Sriharikota, 2 Nov

ISRO will launch its heaviest satellite onboard an Indian rocket on Sunday, when the heavylift LVM3M5 vehicle will carry a 4,410 kg communication satellite to a Geosynchronous Transfer Orbit (GTO).

ISRO's CMS-03 satellite is all set to be launched from this space port and the countdown is "progressing smoothly", ISROofficials said on Sunday.

This will be the heaviest satellite to be launched from Indian soil and into a GTO, the space agency said. Also, this is ISRO's heaviest satellite to be launched using a home-made rocket.

The Bengaluru-headquartered space agency has been utilising launch vehicles provided by France-headquartered Arianespace for launching over 4,000 kg heavy satellites from French Guiana. ISRO had previously launched its heaviest communication satellite GSAT-11 on 5 December, 2018 from Kourou launch base, French Guiana by Ariane-5 VA-246 rocket. It weighed about 5,854 kg.

The CMS-03 satellite will travel onboard the 43.5 metre tall LVM3-M5 rocket, dubbed as 'Baahubali' for its heavylift capability.

The space agency said that the launch vehicle has been fully assembled and integrated with the spacecraft and it has been moved to the second launch pad here for taking up pre-launch operations.

In a social media update on Sunday, ISRO said, "Launch Day for LVM3M5. India's heavy-lift rocket (to) launch CMS03 today at 17.26" hrs.

"The 24 hour Countdown (which began on Saturday at 5.26 pm) is progressing smoothly", an ISRO official told PTI on Sunday.

LVM-3 (Launch Vehicle Mark-3) is the new heavy lift launch vehicle of ISRO and is used for placing 4,000 kg spacecraft in the GTO in a cost-effective manner, ISRO said.

While it is being claimed that satellite's applications include military surveillance, there has been no official word from ISRO on the matter.

"CMS-03 is a multi-band communication satellite that will provide services over a wide oceanic region including the Indian landmass," ISRO said.

This three stage launch vehicle with two solid motor strap-ons (S200), a liquid propellant core stage (L110) and a cryogenic stage (C25) gives ISRO full self-reliance in launching heavier communication satellites that weigh up to 4,000 kg in GTO.

LVM3 is also termed by ISRO scientists as Geosynchronous Satellite Launch Vehicle (GSLV) Mk III.

It is the fifth operational flight, ISRO said.

The previous mission of LVM-3 rocket was the successful launch of Chandrayaan-3 mission, wherein, India became the first country to land successfully near the lunar South pole in 2023, according to ISRO.

The LVM3 rocket is capable to carry payload to GTO weighing 4,000 kg and for Low Earth Orbit payloads of 8,000 kg with its powerful cryogenic stage.

The two S200 solid rocket boosters located on the sides of the rocket provide the thrust required for lift off. The S200 boosters aredeveloped at Vikram Sarabhai Space Centre, Thiruvananthapuram.

The third stage is L110 Liquid Stage and is powered by two Vikas engines designed and developed at the Liquid Propulsion Systems Centre.