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As airplanes age there is an ever increasing likelihood that protective surfaces will break down or be damaged, which, with continual cycling of air temperature and humidity means a corresponding increase in the likelihood of corrosion. At the same time, the continual cycling of the structure means an ever increasing likelihood of structural fatigue damage. This gives rise to one of the most significant “Aging Airplane” safety concerns, which is the potential for corrosion combining with other forms of damage, such as fatigue. The most effective and safest way to negate potential combinations of significant corrosion and fatigue damage, is to implement fleet-wide corrosion prevention and control programs, with defined minimum standards. This is preferable to reliance on inspection requirements, which are difficult to determine and would result in highly restrictive structural maintenance programs.

The IATCS coolant has experienced a number of anomalies in the time since the US Lab was first activated on Flight 5A in February 2001. These have included: 1) a decrease in coolant pH, 2) increases in inorganic carbon, 3) a reduction in phosphate concentration, 4) an increase in dissolved nickel and precipitation of nickel salts, and 5) increases in microbial concentration. These anomalies represent some risk to the system, have been implicated in some hardware failures and are suspect in others. The ISS program has conducted extensive investigations of the causes and effects of these anomalies and has developed a comprehensive program to remediate the coolant chemistry of the on-orbit system as well as provide a robust and compatible coolant solution for the hardware yet to be delivered.

The fluid in the Internal Active Thermal Control System (IATCS) of the International Space Station (ISS) is water based. The fluid in the ISS Laboratory Module and Node 1 initially contained a mix of water, phosphate (corrosion control), borate (pH buffer), and silver sulfate (Ag2SO4) (microbial control) at a pH of 9.5±0.5. Over time, the chemistry of the fluid changed. Fluid changes included a pH drop from 9.5 to 8.3 due to diffusion of carbon dioxide (CO2) through Teflon® (DuPont) hoses, increases in dissolved nickel (Ni) levels, deposition of silver (Ag) to metal surfaces, and precipitation of the phosphate (PO4) as nickel phosphate (NiPO4). The drop in pH and unavailability of a antimicrobial has provided an environment conducive to microbial growth. Microbial levels in the fluid have increased from <10 colony-forming units (CFUs)/100 mL to 106 CFUs/100 mL.

The main objective of this work is to investigate, by means of numerical simulations, the performance of the engine nacelle ventilation cooling system of a helicopter under hover and forward flight conditions, and to propose a simplified method of evaluating the performance based on rotor downwash flow by taking the synthetical effect of engine nacelle, exhaust ejector and external flow of a helicopter into account. For the engine nacelle of a helicopter, an integrated model of the nacelle and exhaust ejector was set up including the domain of external flow. The unstructured grid and finite volume method were applied for domains and control equations discreteness, and the standard k-ε model was applied for solving turbulent control equations. Using the business CFD software, the flow field and the temperature field in the nacelle were calculated for single inlet scheme and double inlets scheme, total up to 9 schemes. The performance of the exhaust ejector was computed.

The permanently increasing number of convenience and safety functions leads to higher complexity of in-car electronics and the rapidly growing amount of sensors, actuators and electronic control units places higher demands on high- speed data communication protocols. Safety-critical systems need deterministic protocols with fault-tolerant behavior. The need for on-board diagnosis calls for flexible use of bandwidth and an ever-increasing number of functions necessitates a flexible means of extending the system. None of the communication solutions available on the market until now (like CAN or TTP) have been able to fulfill all these demands. To solve these problems, BMW together with several semiconductor companies has developed a new protocol for safety-critical applications in automotive vehicles.

This paper describes the development, operation and testing of an across-gimbal ambient thermal transport system (GATTS) for carrying cryocooler waste heat across a 2-axis gimbal. The principal application for the system is space-based remote sensing spacecraft with gimbaled cryogenics optics and/or infrared sensors. GATTS uses loop heat pipe (LHP) technology with ammonia as the working fluid and small diameter stainless steel tubing to transport 100–275 W across a two-axis gimbal. The tubing is coiled around each gimbal axis to provide flexibility (less than 0.68 N-m [6 lbf-in] of tubing-induced torque per axis) and fatigue life. Stepper motors are implemented to conduct life cycling and to assess the impact of motion on thermal performance. An LHP conductance of approximately 7.5 W/C was demonstrated at 200 W, with and without gimbal motion. At the time this paper was written, the gimbal had successfully completed over 500,000 cycles of operation with no performance degradation.

The Multi-angle Imaging SpectroRadiometer (MISR) instrument was launched aboard NASA’s Earth Observing System (EOS) Terra spacecraft on December 18, 1999. The overall mission design lifetime for the instrument is 6 years. The EOS Terra spacecraft was placed in a sun-synchronous near-circular polar orbit with an inclination of 98.3 degrees and a mean altitude of 705 km. The overall objective of MISR is to provide a means to study the ecology and climate of Earth through the acquisition of global multiangle imagery on the daylit side of Earth. MISR views the sunlit Earth simultaneously at nine widely spaced angles, collects global images with high spatial detail in four colors at every angle. The images acquired, once calibrated, provide accurate measurements of brightness, contrast and color of reflected sunlight.

The progress on the development of a sensor for monitoring spacecraft air quality is reported. A 1.55 μm external-cavity tunable diode laser is used as a light source that can be incorporated in either cw-Integrated Cavity Output Spectroscopy (cw-ICOS) or cw-Cavity Ringdown Spectroscopy (cw-CRDS). Both techniques exploit the sensitivity enhancements provided by the long effective pathlength from the optical cavity created between two mirrors. Initial experiments of cw-ICOS have been performed to determine the sensitivity, selectivity, and reproducibility of this method. Passing the laser beam through a flame supported on an atomic absorption burner produced a dense spectrum of absorption lines in the 1545–1560 nm region. While most of the absorbance peaks observed in the flame were assigned to water, a number of spectral features have been assigned to the OH radical.

In this paper we discuss the results of theoretical and experimental study of key components of the optical waveguide (OW) solar plant lighting system. In this system, solar radiation is collected by the concentrator which transfers the concentrated solar radiation to the OW transmission line consisting of low-loss optical fibers. The OW line transmits the solar radiation to the selective beam splitter where the solar spectra is divided into two components: plant lighting spectra (400 nm < λ < 700 nm) and power generation spectra (λ > 700 nm). The plant lighting spectra are transmitted to the plant growth chamber where the solar radiation from the optical fibers is de-focused for optimum intensity for plant growing. The power generation spectra are transmitted to the photovoltaic (PV) power generator for power generation.

Productivity bottlenecks for integrated thermal, structural, and optical design activities were identified and systematically eliminated, making possible automated exchange of design information between different engineering specialties. The problems with prior approaches are summarized, then the implementation of the corresponding solutions is documented. Although the goal of this project was the automated evaluation of coupled thermal/optical/structural designs, significant process improvements were achieved for subset activities such as stand-alone thermal, thermal/ structural, and structural/optical design analysis.

Focusing mirrors for X-ray astronomy are almost always located near the open aperture of the X-ray telescope. Such a mirror is typically a concentric nest of near-cylindrical paraboloids. Controlling the mirror temperature and reducing thermal radiation to space is essential to reducing optical distortion of the mirror assembly. This has been successfully done in the past by a partially open structure, termed a precollimator, between the mirror and space; or in the case of metal mirrors, by conduction from the support structure. As designs for future missions strive for more collecting area to “see” fainter objects, the individual mirrors become more numerous and thinner, presenting new challenges to thermal control. We report here studies by the Smithsonian Astrophysical Observatory on thermal control of a 1.6m-diameter X-ray mirror assembly for the Constellation-X mission. The mirrors are 0.3 mm thick, and the nest contains of order 100-200 mirrors.

IASI instrument is an earth observation instrument which will be launched on the MetOp meteorological polar platform. IASI mission consists of providing vertical profiles of temperature and humidity, land and sea surface temperature, gases monitoring and cloud radiation. From a thermal point of view, the challenges in IASI design are to keep the optical pathway spatially stable, to maintain the optics and their supports to a constant temperature level and to remove the high power dissipated by the electronic boxes. Moreover, the instrument thermal control shall guarantee well controlled environments to many subsystems. Among them, IASI includes a very accurate black body reference (BBC), a three-stage cryogenic passive radiator at 100K (CBS), an infrared camera (IIS) using a microbolometer and three complex dissipative mechanisms (SCAU,CCFD,CD). To achieve these aims, an automatic P.I. active thermal control algorithm is used in association with a passive thermal control system.

This document describes the results and methodology of a study to optimize the shape of the inflatable, optically transparent portion of a Martian greenhouse. The inflatable portion is comprised of individual, square patches, which are optimized for maximum, optical transmittance and minimum internal stress. The preferred Sequential Quadratic Programming optimization methodology requires the structural responses of the pressure loaded patch and the gradients of these responses to predict the optimized shape. The structural responses are obtained from nonlinear finite element methods. The Corrotational formulation was the chosen non-linear, finite element formulation with a load controlled, Newton Raphson solver. The gradients are obtained from a sensitivity analysis, which determines how the structural responses depend on the optimization variables. This paper discusses the details of these processes.

The Smart Radiation Device (SRD) is a new thermal control material that decreases the temperature variation by changing the emissivity without using electrical instruments or mechanical parts. The emissivity of the SRD changes physically depending on its temperatures. Bonded only to the external surface of the spacecrafts, the SRD controls the temperature. The drawback of the SRD is the high solar absorptance. The multi-layer film for SRD was designed in order to decrease the solar absorptance from 0.81 to less than 0.2 by putting multi-layer film on it and the optical performance of the Smart Radiation Device with Multi-layer film (SRDM) was evaluated.

The Mid-Infrared Instrument (MIRI) is one of four scientific instruments on the James Webb Space Telescope (JWST) observatory, scheduled for launch in 2013. It will provide unique capabilities to probe the distant or deeply dust-enshrouded regions of the Universe, investigating the history of star formation both near and far. The MIRI is the coldest instrument on the observatory. Its thermal design is driven by requirements to cool its Optics Module (OM) to below 15.5 K and detectors within this to below 6.7 K. The MIRI OM is accommodated within the JWST Integrated Science Instrument Module (ISIM) which is cooled passively to between 32 and 40 K. The instrument temperatures are achieved by a combination of thermal isolation of the OM from the ISIM supplemented with active cooling of the OM by a dedicated cryocooler.

The Tropospheric Emission Spectrometer (TES), launched on NASA's Earth Observing System Aura spacecraft on July 15, 2004 has successfully completed over three years in space and has captured a number of important lessons. The instrument primary science objective is the investigation and quantification of global climate change. TES measures the three-dimensional distribution of ozone and its precursors in the lower atmosphere on a global scale. It is an infrared (IR) high resolution, imaging Fourier Transform Spectrometer (FTS) with a 3.3 to 15.4 μm spectral coverage required for space-based measurements to profile essentially all infrared-active molecules present in the Earth's lower atmosphere. The nominal on-orbit mission lifetime is 5 years. The Aura spacecraft flies in a sun-synchronous near-circular polar orbit with 1:38 pm ascending node.

Unmanned Air Vehicles (UAVs) are becoming more and more important in our lives. UAVs, light and heavy, are playing an important role in the modern battle field. The technology which is developed for military purposes is slowly moving toward civilian applications. UAVs can be considered as “flying robots” with the capability to perform missions autonomously or under the remote control of a human operator. Latest UAV technology allows it to operate at different regions of the world and to send information and receive commands from a single protected ground station. The modern UAVs utilize state of the art airframe structures, efficient aerodynamic design, efficient propulsion systems, innovative electro optical sensors, long range communication devices and the latest computers technology.

Signal Jitter is an impediment that continues to affect many technologies. Its presence in optical tracking devices is manifested in tracking data and affects the device's accuracy and latency. Previous studies have investigated several smoothing techniques to reduce jitter, while accounting for engine vibration as an external source. This paper will delve further into the research by exploring the characteristic behavior of the optical tracking data, so that a more intuitive selection of a smoother can be made. This process will not only justify the suitability of a smoothing technique for SVS, but also lead to increased tracking efficiency.

We present optical backscatter reflectometry, a commercially available method for testing and troubleshooting of short haul fiber optic links. Short-length optical communications networks like those in avionics and aerospace applications require frequent heath assessment. Precise recognition and localization of faults, accurate measurement of loss though the link are critical to maintaining signal integrity. The optical backscatter reflectometry method makes it possible to detect and localize bends, breaks, bad splices, and poor connections with up to 10 micron spatial resolution with no dead zone. Links can be measured with 1 mm resolution over up to 2000 m of fiber length. In addition to fault location and loss measurement, this measurement technique makes possible distributed temperature and strain measurements along standard optical fiber. We will provide measurement examples demonstrating capabilities not currently supported by conventional measurement tools.

The integration of Optical Tracking with Synthetic Vision Systems (SVS), offers a solution that could improve precision, control and safety for pilots during low visibility flights. However, this assimilation cannot be achieved without addressing the issue of jitter presence, which is the primary cause of performance reduction in many tracking devices. It is therefore necessary to investigate the effect of jitter on a viable Commercial-Off-The-Shelf (COTS) optical tracking device that could be incorporated with an SVS enabled display. Aspects of this investigation include the characterization, measurement and reduction of jitter. In this paper, the measurement and characterization processes are discussed.