The GSLV D-6 is the second successful consecutive launch of the GSLV series with indigenous cryogenic upper stage. ISRO had on January 5, 2014 launch GSLV D-5, after a similar attempt failed in 2010.
For the country, ISRO perfecting the cryogenic engine technology is crucial as precious foreign exchange can be saved by launching communication satellites on its own. Currently ISRO flies its heavy communication satellites by European space agency Ariane.
ISRO has already perfected it's Polar Launching Vehicle for launching lighter satellites which has decades of success stories. It has already put 45 foreign satellites of 9 nations into orbit. ISRO is to put 9 satellites in space using PSLV launcher for the United States in 2015-2016.