Chennai: India is priming to fire into orbit October 12 a satellite designed to help study climatic and atmospheric changes in the tropics, the country's space agency said on Thursday.

“The rocket and its payload have been assembled and the heat shield has been closed. The first round of tests is over and we will have a final review. The launch rehearsal will be on October 8,' an official of Indian Space Research Organisation (ISRO) said.

Preparations are in full swing at Sriharikota, the rocket launch site in Tamil Nadu around 80 km from Chennai, and Indian space scientists say they are confident they will be able to fill the ferrying vessel with propellant October 10.

The official, who did not want to be identified, said the Polar Satellite Launch Vehicle (PSLV) will ferry the 1,000-kg Megha Tropique and three smaller satellites together weighing 45 kg.

Megha Tropiques is an Indo-French collaboration to study climatic and atmospheric changes in tropical regions and will make India the second nation in the world to launch such a space mission.

The Tropical Rainfall Measuring Mission (TRMM) -- a joint mission of NASA and the Japan Aerospace Exploration Agency (JAXA) designed to monitor and study tropical rainfall -- was launched November 27, 1997.

According to Indian space officials, ISRO will bear the launch cost of around Rs.90 crore while French space agency Centre National d'etudes Spatiales (CNES) has spent around Rs.300 crore.

The CNES has built three instruments of Megha Tropiques: SAPHIR, SCARAB; GPS-ROS. The fourth, MADRAS, is a joint effort of ISRO and CNES.

The three nano satellites that will be ferried by the PSLV rocket are a 10-kg SRMSAT built by students of SRM University near Chennai; a 3-kg remote sensing satellite Jugnu from the Indian Institute of Technology-Kanpur; and a 30-kg VesselSat from Luxumbourg to locate ships on high seas.

For ISRO, this will be the third rocket launch this year from India. In April, the agency successfully launched remote sensing satellite Resourcesat-2 and two others. In July, communication satellite GSAT-12 was put in orbit.

Though ISRO had said that another rocket launch, carrying remote sensing satellite Risat, lack of time has put it in doubt.

“Normally there needs to be a month's time gap between two launches to refurbish the launch pad,” an ISRO official said.

“Given this situation, the preparations for the next launch can start only by mid-November, leaving just 45 days in this calendar year. So there may not be fourth launch this year.”