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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 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1986

Autonomously managed electrical power systems

The electric power systems for future spacecraft such as the Space Station will necessarily be more sophisticated and will exhibit more nearly autonomous operation than earlier spacecraft. These new power systems will be more reliable and flexible than their predecessors offering greater utility to the users. Automation approaches implemented on various power system breadboards are investigated. These breadboards include the Hubble Space Telescope power system test bed, the Common Module Power Management and Distribution system breadboard, the Autonomusly Managed Power System (AMPS) breadboard, and the 20 kilohertz power system breadboard. Particular attention is given to the AMPS breadboard. Future plans for these breadboards including the employment of artificial intelligence techniques are addressed.

Callis, Charles P.↗
NASA NTRS1998

Electrical Grounding Architecture for Unmanned Spacecraft

This handbook is approved for use by NASA Headquarters and all NASA Centers and is intended to provide a common framework for consistent practices across NASA programs. This handbook was developed to describe electrical grounding design architecture options for unmanned spacecraft. This handbook is written for spacecraft system engineers, power engineers, and electromagnetic compatibility (EMC) engineers. Spacecraft grounding architecture is a system-level decision which must be established at the earliest point in spacecraft design. All other grounding design must be coordinated with and be consistent with the system-level architecture. This handbook assumes that there is no one single 'correct' design for spacecraft grounding architecture. There have been many successful satellite and spacecraft programs from NASA, using a variety of grounding architectures with different levels of complexity. However, some design principles learned over the years apply to all types of spacecraft development. This handbook summarizes those principles to help guide spacecraft grounding architecture design for NASA and others.

Source record↗
NASA NTRS2008

Development and Testing of Space Fission Technology at NASA-MSFC

The Early Flight Fission Test Facility (EFF-TF) at NASA-Marshall Space Flight Center (MSFC) provides a capability to perform hardware-directed activities to support multiple inspace nuclear reactor concepts by using a non-nuclear test methodology. This includes fabrication and testing at both the module/component level and near prototypic reactor configurations allowing for realistic thermal-hydraulic evaluations of systems. The EFF-TF is currently performing non-nuclear testing of hardware to support a technology development effort related to an affordable fission surface power (AFSP) system that could be deployed on the Lunar surface. The AFSP system is presently based on a pumped liquid metal-cooled reactor design, which builds on US and Russian space reactor technology as well as extensive US and international terrestrial liquid metal reactor experience. An important aspect of the current hardware development effort is the information and insight that can be gained from experiments performed in a relevant environment using realistic materials. This testing can often deliver valuable data and insights with a confidence that is not otherwise available or attainable. While the project is currently focused on potential fission surface power for the lunar surface, many of the present advances, testing capabilities, and lessons learned can be applied to the future development of a low-cost in-space fission power system. The potential development of such systems would be useful in fulfilling the power requirements for certain electric propulsion systems (magnetoplasmadynamic thruster, high-power Hall and ion thrusters). In addition, inspace fission power could be applied towards meeting spacecraft and propulsion needs on missions further from the Sun, where the usefulness of solar power is diminished. The affordable nature of the fission surface power system that NASA may decide to develop in the future might make derived systems generally attractive for powering spacecraft and propulsion systems in space. This presentation will discuss work on space nuclear systems that has been performed at MSFC's EFF-TF over the past 10 years. Emphasis will be place on both ongoing work related to FSP and historical work related to in-space systems potentially useful for powering electric propulsion systems.

Polzin, Kurt↗
NASA NTRS2009

Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

In this paper, we investigate the use of Bayesian networks to construct large-scale diagnostic systems. In particular, we consider the development of large-scale Bayesian networks by composition. This compositional approach reflects how (often redundant) subsystems are architected to form systems such as electrical power systems. We develop high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems. The largest among these 24 Bayesian networks contains over 1,000 random variables. Another BN represents the real-world electrical power system ADAPT, which is representative of electrical power systems deployed in aerospace vehicles. In addition to demonstrating the scalability of the compositional approach, we briefly report on experimental results from the diagnostic competition DXC, where the ProADAPT team, using techniques discussed here, obtained the highest scores in both Tier 1 (among 9 international competitors) and Tier 2 (among 6 international competitors) of the industrial track. While we consider diagnosis of power systems specifically, we believe this work is relevant to other system health management problems, in particular in dependable systems such as aircraft and spacecraft. (See CASI ID 20100021910 for supplemental data disk.)

Mengshoel, Ole Jakob↗
NASA NTRS2014

The Use of Software Agents for Autonomous Control of a DC Space Power System

In order to enable manned deep-space missions, the spacecraft must be controlled autonomously using on-board algorithms. A control architecture is proposed to enable this autonomous operation for an spacecraft electric power system and then implemented using a highly distributed network of software agents. These agents collaborate and compete with each other in order to implement each of the control functions. A subset of this control architecture is tested against a steadystate power system simulation and found to be able to solve a constrained optimization problem with competing objectives using only local information.

autonomous control↗
NASA NTRS2018

International Space Station Spacecraft Charging Environments: Modeling, Measurement and Implications for Future Human Space Flight Programs

Spacecraft charging analysis and migration is an interdisciplinary subject combining aspects of electrostatics, plasma physics, ionizing radiation, and materials science, as well as electronic system electromagnetic interference and compatibility (EMI/EMC) effects. Spacecraft charging hazards are caused by the accumulation of electrical charge on spacecraft and spacecraft components produced by interactions with space plasmas, energetic charged particles, and solar UV photons as well as spacecraft electrical power and propulsion systems operations. Spacecraft charging hazard effects include both hard and soft avionics and electrical power system anomalies and have led to the partial or complete loss of numerous spacecraft. The International Space Station (ISS) orbital altitude and inclination (~400 km and 51.6o) determined the dominant natural environment factors affecting ISS spacecraft charging; high speed flight through the geomagnetic field and electrical power system interaction with the cold, high-density ionospheric plasma. In addition ISS is exposed to energetic auroral electrons at high latitude. In this paper we present the results of ISS spacecraft charging modeling and measurements and compare the measurements with numerical modeling of ISS charging processes. ISS is a large metallic structure and flight through the geomagnetic field at orbital speed dominates ISS charging. Collection of ionospheric electrons by the large 160V PV arrays is the next largest contributor. Charging by auroral electrons is detectable but makes a relatively minor contribution. Finally we report the observation of short duration (~ 1 sec) rapid charging peaks associated with shunt/un-shunt operations of the 160V PV arrays, a phenomena not predicted before flight. ISS spacecraft charging environments are radically different from those encountered at higher altitudes in Earth?s magnetosphere and in cis-Lunar space. We present a brief review of those charging environments and an assessment of the applicability of ISS spacecraft charging management and experience to future human spaceflight programs beyond LEO.

Koontz, Steven L.↗
NASA NTRS1983

Battery model for electrical power system energy balance

A model to simulate nickel-cadmium battery performance and response in a spacecraft electrical power system energy balance calculation was developed. The voltage of the battery is given as a function of temperature, operating depth-of-charge (DOD), and battery state-of-charge. Also accounted for is charge inefficiency. A battery is modeled by analysis of the results of a multiparameter battery cycling test at various temperatures and DOD's.

Hafen, D. P.↗
NASA NTRS1987

The results of application studies for space nuclear power

The results are summarized of the studies over the last several years to identify and characterize potential applications for the SP-100 space nuclear reactor power system in powering spacecraft. SP-100 is a space power system based on a fast spectrum nuclear reactor with thermoelectric power conversion and liquid metal and heat pipe thermal transport. SP-100 reactor systems are designed to provide electric power with user designated characteristics at levels in the range from 10 to 1000 kWe. The use of nuclear reactors such as SP-100 as a power source provides a potential means of providing uninterrupted electrical power as required for many of todays space missions within acceptable cost and safety constraints.

Isenberg, L.↗
NASA NTRS2014

Low-Cost, Class D Testing of Spacecraft Photovoltaic Systems Can Reduce Risk

The end-to-end verification of a spacecraft photovoltaic power generation system requires light! Specifically, the standard practice for doing so is the Large Area Pulsed Solar Simulation (LAPSS). A LAPSS test can characterize a photovoltaic system's efficiency via its response to rapidly applied impulses of simulated sunlight. However, a Class D program on a constrained budget and schedule may not have the resources to ship an entire satellite for a LAPSS test alone. Such was the case with the Lunar Atmospheric and Dust Environment Explorer (LADEE) program, which was also averse to the risk of hardware damage during shipment. When the Electrical Power System (EPS) team was denied a spacecraft-level LAPSS test, the lack of an end-to-end power generation test elevated to a project-level technical risk. The team pulled together very limited resources to not only eliminate the risk, but build a process to monitor the health of the system through mission operations. We discuss a process for performing a low-cost, end-to-end test of the LADEE photovoltaic system. The approach combines system-level functional test, panel-level performance results, and periodic inspection (and repair) up until launch. Following launch, mission operations tools are utilized to assess system performance based on a scant amount of data. The process starts in manufacturing at the subcontractor. The panel manufacturer provides functional test and LAPSS data on each individual panel. We apply an initial assumption that the per-panel performance is sufficient to meet the power generation requirements. The manufacturer's data is also carried as the performance allocation for each panel during EPS system modeling and initial mission operations. During integration and test, a high-power, professional theater lamp system provides simulated sunlight to each panel on the spacecraft, thereby permitting a true end-to-end system test. A passing test results in a step response to nearly full-rated current at the appropriate solar array switch in the power system. A metal-halide bulb, infrared imagers, and onboard spacecraft measurements are utilized to minimize risk of thermal damage during test. Data is provided to support test results for both passing and marginal panels. Prior to encapsulation in the launch vehicle, each panel is inspected for damage by the panel manufacturer. Cracked cells or other damage is amended on-site. Because the photovoltaic test system is inexpensive and portable, each repaired panel can be re-verified immediately. Post-launch, the photovoltaic system is again characterized for per-panel deviations from the manufacturer's performance test. This proved especially tricky as the LADEE spacecraft performs only one current measurement on the entire array. The algorithm for Matlab tools to assess panel performance based on spacecraft attitude is discussed. While not as precise and comprehensive as LAPSS, the LADEE approach leverages minimal resources into an ongoing assessment program that can be applied through numerous stages of the mission. The project takes a true Class D approach in assessing the technical value of a spacecraft level performance test versus the programmatic risk of shipping the spacecraft to another facility. The resources required are a fraction of that for a LAPSS test, and is easy to repeat. Further, the test equipment can be handed down to future projects without building an on-site facility.

photovoltaic↗
NASA NTRS2005

Advanced Electrical Materials and Components Development: An Update

The primary means to develop advanced electrical components is to develop new and improved materials for magnetic components (transformers, inductors, etc.), capacitors, and semiconductor switches and diodes. This paper will give an update of the Advanced Power Electronics and Components Technology being developed by the NASA Glenn Research Center for use in future Power Management and Distribution subsystems used in space power systems for spacecraft and lunar and planetary surface power. The initial description and status of this technology program was presented two years ago at the First International Energy Conversion Engineering Conference held at Portsmouth, Virginia, August 2003. The present paper will give a brief background of the previous work reported and a summary of research performed the past several years on soft magnetic materials characterization, dielectric materials and capacitor developments, high quality silicon carbide atomically smooth substrates, and SiC static and dynamic device characterization under elevated temperature conditions. The rationale for and the benefits of developing advanced electrical materials and components for the PMAD subsystem and also for the total power system will also be briefly discussed.

Schwarze, Gene E.↗
NASA NTRS1990

Development of an automated electrical power subsystem testbed for large spacecraft

The NASA Marshall Space Flight Center (MSFC) has developed two autonomous electrical power system breadboards. The first breadboard, the autonomously managed power system (AMPS), is a two power channel system featuring energy generation and storage and 24-kW of switchable loads, all under computer control. The second breadboard, the space station module/power management and distribution (SSM/PMAD) testbed, is a two-bus 120-Vdc model of the Space Station power subsystem featuring smart switchgear and multiple knowledge-based control systems. NASA/MSFC is combining these two breadboards to form a complete autonomous source-to-load power system called the large autonomous spacecraft electrical power system (LASEPS). LASEPS is a high-power, intelligent, physical electrical power system testbed which can be used to derive and test new power system control techniques, new power switching components, and new energy storage elements in a more accurate and realistic fashion. LASEPS has the potential to be interfaced with other spacecraft subsystem breadboards in order to simulate an entire space vehicle. The two individual systems, the combined systems (hardware and software), and the current and future uses of LASEPS are described.

Hall, David K.↗
NASA NTRS2013

The Need for Intelligent Control of Space Power Systems

As manned spacecraft venture farther from Earth, the need for reliable, autonomous control of vehicle subsystems becomes critical. This is particularly true for the electrical power system which is critical to every other system. Autonomy can not be achieved by simple scripting techniques due to the communication latency times and the difficulty associated with failures (or combinations of failures) that need to be handled in as graceful a manner as possible to ensure system availability. Therefore an intelligent control system must be developed that can respond to disturbances and failures in a robust manner and ensure that critical system loads are served and all system constraints are respected.

May, Ryan David↗
NASA NTRS2009

Developing Large-Scale Bayesian Networks by Composition: Fault Diagnosis of Electrical Power Systems in Aircraft and Spacecraft

This CD contains files that support the talk (see CASI ID 20100021404). There are 24 models that relate to the ADAPT system and 1 Excel worksheet. In the paper an investigation into the use of Bayesian networks to construct large-scale diagnostic systems is described. The high-level specifications, Bayesian networks, clique trees, and arithmetic circuits representing 24 different electrical power systems are described in the talk. The data in the CD are the models of the 24 different power systems.

Mengshoel, Ole Jakob↗