Dr K Kasturirangan, chairman of ISRO, (left) and Prof. Bensoussan, President CNES, sign the MOU. Photo: ISRO

The Indian Space Research Organisation (ISRO) and the French Space Agency (CNES) signed a Memorandum of Understanding (MOU) Wednesday for the design of a joint satellite mission, Megha Tropiques, for atmospheric research. The MOU was signed by Dr K Kasturirangan, Chairman, ISRO and Prof Bensoussan, President, CNES at Antariksh Bhavan, Bangalore, the headquarters of ISRO.

Megha Tropiques (Megha meaning cloud in Sanskrit and Tropiques meaning tropics in French) will be a satellite mission for conducting research on the contribution of water cycle in the tropical atmosphere to the climate dynamics. The satellite is proposed to carry three scientific instruments:

• a Multi-frequency Microwave Scanning Radiometer, MADRAS, providing information on rain above the oceans, integrated water vapour content in the atmosphere, liquid water in clouds, convective rain over land and sea.
  
  
• a Multi-channel Microwave Instrument, SAPHIR, providing vertical humidity profile in the atmosphere and
  
  
• a Multi-channel instrument, SCARAB, providing data on the earth's radiation budget.
  
  

Of these three instruments, MADRAS will be developed jointly by CNES and ISRO while the other two instruments will be supplied by CNES. The Megha Tropiques will use the 'PROTEUS' spacecraft platform developed by CNES.

ISRO will launch the satellite on its Polar Satellite Launch Vehicle, PSLV, into an orbit at a height of 867 km and an inclination of 20 degrees, with respect to the equatorial plane. In this orbit, Megha Tropique can collect data repetitively over the tropics and supplement and complement the data obtained from geostationary and polar orbit satellites. The satellite will be controlled in orbit by CNES, and the scientific data will be received and distributed by ISRO from Bangalore. The launch is planned for the end 2005.

It is well known that the tropical region is the domain of squall lines and cyclones and is characterised by large intra-seasonal, inter-seasonal and inter-annual variations that have led to several catastrophic events such as droughts and floods. Changes in energy and water budget of the land-ocean-atmosphere systems in the tropics influences the global climate to a great extent. The exchange of energy in the inter-tropical zone influences the climate of the rest of the planet. These systems interact with the general circulation of the atmosphere in ways that are yet to be fully understood and hence reducing the reliability in the prediction of the weather and climate events. It is in this context that data from the unique combination of scientific payloads and the special orbit of the satellite makes Megha Tropiques invaluable for climate research.

In addition to Indian and French scientists who will be taking part in the data analysis, international teams of scientists working on global climate related studies have also expressed keen interest in the satellite programmes.

It may be recalled that a Statement of Intent had been signed by ISRO and CNES in November 1999 for conducting the pre-feasibility studies for undertaking the joint Megha Tropiques mission. The studies conducted, pursuant to that Statement of Intent, have yielded a baseline configuration of the satellite and its instruments, the choice of the optimum orbit, the satellite launch vehicle, satellite operations and scientific research plan. The MOU signed today enables both ISRO and CNES to start detailed design of the Megha Tropiques mission.

The MOU signed is also a major milestone in the long standing relationship between Indian and French space agencies. It is to be noted that ISRO and CNES have a long standing collaboration and several joint research projects have been undertaken by the agencies. Several meteorological payloads, developed by CNES, have also been flown by Indian sounding rockets from Thumba and Sriharikota.