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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 163 records · Page 9
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Camera-on-a-Chip

Jet Propulsion Laboratory's research on a second generation, solid-state image sensor technology has resulted in the Complementary Metal- Oxide Semiconductor Active Pixel Sensor (CMOS), establishing an alternative to the Charged Coupled Device (CCD). Photobit Corporation, the leading supplier of CMOS image sensors, has commercialized two products of their own based on this technology: the PB-100 and PB-300. These devices are cameras on a chip, combining all camera functions. CMOS "active-pixel" digital image sensors offer several advantages over CCDs, a technology used in video and still-camera applications for 30 years. The CMOS sensors draw less energy, they use the same manufacturing platform as most microprocessors and memory chips, and they allow on-chip programming of frame size, exposure, and other parameters.

Source record↗
NASA NTRS2021

High operating temperature T2SL digital focal plane arrays for earth remote sensing instruments

In this presentation, we will report our recent efforts in achieving high performance in Antimonides type-II superlattice (T2SL) based infrared photodetectors using the barrier infrared detector (BIRD) architecture. The high operating temperature (HOT) BIRD focal plane arrays (FPAs) offer the same high performance, uniformity, operability, manufacturability, and affordability advantages as InSb. However, mid-wavelength infrared (MWIR) HOT-BIRD FPAs can operate at significantly higher temperatures (>150K) than InSb FPAs (typically 80K). Moreover, while InSb has a fixed cutoff wavelength (~5.4 µm), the HOT-BIRD offers a continuous adjustable cutoff wavelength, ranging from ~4 µm to >15 µm, and is therefore also suitable for long wavelength infrared (LWIR) as well. The LWIR detectors based on the BIRD architecture has also demonstrated significant operating temperature advantages over those based on traditional p-n junction designs. Two 6U SmalSat missions CIRAS (Cubesat Infrared Atmospheric Sounder) and HyTI (Hyperspectral Thermal Imager) are based on JPL’s T2SL BIRD focal plane arrays (FPAs). Based on III-V compound semiconductors, the BIRD FPAs offer a breakthrough solution for the realization of low cost (high yield), high-performance FPAs with excellent uniformity and pixel-to-pixel operability. We have also exploring the possibilities of integrating either metasurface resonator cavity or metasurface based flatlens with individual pixels to improve the signal-to-noise ratio of the detectors. Furthermore, we will discuss the advantages of the utilization of all digital read out integrated circuits with HOT-BIRDs.

Ghuman, and Parminder↗
NASA NTRS2021

Digital Mid-Wavelength and Long-Wavelength Infrared Focal Planes for SmallSat Applications

In this presentation, we will report our recent efforts in achieving high performance in Antimonides type-II superlattice (T2SL) based infrared photodetectors using the barrier infrared detector (BIRD) architecture. The high operating temperature (HOT) BIRD focal plane arrays (FPAs) offer the same high performance, uniformity, operability, manufacturability, and affordability advantages as InSb. However, mid-wavelength infrared (MWIR) HOT-BIRD FPAs can operate at significantly higher temperatures (>150K) than InSb FPAs (typically 80K). Moreover, while InSb has a fixed cutoff wavelength (~5.4 µm), the HOT-BIRD offers a continuous adjustable cutoff wavelength, ranging from ~4 µm to >15 µm, and is therefore also suitable for long wavelength infrared (LWIR) as well. The LWIR detectors based on the BIRD architecture has also demonstrated significant operating temperature advantages over those based on traditional p-n junction designs. Two 6U SmalSat missions CIRAS (Cubesat Infrared Atmospheric Sounder) and HyTI (Hyperspectral Thermal Imager) are based on JPL’s T2SL BIRD focal plane arrays (FPAs). Based on III-V compound semiconductors, the BIRD FPAs offer a breakthrough solution for the realization of low cost (high yield), high-performance FPAs with excellent uniformity and pixel-to-pixel operability. Furthermore, we will discuss the advantages of the utilization of all digital read out integrated circuits with HOT-BIRDs.

Pagano, Thomas↗
NASA NTRS1979

Development and validation of a piloted simulation of a helicopter and external sling load

A generalized, real time, piloted, visual simulation of a single rotor helicopter, suspension system, and external load is described and validated for the full flight envelope of the U.S. Army CH-54 helicopter and cargo container as an example. The mathematical model described uses modified nonlinear classical rotor theory for both the main rotor and tail rotor, nonlinear fuselage aerodynamics, an elastic suspension system, nonlinear load aerodynamics, and a loadground contact model. The implementation of the mathematical model on a large digital computing system is described, and validation of the simulation is discussed. The mathematical model is validated by comparing measured flight data with simulated data, by comparing linearized system matrices, eigenvalues, and eigenvectors with manufacturers' data, and by the subjective comparison of handling characteristics by experienced pilots. A visual landing display system for use in simulation which generates the pilot's forward looking real world display was examined and a special head up, down looking load/landing zone display is described.

Shaughnessy, J. D.↗
NASA NTRS1992

ICI optical data storage tape

Optical data storage tape is now a commercial reality. The world's first successful development of a digital optical tape system is complete. This is based on the Creo 1003 optical tape recorder with ICI 1012 write-once optical tape media. Flexible optical media offers many benefits in terms of manufacture; for a given capital investment, continuous, web-coating techniques produce more square meters of media than batch coating. The coated layers consist of a backcoat on the non-active side; on the active side there is a subbing layer, then reflector, dye/polymer, and transparent protective overcoat. All these layers have been tailored for ease of manufacture and specific functional characteristics.

Mclean, Robert A.↗
NASA NTRS2009

Reconfigurable, Bi-Directional Flexfet Level Shifter for Low-Power, Rad-Hard Integration

Two prototype Reconfigurable, Bi-directional Flexfet Level Shifters (ReBiLS) have been developed, where one version is a stand-alone component designed to interface between external low voltage and high voltage, and the other version is an embedded integrated circuit (IC) for interface between internal low-voltage logic and external high-voltage components. Targeting stand-alone and embedded circuits separately allows optimization for these distinct applications. Both ReBiLS designs use the commercially available 180-nm Flex fet Independently Double-Gated (IDG) SOI CMOS (silicon on insulator, complementary metal oxide semiconductor) technology. Embedded ReBiLS circuits were integrated with a Reed-Solomon (RS) encoder using CMOS Ultra-Low-Power Radiation Tolerant (CULPRiT) double-gated digital logic circuits. The scope of the project includes: creation of a new high-voltage process, development of ReBiLS circuit designs, and adjustment of the designs to maximize performance through simulation, layout, and manufacture of prototypes. The primary technical objectives were to develop a high-voltage, thick oxide option for the 180-nm Flexfet process, and to develop a stand-alone ReBiLS IC with two 8-channel I/O busses, 1.8 2.5 I/O on the low-voltage pins, 5.0-V-tolerant input and 3.3-V output I/O on the high-voltage pins, and 100-MHz minimum operation with 10-pF external loads. Another objective was to develop an embedded, rad-hard ReBiLS I/O cell with 0.5-V low-voltage operation for interface with core logic, 5.0-V-tolerant input and 3.3-V output I/O pins, and 100-MHz minimum operation with 10- pF external loads. A third objective was to develop a 0.5- V Reed-Solomon Encoder with embedded ReBilS I/O: Transfer the existing CULPRiT RS encoder from a 0.35-micron bulk-CMOS process to the ASI 180-nm Flexfet, rad-hard SOI Process. 0.5-V low-voltage core logic. 5.0-V-tolerant input and 3.3-V output I/O pins. 100-MHz minimum operation with 10- pF external loads. The stand-alone ReBiLS chip will allow system designers to provide efficient bi-directional communication between components operating at different voltages. Embedding the ReBiLS cells into the proven Reed-Solomon encoder will demonstrate the ability to support new product development in a commercially viable, rad-hard, scalable 180-nm SOI CMOS process.

DeGregorio, Kelly↗
NASA NTRS2011

Monitoring Digital Closed-Loop Feedback Systems

A technique of monitoring digital closed-loop feedback systems has been conceived. The basic idea is to obtain information on the performances of closed-loop feedback circuits in such systems to aid in the determination of the functionality and integrity of the circuits and of performance margins. The need for this technique arises as follows: Some modern digital systems include feedback circuits that enable other circuits to perform with precision and are tolerant of changes in environment and the device s parameters. For example, in a precision timing circuit, it is desirable to make the circuit insensitive to variability as a result of the manufacture of circuit components and to the effects of temperature, voltage, radiation, and aging. However, such a design can also result in masking the indications of damaged and/or deteriorating components. The present technique incorporates test circuitry and associated engineering-telemetry circuitry into an embedded system to monitor the closed-loop feedback circuits, using spare gates that are often available in field programmable gate arrays (FPGAs). This technique enables a test engineer to determine the amount of performance margin in the system, detect out of family circuit performance, and determine one or more trend(s) in the performance of the system. In one system to which the technique has been applied, an ultra-stable oscillator is used as a reference for internal adjustment of 12 time-to-digital converters (TDCs). The feedback circuit produces a pulse-width-modulated signal that is fed as a control input into an amplifier, which controls the circuit s operating voltage. If the circuit s gates are determined to be operating too slowly or rapidly when their timing is compared with that of the reference signal, then the pulse width increases or decreases, respectively, thereby commanding the amplifier to increase or reduce, respectively, its output level, and "adjust" the speed of the circuits. The nominal frequency of the TDC s pulse width modulated outputs is approximately 40 kHz. In this system, the technique is implemented by means of a monitoring circuit that includes a 20-MHz sampling circuit and a 24-bit accumulator with a gate time of 10 ms. The monitoring circuit measures the duty cycle of each of the 12 TDCs at a repetition rate of 28 Hz. The accumulator content is reset to all zeroes at the beginning of each measurement period and is then incremented or decremented based of the value of the state of the pulse width modulated signal. Positive or negative values in the accumulator correspond to duty cycles greater or less, respectively, than 50 percent.

Katz, Richard↗
NASA NTRS1989

Human factors model concerning the man-machine interface of mining crewstations

The U.S. Bureau of Mines is developing a computer model to analyze the human factors aspect of mining machine operator compartments. The model will be used as a research tool and as a design aid. It will have the capability to perform the following: simulated anthropometric or reach assessment, visibility analysis, illumination analysis, structural analysis of the protective canopy, operator fatigue analysis, and computation of an ingress-egress rating. The model will make extensive use of graphics to simplify data input and output. Two dimensional orthographic projections of the machine and its operator compartment are digitized and the data rebuilt into a three dimensional representation of the mining machine. Anthropometric data from either an individual or any size population may be used. The model is intended for use by equipment manufacturers and mining companies during initial design work on new machines. In addition to its use in machine design, the model should prove helpful as an accident investigation tool and for determining the effects of machine modifications made in the field on the critical areas of visibility and control reach ability.

Rider, James P.↗
NASA NTRS1996

Technology Directions for the 21st Century, volume 1

For several decades, semiconductor device density and performance have been doubling about every 18 months (Moore's Law). With present photolithography techniques, this rate can continue for only about another 10 years. Continued improvement will need to rely on newer technologies. Transition from the current micron range for transistor size to the nanometer range will permit Moore's Law to operate well beyond 10 years. The technologies that will enable this extension include: single-electron transistors; quantum well devices; spin transistors; and nanotechnology and molecular engineering. Continuation of Moore's Law will rely on huge capital investments for manufacture as well as on new technologies. Much will depend on the fortunes of Intel, the premier chip manufacturer, which, in turn, depend on the development of mass-market applications and volume sales for chips of higher and higher density. The technology drivers are seen by different forecasters to include video/multimedia applications, digital signal processing, and business automation. Moore's Law will affect NASA in the areas of communications and space technology by reducing size and power requirements for data processing and data fusion functions to be performed onboard spacecraft. In addition, NASA will have the opportunity to be a pioneering contributor to nanotechnology research without incurring huge expenses.

Crimi, Giles F.↗
NASA NTRS1988

An adaptive array antenna for mobile satellite communications

The adaptive array is linearly polarized and consists essentially of a driven lambda/4 monopole surrounded by an array of parasitic elements all mounted on a ground plane of finite size. The parasitic elements are all connected to ground via pin diodes. By applying suitable bias voltages, the desired parasitic elements can be activated and made highly reflective. The directivity and pointing of the antenna beam can be controlled in both the azimuth and elevation planes using high speed digital switching techniques. The antenna RF losses are neglible and the maximum gain is close to the theoretical value determined by the effective aperture size. The antenna is compact, has a low profile, is inexpensive to manufacture and can handle high transmitter power.

Milne, Robert↗
NASA NTRS1989

SQUID With Integral Flux Concentrator

In improved superconducting quantum interference device (SQUID), change in size and shape of superconducting ring improves coupling to external signal coil and eases coil-positioning tolerances. More rugged and easier to manufacture than conventional SQUID's with comparable electrical characteristics. Thin-film superconducting flux concentrator utilizes Meissner effect to deflect magnetic field of signal coil into central hole of SQUID. Used in magnetometers, ammeters, analog-to-digital converters, and related electronic applications in which high signal-to-noise ratios required.

Peters, Palmer N.↗
NASA NTRS1993

Differential temperature stress measurement employing array sensor with local offset

The instrument has a focal plane array of infrared sensors of the integrating type such as a multiplexed device in which a charge is built up on a capacitor which is proportional to the total number of photons which that sensor is exposed to between read-out cycles. The infrared sensors of the array are manufactured as part of an overall array which is part of a micro-electronic device. The sensor achieves greater sensitivity by applying a local offset to the output of each sensor before it is converted into a digital word. The offset which is applied to each sensor will typically be the sensor's average value so that the digital signal which is periodically read from each sensor of the array corresponds to the portion of the signal which is varying in time. With proper synchronization between the cyclical loading of the test object and the frame rate of the infrared array the output of the A/D converted signal will correspond to the stress field induced temperature variations. A digital lock-in operation may be performed on the output of each sensor in the array. This results in a test instrument which can rapidly form a precise image of the thermoelastic stresses in an object.

Lesniak, Jon R.↗
NASA NTRS2010

Effects of Hydrocarbon-Based Grease on Rapid Prototype Material Used for Grease Retention Shrouds

Effects of hydrocarbon-based greases on specific rapid prototype (RP) materials used to fabricate grease retention shrouds (GRS) were explored in this study. Grease retention shrouds are being considered as a way to maintain adequate grease lubrication at the gear mesh in a prototype research transmission system. Due to their design and manufacturing flexibility, rapid prototype materials were chosen for the grease retention shrouds. In order to gain a better understanding of the short and long term effects grease pose on RP materials, research was conducted on the interaction of hydrocarbon-based grease with RP materials. The materials used in this study were durable polyamide (nylon), acrylonitrile butadiene styrene (ABS), and WaterClear 10120. Testing was conducted using Mobilgrease 28 and Syn-Tech 3913G grease (gear coupling grease). These greases were selected due to their regular use with mechanical components. To investigate the effect that grease has on RP materials, the following methods were used to obtain qualitative and quantitative data: Fourier transform infrared spectroscopy (FT-IR), interference profilometer measurements, digital camera imaging, physical shape measurement, and visual observations. To record the changes in the RP materials due to contact with the grease, data was taken before and after the grease application. Results showed that the WaterClear 10120 RP material provided the best resistance to grease penetration as compared to nylon and ABS RP materials. The manufacturing process, and thus resulting surface conditions of the RP material, played a key role in the grease penetration properties and resilience of these materials.

Zakrajsek, Andrew J.↗
NASA NTRSDate not supplied

Finite Element Analysis Validation for Stitched, Blade-Stiffened Aerospace Structures

Increased performance and manufacturing rates for aircraft or spacecraft structures may be achieved using stitched and resin infused composite structures. In order to carry out design and analysis of stitched composites, 2-dimensional (2-D) and 3-dimensional (3-D) modeling approaches for stitched and non-stitched carbon fiber vacuum-infused parts were developed. These analysis approaches will be compared with data from previous test specimens tested at the NASA Langley Research Center (LaRC) under tension and bending load conditions. The preliminary results presented herein for the 2-D and 3-D models capture the strain patterns observed in digital image correlation (DIC) data for stitched, blade-stiffened specimens tested in either tension or bending. The analysis method study presented for these specimens is part of a larger analysis development effort planned for stitched composites, with the modeling practices developed here contributing to those that may be applied to a new set of blade- stiffened test specimens that are currently being manufactured for testing as well as the design of a blade stringer pull-off test. These future tests are expected to provide opportunities to validate the developed modeling approaches for predictive purposes, and to provide opportunities for further refinement of the modeling approaches.

HiCAM↗
NASA NTRS1983

Classification of journal surfaces using surface topography parameters and software methods to compensate for stylus geometry

Measurements made with a stylus surface tracer which provides a digitized representation of a surface profile are discussed. Parameters are defined to characterize the height (e.g., RMS roughness, skewness, and kurtosis) and length (e.g., autocorrelation) of the surface topography. These are applied to the characterization of crank shaft journals which were manufactured by different grinding and lopping procedures known to give significant differences in crank shaft bearing life. It was found that three parameters (RMS roughness, skewness, and kurtosis) are necessary to adequately distinguish the character of these surfaces. Every surface specimen has a set of values for these three parameters. They can be regarded as a set coordinate in a space constituted by three characteristics axes. The various journal surfaces can be classified along with the determination of a proper wavelength cutoff (0.25 mm) by using a method of separated subspace. The finite radius of the stylus used for profile tracing gives an inherent measurement error as it passes over the fine structure of the surface. A mathematical model is derived to compensate for this error.

Li, C. J.↗
NASA NTRSDate not supplied

Autonomous In-space Construction, Maintenance, and Reconfiguration Using Programmable Meta-Material

NASA ARC's Coded Structures Laboratory (CSL) is developing autonomous construction, maintenance, and reconfiguration technologies to meet long-duration and deep space infrastructure needs, in accordance with long-term NASA goals of "in-space reliance" and "mass-less exploration." We seek to achieve these capabilities by utilizing a "programmable meta-material" approach that integrates emerging advances in materials (mechanical meta-materials), manufacturing (cooperative mobile robotics), and autonomy (multi-agent planning algorithms). Through the ARMADAS project, we have shown assembly of high-performance engineered cellular materials using multiple cooperating mobile robotic assemblers. In this paper, we describe how such a programmable meta-material architecture may shift the paradigm of how we design, build, manufacture, and operate future space infrastructure and assets. The core of a programmable meta-material architecture consists of 3 main technology sub-areas: the structure, the assembly agents, and the assembly algorithms. We co-design these systems to ensure an adaptable system that can create and reconfigure structures from a base set of building block components. From this core technology, we can branch out and expand the capability of the system through additional secondary component types and robotic agents to perform activities such as inspections, maintenance, repair, payload installation, or perform power and communications interconnect. As these technologies mature, future designers will be able to utilize the system to rapidly integrate and operate assets in space or on planetary surfaces from a set of well-tested part library, or create their own modules to integrate into the system. A core trait to the development of this system is the automation approach. Because of the modular and functional discrete (pixel-like) nature of the structural system, a diverse set of powerful algorithms for analysis, planning, and simulation can be adapted and leveraged to optimize construction, maintenance, and dynamic reorganization (as hardware with programmable form and function). With an ability to free the design space from launch vehicle constraints and fundamentally shift how a mission is designed and conducted, we discuss the influence of a programmable meta-material architecture on mission design, build, and operations. For the "design phase", we discuss project lifecycle effects, costs, time, and performance. For the "build phase", we discuss reusability, ISRU, manufacturing, material logistics, and scalability. And for "operations", we discuss autonomy, maintenance and upgrades, reliability, and reconfiguration. Autonomy and modularity are the primary enabling traits of this system. Engineering systems that utilize a modular and reconfiguration building block approach such as digital communication and computation systems, currently lead all other areas of technology in size and complexity scalability. NASA is extending the benefits and flexibility of digital systems to hardware systems, to optimize materials lifecycle management and expand our space exploration mission capabilities.

in space assembly↗
NASA NTRS1988

Optical Rotary Joint For Data Transfer

Proposed joint increases bandwidth and reduces errors. Scheme for transferring digital data across rotary joint uses light instead of electrical signals. Optical joint offers greater bandwidth and operates at considerably lower error rate. Concept applied to transfer of highspeed data to rotating antennas or across joints of robots and manipulators in automated manufacturing.

Becker, Fred J.↗
NASA NTRS2023

Factories-in-Space for Servicing, Assembly, & Manufacturing

Space 2.0 is a promising frontier for scientific exploration and the advancement of commerce, security, and technology. To effectively harness this potential, it is imperative to establish a multifunctional, resilient, and sustainable infrastructure that enables the maintenance and production of space-based systems. This capability is a driver for mission success on-orbit and for interplanetary travel to other celestial bodies. Central to this infrastructure is the establishment of orbital manufacturing facilities, referred to as 'factories-in-space' (FiS), which serve as critical nodes in the supply chain for the servicing, assembly, and production of systems essential for space-based operations. This paper presents a framework for understanding the key principles and design considerations underpinning FiS.

Technology↗