The countdown for the prestigious Mars Orbiter Mission spacecraft began at 06.08 hours today.
The spacecraft will be on board PSLV-C25, which will blast off from the Satish Dhawan Space Centre SHAR, Sriharikota in Andhra Pradesh, at 14.38 hours on Tuesday.
The pre-count down activities of the Rs 450-crore launch mission commenced at 08:45 hours on Saturday.
The launch rehearsal of PSLV-C25/Mars Orbiter Mission was completed successfully on Thursday afternoon. The vehicle systems powered and health was normal during the rehearsal, the ISRO said.
The rehearsal simulated the entire procedure of the final eight-hour countdown, right up to the ignition.
Once launched, the spacecraft would go around the earth for about 25 days before embarking on November 30 for a 300-day voyage to orbit Mars, where it is planned to reach in September 2014.