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Context.The Extreme Ultraviolet Imager (EUI) is part of the remote sensing instrument package of the ESA/NASA Solar Orbiter mission that will explore the inner heliosphere and observe the Sun from vantage points close to the Sun and out of the ecliptic. Solar Orbiter will advance the “connection science” between solar activity and the heliosphere.Aims.With EUI we aim to improve our understanding of the structure and dynamics of the solar atmosphere, globally as well as at high resolution, and from high solar latitude perspectives.Methods.The EUI consists of three telescopes, the Full Sun Imager and two High Resolution Imagers, which are optimised to image in Lyman-αand EUV (17.4 nm, 30.4 nm) to provide a coverage from chromosphere up to corona. The EUI is designed to cope with the strong constraints imposed by the Solar Orbiter mission characteristics. Limited telemetry availability is compensated by state-of-the-art image compression, onboard image processing, and event selection. The imposed power limitations and potentially harsh radiation environment necessitate the use of novel CMOS sensors. As the unobstructed field of view of the telescopes needs to protrude through the spacecraft’s heat shield, the apertures have been kept as small as possible, without compromising optical performance. This led to a systematic effort to optimise the throughput of every optical element and the reduction of noise levels in the sensor.Results.In this paper we review the design of the two elements of the EUI instrument: the Optical Bench System and the Common Electronic Box. Particular attention is also given to the onboard software, the intended operations, the ground software, and the foreseen data products.Conclusions.The EUI will bring unique science opportunities thanks to its specific design, its viewpoint, and to the planned synergies with the other Solar Orbiter instruments. In particular, we highlight science opportunities brought by the out-of-ecliptic vantage point of the solar poles, the high-resolution imaging of the high chromosphere and corona, and the connection to the outer corona as observed by coronagraphs.

Cosmic rays affect the performance of any detector in space through the creation of spurious signal and/or slow build-up of radiation damage. To mitigate the effects of these high-energy particles on the observations of next-generation space missions, the interaction between state-of-the-art detectors will have to be understood through simulation and experimental verification. We present the first measurement results of a new cryogenic system designed to become a common-user test facility to evaluate the effects of high-energy particles on arrays of these high-sensitivity detectors. The system is based on pulse-tube precooled dilution refrigerator with a large experimental volume (o = 29 cm, H = 30 cm). At 100 mK the system provides 650 µW of cooling power and an out-of-the box thermal stability of 76 µK rms. A first experiment with a semiconducting bolometer from the DIABOLO experiment shows a responsivity and noise level consistent with previous measurement in different cryogenic systems. However, the pulse-tube induced vibrations show as clear features in the noise. To irradiate the detectors a particle beam, such as the 25 MeV proton beam of the nearby ALTO facility, can be coupled to one of four ports. Simulations show that the aluminum-coated Mylar windows do not significantly affect the 25 MeV proton beam of TANDEM. First experiments at the ALTO facility for system verification are expected early 2019. Until that time, the thermal stability, vibration damping and EMI shielding will be improved and a flexible wiring will be developed, to accommodate multiple detector types.

The understanding of the solar outer atmosphere requires a simultaneous combination of imaging and spectral observations concerning the far UV lines that arise from the high chromospheres up to the corona. These observations must be performed with enough spectral, spatial and temporal resolution to reveal the small atmospheric structures and to resolve the solar dynamics. An Imaging Fourier Transform Spectrometer working in the far-UV (IFTSUV, Figure 1) is an attractive instrumental solution to fulfill these requirements. However, due to the short wavelength, to preserve IFTSUV spectral precision and Signal to Noise Ratio (SNR) requires a high optical surface quality and a very accurate (linear and angular) metrology to maintain the optical path difference (OPD) during the entire scanning process by: optical path difference sampling trigger; and dynamic alignment for tip/tilt compensation (Figure 2).

PILOT (Polarized Instrument for Long wavelength Observations of the Tenuous interstellar medium) is a balloonborne astronomy experiment designed to study the polarization of dust emission in the diffuse interstellar medium in our Galaxy. The PILOT instrument allows observations at wavelengths 240 μm (1.2THz) with an angular resolution about two arc-minutes. The observations performed during the first flight in September 2015 at Timmins, Ontario Canada, have demonstrated the optical performances of the instrument.

PILOT is a balloon-borne astronomy experiment designed to study the polarization of dust emission in the diffuse interstellar medium in our Galaxy at wavelengths 240 and 550 µm with an angular resolution of about two arc-min. PILOT optics is composed of an off-axis Gregorian telescope and a refractive re-imager system. All these optical elements, except the primary mirror, are in a cryostat cooled to 3K. We used optical and 3D measurements combined with thermo-elastic modeling to perform the optical alignment. This paper describes the system analysis, the alignment procedure, and finally the performances obtained during the first flight in September 2015

International audience; The Polarized Instrument for Long‐wavelength Observation of the Tenuous interstellar medium (PILOT) is a balloon‐borne astronomy experiment designed to study the linear polarization of thermal dust emission in two photometric bands centred at wavelengths 240 mu m (1.2 THz) and 550 mu m (545 GHz), with an angular resolution of a few arcminutes. Several end‐to‐end tests of the instrument were performed on the ground between 2012 and 2014, in order to prepare for the first scientific flight of the experiment that took place in September 2015 from Timmins, Ontario, Canada. This paper presents the results of those tests, focussing on an evaluation of the instrument's optical performance. We quantify image quality across the extent of the focal plane, and describe the tests that we conducted to determine the focal plane geometry, the optimal focus position, and sources of internal straylight. We present estimates of the detector response, obtained using an internal calibration source, and estimates of the background intensity and background polarization.

Baffles provide the considerable advantage of the free surface stability that enhances the turbine's shaft longevity on the other hand it increases the energy consumption due to the flow obstruction that they introduce. So the main issue of the present study is to find a balance between both advantages and disadvantages of baffles. To do so we've investigated numerically the influence of two parameters on the power consumption. First, the baffles radius of curvature varying from Rc*=0 to Rc*=7/30 and secondly the impeller's sense of rotation of. The results were obtained thanks to the ANSYS CFX code; the Navier-Stokes equations were coupled to the standard k_e turbulence model and solved with the Multiple Reference Frames (MRF) method. DOI: http://dx.doi.org/10.5755/j01.mech.22.3.12663

The Polarimetric and Helioseismic Imager (PHI) on board of Solar Orbiter will observe the Sun to measure the photospheric vector magnetic field and the line-of-sight velocity. It will employ a narrowband filtergraph (FG) to scan the FeI 6173 A absorption line. At different spectral positions, the polarization state of the incoming light will be analyzed. The FG will provide a tuning range to scan the line, the continuum, and to compensate for the spacecraft radial velocity, as it will approach to the Sun down to 0.28 AU. The FG includes a Fabry-Perot etalon and two narrowband prefilters. The bandpass of the narrowest one has a nominal Full Width at Half Maximum (FWHM) of 2.7 A. The measurement of the prefilters characteristics is essential for the instrument calibration. Here we present the results of the breadboard prefilters characterization, which is an important milestone in the development of the instrument.

The Polarized Instrument for Long wavelength Observation of the Tenuous interstellar medium (PILOT) is a balloon borne experiment designed to measure the polarized emission from dust grains in the galaxy in the submillimeter range. The payload is composed of a telescope at the optical focus of which is placed a camera using 2048 bolometers cooled to 300 mK. The camera performs polarized optical measurements in two spectral bands (240 μm and 550 μm). The polarization measurement is based on a cryogenic rotating half-wave plate and a fixed mesh grid polarizer placed at 45o separating the beam into two orthogonal polarized components each detected by a detector array. The Institut d’Astrophysique Spatiale (Orsay, France) is responsible for the design, integration, tests and spectral calibration of the camera. Two optical benches have been designed for its imaging and polarization characterization and spectral calibration. Theses setups allow to validate the alignment of the camera cryogenic optics, to check the optical quality of the images, to characterize the time and intensity response of the detectors, and to measure the overall spectral response. A numerical photometric model of the instrument was developed for the optical configuration during calibration tests (spectral), functional tests (imager) on the ground, and flight configuration at the telescope focus, giving an estimate of the optical power received by the detectors for each configuration.

The spectroscopy of the far UV emission lines of the solar spectrum combined with an imaging capability is essential to understand the physics of the outer solar atmosphere. An imaging Fourier transform spectrometer (IFTSUV) is an attractive instrumental solution to perform such far-UV solar observations. Working in the far UV involves high precision metrology to maintain the optical path difference (OPD) during the entire scanning process of the interferogram. It also involves a compact all-reflection design for UV applications. We present the specification of a servo-system that enables dynamic tip/tilt alignment compensation and OPD sampling measurement of the IFTSUV scanning mirror. We also discuss the first experimental results of a breadboard as well as the preliminary design of a space-based device.

The Molecular Hydrogen Explorer (H2EX) proposed for the 2015 - 2025 Cosmic Vision Call issued by ESA in 2007 was designed to make surveys of the molecular gas from its first rotational lines in various extragalactic and galactic sites. The design study led to the proposition of a mid-infrared (8 to 29 μm) Imaging Fourier transform Spectrometer (IFTS) making possible integral field spectroscopy on a 20' wide field and a maximum resolution up to 3×10 4 at 10 μm. To reach this goal, an all-mirror payload was outlined, made of a 1.2m telescope matched to a dual output interferometer, imaging the field on two 1024×1024 Si:As IBC detectors. The payload was designed to re-use the platform developed for the Planck mission. Such a wide field and high spectral resolution IFTS on a large spectral domain can have further applications, with the necessary adaptation to each case, for future large aperture cryogenic telescopes in the mid-infrared, or in the near-infrared behind future ELTs, in a site like Dome C in Antarctica, and out of astronomy, for remote sensing of Earth atmosphere.

Herein, we report a lightweight manipulator with potential application as a prosthetic finger. Our design features lightweight construction using low cost actuators. To reduce power consumption, force and motion actuation are separated. Low cost miniature DC motors provide motion for the digit, while a magnetorheological fluid piston acts as a force brake. This combination of actuators improves efficiency and reduces weight. Control is provided by networked low cost microcontrollers, and is separated into high level coordination and low level position control. The end device will be low cost, efficient, and lightweight with low failure cost and easy substitution of parts for customization.

An evaluation of novel tactile navigation system for the blind is described in this paper. The handle processes ultrasonic sensor signals and conveys information to the user through variable and synchronized vibrations, which will enhance the sense of orientation and distance for the user. Various tactile perception patterns are used to convey information to the user using sensitivity of the hand. These schemes give feedback to the user using various vibrating patterns which are dependent on three parameters namely intensity of vibration, location of the vibro-tactile actuator and the pulse duration of sensing signal. We are showing different navigation scenario results of the device on 15 sighted users of different age group, genders and hand sizes by making them blindfolded. The prototype has an ergonomic design, is lightweight, compact, and adjustable to different hand sizes

This paper presents a novel tactile navigation system for the blind. The device is portable and cost effective, and will allow visually impaired individuals to navigate through familiar and non-familiar environments without relying on the assistance of a guide. The “Tactile Handle” consists of an array of vibro-tactile actuators positioned to match the finger phalanxes, proximity sensors, and an embedded micro-controller. The handle processes sensor signals and outputs information to the user through variable and synchronized vibrations, which will enhance the sense of orientation and distance for the user. The prototype has an ergonomic design, is lightweight, compact, and adjustable to different hand sizes. This paper describes the concept of its use as a navigation system for the visually impaired and the preliminary results for the tactile perception of 30 sighted users of different genders and hand sizes.

International audience; Solar Orbiter mission will study the Sun to the proximity of 0.28 AU, reaching solar latitudes up to 34°. This spacecraft will be launched in 2017 and will represent a complete approach to heliophysics. The Polarimetric and Helioseismic Imager (PHI), on board of Solar Orbiter, will provide the most important data for helioseismology. PHI will measure the photospheric vector magnetic field and the line-of-sight velocity observing the FeI 6173 A absorption line with a narrowband filtergraph (FG). At different spectral positions, the polarization state of the incoming light will be analyzed. The FG will provide a tuning range to compensate the spacecraft radial velocity and to scan the continuum at both sides of the absorption line. Thus, the fine tuning of the FG is essential for the instrument performance. Here we present the FG characterization and calibration status as they represent an important milestone in the development of the instrument.

This paper describes the Polarimetric and Helioseismic Imager on the Solar Orbiter mission (SO/PHI), the first magnetograph and helioseismology instrument to observe the Sun from outside the Sun-Earth line. It is the key instrument meant to address the top-level science question: How does the solar dynamo work and drive connections between the Sun and the heliosphere? SO/PHI will also play an important role in answering the other top-level science questions of Solar Orbiter, as well as hosting the potential of a rich return in further science. SO/PHI measures the Zeeman effect and the Doppler shift in the FeI 617.3nm spectral line. To this end, the instrument carries out narrow-band imaging spectro-polarimetry using a tunable LiNbO_3 Fabry-Perot etalon, while the polarisation modulation is done with liquid crystal variable retarders (LCVRs). The line and the nearby continuum are sampled at six wavelength points and the data are recorded by a 2kx2k CMOS detector. To save valuable telemetry, the raw data are reduced on board, including being inverted under the assumption of a Milne-Eddington atmosphere, although simpler reduction methods are also available on board. SO/PHI is composed of two telescopes; one, the Full Disc Telescope (FDT), covers the full solar disc at all phases of the orbit, while the other, the High Resolution Telescope (HRT), can resolve structures as small as 200km on the Sun at closest perihelion. The high heat load generated through proximity to the Sun is greatly reduced by the multilayer-coated entrance windows to the two telescopes that allow less than 4% of the total sunlight to enter the instrument, most of it in a narrow wavelength band around the chosen spectral line., Comment: 36 pages, 41 figures