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Both Planck and Herschel satellite are cryogenic payloads, the first one having a cold point around 0.1 [K], the second one around 0.3 [K]. Not only the detectors are cooled, but also major subsystems and systems of the spacecraft’s. The Centre Spatial de Liège (CSL) is involved in the testing of several parts of the spacecraft’s, starting from optical tests on the mirrors or on the telescopes, going on with cryogenic vibration testing of scientific focal plane instruments, ending with the full Planck spacecraft testing. Each test requires temperature lower than 20 [K], in volumes ranging from 1 [m3] to 60 [m3], cooling down several kilograms to more than one ton, and withstanding heat load up to 150 [W] in stabilization. These tests are done is 4 different facilities of CSL, linked to a common cold Helium network. This latter allows full flexibility for operation of the different facilities quasi independently.

We report on a feasibility study of an optical micro-electro-mechanical systems (MEMS) flow sensor to measure flow rate using Moiré fringe displacement of a floating element. Due to constraints on weight, power, and size for space environmental systems, the development of sensor components that minimize the equivalent systems mass (ESM) while maintaining or exceeding required specifications is highly desirable. A feature of the optical detection method is a physical separation of electrical components from the flow stream. The geometric Moiré fringe shift optically amplifies small displacements by the ratio of the fringe pitch to the movable grating pitch that is detected using an external CCD imager, providing an electrically isolated, robust, direct scheme for detecting flow from shear stress induced displacement.

Aim of the Closed Habitat Environmental Control Sensors (CHECS) project has been the setting up of a complete, lightweight sensing system for monitoring the ambient conditions of plant growth in space missions. A complete sensor system has been developed and tested, based on a deep knowledge of plant needs, and on the typical plant behaviour in stress conditions. The main characteristic of the system is its compatibility with Silicon technology. This means high integrability, reduced dimensions, low weight, redundancy, simplicity and high reliability. All the sensors composing the systems have been produced by means of well developed solid state technology, including the MicroSystem Technology (MST) and Porous Silicon Technology (PST). The latter has proved in the last year to have considerable advantages over other approaches.

Herschel is the fourth cornerstone mission in the European Space Agency (ESA) science programme. It will perform imaging photometry and spectroscopy in the far infrared and submillimetre part of the spectrum, covering the 57-670 µm wavelength range. This successor of the Infrared Space Observatory (ISO) is scheduled to be launched by an Ariane 5 in 2007. Once operational Herschel will offer a minimum of three years of routine observations. EADS-ASTRIUM, in charge of the Extended Payload Module, has involved AIR LIQUIDE in the design and manufacturing of major components of the spacecraft cryostat: the two Helium Tanks, all Thermal Links [1.6 K - 9 K], the Optical Bench Helium Cooling Loop, the three Thermal Shields and all the Helium System Tubing from the tanks to the Cryostat Vacuum Vessel. All these elements contribute to the final aim of the system to provide the required cold environment to the Herschel Focal Plane Units.

Dynamic interactions of pairs of co-rotating vortex filaments, typical of those emanating from wing tips and flap tips are studied. Time history of the motion of individual filaments has been obtained in a water tunnel using an optical method. It is demonstrated that before their merger, co-rotating vortex filaments tend to oscillate along preferred directions. Also, the motion appears to be unstable with increasing amplitude over a wide range of frequencies. These conclusions are shown to be consistent with analytical predictions. It is also shown that the merger location correlates well with the vortex strength. Comparisons with analytical and computational results are provided where appropriate.

The thermal design and modeling of NASA’s James Webb Space Telescope (JWST) Integrated Science Instrument Module (ISIM) is described. The ISIM utilizes a series of large radiators to passively cool its three near-infrared instruments to below 37 Kelvin. A single mid-infrared instrument is further cooled to below 7 Kelvin via stored solid Hydrogen (SH2). These complex cooling requirements, combined with the JWST concept of a large deployed aperture optical telescope, also passively cooled to below 50 Kelvin, makes JWST one of the most unique and thermally challenging space missions flown to date. Currently in the preliminary design stage and scheduled for launch in 2010, NASA’s JWST is expected to replace the Hubble Space Telescope as the premier space based astronomical observatory.

SCIAMACHY is a German-Dutch Earth observation instrument which is to fly aboard the Envisat-1 spacecraft It is an 8 channel spectrometer designed to analyse sun light which is scattered on higher layers of the atmosphere. Two of the channels perform measurements in the Infra-Red. For these channels a low and stable temperature level of the instrument is required (< -20 °C) to minimise the impact of IR background radiation on the measurements. Additionally, the system requirement on spectral stability requires the variation in thermal gradient to be very small. This paper presents the flow down from system to thermal requirements and gives a rationale for the Thermal Control Sub-system (TCS) design concept which was established to meet these severe requirements. Added to this are some of the analyses results which support the TCS design. The presented TCS design reflects the PDR status.

Thermal control materials of different types are being used on the spacecraft for temperature control viz. Thermal control tapes, Thermal control paints, Anodised surfaces and Optical solar reflectors. This paper covers the measurement of emittance at different temperatures on various Optical Solar Reflectors ( OSR ) both rigid and flexible types. The rigid OSRs evaluated are OCLI - USA, PPE - UK and ISRO - INDIA. The flexible OSR is from SHELDAHL - USA. The emittance of the OSRs were measured in the temperature range 223K - 373K using steady state calorimetric method. Measurements were done on a square sample with OSRs affixed on each face. The sample has a built in heater and an evacuated low temperature radiation receiver is used for the test environment. Experimental results, temperature dependence of the total hemispherical emittance relation for each of these OSRs and error estimation are presented in this paper.

This paper presents a summary of the design, development, and ground verification of the BETSU (Brilliant Eyes Thermal Storage Unit) experiment. The BETSU utilizes 2-methyl pentane as a 120 K PCM (Phase Change Material) and will be flown on board the Shuttle in early 1994. There has been very limited experience with the space flight of cryogenic phase change materials. Space applications for a cryogenic TSU include the storage of energy for the cooling of temperature sensitive sensor components such as focal planes, optics, mirrors, and telescopes. Based on ground test data, trade studies were performed which show the significant weight and cost benefits of the BETSU technology.

Joining of a PdCr Strain Gage with a Hastelloy X carrier shim to Inconel by a rapid infrared processing technique has been investigated at 1150 °C using a nickel based brazing alloy AMS 4777, Ni-7Cr-3Fe-3.2B-4.5Si-.06C in wt%. The effects of the infrared joining parameters on the joint and base material microstructure, joint shear strength, and delamination tendency of the PdCr gage was investigated. Results show that the joint shear strength is as high as 503 MPa when processed at approximately 1150 °C for 120 seconds. Microstructural examinations of the joint with both an optical microscope and a scanning electron microscope indicate that good wetting exists between the brazing alloy with both the Hastelloy X and Inconel 718. And, the Hastelloy X and Inconel 718 exhibits no noticeable change in microstructure due to the rapid processing cycle of the infrared heating process while the stabilized PdCr wire gage shows little change in resistance.

Analytical predictions and laboratory measurements were made for the relative total temperature experienced at the tip diameter of a radial-inflow turbine used in an air turbine starter (ATS). The predictions showed that at freerun conditions the blade tip temperature would be significantly higher than the turbine inlet temperature. Tests to confirm this prediction were performed on an ATS modified to accept an optical pyrometer. The pyrometer was focused on the suction side of the blade at the tip radius. Blade temperature measurements conducted at the maximum attainable speed of the ATS verified the prediction to be within the error of the pyrometer measuring system.

Measurements of the gas state properties in hypersonic propulsion system research present unique problems demanding unconventional diagnostic measurement system design solutions. To resolve transient flowfield structures in these high-speed flows, the diagnostic instruments must have high spatial (on the order of 1 mm) and high temporal (on the order of nanoseconds) resolution. These requirements generally demand implementation of nonintrusive techniques. A review is given of nonintrusive techniques, which have been applied to flowfield diagnostics, including Planar Laser Induced Fluorescence (PLIF), Raman Spectrometry, Coherent Anti-Stokes Raman Spectrometry (CARS), and Rayleigh Scattering. A discussion is given of issues associated with the selection of equipment for PLIF and Raman systems, and of lessons learned in their application.

The Thermal Infrared Radiometer (TIR) is part of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) complement of instruments to be flown on NASA's Earth Observing System (EOS) spacecraft. ASTER'S function is to measure atmospheric and terrestrial optical and thermal emissions. TIR provides coverage of the long wave emissions and utilizes several independent thermal control elements to support the exacting thermal requirements of the optical train and electronic assemblies. The widely differing temperature ranges and narrow control bands of the instrument components dictate the need for a combination of active and passive thermal control techniques. The very low temperature required of the thermal emission detector using a Stirling cycle cooler, contrasts with the moderate temperatures needed by the optical train and blackbody. These components are cooled by uniquely configured remote radiators and thermostatically controlled heaters.

On-board, tactical airborne sensor systems perform functions such as target acquisition, track, designation, identification, recognition, threat warning, threat count, missile launch detection and ground mapping in support of situation awareness, self-defense, navigation, target attack, weapon support and reconnaissance. Next generation tactical aircraft in development want those functions performed by sensor suits which exploit modular avionics concepts; exhibit low signature and enhanced stealthiness; have increased availability through increased functional redundancy; and are easy and less costly to maintain. Integrated IR sensors incorporating modular avionics concepts can satisfy those needs. Current IR systems for airborne tactical applications are packaged in either aftermarket pod mounted configurations or in chin mounted protuberances.

Solar flares which produce significant numbers of energetic protons are accompanied by optical, radio and x-ray emissions. Thus the capability for providing early warning of solar proton events (SPEs) is possible if the particle fluxes can be correlated with the electromagnetic signatures from the sun. We have continued to develop and refine the correlations between the proton fluxes in the SPE's and their electromagnetic emissions. Data from over most of solar cycle 21 and the early portion of cycle 22 have been used to extend our data base and improve the correlations between peak proton fluxes and the x-ray fluences which arrive at the earth earlier than the protons. A simple relationship has been derived between the probability of occurrence of an SPE and the observed x-ray fluence.

Laser Velocimetry (LV) is often utilized as an off-the-shelf nonintrusive measurement technique for low speed, steady state flows. However, in complex, supersonic flows, the application of LV becomes highly specialized. Setups must often contend with limited optical access, poor signal-to-noise ratios, and limited tunnel run times. Furthermore, seeding particles must survive large ranges of flow temperatures and pressures, and extensive data analysis and interpretation are required to ascertain whether measured particle velocities are representative of the fluid flow. Several examples of LV studies in the supersonic regime demonstrate recent advancements and the current state-of-the-art of this measurement technique. Results are included from three wind tunnel facilities, operating at freestream Mach numbers of 1.9, 3, and 6, and track an evolution of applications from flat plate boundary layers to the complex flowfield of a supersonic inlet.

Aerodynamics plays a major role in the design of all kinds of vehicles throughout automotive history. Initially the main topic under investigation was the aerodynamic drag reduction to achieve high-energy efficiency, however in the late ‘60s the vertical aerodynamic forces gained traction, particularly in high performance cars. The automotive market usually treats design, aerodynamics and vehicle dynamics in different departments. This paper proposes an integrated approach for the aerodynamics development in which a sport car is defined as reference vehicle. The objective of the concurrent engineering operation is to control the aerodynamic forces by implementing active surfaces control finally improving vehicle lap time. The vehicle dynamics analysis is carried out in cooperation with vehicle aerodynamics in order to perform the hardware and software design of the active system.

This paper focuses on the design, construction, preliminary testing, and potential applications of three forms of miniaturized analytical instrumentation. The first is an optical fiber instrument for monitoring pH and other cations in aqueous solutions. The instrument couples chemically selective indicators that have been immobilized at porous polymeric films with a hardware package that provides the excitation light source, required optical components, and detection and data processing hardware. The second is a new form of a piezoelectric mass sensor. The sensor was fabricated by the deposition of a thin (5.5 μm) film of piezoelectric aluminum nitride (AlN). The completed deposition process yields a thin film resonator (TFR) that is shaped as a 400 μm square and supports a standing bulk acoustic wave in a longitudinal mode at frequencies of ∼1 GHz.

Life support systems for manned exploration missions are becoming increasingly complex. In next-generation manned space exploration, closed-loop control of all life support systems must be established, particularly for missions requiring extended human occupation of space or the lunar or martian surface. To accomplish this control, sensors must be developed that are capable of monitoring and feeding back information on the concentrations of a number of chemical and biochemical substances. Two critical sets of variables that must be monitored are: oxygen concentration and flow in crew air supply (both in capsules and in suits and masks); carbon dioxide, oxygen, and moisture content in hydroponic or other food- and oxygen-producing life support systems.

Aircraft modifications have been developed to make F/A-18D Hornets capable of being converted to a reconnaissance configuration which includes both optical and infrared sensors. A major design challenge was to prevent fog formation on the two exterior moldline windows used for viewing by these sensors. Antifogging was required during a rapid 7620 m/min (25,000 ft/min) descent into humid atmospheric conditions following a sustained cold soak at altitude. This paper describes the design development and laboratory verification testing of the two unique antifog systems selected to meet this requirement.