Results for “Power Development” — Page 42

NASA NTRSDate not supplied

Power Measurements to Excavate Lunar Soil Simulant GRC-3B Using Arc Backhoe Trajectories

Understanding, mitigating, and minimizing power and mass requirements are crucial to developing the next generation excavation technologies for lunar and planetary in-situ resource utilization (ISRU). Towards this end, electrical power to the Advanced Planetary Excavator (APEX) was measured while excavating granular lunar soil simulant GRC-3B. Using a 21.6-cm wide bucket having a 30° leading edge, arc-shaped backhoe trajectories were dug to depths of 5, 10, and 20 cm with rake angles of 10, 20, and 30 degrees. Maximum net power, net energy, net energy per mass excavated, rate of mass excavated, horizontal distance from soil entry to exit (at bucket tip), and the trajectory to bucket volume percentage are presented to inform the scientific community as trajectories and designs are planned for future missions. Using APEX’s capability to evaluate power and energy consumption of excavation tools and processes gives guidance to developing power requirements and efficient methods for lunar excavation.

Excavation↗

NASA NTRS2006

Stretched Lens Array (SLA) for Collection and Conversion of Infrared Laser Light: 45% Efficiency Demonstrated for Near-Term 800 W/kg Space Power System

For the past 2% years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system.

O'Neill, Mark↗

NASA NTRS2010

Development and Testing of an Ultracapacitor Based Uninterruptible Power Supply (UPS) System

The NASA Glenn Research Center (GRC) initiated the development and testing of an ultracapacitor based uninterruptible power supply (UPS) system as a means to provide backup power for the many critical NASA applications. A UPS system typically utilizes batteries for energy storage. The battery is the most vulnerable part of the UPS system, requiring regular maintenance and replacement. Battery performance is also extremely temperature dependent. Ultracapacitors are ideal for UPS systems where long life, maintenance free operation, and excellent low temperature performance is essential. State of the art symmetric ultracapacitors were used for these tests. The ultracapacitors were interconnected in an innovative configuration to minimize interconnection impedance, and to provide voltage balancing. Ultracapacitors can be charged extremely rapidly and supply high current, which are essential characteristics for an effective UPS system. Charging ultracapacitors is significantly less complex than charging batteries since there is no chemical reaction occurring while charging ultracapacitors. The report concludes that the implementation of symmetric ultracapacitors in a UPS system can provide significant improvements in power system performance and reliability.

Eichenberg, Dennis J.↗

NASA NTRS1990

Programmatic status of NASA's CSTI high capacity power Stirling space power converter program

An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Development Program. This work is being conducted under NASA's Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. The status of test activities with the Space Power Research Engine (SPRE) is discussed. Design deficiencies are gradually being corrected and the power converter is now outputting 11.5 kWe at a temperature ratio of 2 (design output is 12.5 kWe). Detail designs were completed for the 1050 K Component Test Power Converter (CTPC). The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, gas bearings, superalloy joining technologies and high efficiency alternators. An update of progress in these technologies is provided.

Dudenhoefer, James E.↗

NASA NTRS1992

The 10 kW power electronics for hydrogen arcjets

A combination of emerging mission considerations such as 'launch on schedule', resource limitations, and the development of higher power spacecraft busses has resulted in renewed interest in high power hydrogen arcjet systems with specific impulses greater than 1000 s for Earth-space orbit transfer and maneuver applications. Solar electric propulsion systems with about 10 kW of power appear to offer payload benefits at acceptable trip times. This work outlines the design and development of 10 kW hydrogen arcjet power electronics and results of arcjet integration testing. The power electronics incorporated a full bridge switching topology similar to that employed in state of the art 5 kW power electronics, and the output filter included an output current averaging inductor with an integral pulse generation winding for arcjet ignition. Phase shifted, pulse width modulation with current mode control was used to regulate the current delivered to arcjet, and a low inductance power stage minimized switching transients. Hybrid power Metal Oxide Semiconductor Field Effect Transistors were used to minimize conduction losses. Switching losses were minimized using a fast response, optically isolated, totem-pole gate drive circuit. The input bus voltage for the unit was 150 V, with a maximum output voltage of 225 V. The switching frequency of 20 kHz was a compromise between mass savings and higher efficiency. Power conversion efficiencies in excess of 0.94 were demonstrated, along with steady state load current regulation of 1 percent. The power electronics were successfully integrated with a 10 kW laboratory hydrogen arcjet, and reliable, nondestructive starts and transitions to steady state operation were demonstrated. The estimated specific mass for a flight packaged unit was 2 kg/kW.

Hamley, John A.↗

NASA NTRS2006

Power System Concepts for the Lunar Outpost: A Review of the Power Generation, Energy Storage, Power Management and Distribution (PMAD) System Requirements and Potential Technologies for Development of the Lunar Outpost

This paper will review potential power system concepts for the development of the lunar outpost including power generation, energy storage, and power management and distribution (PMAD). In particular, the requirements of the initial robotic missions will be discussed and the technologies considered will include cryogenics and regenerative fuel cells (RFC), AC and DC transmission line technology, high voltage and low voltage power transmission, conductor materials of construction and power beaming concepts for transmitting power to difficult to access locations such as at the bottom of craters. Operating conditions, component characteristics, reliability, maintainability, constructability, system safety, technology gaps/risk and adaptability for future lunar missions will be discussed for the technologies considered.

Khan, Z.↗

NASA NTRSDate not supplied

Human Mars Surface Mission Surface Power Impacts on Timeline and Traverse Capabilities

The National Aeronautics and Aerospace Administration’s (NASA) Mars Architecture Team (MAT) developed a concept for power management operations to support a thirty-day, minimal infrastructure Mars surface mission. The surface elements in this minimal surface mission concept include three landers as platforms for surface operations, a crewed Mars ascent vehicle (MAV), an unpressurized rover, and a pressurized rover where the crew will live for the duration of the thirty-day mission. In this analysis the power system is a ten kilowatt fission power system, which has been selected for its resiliency to dust storms, and will provide power for all aspects of the surface mission including thermal management of propellant and electronic systems, communications, and battery recharge of mobile surface assets. Developing a power management plan with the consideration of the various elements and mission phases helps define the traverse and exploration capabilities for the crew in the pressurized rover. Also, considerations need to be made for the different power requirements for each phase of the surface mission including arrival, offload, surface exploration, launch preparation, and departure. The described analysis aims to achieve a balance of maintaining power to critical systems while enabling desired traverse and exploration range in the pressurized rover. Additionally, a few enhancing technologies were explored that could expand the power capability if the additional capacity is necessary in the future. This study is used as a baseline to understand the constraints on all aspects of the surface mission for a minimal surface infrastructure human Mars campaign if a ten-kilowatt fission surface power system is available on the surface.

Michael B. Chappell↗

NASA NTRSDate not supplied

Human Mars Mission Surface Power Impacts on Timeline and Traverse Capabilities

The National Aeronautics and Aerospace Administration’s (NASA) Mars Architecture Team (MAT) developed a concept for power management operations to support a thirty-day, minimal infrastructure Mars surface mission. The surface elements in this minimal surface mission concept include three landers as platforms for surface operations, a crewed Mars ascent vehicle (MAV), an unpressurized rover, and a pressurized rover where the crew will live for the duration of the thirty-day mission. In this analysis the power system is a ten kilowatt fission power system, which has been selected for its resiliency to dust storms, and will provide power for all aspects of the surface mission including thermal management of propellant and electronic systems, communications, and battery recharge of mobile surface assets. Developing a power management plan with the consideration of the various elements and mission phases helps define the traverse and exploration capabilities for the crew in the pressurized rover. Also, considerations need to be made for the different power requirements for each phase of the surface mission including arrival, offload, surface exploration, launch preparation, and departure. The described analysis aims to achieve a balance of maintaining power to critical systems while enabling desired traverse and exploration range in the pressurized rover. Additionally, a few enhancing technologies were explored that could expand the power capability if the additional capacity is necessary in the future. This study is used as a baseline to understand the constraints on all aspects of the surface mission for a minimal surface infrastructure human Mars campaign if a ten-kilowatt fission surface power system is available on the surface.

Michael B Chappell↗

NASA NTRS1971

Advanced Power Conditioning System

The second portion of the advanced power conditioning system development program is reported. Five 100-watt parallel power stages with majority-vote-logic feedback-regulator were breadboarded and tested to the design goals. The input voltage range was 22.1 to 57.4 volts at loads from zero to 500 watts. The maximum input ripple current was 200 mA pk-pk (not including spikes) at 511 watts load; the output voltage was 56V dc with a maximum change of 0.89 volts for all variations of line, load, and temperature; the maximum output ripple was 320 mV pk-pk at 512 watts load (dependent on filter capacitance value); the maximum efficiency was 93.9% at 212 watts and 50V dc input; the minimum efficiency was 87.2% at 80-watt load and 50V dc input; the efficiency was above 90% from 102 watts to 372 watts; the maximum excursion for an 80-watt load change was 2.1 volts with a recovery time of 7 milliseconds; and the unit performed within regulation limits from -20 C to +85 C. During the test sequence, margin tests and failure mode tests were run with no resulting degradation in performance.

Johnson, N. L.↗

NASA NTRS1983

Advanced electrical power system technology for the all electric aircraft

The application of advanced electric power system technology to an all electric airplane results in an estimated reduction of the total takeoff gross weight of over 23,000 pounds for a large airplane. This will result in a 5 to 10 percent reduction in direct operating costs (DOC). Critical to this savings is the basic electrical power system component technology. These advanced electrical power components will provide a solid foundation for the materials, devices, circuits, and subsystems needed to satisfy the unique requirements of advanced all electric aircraft power systems. The program for the development of advanced electrical power component technology is described. The program is divided into five generic areas: semiconductor devices (transistors, thyristors, and diodes); conductors (materials and transmission lines); dielectrics; magnetic devices; and load management devices. Examples of progress in each of the five areas are discussed. Bipolar power transistors up to 1000 V at 100 A with a gain of 10 and a 0.5 microsec rise and fall time are presented. A class of semiconductor devices with a possibility of switching up to 100 kV is described. Solid state power controllers for load management at 120 to 1000 V and power levels to 25 kW were developed along with a 25 kW, 20 kHz transformer weighing only 3.2 kg.

Finke, R. C.↗

NASA NTRS1983

Advanced electrical power system technology for the all electric aircraft

The application of advanced electric power system technology to an all electric airplane results in an estimated reduction of the total takeoff gross weight of over 23,000 pounds for a large airplane. This will result in a 5 to 10 percent reduction in direct operating costs (DOC). Critical to this savings is the basic electrical power system component technology. These advanced electrical power components will provide a solid foundation for the materials, devices, circuits, and subsystems needed to satisfy the unique requirements of advanced all electric aircraft power systems. The program for the development of advanced electrical power component technology is described. The program is divided into five generic areas: semiconductor devices (transistors, thyristors, and diodes); conductors (materials and transmission lines); dielectrics; magnetic devices; and load management devices. Examples of progress in each of the five areas are discussed. Bipolar power transistors up to 1000 V at 100 A with a gain of 10 and a 0.5 microsec rise and fall time are presented. A class of semiconductor devices with a possibility of switching up to 100 kV is described. Solid state power controllers for load management at 120 to 1000 V and power levels to 25 kW were developed along with a 25 kW, 20 kHz transformer weighing only 3.2 kg. Previously announced in STAR as N83-24764

Finke, R. C.↗

NASA NTRS1986

Optimization of spherical facets for parabolic solar concentrators

Solar concentrator designs which employ deployable hexagonal panels are being developed for space power systems. An offset optical configuration has been developed which offers significant system level advantages over previously proposed collector designs for space applications. Optical analyses have been performed which show offset reflector intercept factors to be only slightly lower than those for symmetric reflectors with the same slope error. Fluxes on the receiver walls are asymmetric but manageable by varying the tilt angle of the receiver. Greater producibility is achieved by subdividing the hexagonal panels into triangular mirror facets of spherical contour. Optical analysis has been performed upon these to yield near-optimum sizes and radii.

White, J. E.↗

NASA NTRS2000

Solar Power System Options for the Radiation and Technology Demonstration Spacecraft

The Radiation and Technology Demonstration (RTD) Mission has the primary objective of demonstrating high-power (10 kilowatts) electric thruster technologies in Earth orbit. This paper discusses the conceptual design of the RTD spacecraft photovoltaic (PV) power system and mission performance analyses. These power system studies assessed multiple options for PV arrays, battery technologies and bus voltage levels. To quantify performance attributes of these power system options, a dedicated Fortran code was developed to predict power system performance and estimate system mass. The low-thrust mission trajectory was analyzed and important Earth orbital environments were modeled. Baseline power system design options are recommended on the basis of performance, mass and risk/complexity. Important findings from parametric studies are discussed and the resulting impacts to the spacecraft design and cost.

Kerslake, Thomas W.↗

NASA NTRS2002

Solar Electric Propulsion Technologies Being Designed for Orbit Transfer Vehicle Applications

There is increasing interest in employing Solar Electric Propulsion (SEP) for new missions requiring transfer from low Earth orbit to the Earth-Moon Lagrange point, L1. Mission architecture plans place the Gateway Habitat at L1 in the 2011 to 2016 timeframe. The Gateway Habitat is envisioned to be used for Lunar exploration, space telescopes, and planetary mission staging. In these scenarios, an SEP stage, or "tug," is used to transport payloads to L1--such as the habitat module, lunar excursion and return vehicles, and chemical propellant for return crew trips. SEP tugs are attractive because they are able to efficiently transport large (less than 10,000 kg) payloads while minimizing propellant requirements. To meet the needs of these missions, a preliminary conceptual design for a general-purpose SEP tug was developed that incorporates several of the advanced space power and in-space propulsion technologies (such as high-power gridded ion and Hall thrusters, high-performance thin-film photovoltaics, lithium-ion batteries, and advanced high-voltage power processing) being developed at the NASA Glenn Research Center. A spreadsheet-based vehicle system model was developed for component sizing and is currently being used for mission planning. This model incorporates a low-thrust orbit transfer algorithm to make preliminary determinations of transfer times and propellant requirements. Results from this combined tug mass estimation and orbit transfer model will be used in a higher fidelity trajectory model to refine the analysis.

Sarver-Verhey, Timothy R.↗

NASA NTRS2005

Concept Developed for an Implanted Stimulated Muscle-Powered Piezoelectric Generator

Implanted electronic devices are typically powered by batteries or transcutaneous power transmission. Batteries must be replaced or recharged, and transcutaneous power sources burden the patient or subject with external equipment prone to failure. A completely self-sustaining implanted power source would alleviate these limitations. Skeletal muscle provides an available autologous power source containing native chemical energy that produces power in excess of the requirements for muscle activation by motor nerve stimulation. A concept has been developed to convert stimulated skeletal muscle power into electrical energy (see the preceding illustration). We propose to connect a piezoelectric generator between a muscle tendon and bone. Electrically stimulated muscle contractions would exert force on the piezoelectric generator, charging a storage circuit that would be used to power the stimulator and other devices.

Lewandowski, Beth↗

NASA NTRS1991

Betavoltaics Of Increased Power

Batteries of newly developed betavoltaic cells proposed as long-lived sources of power of order of watts. High-power betavoltaic cell resembles solar photo voltaic cell, except it includes layer of beta-emitting material. Betavoltaic battery cells are stacked as in chemical battery, and surrounded by material containing beta rays. Intended for use aboard spacecraft, batteries also used in surgically implanted devices requiring high power.

Pool, Frederick S.↗

NASA NTRS2005

Description of the Prometheus Program Alternator/Thruster Integration Laboratory (ATIL)

The Project Prometheus Alternator Electric Thruster Integration Laboratory's (ATIL) primary two objectives are to obtain test data to influence the power conversion and electric propulsion systems design, and to assist in developing the primary power quality specifications prior to system Preliminary Design Review (PDR). ATIL is being developed in stages or configurations of increasing fidelity and complexity in order to support the various phases of the Prometheus program. ATIL provides a timely insight of the electrical interactions between a representative Permanent Magnet Generator, its associated control schemes, realistic electric system loads, and an operating electric propulsion thruster. The ATIL main elements are an electrically driven 100 kWe Alternator Test Unit (ATU), an alternator controller using parasitic loads, and a thruster Power Processing Unit (PPU) breadboard. This paper describes the ATIL components, its development approach, preliminary integration test results, and current status.

Baez, Anastacio N.↗

NASA NTRS2007

Stirling System Modeling for Space Nuclear Power Systems

A dynamic model of a high-power Stirling convertor has been developed for space nuclear power systems modeling. The model is based on the Component Test Power Convertor (CTPC), a 12.5-kWe free-piston Stirling convertor. The model includes the fluid heat source, the Stirling convertor, output power and heat rejection. The Stirling convertor model includes the Stirling cycle thermodynamics, heat flow, mechanical mass-spring damper systems, and the linear alternator. The model was validated against test data. Both nonlinear and linear versions of the model were developed. The linear version algebraically couples two separate linear dynamic models; one model of the Stirling cycle and one model of the thermal system, through the pressure factors. Future possible uses of the Stirling system dynamic model are discussed. A pair of commercially available 1-kWe Stirling convertors is being purchased by NASA Glenn Research Center. The specifications of those convertors may eventually be incorporated into the dynamic model and analysis compared to the convertor test data. Subsequent potential testing could include integrating the convertors into a pumped liquid metal hot-end interface. This test would provide more data for comparison to the dynamic model analysis.

Lewandowski, Edward J.↗