established for LEO to GEO transfer.

Dailey, C. L.↗

NASA NTRS1985

Rationale for a GRAVSAT-MAGSAT mission: A perspective on the problem of external/internal transient field effects

The Earth's magnetic field at MAGSAT altitudes not only has contributions from the Earth's core and static magnetization in the lithosphere, but also from external electric current systems in the ionosphere and magnetosphere, along with induced electric currents flowing in the conducting earth. Hermance assessed these last two contributions; the external time-varying fields and their associated internal counter-parts which are electromagnetically induced. It is readily recognized that during periods of magnetic disturbance, external currents often contribute from 10's to 100's of nanoteslas (gammas) to observations of the Earth's field. Since static anomalies from lithospheric magnetization are of this same magnitude or less, these external source fields must be taken into account when attempting to delineate gross structural features in the crust.

Hermance, J. F.↗

NASA NTRS1986

Requirements specification for nickel cadmium battery expert system

The requirements for performance, design, test, and qualification of a computer program identified as NICBES, Nickel Cadmium Battery Expert System, is established. The specific spacecraft power system configuration selected was the Hubble Space Telescope (HST) Electrical Power System (EPS) Testbed. Power for the HST comes from a system of 13 Solar Panel Arrays (SPAs) linked to 6 Nickel Cadmium Batteries which are connected to 3 Busses. An expert system, NICBES, will be developed at Martin Marietta Aerospace to recognize a testbed anomaly, identify the malfunctioning component and recommend a course of action. Besides fault diagnosis, NICBES will be able to evaluate battery status, give advice on battery status and provide decision support for the operator. These requirements are detailed.

Source record↗

NASA NTRS1993

Model-based reasoning for power system management using KATE and the SSM/PMAD

The overall goal of this research effort has been the development of a software system which automates tasks related to monitoring and controlling electrical power distribution in spacecraft electrical power systems. The resulting software system is called the Intelligent Power Controller (IPC). The specific tasks performed by the IPC include continuous monitoring of the flow of power from a source to a set of loads, fast detection of anomalous behavior indicating a fault to one of the components of the distribution systems, generation of diagnosis (explanation) of anomalous behavior, isolation of faulty object from remainder of system, and maintenance of flow of power to critical loads and systems (e.g. life-support) despite fault conditions being present (recovery). The IPC system has evolved out of KATE (Knowledge-based Autonomous Test Engineer), developed at NASA-KSC. KATE consists of a set of software tools for developing and applying structure and behavior models to monitoring, diagnostic, and control applications.

Morris, Robert A.↗

NASA NTRS2005

Chapter 17 - Airframe Tests

This Section outlines the flight testing required to demonstrate that each of the systems installed in an aircraft is suitable for its operational role(s). It is primarily written from the perspective of a military Flight Test Engineer (FTE) but most of the contents are applicable to civil aircraft. Reflecting the introductory nature of this Volume, its scope is limited to systems normally found in all aircraft, e.g., fuel, hydraulic, electrical, etc., systems. The tests described below are usually made under the prevailing ambient conditions and, to assess behaviour under climatic extremes and in all weathers, further testing is conducted as described in Section 18. Tests of the propulsion system are covered separately in Section 23, but for systems associated with specific roles the reader should consult appropriate specialized sources.

J K Appleford↗