Isro launches heaviest CommSat from India, to boost Navy’s reach across IOR

Isro on Sunday launched the 4,410kg CMS-03 or the Gsat-7R, a communication satellite that will enhance telecommunication coverage across the strategic Indian Ocean Region (IOR) for the Indian Navy.The launch of the heaviest communication satellite from Indian soil onboard LVM3-M5 from the second launch pad at the Satish Dhawan Space Centre, Sriharikota, marked the fifth operational flight of LVM3. The mission also saw a new in-orbit experiment — a successful re-ignition of the cryogenic upper stage About 16 minutes after lift-off, LVM-3 placed Gsat-7R into a sub-Geosynchronous Transfer Orbit (sub-GTO) with a perigee (farthest point from Earth) of only 26,700km.

The multi-band communication satellite will provide services across a wide oceanic region, including the Indian landmass, and can also offer civilian applications.

Boost To Navy Comms

Gsat-7R is designed to replace Gsat-7 (Rukmini), which was launched in 2013 is primarily dedicated to the Indian Navy, while Isro had launched another satellite from the same family — Gsat-7A — for the Indian Air Force. As per the Navy, Gsat-7R includes many indigenous state-of-the-art components developed specifically to meet its operational requirements.

The Navy said that in an era of complex security challenges, the satellite represents its determination to protect the nation’s maritime interests leveraging advanced technology through self-reliance.“Gsat-7R will provide robust telecommunication coverage across the Indian Ocean Region. Its payload includes transponders capable of supporting voice, data, and video links over multiple communication bands.

This satellite will significantly enhance connectivity with high-capacity bandwidth, enabling seamless and secure communication links between ships, aircraft, submarines, and Maritime Operations Centres,” the Navy added.

UR Rao Satellite Centre director M Sankaran said the satellite carries advanced payloads in multiple frequency bands — UHF, S-band, C-band and Ku-band — and includes several indigenous technologies such as a 1,200-litre propulsion tank and collapsible antenna systems.

“All systems are functioning normally. The satellite is healthy, and all isolation valves have opened as expected,” he said.

Mass Challenge

As per Isro’s own description of LVM-3, its capacity to GTO (around 36,000km perigee) is only 4,000 tonnes. Until Sunday, all satellites Isro put into GTO using an LVM-3 have weighed under 4,000kg —anything heavier than that has been launched using foreign launch vehicles. Isro chairman V Narayanan said: “...The vehicle performance was enhanced to increase its payload capacity by 10%.

The satellite has a life of 15 years and carries a host of new technologies. We accomplished this mission despite difficult weather conditions.” While the satellite is to be placed in GTO, the initial intended parking orbit, given LVM-3’s capacity, was not the typical GTO (170km x 36,000km). The LVM-3 placed the satellite into a sub-GTO.“LVM-3 performed beyond its nominal capacity, reaching an elliptical orbit,” Narayanan said, adding that to enhance the payload capacity, several changes were made, including improving thrust of the cryogenic engine, optimising telemetry systems, reducing heat shield’s weight from 245kg to 160kg, and lowering the achieved GTO altitude.The satellite will be moved to its final orbit (a GTO) through a series of orbit-raising manoeuvres carried out by firing the liquid apogee motors (LAMs) on the satellite.

7 Launches Before March

Narayanan, while pointing out that LVM-3’s previous mission had seen the launch of Chandrayaan-3, which eventually saw India become the first to soft-land near the lunar south pole, said Isro has a packed schedule for the remainder of the fiscal.He said seven launches were planned before the end of the financial year, including LVM3-M6 carrying a commercial satellite (US’ Bluebird) in Dec, PSLV-C62 and SSLV-L1 missions with customer payloads, the first industry-built PSLV that will carry a satellite demonstrating 34 new technologies, GSLV-F16 mission, and the first uncrewed Gaganyaan mission.