Showing papers by "Jean-Marc Defise published in 2010"

First light of SWAP on-board PROBA2

Abstract: The SWAP telescope (Sun Watcher using Active Pixel System detector and Image Processing) is an instrument launched on 2nd November 2009 on-board the ESA PROBA2 technological mission. SWAP is a space weather sentinel from a low Earth orbit, providing images at 174 nm of the solar corona. The instrument concept has been adapted to the PROBA2 mini-satellite requirements (compactness, low power electronics and a-thermal opto-mechanical system). It also takes advantage of the platform pointing agility, on-board processor, Packetwire interface and autonomous operations. The key component of SWAP is a radiation resistant CMOS-APS detector combined with onboard compression and data prioritization. SWAP has been developed and qualified at the Centre Spatial de Liege (CSL) and calibrated at the PTBBessy facility. After launch, SWAP has provided its first images on 14th November 2009 and started its nominal, scientific phase in February 2010, after 3 months of platform and payload commissioning. This paper summarizes the latest SWAP developments and qualifications, and presents the first light results.

The technical challenges of the Solar-Orbiter EUI instrument

Abstract: The Extreme Ultraviolet Imager (EUI) onboard Solar Orbiter consists of a suite of two high-resolution imagers (HRI) and one dual-band full Sun imager (FSI) that will provide EUV and Lyman-α images of the solar atmospheric layers above the photosphere. The EUI instrument is based on a set of challenging new technologies allowing to reach the scientific objectives and to cope with the hard space environment of the Solar Orbiter mission. The mechanical concept of the EUI instrument is based on a common structure supporting the HRI and FSI channels, and a separated electronic box. A heat rejection baffle system is used to reduce the Sun heat load and provide a first protection level against the solar disk straylight. The spectral bands are selected by thin filters and multilayer mirror coatings. The detectors are 10μm pitch back illuminated CMOS Active Pixel Sensors (APS), best suited for the EUI science requirements and radiation hardness. This paper presents the EUI instrument concept and its major sub-systems. The current developments of the instrument technologies are also summarized.

Continuous Solar Simulator for Concentrator Photovoltaic Systems

Abstract: A continuous solar simulator for measuring performance of concentrator photovoltaic (CPV) systems is presented. The illumination system is based on a Xenon lamp, a homogenizer rod, shaping optics and a 30cm diameter collimator. The design optimises the reproduction of the characteristics of direct solar illumination: 32’ divergence, high spatial homogeneity, sun-like spectral distribution, with a maximum intensity of 250W/m2. It accommodates pass-band and attenuation filters to tune the beam output. It operates in continuous mode, allowing to investigate CPV thermal aspects as well. The present paper addresses the concept design of the solar simulator and associated performance results.

First steps in the development of a piston sensor for large aperture space telescopes

Abstract: Nowadays spaceborne missions for astronomy or Earth imaging need high resolution observation which implies the development of large aperture telescopes. This can be achieved by multi-aperture telescopes or large segmented telescopes. One of the major issues is the phasing of the sub-apertures or the segments of such telescopes. A cophasing sensor is therefore mandatory to achieve the ultimate resolution of these telescopes. In this framework, Liege Space Center (CSL) concern is the development of a compact cophasing sensor to phase new large lightweight segmented mirrors for future space telescopes. The sensor concept has its origins in new phase retrieval algorithms which have been recently developed. In this paper, we outline the concept and the experimental validation results of our piston sensor breadboard which is currently under development in our laboratory. Finally, future prospects and further developments of our experiment are presented.

Towards a New Formation Flying Solar Coronagraph

Abstract: We briefly describe an investigation aiming at the development of a giant solar coronagraph instrument onboard of two satellites, separated by about 150 m in formation flight for the detailed observation of the solar coronal plasma. The European Space Agency (ESA) has selected this instrument as the only payload onboard the Proba 3 satellites which will be launched in 2013. The Greek team is developing the command control board of the coronagraph.