President Pranab Mukherjee and Prime Minister Narendra Modi today congratulated Indian Space Research Organization, ISRO on PSLV's successful launch of ASTROSAT. In his message to Chairman of ISRO, A.S. Kiran Kumar, President Pranab Mukherjee said, with the successful launch of Astrosat, the nation has become the fourth country in the world to have launched a space observatory, which will be useful in the improved study of celestial objects and the universe. <br/><br/>The President said, the nation is proud of this impressive achievement, which has demonstrated, yet again, India's increasing space capabilities. In a tweet, Mr Modi said, this is one more grand accomplishment for Indian science and the scientists.