Passive Wireless SAW Sensors for IVHM

NASA aeronautical programs require integrated vehicle health monitoring (IVHM) to ensure the safety of the crew and the vehicles. Future IVHM sensors need to be small, light weight, inexpensive, and wireless. Surface acoustic wave (SAW) technology meets all of these constraints. In addition it operates in harsh environments and over wide temperature ranges, and it is inherently radiation hardened. This paper presents a survey of research opportunities for universities and industry to develop new sensors that address anticipated IVHM needs for aerospace vehicles. Potential applications of passive wireless SAW sensors from ground testing to high altitude aircraft operations are presented, along with some of the challenges and issues of the technology

2012 PWST Workshop Summary

No abstract availabl

Wireless Sensor Applications in Extreme Aeronautical Environments

NASA aeronautical programs require rigorous ground and flight testing. Many of the testing environments can be extremely harsh. These environments include cryogenic temperatures and high temperatures (greater than 1500 C). Temperature, pressure, vibration, ionizing radiation, and chemical exposure may all be part of the harsh environment found in testing. This paper presents a survey of research opportunities for universities and industry to develop new wireless sensors that address anticipated structural health monitoring (SHM) and testing needs for aeronautical vehicles. Potential applications of passive wireless sensors for ground testing and high altitude aircraft operations are presented. Some of the challenges and issues of the technology are also presented

Surface Acoustic Wave (saw) Cryogenic Liquid And Hydrogen Gas Sensors

This research was born from NASA Kennedy Space Center’s (KSC) need for passive, wireless and individually distinguishable cryogenic liquid and H2 gas sensors in various facilities. The risks of catastrophic accidents, associated with the storage and use of cryogenic fluids may be minimized by constant monitoring. Accidents involving the release of H2 gas or LH2 were responsible for 81% of total accidents in the aerospace industry. These problems may be mitigated by the implementation of a passive (or low-power), wireless, gas detection system, which continuously monitors multiple nodes and reports temperature and H2 gas presence. Passive, wireless, cryogenic liquid level and hydrogen (H2) gas sensors were developed on a platform technology called Orthogonal Frequency Coded (OFC) surface acoustic wave (SAW) radio frequency identification (RFID) tag sensors. The OFC-SAW was shown to be mechanically resistant to failure due to thermal shock from repeated cycles between room to liquid nitrogen temperature. This suggests that these tags are ideal for integration into cryogenic Dewar environments for the purposes of cryogenic liquid level detection. Three OFC-SAW H2 gas sensors were simultaneously wirelessly interrogated while being exposed to various flow rates of H2 gas. Rapid H2 detection was achieved for flow rates as low as 1ccm of a 2% H2, 98% N2 mixture. A novel method and theory to extract the electrical and mechanical properties of a semiconducting and high conductivity thin-film using SAW amplitude and velocity dispersion measurements were also developed. The SAW device was shown to be a useful tool in analysis and characterization of ultrathin and thin films and physical phenomena such as gas adsorption and desorption mechanisms

Emerging Needs for Pervasive Passive Wireless Sensor Networks on Aerospace Vehicles

NASA is investigating passive wireless sensor technology to reduce instrumentation mass and volume in ground testing, air flight, and space exploration applications. Vehicle health monitoring systems (VHMS) are desired on all aerospace programs to ensure the safety of the crew and the vehicles. Pervasive passive wireless sensor networks facilitate VHMS on aerospace vehicles. Future wireless sensor networks on board aerospace vehicles will be heterogeneous and will require active and passive network systems. Since much has been published on active wireless sensor networks, this work will focus on the need for passive wireless sensor networks on aerospace vehicles. Several passive wireless technologies such as microelectromechanical systems MEMS, SAW, backscatter, and chipless RFID techniques, have all shown potential to meet the pervasive sensing needs for aerospace VHMS applications. A SAW VHMS application will be presented. In addition, application areas including ground testing, hypersonic aircraft and spacecraft will be explored along with some of the harsh environments found in aerospace applications

Micro-saw devices based on randomly-oriented PZT films: Design, fabrication and characterization

The main objective of this work was to research and develop a sensor device to monitor gas leakage in cryogenic temperatures and high vacuum. In addition, the sensor device should be small in size, function with low power, and display a short recovery time. The end application for this technology would be to monitor fuel leaks of hydrazine when refueling space satellites. To meet the specified requirements, an acoustic wave device was studied in this work. A micro-surface acoustic wave (muSAW) device was fabricated through a multi-layer thin film technique, where the active sensing material is based on a 300 nm thick PbZr0.52Tii0.48O3 (PZT) piezoelectric film grown via a sol-gel process. The electrodes were based on Si/SiO2/TiOx/Pt and Si/SiO 2/TiOx multi-layered structures and were fabricated by thermal oxidation and sputtering techniques. Improved deposition and crystallization methods for the PZT film were developed in this work which resulted in crack- and porous-free texturized and randomly-oriented PZT films. The phase, chemistry and microstructure of the PZT films were determined by X-ray diffraction (XRD), Energy Dispersive X-Ray Analysis (EDX), Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) techniques. The surface energy of the films was measured by means of a static sessile drop method. The ferroelectric and electrical characterization of the film was completed longitudinally by measuring the polarization-voltage (P-V), capacitance-voltage (C-V) and current-voltage (I-V) curves. The propagation wave velocity for the multi-layered structure was approximated using an electromechanical equivalent model and the results were used to design the interdigitated transducers (IDTs) for the SAW devices. IDTs were later deposited over the PZT via photolithography process. Finally, the electro-acoustic frequency response in |S21| mode was measured using a vector network analyzer (VNA) and Rayleigh mode SAW and non-Rayleigh mode SAW responses were observed

Wireless Sensor Needs Defined by SBIR Topics

This slide presentation reviews the needs for wireless sensor technology from various U.S. government agencies as exhibited by an analysis of Small Business Innovation Research (SBIR) solicitations. It would appear that a multi-agency group looking at overlapping wireless sensor needs and technology projects is desired. Included in this presentation is a review of the NASA SBIR process, and an examination of some of the SBIR projects from NASA, and other agencies that involve wireless sensor developmen

Small business innovation research. Abstracts of 1988 phase 1 awards

Non-proprietary proposal abstracts of Phase 1 Small Business Innovation Research (SBIR) projects supported by NASA are presented. Projects in the fields of aeronautical propulsion, aerodynamics, acoustics, aircraft systems, materials and structures, teleoperators and robots, computer sciences, information systems, data processing, spacecraft propulsion, bioastronautics, satellite communication, and space processing are covered