Chennai, Nov 3 (IANS): The countdown for the India's ambitious Rs.430-crore Mars Orbiter Mission (MOM) began Sunday 6.08 a.m. at Sriharikota rocket port in Andhra Pradesh, a space agency official said.

The countdown to the flight of Indian rocket Polar Satellite Launch Vehicle (PSLV-C25) will be for 56.30 hours which is expected to blast off at 2.38 p.m. Tuesday, said an Indian Space Research Organisation (ISRO) official who did not wish to be named.

On Saturday, all the pre-countdown activities were carried out after ISRO's Launch Authorisation Board (LAB) gave it the green signal for the rocket's flight Nov 1 from Sriharikota, around 80 km from here.

According to ISRO, the MOM objectives are two fold -- technological and scientific.

The technological objectives include design and realisation of Mars orbiter with a capability to survive and perform Earth bound manoeuvres, cruise phase of 300 days, Mars orbit insertion/capture, and on-orbit phase around Mars.

It will also enable deep space communication, navigation, mission planning and management and incorporate autonomous features to handle contingency situations.

The scientific mission will be to explore the Mars surface features, morphology, mineralogy and Martian atmosphere by indigenous scientific instruments.