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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 37 records · Page 2

All sources NASA NTRS DOE OSTI

NASA NTRS1973

Development of a ruggedized 20-watt, 2.3- gigahertz transistor

This program was to develop a ruggedized transistor capable of meeting the following CW objectives at 2.3 gigahertz: a power output of 20 watts, a power gain of 6 db, and an efficiency of 40 percent. Devices developed produced the following CW performance at 2.3 gigahertz: a power output of 23 watts, a power gain of 7.7 db, and an efficiently of 40.0 percent. This performance was achieved with an eight-cell TA8407 transistor design having the following modifications: a thin pellet, high-frequency diffusion, high-level emitter ballasting, an optimized emitter-bonding configuration for uniform power sharing, and a package that provides for some internal matching through the use of distributed line techniques.

Source record↗

NASA NTRS1974

A comparison of the geomagnetic ap index with fluctuations in B and V - Mariner 5

Mariner 5 data for the interplanetary magnetic field and the solar wind velocity are compared with terrestrial ap values for the period from June 15, to August 22, 1967. It is concluded that fluctuations in the interplanetary magnetic field are more closely coupled to geomagnetic activity as measured with the ap index than are fluctuations in the solar wind velocity. During periods of high-level activity, the data support the Dessler and Walters (1964) model where the magnetic field is the primary causal agent of geomagnetic activity.

Jones, D. E.↗

NASA NTRS1975

New broadband square-law detector

Compact device has wide dynamic range, accurate square-law response, good thermal stability, high-level dc output with immunity to ground-loop problems, ability to insert known time constants for radiometric applications, and fast response times compatible with computer systems.

Reid, M. S.↗

NASA NTRS1975

A new broadband square law detector

A broadband constant law detector was developed for precision power measurements, radio metric measurements, and other applications. It has a wide dynamic range and an accurate square law response. Other desirable characteristics, which are all included in a single compact unit, are: (1) high-level dc output with immunity to ground loop problems; (2) fast response times; (3) ability to insert known time constants; and (4) good thermal stability. The detector and its performance are described in detail. The detector can be operated in a programmable system with a ten-fold increase in accuracy. The use and performance of the detector in a noise-adding radiometer system is also discussed.

Reid, M. S.↗

NASA NTRS1974

Experientally guided robots

This paper argues that an experientally guided robot is necessary to successfully explore far-away planets. Such a robot is characterized as having sense organs which receive sensory information from its environment and motor systems which allow it to interact with that environment. The sensori-motor information which it receives is organized into an experiential knowledge structure and this knowledge in turn is used to guide the robot's future actions. A summary is presented of a problem solving system which is being used as a test bed for developing such a robot. The robot currently engages in the behaviors of visual tracking, focusing down, and looking around in a simulated Martian landscape. Finally, some unsolved problems are outlined whose solutions are necessary before an experientally guided robot can be produced. These problems center around organizing the motivational and memory structure of the robot and understanding its high-level control mechanisms.

Merriam, E. W.↗

NASA NTRS1976

A/D converter

Two-part dual-slope system converts both low-level and high-level analog signals at 500 8-bit words/second with an accuracy of 3 percent.

Mason, M. D.↗

NASA NTRS1977

DSN automation

An overall hierarchical automation philosophy along with the results of the radio frequencies automation effort undertaken 2 years ago are summarized. A brief description of each subassembly controller's salient features, the software development process, and the common software used by these controllers will be presented. Comments will be made with respect to the relative advantages of high-level language and assembly language, the operational effectiveness of operator Macro commands, and the program development, and a list of suggested future effort will be given.

Crow, R. B.↗

NASA NTRS1976

Study and development of techniques for automatic control of remote manipulators

An overall conceptual design for an autonomous control system of remote manipulators which utilizes feedback was constructed. The system consists of a description of the high-level capabilities of a model from which design algorithms are constructed. The autonomous capability is achieved through automatic planning and locally controlled execution of the plans. The operator gives his commands in high level task-oriented terms. The system transforms these commands into a plan. It uses built-in procedural knowledge of the problem domain and an internal model of the current state of the world.

Shaket, E.↗

NASA NTRS1977

Data representations in PDP-10 MacLISP

The internal representations of the various MacLISP data types are presented and discussed. Certain implementation tradeoffs are considered. The ultimate decisions on these tradeoffs are discussed in the light of MacLISP's prime objective of being an efficient high-level language for the implementation of large systems such as MACSYMA. The basic strategy of garbage collection is outlined, with reference to the specific representations involved. Certain clever tricks are explained and justified. The address space crunch is explained and some alternative solutions explored.

Steele, G. L., Jr.↗

NASA NTRS1976

Examples of synoptic changes in ozone and circulation in the stratosphere

The Backscatter Ultraviolet (BUV) experiment on board the Nimbus 4 polar orbiting satellite has been measuring the total ozone content and high-level atmospheric ozone profiles since early 1970. Synoptic type analyses of these data are now being accomplished and compared with appropriate constant-pressure analyses of stratospheric circulation. Ozone changes during a stratospheric warming of early 1971 are investigated by comparison with circulation changes in the layer between 30 mb (24 km) and 2 mb (42 km). A general increase in ozone concentrations, more pronounced in the higher latitudes, is noted during the warming period. Plans for future investigation are discussed, including analysis of ozone observations beginning from 1970 on every two-day basis for comparison with constant-pressure height, temperature, and wind charts analyzed with the aid of radiosonde, rocketsonde, and satellite data.

Finger, F. G.↗

NASA NTRS1977

Wind estimates from cloud motions - Results from Phases I, II and III of an in situ aircraft verification experiment

An experiment is in progress to verify geostationary-satellite-derived cloud-motion wind estimates by in-situ aircraft wind-velocity measurements. One or more low-level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high-level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. To date the experiment has been conducted over tropical oceans and in the western Gulf of Mexico. A total of 60 h have been spent tracking some 40 tropical cumulus and five cirrus clouds. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at cloud base. The magnitude of the vector difference between the cloud motion and the cloud-base wind is less than 1.3 m/s for 67% of the cases with track lengths of 1 h or longer. Similarly, the vector differences between the cloud motion and the wind at sub-cloud (150 m), mid-cloud, and cloud-top levels are 1.5, 3.6 and 7.0 m/s, respectively. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/s.

Hasler, A. F.↗

NASA NTRS1977

A database system to support image algorithm evaluation

The design is given of an interactive image database system IMDB, which allows the user to create, retrieve, store, display, and manipulate images through the facility of a high-level, interactive image query (IQ) language. The query language IQ permits the user to define false color functions, pixel value transformations, overlay functions, zoom functions, and windows. The user manipulates the images through generic functions. The user can direct images to display devices for visual and qualitative analysis. Image histograms and pixel value distributions can also be computed to obtain a quantitative analysis of images.

Lien, Y. E.↗

NASA NTRS1976

Application of gaseous core reactors for transmutation of nuclear waste

An acceptable management scheme for high-level radioactive waste is vital to the nuclear industry. The hazard potential of the trans-uranic actinides and of key fission products is high due to their nuclear activity and/or chemical toxicity. Of particular concern are the very long-lived nuclides whose hazard potential remains high for hundreds of thousands of years. Neutron induced transmutation offers a promising technique for the treatment of problem wastes. Transmutation is unique as a waste management scheme in that it offers the potential for "destruction" of the hazardous nuclides by conversion to non-hazardous or more manageable nuclides. The transmutation potential of a thermal spectrum uranium hexafluoride fueled cavity reactor was examined. Initial studies focused on a heavy water moderated cavity reactor fueled with 5% enriched U-235-F6 and operating with an average thermal flux of 6 times 10 to the 14th power neutrons/sq cm-sec. The isotopes considered for transmutation were I-129, Am-241, Am-242m, Am-243, Cm-243, Cm-244, Cm-245, and Cm-246.

Schnitzler, B. G.↗

NASA NTRS2024

Expansion of Check-Cases for 6DOF Simulation

This is the Appendix containing a description of the solution for Case 1 in the assessment, “Expansion of Check-Cases for 6DOF Simulation”. For cases of spherical gravity, it is possible to provide a two-body solution without recourse to numerical integration and thus it is accurate to machine precision. Python code for a Keplerian Propagator (propagate.py) which produced a reference trajectory for Case 1 is provided in this appendix. There is also code for generating test cases which was used as an independent verification of the propagator. This is a high-level description of the algorithm employed. The documentation of each function includes implementation details, including equations for each task.

Modeling↗

NASA NTRSDate not supplied

CLDP/ISS Glovebox Technical Interchange Meeting

This presentation is designed to provide a high-level overview of the Microgravity Science Glovebox (MSG) and the Life Sciences Glovebox (LSG) facilities onboard the International Space Station. In addition, it provides metrics and lessons-learned information intended for the Commercial Low-Earth Orbit Development Program (CLDP) Partners.

glovebox↗

NASA NTRS2026

xEMU Spacesuit Boot Lunar South Pole Thermal Vacuum Testing

The Exploration Extravehicular Mobility Unit (xEMU) spacesuit lunar boot was evaluated in the Jet Propulsion Lab (JPL) CITADEL thermal vacuum chamber at lunar South Pole conditions. The JPL CITADEL chamber provides a radiation environment and contact plate temperature of 48K, simulating the temperature of a lunar Permanently Shadowed Region (PSR) at the South Pole of the Moon. The main objectives of the test series are: to evaluate the risk lunar PSRs pose to advanced spacesuit boots, validate the xEMU lunar boot thermal model, and to develop a test methodology to evaluate lunar spacesuit boots. To simulate the thermal effects of a crewmember’s foot inside the boot, a thermal manikin foot was developed to inject heat into the spacesuit boot. Thermal data was collected through a variety of sensors including thermocouples, thermistors, heat flux sensors, and infrared cameras. A test matrix was developed to investigate the variables of foot contact force, simulated skin temperature, external contact plate temperature, and ventilation flowrate. The JPL CITADEL chamber includes a loadlock (airlock) that afforded the ability to simulate the transition of the boot from a thermally neutral IVA condition to a cold EVA condition within seconds. This paper will document the test design, test objectives, success criteria, test support equipment, spacesuit boot to chamber interfaces, and configuration of the test article. Additionally, this paper will document the high-level results of the testing. More detailed test results will be presented in a different paper.

Ben Swartout↗

NASA NTRS2026

xEMU Spacesuit Boot Lunar South Pole Thermal Vacuum Testing

The Exploration Extravehicular Mobility Unit (xEMU) spacesuit lunar boot was evaluated in the Jet Propulsion Lab (JPL) CITADEL thermal vacuum chamber at lunar South Pole conditions. The JPL CITADEL chamber provides a radiation environment and contact plate temperature of 48K, simulating the temperature of a lunar Permanently Shadowed Region (PSR) at the South Pole of the Moon. The main objectives of the test series were: to evaluate the risk lunar PSRs pose to advanced spacesuit boots, validate the xEMU lunar boot thermal model, and develop a test methodology to evaluate lunar spacesuit boots. To simulate the thermal effects of a crewmember’s foot inside the boot, a thermal manikin foot was developed to inject heat into the spacesuit boot. Thermal data was collected through a variety of sensors including thermocouples, thermistors, heat flux sensors, and infrared cameras. A test matrix was developed to investigate the variables of foot contact force, simulated skin temperature, external contact plate temperature, and ventilation flowrate. The JPL CITADEL chamber includes a loadlock (airlock) that afforded the ability to simulate the transition of the boot from a thermally neutral IVA condition to a cold EVA condition within seconds. This paper will document the test design, test objectives, success criteria, test support equipment, spacesuit boot to chamber interfaces, and configuration of the test article. Additionally, this paper will document the high-level results of the testing. More detailed test results will be presented in a different paper.

TVAC↗

NASA NTRS2026

The Contaminant Footprint of Landed Spacecraft: Toward an Inventory and Modelling Framework

All spacecraft generate and carry contaminants, i.e., unwanted and potentially harmful material. When a spacecraft lands and operates in near-vacuum, as onto Earth’s Moon, it introduces contaminants into its environment that may compromise mission science objectives and engineering performance. Contamination of solar system bodies may irrevocably degrade targets of unique value to planetary scientists, for instance, as lunar landed spacecraft introduce propellant effluents into the otherwise pristine ice of the Moon’s permanently shadowed regions. NASA’s planetary protection discipline seeks to ensure that solar system bodies are not contaminated, for scientific purposes, by terrestrial material (i.e., forward contamination). This interest aligns with planetary science interest in mitigating the transport of terrestrial contaminants onto solar system bodies and in controlling types of contamination that could compromise the scientific value of samples or measurements. NASA, and other entities that practice planetary science, have compelling and multidisciplinary interests in the preservation of special regions and sampling sites of high scientific value – including lunar permanently shadowed regions (PSRs) – from inadvertent contamination by any spacecraft, and in understanding the contamination of such regions by all spacecraft. Organic molecular contamination here represents a primary threat. Organic molecules will be introduced to solar system bodies by nominal landed spacecraft and crew processes – including by the action of descent and ascent engines; natural materials outgassing; and crew environmental and life support system sources. Molecular contaminants can also travel in the free-molecular sense at global scale across near-vacuum bodies, including into regions where they may be permanently trapped. This presentation will address a high-level study to identify sources of contaminants – in particular, organic material – generated by landed spacecraft along with the transport vectors by which these contaminants can reach sites of scientific interest on bodies like the Moon. A vision for an integrated modeling framework for the organic contamination footprint of spacecraft missions, individually and collectively, will also be described and presented along with initial conclusions related to organic molecular transport.

Gas Dynamics↗