Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Electrical Systems”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 955 records · Page 53
All sourcesNASA NTRSDOE OSTI
NASA NTRS1990

An analysis of space power system masses

Various space electrical power system masses are analyzed with particular emphasis on the power management and distribution (PMAD) portion. The electrical power system (EPS) is divided into functional blocks: source, interconnection, storage, transmission, distribution, system control and load. The PMAD subsystem is defined as all the blocks between the source, storage and load, plus the power conditioning equipment required for the source, storage and load. The EPS mass of a wide range of spacecraft is then classified as source, storage or PMAD and tabulated in a database. The intent of the database is to serve as a reference source for PMAD masses of existing and in-design spacecraft. The PMAD masses in the database range from 40 kg/kW to 183 kg/kW across the spacecraft systems studied. Factors influencing the power system mass are identified. These include the total spacecraft power requirements, total amount of load capacity and physical size of the spacecraft. It is found that a new utility class of power systems, represented by Space Station Freedom, is evolving.

Kenny, Barbara H.↗
NASA NTRS1990

An analysis of space power system masses

Various space electrical power system masses are analyzed with particular emphasis on the power management and distribution (PMAD) portion. The electrical power system (EPS) is divided into functional blocks: source, interconnection, storage, transmission, distribution, system control and load. The PMAD subsystem is defined as all the blocks between the source, storage and load, plus the power conditioning equipment required for the source, storage and load. The EPS mass of a wide range of spacecraft is then classified as source, storage or PMAD and tabulated in a database. The intent of the database is to serve as a reference source for PMAD masses of existing and in-design spacecraft. The PMAD masses in the database range from 40 kg/kW to 183 kg/kW across the spacecraft systems studied. Factors influencing the power system mass are identified. These include the total spacecraft power requirements, total amount of load capacity and physical size of the spacecraft. It is found that a new utility class of power systems, represented by Space Station Freedom, is evolving.

Kenny, Barbara H.↗
NASA NTRS2024

NASA’s Small Spacecraft Electric Propulsion (SSEP) System

Developed by NASA’s Glenn Research Center, the Small Spacecraft Electric Propulsion (SSEP) Technology Suite, LEW-TOPS-162, enables a compact, high-performance, enduring and scalable primary propulsion system for small spacecraft. The SSEP belongs to a class of in-space propulsion known as solar electric propulsion (SEP), where thrust is derived from solar energy and solar panels, rather than heavy, combustible stored chemicals. Combining electrostatics with magnetism, the SSEP converts solar energy to thrust by trapping ejected electrons in doughnut-like ring contained within an annular magnetic field of its thruster. This creates a Hall current, a circulating swirl of electrons, and enables Hall Effect Thrusters (HETs). Thrust is generated when an ejected neutral gas impacts an electron in the Hall current, ionizing it, and abruptly accelerating it perpendicular to the Hall current due to the electrostatic field of the circulating electrons.

Solar Electric Propulsion↗
NASA NTRS1973

Performance of electrical subsystem of 2- to 15-kilowatt Brayton power conversion system

The electrical subsystem of the 2-to 15-kilowatt Brayton power conversion system was evaluated under various operating and off-design temperature conditions in a vacuum environment. Overall operation was satisfactory. Speed controller operation is a major cause of distortion in the system ac voltage and current waveforms. This distortion has a small, but potentially significant effect on the performance of individual subsystem components.

Secunde, R. R.↗
NASA NTRS1990

An expert system for simulating electric loads aboard Space Station Freedom

Space Station Freedom will provide an infrastructure for space experimentation. This environment will feature regulated access to any resources required by an experiment. Automated systems are being developed to manage the electric power so that researchers can have the flexibility to modify their experiment plan for contingencies or for new opportunities. To define these flexible power management characteristics for Space Station Freedom, a simulation is required that captures the dynamic nature of space experimentation; namely, an investigator is allowed to restructure his experiment and to modify its execution. This changes the energy demands for the investigator's range of options. An expert system competent in the domain of cryogenic fluid management experimentation was developed. It will be used to help design and test automated power scheduling software for Freedom's electric power system. The expert system allows experiment planning and experiment simulation. The former evaluates experimental alternatives and offers advice on the details of the experiment's design. The latter provides a real-time simulation of the experiment replete with appropriate resource consumption.

Kukich, George↗
NASA NTRS1990

An expert system for simulating electric loads aboard Space Station Freedom

Space Station Freedom will provide an infrastructure for space experimentation. This environment will feature regulated access to any resources required by an experiment. Automated systems are being developed to manage the electric power so that researchers can have the flexibility to modify their experiment plan for contingencies or for new opportunities. To define these flexible power management characteristics for Space Station Freedom, a simulation is required that captures the dynamic nature of space experimentation; namely, an investigator is allowed to restructure his experiment and to modify its execution. This changes the energy demands for the investigator's range of options. An expert system competent in the domain of cryogenic fluid management experimentation, was developed. It will be used to help design and test automated power scheduling software for Freedom's electric power system. The expert system allows experiment planning and experiment simulation. The former evaluates experimental alternatives and offers advice on the details of the experiment's design. The latter provides a real-time simulation of the experiment replete with appropriate resource consumption.

Kukich, George↗
NASA NTRS1968

Systems Division

Solar electric propulsion system for spacecraft asteroid probe, numerical integration calculation of lunar ephemeris, and effect of precession and nutation errors on radar observations

Source record↗
NASA NTRS1976

Design, economic and system considerations of large wind-driven generators

The increased search for alternative energy sources has lead to renewed interest and studies of large wind-driven generators. This paper presents the results and considerations of such an investigation. The paper emphasizes the concept selection of wind-driven generators, system optimization, control system design, safety aspects, economic viability on electric utility systems and potential electric system interfacing problems.

Jorgensen, G. E.↗
NASA NTRS1984

Results of electric-vehicle propulsion system performance on three lead-acid battery systems

Three types of state of the art 6 V lead acid batteries were tested. The cycle life of lead acid batteries as a function of the electric vehicle propulsion system design was determined. Cycle life, degradation rate and failure modes with different battery types (baseline versus state of the art tubular and thin plate batteries were compared. The effects of testing strings of three versus six series connected batteries on overall performance were investigated. All three types do not seem to have an economically feasible battery system for the propulsion systems. The tubular plate batteries on the load leveled profile attained 235 cycles with no signs of degradation and minimal capacity loss.

Ewashinka, J. G.↗
NASA NTRS1984

Results of electric-vehicle propulsion system performance on three lead-acid battery systems

Three types of state of the art 6 V lead acid batteries were tested. The cycle life of lead acid batteries as a function of the electric vehicle propulsion system design was determined. Cycle life, degradation rate and failure modes with different battery types (baseline versus state of the art tubular and thin plate batteries) were compared. The effects of testing strings of three versus six series connected batteries on overall performance were investigated. All three types do not seem to have an economically feasible battery system for the propulsion systems. The tubular plate batteries on the load leveled profile attained 235 cycles with no signs of degradation and minimal capacity loss.

Ewashinka, J. G.↗
NASA NTRS1979

Investigation of a generator system for generating electrical power, to supply directly to the public network, using a windmill

A windpowered generator system is described which uses a windmill to convert mechanical energy to electrical energy for a three phase (network) voltage of constant amplitude and frequency. The generator system controls the windmill by the number of revolutions so that the power drawn from the wind for a given wind velocity is maximum. A generator revolution which is proportional to wind velocity is achieved. The stator of the generator is linked directly to the network and a feed converter at the rotor takes care of constant voltage and frequency at the stator.

Tromp, C.↗
NASA NTRS1987

Analysis of Solar Electrical and Thermal Systems

Report describes computer program for parametric analysis of alternative ways of generating heat and electrical power on satellite or spacecraft. Program, Solar Space Power Analysis Code (SOSPAC), examines changes in area, weight, and cost of generator system for changing conditions, in particular for changes in ratio of thermal to electrical outputs. Outlines execution procedure and presents sample set of input data. Gives example of mass and area calculations for sample data for each type of generator system and illustrates results with variety of charts.

Selcuk, M. Kudret↗
NASA NTRS1982

Electric ECS

Materials illustrating a presentation on electric environmental control systems for electric flight systems are presented. Requirements are outlined and schematics presented.

Moeller, D. O.↗
NASA NTRS2004

International Space Station Nickel-Hydrogen Batteries Approached 3-Year On-Orbit Mark

The International Space Station's (ISS) electric power system (EPS) employs nickel-hydrogen (Ni-H2) batteries as part of its power system to store electrical energy. The batteries are charged during insolation and discharged, providing station power, during eclipse. The batteries are designed to operate at a maximum 35-percent depth of discharge during normal operation. Thirty-eight individual pressure vessel Ni-H2 battery cells are series-connected and packaged in an orbital replacement unit (ORU), and two ORUs are series-connected, using a total of 76 cells, to form one battery. When the ISS is in its assembly-complete form, the electrical power system will have a total of 24 batteries (48 ORUs) on-orbit. The ISS is the first application for low-Earth-orbit cycling of this quantity of series-connected cells.

Dalton, Penni J.↗