Vastavam web: ISRO is preparing to launch the most heaviest 640 tonnes GSLV Mark-III racket satellite launch vehicle in june. It is the heaviest racket vehicle in the history of ISRO. The notable aspect of this rocket is that the main and bigger cryogenic engine has been developed by our native scientists and launching such a heavy racket is for the first time in our country. K.Sivam, the director of Vikram Sarabai Space Centre told, GSLV Mark-III will be tested from Sriharikota, it is the heaviest racket vehicle, it can give service for 15 years. The success of this satellite can make it feasible to launch heavy rackets into space, said The Director Sivan.