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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
NASA NTRS1979

DRIRU II - The NASA standard high performance Inertial Reference Unit

This paper discusses the design configuration, performance and environmental capability of NASA's Dry Rotor Inertial Reference Unit (DRIRU II) for use in spacecraft precision attitude stabilization systems. The system is a self-contained, strapdown, dual rate sensing unit for spacecraft requiring high accuracy, reliability and low power consumption. Modular construction of the basic unit, arrangement of gyros, electronic modules and power supplies, signal flow, and mounting are described. DRIRU II is designed to meet specified performance requirements for a minimum of two years of operating time in orbit and a reliability prediction analysis is presented. The characteristics of test equipment are given together with the results of the environmental, radiation, and magnetic field sensitivity tests. DRIRU II may be modified for unique requirements and the rate range and resolution options are tabulated. The flexibility of the unit afforded by the use of dry tuned gimbal gyros and its modular construction results in a system capable of satisfying the demanding requirements of a broad spectrum of future applications. The units are planned for the Solar Max, Landsat-D and ASPS missions in the 1980's.

Irvine, R. B.↗
NASA NTRS1982

Equipment Analysis

Magnavox Government & Electronics Company originally used the NASTRAN program in the design stage of heavy aluminum fixtures for vibration testing. Program also used to compare the resonant frequencies of the circuitry to predict whether failures may occur because of high vibration levels. The company engineers can then make design alterations to improve the equipment's vibration resistance. Method allows Magnavox to insure reliability and reduce any possibility of vibration-caused failure in critical defense products they manufacture. Magnavox uses another COSMIC software package called GENOPTICS in the development of a Digital Optical Recorder, and also in research and development of other optical systems. This enables use of an optically recorded disc to store and retrieve digital data. It is reported that this program provides accurate results and that its use saved six man-months of time that would have been needed to develop a comparable software package.

Source record↗
NASA NTRS2008

FAA Airport Design Competition for Universities

Raise awareness of the importance of airports to the National Airspace System infrastructure. Increase the involvement of the academic community in addressing airport operations and infrastructure issues and needs. Engage U.S. students in the conceptualization of applications, systems and equipment capable of addressing related challenges in a robust, reliable and comprehensive manner. Encourage U.S. undergraduate and graduate students to contribute innovative ideas and solutions to airport and runway safety issues. Provide the framework and incentives for quality educational experiences for university students. d Develop an awareness of and an interest in airports as a vital and interesting area for engineering and technology careers.

Sandy, Mary↗
NASA NTRSDate not supplied

Application of Regolith Polymer Composite FFF Construction in Simulated Lunar Conditions

NASA’s Artemis program has the lofty goal of creating a sustained lunar presence to provide unprecedented opportunities for scientific discovery and to ensure American industry’s access to the unlimited resources and commercial potential in space. To achieve this goal, NASA must incrementally develop and expand its capabilities beyond the short lunar stays of the Apollo program to a robust continued presence with infrastructure and equipment to reduce mission risk by providing safer and more reliable access to the surface, its resources, and protection from the environment. Kennedy Space Center’s Swamp Works Granular Mechanics and Regolith Operations laboratory has partnered with AI SpaceFactory to develop the architectural and structural design of a robotically constructable unpressurized shelter. The shelter, called Lina is designed to protect astronauts and surface assets from radiation, meteoroid impact, moon quakes and thermal gradients. A Fused Filament Fabrication (FFF) construction process using regolith polymer composites was developed. The construction system and associated print parameters are discussed along with the environmental simulation equipment and a summary of test conditions. Test samples were printed in simulated lunar dirty thermal vacuum conditions (~-180 C, ~10-3 torr) and subjected to a series of tests. The resulting strength properties are summarized here, the full details of the material characteristics are provided in a related paper. Lina’s structural design criteria and the resulting initial structure design are detailed in two related papers, this paper presents an update to Lina’s design based on the achieved material strength properties. Finally, a scaled down version of the updated Lina was built on a regolith simulant surface using a novel anchoring technique in simulated lunar vacuum conditions.

lunar infrastructure↗
NASA NTRS2019

Characterization of a Fixed-Volume Release System for Initiating an Arc Discharge in a Heaterless Hollow Cathode

Heaterless hollow cathodes may provide improved reliability, simplicity, and portability when compared with traditional heater-equipped hollow cathodes, traits which are well suited for low-power Hall-effect thrusters that are currently being developed for small satellite propulsion. Despite the advantages, there are concerns that the ignition process in heaterless hollow cathodes may impose an excessive burden on the propellant feed and/or electrical systems of a small satellite. To address this concern, a fixed-volume release flow protocol, which can be used to temporarily increase the propellant mass flow rate, was developed, modeled, and experimentally evaluated. The new protocol allowed for a heaterless hollow cathode to be ignited reliably with a moderate bias voltage and a minimal electrical power requirement. Specifically, a xenon fed heaterless hollow cathode was ignited with a 375 V bias using 17.3 mg of propellant. Repeating the tests with krypton showed that ignition could be achieved in the same heaterless hollow cathode assembly with a 300 V bias using 13.1 mg of propellant. We judge that a fixed-volume release system could be implemented in a satellite feed system while introducing minimal additional complexity.

Heaterless↗
NASA NTRS2019

Characterization of a Fixed-Volume Release System for Initiating an Arc Discharge in a Heaterless Hollow Cathode

Heaterless hollow cathodes may provide improved reliability, simplicity, and portability when compared with traditional heater-equipped hollow cathodes, traits which are well suited for low-power Hall-effect thrusters that are currently being developed for small satellite propulsion. Despite the advantages, there are concerns that the ignition process in heaterless hollow cathodes may impose an excessive burden on the propellant feed and/or electrical systems of a small satellite. To address this concern, a fixed-volume release flow protocol, which can be used to temporarily increase the propellant mass flow rate, was developed, modeled, and experimentally evaluated. The new protocol allowed for a heaterless hollow cathode to be ignited reliably with a moderate bias voltage and a minimal electrical power requirement. Specifically, a xenon fed heaterless hollow cathode was ignited with a 375 V bias using 17.3 mg of propellant. Repeating the tests with krypton showed that ignition could be achieved in the same heaterless hollow cathode assembly with a 300 V bias using 13.1 mg of propellant. We judge that a fixed-volume release system could be implemented in a satellite feed system while introducing minimal additional complexity.

Heaterless↗
NASA NTRS2013

A Multi-Environment Thermal Control System With Freeze-Tolerant Radiator

Future space exploration missions require advanced thermal control systems (TCS) to dissipate heat from spacecraft, rovers, or habitats operating in environments that can vary from extremely hot to extremely cold. A lightweight, reliable TCS is being developed to effectively control cabin and equipment temperatures under widely varying heat loads and ambient temperatures. The system uses freeze-tolerant radiators, which eliminate the need for a secondary circulation loop or heat pipe systems. Each radiator has a self-regulating variable thermal conductance to its ambient environment. The TCS uses a nontoxic, water-based working fluid that is compatible with existing lightweight aluminum heat exchangers. The TCS is lightweight, compact, and requires very little pumping power. The critical characteristics of the core enabling technologies were demonstrated. Functional testing with condenser tubes demonstrated the key operating characteristics required for a reliable, freeze-tolerant TCS, namely (1) self-regulating thermal conductance with short transient responses to varying thermal loads, (2) repeatable performance through freeze-thaw cycles, and (3) fast start-up from a fully frozen state. Preliminary coolant tests demonstrated that the corrosion inhibitor in the water-based coolant can reduce the corrosion rate on aluminum by an order of magnitude. Performance comparison with state-of-the-art designs shows significant mass and power saving benefits of this technology.

Chen, Weibo↗
NASA NTRS1985

Ground processing of the McDonnell Douglas Payload Assist Module (PAM)

The payload assist module (PAM) ground processing operations which have evolved since they were started in 1982 are described. The objective of the changes was to reduce the prelaunch testing of the airborne support equipment to increase the throughput of PAM systems while not compromising the reliability of the system when functioned on-orbit. The changes that resulted from the initial cargo element ground processing, the on-orbit performance of the systems, plus the postflight refurbishment and recertification of the airborne support equipment resulted in significant reductions in labor expenditures and work shifts required to prepare a PAM system for flight.

Bryan, C. E.↗
NASA NTRS2019

Gravity Effects in Two-Phase Microgap Flow

The high power density of emerging electronic devices is driving the transition from remote cooling, which relies on conduction and spreading, to embedded cooling, which extracts dissipated heat on-site. Two-phase microgap coolers employ the forced flow of dielectric fluids undergoing phase change in a heated channel within or between devices. Such coolers must work reliably in all orientations for a variety of applications (e.g., vehicle-based equipment), as well as in microgravity and high-g for aerospace applications, but the lack of acceptable models and correlations for orientation- and gravity-independent operation has limited their use. Reliable criteria for achieving orientation- and gravity-independent flow boiling would enable emerging systems to exploit this thermal management technique and streamline the technology development process. As a first step toward understanding the effect of gravity in two-phase microgap flow and transport, in an earlier effort, the authors studied the effects of evaporator orientation, mass flux, and heat flux on flow boiling of HFE7100 in a 1.01 mm tall by 13.0 mm wide by 12.7 mm long microgap channel. Orientation-independence, defined as achieving similar critical heat fluxes, heat transfer coefficients, and flow regimes across orientations, was achieved for mass fluxes of 400 kg/sq.m-s and greater (corresponding to a Froude number of about 0.8). In the present effort, the authors have studied the effects of gravity, mass flux, and subcooling on flow boiling of HFE7100 in a 0.17 mm tall by 13.0 mm wide by 12.7 mm long microgap channel. The Flow Boiling in Microgap Coolers payload experienced about three minutes of weightlessness and shorter periods of high-g (up to about 5 g) during two recent flights aboard the Blue Origin New Shepard reusable launch vehicle. The results from the flight experiments will be presented and compared with published criteria for achieving gravity-independence.

Robinson, Franklin L.↗
NASA NTRS1995

Alternatives to ozone depleting refrigerants in test equipment

This paper describes the initial results of a refrigerant retrofit project at the Aerospace Guidance and Metrology Center (AGMC) at Newark Air Force Base, Ohio. The objective is to convert selected types of test equipment to properly operate on hydrofluorocarbon (HFC) alternative refrigerants, having no ozone depleting potential, without compromising system reliability or durability. This paper discusses the primary technical issues and summarizes the test results for 17 different types of test equipment: ten environmental chambers, two ultralow temperature freezers, two coolant recirculators, one temperature control unit, one vapor degreaser, and one refrigerant recovery system. The postconversion performance test results have been very encouraging: system capacity and input power remained virtually unchanged. In some cases, the minimum operating temperature increased by a few degrees as a result of the conversion, but never beyond AGMC's functional requirements.

Hall, Richard L.↗
NASA NTRS1970

Statistical complex fatigue data for SAE 4340 steel and its use in design by reliability

A brief description of the complex fatigue machines used in the test program is presented. The data generated from these machines are given and discussed. Two methods of obtaining strength distributions from the data are also discussed. Then follows a discussion of the construction of statistical fatigue diagrams and their use in designing by reliability. Finally, some of the problems encountered in the test equipment and a corrective modification are presented.

Kececioglu, D.↗
NASA NTRS1976

TRAN*STAR 2 evaluation for NOAA data buoy office, part A

The capability of the TRAN*STAR 2 receiver equipment utilizing the U.S. Navy Navigation Satellite System to provide reliable position locations with reasonable accuracy and frequency was evaluated. Two receivers, an antenna, and a test set were procured, and position fix data collected at NSTL from a fixed known location during the months of May and June. The data were processed through a computer program and analyzed. The results of the evaluation are summarized.

Source record↗
NASA NTRS1989

Standard Method For Radiation Tests Of Liquids

Simple procedure provides standard method for radiation tests of liquids. Assures identical handling and dosage so data from different test laboratories compared reliably. Pair of glass vials, joined by frangible neck and equipped with valves, used. Third vial also used. Filled with control specimen and not irradiated. Developed for measuring properties of liquids for use in radiation-resistant liquid-dielectric capacitors, procedure used for any of variety of liquids proposed for use in high-radiation environment - in x-ray and particle-accelerating machines and nuclear reactors, for example.

Bouquet, Frank L.↗
NASA NTRS1991

AI mass spectrometers for space shuttle health monitoring

The facility Hazardous Gas Detection System (HGDS) at Kennedy Space Center (KSC) is a mass spectrometer based gas analyzer. Two instruments make up the HGDS, which is installed in a prime/backup arrangement, with the option of using both analyzers on the same sample line, or on two different lines simultaneously. It is used for monitoring the Shuttle during fuel loading, countdown, and drainback, if necessary. The use of complex instruments, operated over many shifts, has caused problems in tracking the status of the ground support equipment (GSE) and the vehicle. A requirement for overall system reliability has been a major force in the development of Shuttle GSE, and is the ultimate driver in the choice to pursue artificial intelligence (AI) techniques for Shuttle and Advanced Launch System (ALS) mass spectrometer systems. Shuttle applications of AI are detailed.

Adams, F. W.↗
NASA NTRS2005

International Space Station Carbon Dioxide Removal Assembly (ISS CDRA) Concepts and Advancements

An important aspect of air revitalization for life support in spacecraft is the removal of carbon dioxide from cabin air. Several types of carbon dioxide removal systems are in use in spacecraft life support. These systems rely on various removal techniques that employ different architectures and media for scrubbing CO2, such as permeable membranes, liquid amine, adsorbents, and absorbents. Sorbent systems have been used since the first manned missions. The current state of key technology is the existing International Space Station (ISS) Carbon Dioxide Removal Assembly (CDRA), a system that selectively removes carbon dioxide from the cabin atmosphere. The CDRA system was launched aboard UF-2 in February 2001 and resides in the U.S. Destiny Laboratory module. During the past four years, the CDRA system has operated with varying degrees of success. There have been several approaches to troubleshooting the CDRA system aimed at developing work-around solutions that would minimize the impact on astronaut time required to implement interim solutions. The paper discusses some of the short-term fixes applied to promote hardware life and restore functionality, as well as long-term plans and solutions for improving operability and reliability. The CDRA is a critical piece of life support equipment in the air revitalization system of the ISS, and is demonstrated technology that may ultimately prove well-suited for use in lunar or Mars base, and Mars transit life support applications.

ElSherif, Dina↗