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Meftah M.,University Pierre and Marie Curie | Corbard T.,University of Nice Sophia Antipolis | Hauchecorne A.,University Pierre and Marie Curie | Irbah A.,University Pierre and Marie Curie | And 20 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

PICARD is a mission devoted to solar variability observations through imagery and radiometric measurements. The main goal is to provide data for scientific investigation first in the area of solar physics, and second in the assessment of the influence of the solar variability on the Earth climate variability. PICARD contains a double program with in-space and on-ground measurements. The PICARD spacecraft was launched on June 15, 2010, commissioned in-flight in October of the same year and was retired in April 2014. The PICARD ground-based observatory is operational since May 2011. We shall give a short overview of the PICARD instrumentation. New estimates of the absolute values of the total solar irradiance, of the solar spectral irradiance at typical wavelengths, and of the solar oblateness will be given. We will also report about helioseismic studies. Finally, we will present our current results about solar radius variations after six years of solar observation. © 2016 SPIE.

Rouze M.,French National Center for Space Studies | Hauchecorne A.,University of Versailles | Hochedez J.F.,University of Versailles | Irbah A.,University of Versailles | And 6 more authors.
13th International Conference on Space Operations, SpaceOps 2014 | Year: 2014

PICARD is an investigation dedicated to the simultaneous measurement of the absolute total and spectral solar irradiance, the diameter and solar shape, and to the Sun's interior probing by the helioseismology method. The spacecraft was successfully launched into a Sun-synchronous dawn-dusk orbit on 15 June 2010 by a DNEPR-1 launcher for a life expectancy of 2 years; its operational mission ended in March, 2014. The payload consists of the SODISM imager (SOlar Diameter Imager and Surface Mapper) and of two radiometers, SOVAP (SOlar VAriability PICARD) and PREMOS (PREcision MOnitoring Sensor), which measure Total Solar Irradiance. Filter radiometers on PREMOS monitor the Solar Spectral Irradiance in six selected bands in the near UV, visible, and near IR wavelength regions. The SODISM telescope monitors continuously solar activity from the middle ultraviolet (UV) to the near infrared (IR) spectral domains. We shall give an overview of the mission, as well as the behaviour of the instruments in orbit, and the scientific results.

Meftah M.,University of Versailles | Irbah A.,University of Versailles | Hauchecorne A.,University of Versailles | Dame L.,University of Versailles | And 5 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Since the launch of the first artificial satellite in 1957, more than 6,000 satellites have been sent into space. Despite technological advances, the space domain remains little accessible. However, with the miniaturization of electronic components, it has recently become possible to develop small satellites with which scientific goals can be addressed. Micro-satellites have demonstrated that these goals are achievable. However, completion times remain long. Today, we hope through the use of nano-satellites to reduce size, costs, time of development and accordingly to increase accessibility to space for scientific objectives. Nano-satellites have become important tools for space development and utilization, which may lead to new ways of space exploration. This paper is intended to present a future space mission enabled by the development of nano-satellites and the underlying technologies they employ. Our future mission expands observations of the Sun (total solar irradiance and solar spectral irradiance measurements) and of the Earth (outgoing long-wave radiation, short-wave radiation measurements and stratospheric ozone measurements). Constellations of nano-satellites providing simultaneous collection of data over a wide area of geo-space may be built later and present a great interest for Sun-Earth relationships. © 2014 SPIE.

Conscience C.,RMIB | Meftah M.,University of Versailles | Chevalier A.,RMIB | Dewitte S.,RMIB | Crommelynck D.,RMIB
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

PICARD is a Satellite dedicated to the simultaneous measurement of the absolute total and spectral solar irradiance, the diameter and solar shape and the Sun's interior probed by helioseismology method. Its objectives are the study of the origin of the solar variability and the study of the relations between the Sun and the Earth's climate. PICARD was launched on June 15, 2010. The Satellite was placed into the heliosynchronous orbit of 735 km with inclination of 98.28 degrees. The payload consists in two absolute radiometers measuring the TSI (Total Solar Irradiance) and an imaging telescope to determine the solar diameter, the limb shape and asphericity. SOVAP (SOlar VAriability Picard) is an experiment developed by the Belgian STCE (Solar Terrestrial Center of Excellence) with a contribution of the CNRS (Centre National de la Recherche Scientifique) composed of an absolute radiometer provided by the RMIB (Royal Meteorological Institute of Belgium) to measure the TSI and a bolometer provided by the ROB (Royal Observatory of Belgium). The continuous observation of the solar irradiance at the highest possible precision and accuracy is an important objective of the Earth climate change. This requires: high quality metrology in the space environment. In this article, we describe the SOVAP instrument, its performances and uncertainties on the measurements of the TSI. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).

Meftah M.,University of Versailles | Dewitte S.,RMIB | Irbah A.,University of Versailles | Chevalier A.,RMIB | And 4 more authors.
Solar Physics | Year: 2014

The Picard spacecraft was successfully launched on 15 June 2010, into a Sun-synchronous orbit. The mission represents one of the European contributions to solar observations and Essential Climate Variables (ECVs) measurements. The payload is composed of a Solar Diameter Imager and Surface Mapper (SODISM) and two radiometers: SOlar VAriability Picard (SOVAP) and PREcision MOnitor Sensor (PREMOS). SOVAP, a dual side-by-side cavity radiometer, measures the total solar irradiance (TSI). It is the sixth of a series of differential absolute-radiometer-type instruments developed and operated in space by the Royal Meteorological Institute of Belgium. The measurements of SOVAP in the summer of 2010 yielded a TSI value of 1362.1 W m-2 with an uncertainty of ± 2.4 W m-2 (k=1). During the periods of November 2010 and January 2013, the amplitude of the changes in TSI has been on the order of 0.18 %, corresponding to a range of about 2.4 W m-2. © 2013 Springer Science+Business Media Dordrecht.

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