Polder 2 in-flight results and parasol perspectives

This paper presents a global approach of the POLDER 2 mission: from instrument design, pre-flight and in-flight calibrations till the first in-flight results. The POLDER 2 sensor has been developed by the Centre National c'Etudes Spatiales, the French space agency. It is part of the payload of the ADEOS II satellite developed by JAXA and launched in December 2002. POLDER 2 collected global data from April 2003, end of ADEOS II system check out phase, till the loss of the satellite on October 2003 due to a failure of the satellite power supply system. The POLDER 2 sensor is designed to collect global and repetitive observations of the solar radiation reflected by the Earth-Atmosphere system for climate research. The sensor is a wide field-of-view (2400 Kin swath), low resolution (6x7 Km(2) at nadir) multi-spectral imaging radiometer / polarimeter. The instrument concept is based on a telecentric optics, a rotating wheel carrying 15 spectral filters and polarizers, and a bidimensionnal CCD detector array. The multi-disciplinaiy scientific objectives of POLDER 2 lead to severe radio-metric and geometrical requirements, as well as a very accurate calibration of the sensor. These requirements are achieved through a stable instrument design, exhaustive pre-flight and original in-flight calibratiors. A derived model of POLDER 2 instrument will be flown on the payload of the CNES PARASOL micro satellite, the launch of which is planned end 2004. The PARASOL mission is part of the "Aqua train" i.e. the formation flying of 3 satellites following EOS-PM, so called "Aqua".