Chennai, May 17 -- The 24/25-hr countdown for the Sunday launch of PSLV-C61/EOS-09 mission that would enhance earth observation capabilities and provide high-resolution radar imagery, especially of India's border regions, began on Saturday morning. ISRO Sources confirmed to UNI that countdown has began. Whether it is 24 hrs of 25 hrs will be updated, the sources said. This is ISRO's 101st mission. The four-stage 44.5 m tall PSLV-C61, with a lift of mass of 321 tonnes, in its 63rd flight, will take off from the First Launch Pad at 0559 hrs on Sunday morning from the spaceport of Sriharikota, carrying the earth observation satellite EOS-09, weighing 1,692.24 kg. Sources said the countdown began this morning, during which propellant filling ...