MEGHA-TROPIQUES, a satellite for studying the water cycle and energy exchanges in the tropiques

Supported by the French and Indian scientific communities, the MEGHA-TROPIQUES Mission aims at studying the water cycle and the energy exchanges in the tropical belt. It will be jointly developed by the Indian Space Research Organisation (ISRO) and the French Space Agency (CNES). The small satellite (<600 kg) could be launched as early as 2005 by Indian PSLV launcher in a low inclination (22/spl deg/) orbit. The payload will fly on a PROTEUS multi-purpose bus developed in France by ALCATEL. Longwave and shortwave outgoing fluxes from the top of atmosphere will be derived from the ScaRaB radiometer, already developed in France by the LMD (a French Laboratory: Laboratoire de Meteorologie Dynamique). Measurement of the atmospheric water vapour vertical distribution will be given by SAPHIR, a new microwave sounder around 183 GHz to be developed by CETP and DEMIRM (two French laboratories: Centre de l'Environnement Terrestre et Planetaire and Observatoire de Paris). MADRAS, the main and biggest instrument, will scrutinise cloud and precipitation properties. It is a (conical) scanning radiometer with 6 channels (10, 18, 23, 36, 89, 157 GHz) and a resolution ranging from 60 km (10 Ghz) to 6 km (157 GHz). MADRAS will be developed by ISRO with CNES providing the RF rotating assembly (dish, horns, receivers...) to be developed by MMS (France). ISRO will also be responsible for the payload module and the payload integration. The feasibility study is in progress.