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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
NASA NTRS1999

Advanced Interconnect Roadmap for Space Applications

This paper presents the NASA electronic parts and packaging program for space applications. The topics include: 1) Forecasts; 2) Technology Challenges; 3) Research Directions; 4) Research Directions for Chip on Board (COB); 5) Research Directions for HDPs: Multichip Modules (MCMs); 6) Research Directions for Microelectromechanical systems (MEMS); 7) Research Directions for Photonics; and 8) Research Directions for Materials. This paper is presented in viewgraph form.

Galbraith, Lissa↗
NASA NTRS2000

Evaluation of Thermo-Mechanical Stability of COTS Dual-Axis MEMS Accelerometers for Space Applications

Microelectromechanical systems in MEMS is one of the fastest growing technologies in microelectronics, and is of great interest for military and aerospace applications. Accelerometers are the earliest and most developed representatives of MEMS. First demonstrated in 1979, micromachined accelerometers were used in automobile industry for air bag crash- sensing applications since 1990. In 1999, N4EMS accelerometers were used in NASA-JPL Mars Microprobe. The most developed accelerometers for airbag crash- sensing are rated for a full range of +/- 50 G. The range of sensitivity for accelerometers required for military or aerospace applications is much larger, varying from 20,000 G (to measure acceleration during gun and ballistic munition launches), and to 10(exp -6) G, when used as guidance sensors (to measure attitude and position of a spacecraft). The presence of moving parts on the surface of chip is specific to MEMS, and particularly, to accelerometers. This characteristic brings new reliability issues to micromachined accelerometers, including cyclic fatigue cracking of polysilicon cantilevers and springs, mechanical stresses that are caused by packaging and contamination in the internal cavity of the package. Studies of fatigue cracks initiation and growth in polysilicon showed that the fatigue damage may influence MEMS device performance, and the presence of water vapor significantly enhances crack initiation and growth. Environmentally induced failures, particularly, failures due to thermal cycling and mechanical shock are considered as one of major reliability concerns in MEMS. These environmental conditions are also critical for space applications of the parts. For example, the Mars pathfinder mission had experienced 80 mechanical shock events during the pyrotechnic separation processes.

Sharma, Ashok K.↗
NASA NTRS2001

Synthesis of Carbon Nanotubes Array by CVD

Since the properties of multi-wall carbon nanotubes (MWCNT) are superior in many devices such as electronics and sensors, many efforts have been involved in synthesizing particular structural or dimensional MWCNT. Uniform aligned MWCNT array is one of the prototype structures for devices such as filed emission device and microelectromechanical systems in which a large length to diameter ratio may also be required. Most aligned MWCNT recently synthesized by plasma enhanced chemical vapor deposition (CVD) have cone shaped structures. This presentation will illustrate aligned MWCNT array synthesized on silicon substrates using thermal CVD that could produce MWCNT with uniform diameter. An array of nickel particles was used as catalyst for MWCNT growth. A thin Ti or Au buffer layer was coated on the substrate prior to depositing nickel particles. Because the MWCNT size depends on the catalyst particle size, the nickel particle size annealed at various temperatures was investigated. MWCNT were grown on the substrate in the temperature range of 700 C - 1000 C and the pressure range of 1 to 300 torr. Methane and hydrogen gases with methane content of 1 - 10 % were used for the MWCNT synthesis. Morphology, length and diameter of MWCNT were determined by scanning electron microscopy and Raman spectroscopy. The detailed results of synthesis and characterizations will be discussed in the presentation.

Zhu, S.↗
NASA NTRS2001

A Highly Miniaturized Inertial Grade Gyroscope for Space Applications

The evolution of inertial grade gyroscopes for space applications represents well over 50 years of technology development and an investment of hundreds of millions of dollars. The workhorse product which represents the current state-of-the art for commercially available high performance devices is the Litton-Hemishperical Resonator Gyro (HRG) Inertial Measurement Unit (IMU). This product has a performance figure of merit of 0.003 deg/hr bias drift, a volume of 567 cubic inches, weighs 19 pounds, draws about 30 watts and costs over $1 million each. Clearly devices of this magnitude are not conducive to the minimized mass, volume, power, and cost constraints of outer planet missions. An approach to breaking these potential barriers is the use of Microelectromechanical Systems (MEMS) based inertial devices. Although substantially reduced in size, mass power and cost, this approach has produced devices in the tactical performance range of greater than 1 deg/hour bias drift. This level of performance satisfies the preponderance of high market volume requirements such as automotive and tactical munitions but does not meet the limited market quantity requirements for the high precision space based market. Because of the very limited size of the space based market, there is little economic incentive for commercial fabricators of tactical grade devices to address the necessary performance improvements. The Jet Propulsion Laboratory (JPL) in conjunction with Boeing Space Systems (BSS) is addressing this void to satisfy our mutual requirements in this area. The project objective to is to achieve 0.01 deg/hr performance in an IMU which is less than 10 cubic inches in volume, weighs less than 0.5 pounds, draws less than 1 watt and is available in volume production for less than $2500. Reductions of this magnitude will be mission enabling capabilities for a variety of anticipated outer planet mission attributes such as autonomous control and docking, formation flying and robotic outposts. The improved performance will be realized using improved relative precision fabrication, enhanced vibratory drive and sense designs, and statistical data analysis.

Wiberg, D. V.↗
NASA NTRS2000

Effects of Radiation on the Mechanical Properties of Polysilicon and Polydiamond thin Film

Due to its many excellent properties, diamond is being explored as a material for MicroElectroMechanical Systems (MEMS). However, as is true in the case of silicon, a large amount of basic material characterization issues still warrant investigation. This paper presents preliminary results from charged particle irradiation of Chemical Vapor Deposited (CVD) polycrystalline diamond films. The films were simultaneously dosed to a level of 9.4 x l0(exp 13)/sq cm using 700 keV protons and 1 MeV electrons. The samples were then subject to cross-sectional nanoindention analysis and Raman spectroscopy. Polycrystalline silicon was also investigated for comparison purposes. The diamond was unaffected by the irradiation. However, the silicon did indicate a slight decrease in the Young's Modulus.

Newton, Robert L.↗
NASA NTRS2001

Feasibility Study of Thin Film Thermocouple Piles

Historically, thermopile detectors, generators, and refrigerators based on bulk materials have been used to measure temperature, generate power for spacecraft, and cool sensors for scientific investigations. New potential uses of small, low-power, thin film thermopiles are in the area of microelectromechanical systems since power requirements decrease as electrical and mechanical machines shrink in size. In this research activity, thin film thermopile devices are fabricated utilizing radio frequency sputter coating and photoresist lift-off techniques. Electrical characterizations are performed on two designs in order to investigate the feasibility of generating small amounts of power, utilizing any available waste heat as the energy source.

Sisk, R. C.↗
NASA NTRS2001

Novel Low Loss Wide-Band Multi-Port Integrated Circuit Technology for RF/Microwave Applications

In this paper, novel low loss, wide-band coplanar stripline technology for radio frequency (RF)/microwave integrated circuits is demonstrated on high resistivity silicon wafer. In particular, the fabrication process for the deposition of spin-on-glass (SOG) as a dielectric layer, the etching of microvias for the vertical interconnects, the design methodology for the multiport circuits and their measured/simulated characteristics are graphically illustrated. The study shows that circuits with very low loss, large bandwidth, and compact size are feasible using this technology. This multilayer planar technology has potential to significantly enhance RF/microwave IC performance when combined with semi-conductor devices and microelectromechanical systems (MEMS).

Simons, Rainee N.↗
NASA NTRS2001

Novel Vertical Interconnects With 180 Degree Phase Shift for Amplifiers, Filters, and Integrated Antennas

In this paper, novel low loss, wide-band coplanar stripline technology for RF/microwave integrated circuits is demonstrated on high resistivity silicon wafer. In particular, the fabrication process for the deposition of spin-on-glass (SOG) as a dielectric layer, the etching of microvias for the vertical interconnects, the design methodology for the multiport circuits and their measured/simulated characteristics are graphically illustrated. The study shows that circuits with very low loss, large bandwidth and compact size are feasible using this technology. This multilayer planar technology has potential to significantly enhance RF/microwave IC performance when combined with semiconductor devices and microelectromechanical systems (MEMS).

Goverdhanam, Kavita↗
NASA NTRS2001

Micro-Scale Avionics Thermal Management

Trends in the thermal management of avionics and commercial ground-based microelectronics are converging, and facing the same dilemma: a shortfall in technology to meet near-term maximum junction temperature and package power projections. Micro-scale devices hold the key to significant advances in thermal management, particularly micro-refrigerators/coolers that can drive cooling temperatures below ambient. A microelectromechanical system (MEMS) Stirling cooler is currently under development at the NASA Glenn Research Center to meet this challenge with predicted efficiencies that are an order of magnitude better than current and future thermoelectric coolers.

Moran, Matthew E.↗
NASA NTRS2001

MEMS Memory Elements

This paper presents a design example that illustrates the potential of microelectromechanical systems (MEMS) to perform the mechanical positioning required for addressing stored data and to enable an entirely new mechanism for reading and writing magnetic data. Specifically, MEMS sensors and actuators can be used to achieve active servo control of the separation between magnetic probe tips and a media surface with sub-nanometer accuracy. This allows mechanical position to be used to selectively write magnetic marks in a continuous thin-film magnetic media. In addition, MEMS sensors can be used to measure the separation between a magnetic probe tip and the media with a noise floor of roughly 22 picometers, allowing them to be used as position sensors in a magnetic force microscope (MFM) style data detection system.

Carley, L. Richard↗
NASA NTRS2001

Dynamic Response Assessment for the MEMS Accelerometer Under Severe Shock Loads

NASA Goddard Space Flight Center (GSFC) has evaluated the dynamic response of a commercial-off-the-shelf (COTS) microelectromechanical systems (MEMS) device made by Analog Device, Inc. The device is designated as ADXL250 and is designed mainly for sensing dynamic acceleration. It is also used to measure the tilting angle of any system or component from its original level position. The device has been in commercial use (e.g., in automobile airbag deployment system as a dual-axial accelerometer and in the electronic game play-station as a tilting sensor) with success, but NASA needs an in-depth assessment of its performance under severe dynamic shock environments. It was realized while planning this evaluation task that two assessments would be beneficial to NASA's missions: (1) severe dynamic shock response under nominal thermal environments; and (2) general dynamic performance under cryogenic environments. The first evaluation aims at obtaining a good understanding of its micromachined structure within a framework of brittle fracture dynamics, while the second evaluation focuses on the structure integrity under cryogenic temperature conditions. The information we gathered from the manufacturer indicated that the environmental stresses under NASA's evaluation program have been far beyond what the device has experienced with commercial applications, for which the device was designed. Thus NASA needs the outcome of this evaluation in order to make the selection for possible use for its missions. This paper provides details of the first evaluation the dynamic response under severe multi-axial single-pulse shock load. It was performed using finite element tools with nonlinear dynamics procedures.

Fan, Mark S.↗
NASA NTRS1999

Optical Fiber Protection

F&S Inc. developed and commercialized fiber optic and microelectromechanical systems- (MEMS) based instrumentation for harsh environments encountered in the aerospace industry. The NASA SBIR programs have provided F&S the funds and the technology to develop ruggedized coatings and coating techniques that are applied during the optical fiber draw process. The F&S optical fiber fabrication facility and developed coating methods enable F&S to manufacture specialty optical fiber with custom designed refractive index profiles and protective or active coatings. F&S has demonstrated sputtered coatings using metals and ceramics and combinations of each, and has also developed techniques to apply thin coatings of specialized polyimides formulated at NASA Langley Research Center. With these capabilities, F&S has produced cost-effective, reliable instrumentation and sensors capable of withstanding temperatures up to 800? C and continues building commercial sales with corporate partners and private funding. More recently, F&S has adapted the same sensing platforms to provide the rapid detection and identification of chemical and biological agents

Source record↗
NASA NTRS2002

Instrumentation and Controls Division Overview: Sensors Development for Harsh Environments at Glenn Research Center

The Instrumentation and Controls Division is responsible for planning, conducting and directing basic and applied research on advanced instrumentation and controls technologies for aerospace propulsion and power applications. The Division's advanced research in harsh environment sensors, high temperature high power electronics, MEMS (microelectromechanical systems), nanotechnology, high data rate optical instrumentation, active and intelligent controls, and health monitoring and management will enable self-feeling, self-thinking, self-reconfiguring and self-healing Aerospace Propulsion Systems. These research areas address Agency challenges to deliver aerospace systems with reduced size and weight, and increased functionality and intelligence for future NASA missions in advanced aeronautics, economical space transportation, and pioneering space exploration. The Division also actively supports educational and technology transfer activities aimed at benefiting all humankind.

Zeller, Mary V.↗
NASA NTRS2002

STS-113 Crew Interviews: John Herrington, Mission Specialist 2

STS-113 Mission Specialist 2 John Herrington is seen during a prelaunch interview. He answers questions about his inspiration to become an astronaut and his career path, as well as his thoughts on becoming the first Native American in space. He gives details on the mission's goals and significance, which include the transfer of the International Space Station's (ISS) Expedition 6 crew for the Expedition 5 crew, as well as the installation of the ISS's P-1 integrated truss structure. Herrington, who will participate in three EVAs (extravehicular activity), provides details on the installation of the truss structure. He also describes the process of crew transfer, which also involves the transfer of soft goods and scientific experiments, such as the MEMS (microelectromechanical systems)-based Picosatellite Inspector (MEPSI) which will be ejected from the shuttle shortly after it undocks from the ISS.

Source record↗
NASA NTRS2002

Novel On-wafer Radiation Pattern Measurement Technique for MEMS Actuator Based Reconfigurable Patch Antennas

The paper presents a novel on-wafer, antenna far field pattern measurement technique for microelectromechanical systems (MEMS) based reconfigurable patch antennas. The measurement technique significantly reduces the time and the cost associated with the characterization of printed antennas, fabricated on a semiconductor wafer or dielectric substrate. To measure the radiation patterns, the RF probe station is modified to accommodate an open-ended rectangular waveguide as the rotating linearly polarized sampling antenna. The open-ended waveguide is attached through a coaxial rotary joint to a Plexiglas(Trademark) arm and is driven along an arc by a stepper motor. Thus, the spinning open-ended waveguide can sample the relative field intensity of the patch as a function of the angle from bore sight. The experimental results include the measured linearly polarized and circularly polarized radiation patterns for MEMS-based frequency reconfigurable rectangular and polarization reconfigurable nearly square patch antennas, respectively.

Simons, Rainee N.↗
NASA NTRS2002

Micro-Raman Analysis of Irradiated Diamond Films

Owing to its unique and robust physical properties, diamond is a much sought after material for use in advanced technologies such as Microelectromechanical Systems (MEMS). The volume and weight savings promised by MEMS-based devices are of particular interest to spaceflight applications. However, much basic materials science research remains to be completed in this field. Results of micro-Raman analysis of proton (1015 - 1017 H+/cm2 doses) irradiated chemical vapor deposited (CVD) diamond reveals that the microstructure is retained even after high radiation exposure.

Newton, R. L.↗
NASA NTRS2002

An Overview of NASA Glenn Research Center's Antenna R&D and Technology Efforts

This viewgraph presentation provides an overview of antenna research and design efforts being performed at NASA's Glenn Research Center. The following type of antenna research projects are discussed: phased array antennas, thin film ferroelectric reflectarray antenna, microelectromechanical systems (MEMs) based antennas and multi-beam antennas. Project overviews, design issues and research problems for each type of antenna system are covered. Additional topics reviewed included: communication systems of the future and a facility description.

Miranda, Felix A.↗
NASA NTRS2002

The Effects of Proton Radiation on the Structure of Diamond Films

Diamond possesses many of the sought after material properties desired in present day applications and is also quite radiation resistant. These characteristics make it an ideal candidate for insertion into MicroElectroMechanical Systems (MEMS) technologies, particularly for space-based applications. Most prior radiation studies investigated single crystal, bulk diamond specimens, not polycrystalline thin films. This investigation examined the microstructural effects of irradiating polycrystalline diamond films with various proton dosages (10(exp 15) - 10(exp 17) H+/sq cm). Scanning Electron Microscopy, micro-Raman Spectroscopy, and micro-X-ray Diffraction techniques were used to examine the effects as a function of depth. Strain values were calculated. Results indicate that the diamond lattice is retained, even at maximum irradiation levels. Polycrystalline silicon was also examined for comparative purposes.

Newton, Robert Lee↗