Chennai, Nov 13 (IANS): The countdown for the Wednesday evening launch of India's heaviest rocket GSLV-Mk III carrying communication satellite GSAT-29 is in progress at the rocketport in Sriharikota, the Indian space agency said.

According to Indian Space Research Organisation (ISRO), the Geosynchronous Satellite Launch Vehicle (GSLV-Mk III) standing 43.4 metre tall and weighing 640 ton is expected to blast off at 5.08 p.m. on Wednesday.

The countdown for the rocket launch began at 2.50 p.m. on Tuesday.

The rocket carrying the 3,423 kg GSAT-29 will sling it into Geo Transfer Orbit (GTO) just over 16 minutes into its flight.

Then the satellite will be lifted to the final Geo Stationary Orbit (GSO) at a height of 36,000 km from the earth.

With a design life of 10 years, the GSAT-29 satellite carries Ka/Ku-band high throughput communication transponders intended to meet the communication requirements of users including those in remote areas.

In addition, several new technologies such as Q/V-band payload, data transmission through optical communication link will be demonstrated. This will help in realising future advanced satellites, ISRO said.