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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS1987

Technology for submillimeter wave remote sensing

NASA's sub-mm wave technology development program addresses emerging possibilities in spaceborne sensor design for what is one of the few unexplored regions of the spectrum, from 1.0 to 0.1 mm wavelengths. Astrophysics, earth atmosphere research and solar system exploration can all benefit from the development of such sensor capabilities. Technology status evaluations are presented for Shottky-diode and SIS mixers, solid state and backward wave oscillators, intermodulation frequency amplifiers, and digital autocorrelator and acoustooptic spectrometers.

Sokoloski, Martin M.↗
NASA NTRS1987

Advanced heavy lift launch vehicles

The performance requirements of advanced technology-incorporating, next-generation heavy lift launch vehicles (HLLVs) for LEO missions are discussed, and the configurational features facilitated by those technologies are evaluated. These 1990s 'cargo' vehicles will capitalize on advanced avionics, software and automation, novel hot structure and thermal insulation materials, and more powerful liquid-fuel rockets employing either hydrogen or hydrocarbons. The configurations considered include a winged booster. The use of Space Shuttle components is a major cost-minimization strategy in many of these HLLV design efforts.

Shelton, Billy W.↗
NASA NTRS1988

First results from the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS)

After engineering flights aboard the NASA U-2 research aircraft in the winter of 1986 to 1987 and spring of 1987, extensive data collection across the United States was begun with the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) in the summer of 1987 in support of a NASA data evaluation and technology assessment program. This paper presents some of the first results obtained from AVIRIS. Examples of spectral imagery acquired over Mountain View and Mono Lake, California, and the Cuprite Mining District in western Nevada are presented. Sensor performance and data quality are described, and in the final section of this paper, plans for the future are discussed.

Vane, Gregg↗
NASA NTRS1989

Advanced manned space flight simulation and training: An investigation of simulation host computer system concepts

The findings of a preliminary investigation by Southwest Research Institute (SwRI) in simulation host computer concepts is presented. It is designed to aid NASA in evaluating simulation technologies for use in spaceflight training. The focus of the investigation is on the next generation of space simulation systems that will be utilized in training personnel for Space Station Freedom operations. SwRI concludes that NASA should pursue a distributed simulation host computer system architecture for the Space Station Training Facility (SSTF) rather than a centralized mainframe based arrangement. A distributed system offers many advantages and is seen by SwRI as the only architecture that will allow NASA to achieve established functional goals and operational objectives over the life of the Space Station Freedom program. Several distributed, parallel computing systems are available today that offer real-time capabilities for time critical, man-in-the-loop simulation. These systems are flexible in terms of connectivity and configurability, and are easily scaled to meet increasing demands for more computing power.

Montag, Bruce C.↗
NASA NTRS1990

The 30-kW ammonia arcjet technology

The technical results are summarized of a 30 kW class ammonia propellant arcjet technology program. Evaluation of previous arcjet thruster performance, including materials analysis of used thruster components, led to the design of an arcjet with improved performance and thermal characteristics. Tests of the new engine demonstrated that engine performance is relatively insensitive to cathode tip geometry. Other data suggested a maximum sustainable arc length for a given thruster configuration, beyond which the arc may reconfigure in a destructive manner. A flow controller calibration error was identified. This error caused previously reported values of specific impulse and thrust efficiency to be 20 percent higher than the real values. Corrected arcjet performance data are given. Duration tests of 413 and 252 hours, and several tests 100 hours in duration, were performed. The cathode tip erosion rate increased with increasing arc current. Elimination of power source ripple did not affect cathode tip whisker growth. Results of arcjet modeling, diagnostic development and mission analyses are also discussed. The 30 kW ammonia arcjet may now be considered ready for development for a flight demonstration, but widespread application of 30 kW class arcjet will require improved efficiency and lifetime.

Deininger, W. D.↗
NASA NTRS1990

Biological Life Support Technologies: Commercial Opportunities

The papers from the workshop on Biological Life Support Technologies: Commercial Opportunities are presented. The meeting attracted researchers in environmental and bioregenerative systems. The role of biological support technologies was evaluated in the context of the global environmental challenge on Earth and the space exploration initiative, with its goal of a permanent space station, lunar base, and Mars exploration.

Nelson, Mark↗
NASA NTRS1990

Solar electric propulsion for Mars transport vehicles

Solar electric propulsion (SEP) is an alternative to chemical and nuclear powered propulsion systems for both piloted and unpiloted Mars transport vehicles. Photovoltaic solar cell and array technologies were evaluated as components of SEP power systems. Of the systems considered, the SEP power system composed of multijunction solar cells in an ENTECH domed fresnel concentrator array had the least array mass and area. Trip times to Mars optimized for minimum propellant mass were calculated. Additionally, a preliminary vehicle concept was designed.

Solar electric propulsion↗
NASA NTRS1991

An overview of tested and analyzed NTP concepts

If we buy into the goals of the Space Exploration Initiative (SEI) and accept that they are worthy of the hefty investment of our tax dollars, then we must begin to evaluate the technologies which enable their attainment. The main driving technology is the propulsion systems; for interplanetary missions, the safest and most affordable is a Nuclear Thermal Propulsion (NTP) system. An overview is presented of the NTP systems which received detailed conceptual design and, for several, testing.

Walton, James T.↗
NASA NTRS1991

Large area QNDE inspection for airframe integrity

Quantitative Nondestructive Evaluation (QNDE) technology is being developed to provide new options for cost effective inspection of airframes. An R&D effort based on five NDE technologies is addressing questions of structural bonding assessment, corrosion detection, multisite damage detection, and fatigue characterization. The research/applications are being conducted by prioritized focussing and staging of the following technologies: (1) thermal NDE; (2) ultrasonic NDE; (3) coherent optical NDE; (4) magnetic imaging NDE; and (5) radiographic NDE. The focus here is on the most recent applications of thermal NDE technology to large area inspection of lap-joint and stiffener bonds. The approach is based on pulsed radiant heating of the airframe and measurement of the surface temperature of the structure with an infrared imager. Several advantages of the technique are that it is noncontacting, inspects one square meter area in a period of less than 2 minutes and has no difficulty inspecting typical curvatures of the fuselage. Numerical models of heat flow in these geometries are used to determine appropriate techniques for reduction of the infrared images, thereby delineating regions of disbonds. These models are also used to determine the optimum heating and measurement times for maximizing the contrast between bonded and unbonded structures. Good agreement is found between these results and experimental measurements, and a comparison of the two are presented. Also presented are results of measurements on samples with fabricated defects which show the technique is able to clearly indicate regions of disbonds. Measurements on an airframe also clearly image subsurface structure.

Winfree, William P.↗
NASA NTRS1989

Low thrust propulsion literature survey

A literature search was performed to investigate the area of low thrust propulsion. In an effort to evaluate this technology, a number of articles, obtained through the use of the NASA-RECON database, were collected and categorized. The study indicates that although much was done, particularly in the 1960's and 1970's, more can be done in the area of practical navigation and guidance. It is suggested that the older studies be reinvestigated to see what potential there exists for future low thrust applications.

Monroe, Darrel↗
NASA NTRS1992

Superconductivity devices: Commercial use of space

The high T(sub c) superconducting ceramic materials, developed in 1987, are now being extensively investigated for a variety of engineering applications. These applications include such devices as conducting links, rotating and linear bearings, sensors, filters, switches, high Q cavities, magnets, and motors. Some of these devices take advantage of the material's ability to lose all electrical resistance at a critical temperature, T(sub c), while others make use of the repulsion forces generated between the magnetic field of a permanent magnet and a superconductor which is cooled below its T(sub c), Meissner effect. This report describes the work accomplished to date by: (1) reviewing the present state of the art in actuator technology, (2) evaluating processing and fabrication of high strain electrostrictive materials, and (3) testing these electrostrictive materials.

Haertling, Gene↗
NASA NTRS1991

Structural scaling approximations for solar arrays

General scaling rules for a photovoltaic array structure are required in order to compare the effectiveness of different cell technologies. Important evaluation criteria for an array are moment of inertia, resonant frequency of vibrational modes, stiffness against acceleration, and resistance losses in the wiring. Approximate scaling relationships for these parameters for a generic solar array structure are presented.

Landis, Geoffrey A.↗
NASA NTRS1992

Advanced technology wind shear prediction system evaluation

The program overviews: (1) American Airline (AA)/Turbulence Prediction Systems (TPS), which have installed forward looking infrared predictive windshear system on 3 MD-80 aircraft; (2) AA/TPS AWAS III evaluation, which is a joint effort and is installed in the noise landing gear (NLG) area and a data recorder installed in the E/E compartment.

Gering, Greg↗
NASA NTRS1993

NDE of titanium alloy MMC rings for gas turbine engines

Progress in the processing and fabrication of metal matrix composites (MMC's) requires appropriate mechanical and nondestructive testing methods. These methods are needed to characterize properties, assess integrity, and predict the life of engine components such as compressor rotors, blades, and vanes. Capabilities and limitations of several state-of-the-art nondestructive evaluation (NDE) technologies are investigated for characterizing titanium MMC rings for gas turbine engines. The use of NDE technologies such as x-ray computed tomography, radiography, and ultrasonics in identifying fabrication-related problems that caused defects in components is examined. Acousto-ultrasonics was explored to assess degradation of material mechanical properties by using stress wave factor and ultrasonic velocity measurements before and after the burst testing of the rings.

Baaklini, George Y.↗
NASA NTRS1993

Turbulence modeling in aircraft icing

The Icing and Cryogenic Technology Branch develops computational tools which predict ice growth on aircraft surfaces and uses existing CFD technology to evaluate the aerodynamic changes associated with such accretions. Surface roughness, transition location, and laminar, transition, or turbulent convective heat transfer all influence the ice growth process on aircraft surfaces. Turbulence modeling is a critical element within the computational tools used for both ice shape prediction and for performance degradation evaluation.

Potapczuk, Mark G.↗
NASA NTRS1993

Airport surface operations requirements analysis

This report documents the results of the Airport Surface Operations Requirements Analysis (ASORA) study. This study was conducted in response to task 24 of NASA Contract NAS1-18027. This study is part of NASA LaRC's Low Visibility Surface Operations program, which is designed to eliminate the constraints on all-weather arrival/departure operations due to the airport/aircraft ground system. The goal of this program is to provide the capability for safe and efficient aircraft operations on the airport surface during low visibility conditions down to zero. The ASORA study objectives were to (1) develop requirements for operation on the airport surface in visibilities down to zero; (2) survey and evaluate likely technologies; (3) develop candidate concepts to meet the requirements; and (4) select the most suitable concept based on cost/benefit factors.

Groce, John L.↗
NASA NTRS1993

Security aspects of space operations data

This paper deals with data security. It identifies security threats to European Space Agency's (ESA) In Orbit Infrastructure Ground Segment (IOI GS) and proposes a method of dealing with its complex data structures from the security point of view. It is part of the 'Analysis of Failure Modes, Effects Hazards and Risks of the IOI GS for Operations, including Backup Facilities and Functions' carried out on behalf of the European Space Operations Center (ESOC). The security part of this analysis has been prepared with the following aspects in mind: ESA's large decentralized ground facilities for operations, the multiple organizations/users involved in the operations and the developments of ground data systems, and the large heterogeneous network structure enabling access to (sensitive) data which does involve crossing organizational boundaries. An IOI GS data objects classification is introduced to determine the extent of the necessary protection mechanisms. The proposal of security countermeasures is oriented towards the European 'Information Technology Security Evaluation Criteria (ITSEC)' whose hierarchically organized requirements can be directly mapped to the security sensitivity classification.

Schmitz, Stefan↗
NASA NTRS1994

Design of a wheeled articulating land rover

The WALRUS is a wheeled articulating land rover that will provide Ames Research Center with a reliable, autonomous vehicle for demonstrating and evaluating advanced technologies. The vehicle is one component of the Ames Research Center's on-going Human Exploration Demonstration Project. Ames Research Center requested a system capable of traversing a broad spectrum of surface types and obstacles. In addition, this vehicle must have an autonomous navigation and control system on board and its own source of power. The resulting design is a rover that articulates in two planes of motion to allow for increased mobility and stability. The rover is driven by six conical shaped aluminum wheels, each with an independent, internally coupled motor. Mounted on the rover are two housings and a removable remote control system. In the housings, the motor controller board, tilt sensor, navigation circuitry, and QED board are mounted. Finally, the rover's motors and electronics are powered by thirty C-cell rechargeable batteries, which are located in the rover wheels and recharged by a specially designed battery charger.

Stauffer, Larry↗