GSLV Mk-III will make its maiden voyage during the first week of June.

India will attempt to launch its heaviest and most powerful rocket yet next month. The 640-tonne Geosynchronous Satellite Launch Vehicle-Mark III (GSLV Mk III) has been worked on for more than 10 years."Our 12 years of labour is expected to bear fruit this June. Preparation for the June launch of GSLV Mk III rocket carrying communication satellite GSAT-19 is on at Sriharikota," K. Sivan, Director, Vikram Sarabhai Space Centre (VSSC), told news agency IANS.The notable aspect of this rocket is that the main and bigger cryogenic engine has been developed within India, said scientists at the Indian Space Research Organization or ISRO.The rocket was originally meant to fly at the end of the month. "As this is a new rocket, we want to carry out extensive tests and hence there has been a slight change in the launch schedule," Mr Sivan said.According to him, the GSLV Mk-III will make its maiden voyage during the first week of June."The rocket's design carrying capacity is four tonnes. The payload will be gradually increased in the future flights of the GSLV Mk-III," Sivan said.The satellite that it will put into orbit weighs 3.2 tonnes and will the heaviest to be lifted by an Indian rocket.

India presently has two rockets - the Polar Satellite Launch Vehicle (PSLV) and GSLV-Mk II - with a lift-off mass of 415 tonnes and a carrying capacity of 2.5 tonnes.Earlier this month, the GSLV-Mk 11 was used to launch a communications satellite that Prime Minister Narendra Modi has gifted for sharing to neighbours in South Asia. The South Asia Satellite will offer participating countries television services and communications technology for bank ATMs and e-governance, and may even serve as a backup for cellular networks, especially in places where the terrestrial connectivity is weak.