The countdown for India's ambitious Mars Orbiter Mission began at Sriharikota in Andhra Pradesh this morning. Indian Space Research Organisation (ISRO) conducted a full launch rehearsal for the rocket Polar Satellite Launch Vehicle, PSLV-C25 on Thursday. ISRO Chairman K. Radhakrishnan told reporters that the PSLV-C25 rocket carrying the Mars Orbiter Mission will blast off at 2.38 PM on Tuesday. He said PSLV is a reliabel vehicle