Maarg Manthan · Topic 16.26

Rukmini (GSAT-7) Naval Communication Satellite

Science & Technology › Defence Technology and Missile Systems · Topic 16.26

Rukmini is the popular name of GSAT-7, India's first dedicated military communication satellite, built by the Indian Space Research Organisation for the Indian Navy and launched on 29 August 2013 by an Ariane-5 rocket from Kourou in French Guiana. Weighing about 2,650 kg, it is a geostationary satellite that carries transponders in the UHF, S, C and Ku bands and gives coverage over a large part of the Indian Ocean Region, up to about 2,000 nautical miles from the Indian coast. It lets Navy ships, submarines, aircraft and shore stations talk to one another in real time, which makes network centric operations possible. GSAT-7A, the Angry Bird, for the Air Force and Army followed in December 2018, and GSAT-7R, also called CMS-03, was launched in November 2025.

5 min read · UPSC Prelims · Science & Technology · Defence Technology and Missile Systems

At a Glance

User Indian Navy
Launch 29 August 2013, Ariane-5
Orbit Geostationary
Coverage Indian Ocean Region, ~2,000 nm
Successors GSAT-7A (2018), GSAT-7R (2025)
Exam link UPSC Prelims, Science & Technology: Defence Technology and Missile Systems

Where Does It Fit?

This is the last topic of the defence macro. It connects the naval platforms with space technology, since modern fleets and submarines depend on satellites for communication and coordination. Previous topic: Air Independent Propulsion Technology for Submarines. Next topic: S&T Policy Resolutions of 1958, 1983, 2003 and 2013.

What Is GSAT-7 and What Can It Do?

Feature	Details
Name	GSAT-7, nicknamed Rukmini. It was the first satellite dedicated to the Indian Navy
Launch	29 August 2013 by Ariane-5 VA-214 from Kourou, French Guiana, since India’s own launcher could not lift the heavy satellite then
Mass and orbit	About 2,650 kg at launch, placed in geostationary orbit at 74 degrees east
Payload	Transponders in UHF, S band, C band and Ku band, giving voice, data and video links
Coverage	About 2,000 nautical miles, covering the Indian Ocean Region from the Red Sea, Arabian Sea…">Horn of Africa to the Malacca Strait
Users	Warships, submarines, maritime patrol aircraft, shore stations and the Navy’s network
Replacement of older links	Replaced the slower leased satellite capacity and the old short range radio links

Why Does It Matter and What Followed?

Network centric operations: ships and aircraft share a common picture over secure links
Beyond line of sight: ships far from shore are connected in real time
Independence: reduces dependence on commercial and foreign satellite capacity
GSAT-7A: launched on 19 December 2018 by GSLV-F11, for the Air Force and Army in the Ku band, nicknamed Angry Bird; it links drones, ground stations and airborne warning aircraft
GSAT-7R / CMS-03: a heavy replacement naval communication satellite of about 4,400 kg launched in November 2025 by LVM3 from Sriharikota, whose details should be checked
GSAT-6 / GSAT-6A: S band satellites with military use
Defence Space Agency: created in 2019 to coordinate military space assets
Other military satellites: Cartosat series for imaging, RISAT radar imaging satellites and EMISAT, along with the ongoing plan for dozens of military satellites under SBS-3

What Else Should You Remember?

Geostationary orbit: 35,786 km above the equator, where a satellite stays above one point
UHF band: used for mobile and secure naval communication
Ku band: high throughput, used for large data and video
Transponder: receives, amplifies and retransmits signals
Nautical mile: 1.852 km
Name Rukmini: after the consort of Lord Krishna, chosen for the satellite
Ariane: European launcher operated by Arianespace
GSLV and LVM3: Indian launchers that now put heavy satellites into orbit
Space-based surveillance: the SBS-3 programme plans 52 surveillance satellites by 2029, reported by media
NavIC: India’s regional navigation system, also used by the military
Anti-satellite test: Mission Shakti in March 2019 showed India’s ASAT capability
Space debris: military activity adds debris, a concern
Satellite vulnerability: jamming and cyber attacks threaten links
Link: the reach of space tech is in Space Technology Innovations: Nanosatellites, Electric Propulsion, Satellite-Based Internet
Link to ships: fleets that use it are in Frigates, Destroyers and Aircraft Carriers of the Indian Navy
Link to submarines: submarine communication needs special links, as in Indian Submarines and Naval Ships: Project 75, INS Kalvari, INS Kolkata, INS Kiltan
Caution: satellite details for classified military use are only partly public
Satellite design life: military satellites are designed to work for about 8 to 15 years
Redundancy: several satellites and ground stations give resilience if one fails
ISRO role: ISRO builds and launches military satellites for the services, which operate them
Spectrum use: military bands are protected, with coordination under the International Telecommunication Union
Satellite communications on ships: ships carry antennas to track the geostationary satellite
Submarine limit: submarines under water cannot use the satellite and rely on very low frequency radio while submerged

Why Does It Matter for the Exam?

User and year: Navy, 2013
Launcher: Ariane-5 from Kourou
Bands: UHF, S, C, Ku
Current affairs link: GSAT-7R and military satellite plans
Common errors: calling GSAT-7 an Air Force satellite or launching it on a PSLV

As an analytical point, military use of space is now central to naval power in the Indian Ocean. Dedicated satellites give secure and assured links, and growth in numbers and in resilience against jamming and attack is needed.

Why Is This Topic Important?

Satellite GSAT-7
Role Network centric
Follow-ups GSAT-7A, 7R

What Came Next?

The next macro covers science and technology policy. Next topic: S&T Policy Resolutions of 1958, 1983, 2003 and 2013.

Key People and Terms

GSAT Geosynchronous satellite
GEO Geostationary orbit
Transponder Signal relay unit
Network centric warfare Sharing data across forces
UHF Ultra high frequency
Ku band 12 to 18 GHz band

Exam Corner

Points to Remember

GSAT-7 launched 29 August 2013, Ariane-5.
GSAT-7A launched December 2018 on GSLV-F11.
Coverage about 2,000 nautical miles.
Bands: UHF, S, C, Ku.
GSAT-7R launched November 2025.

Do Not Confuse With

GSAT-7 and GSAT-7A Navy versus Air Force and Army
GSAT-7 and NavIC Communication versus navigation
Rukmini and Angry Bird Naval versus Air Force nickname

Memory Hook

Rukmini for the Navy, Angry Bird for the Air Force; GEO eyes over the Indian Ocean.

Mains Angle

Questions ask for user, year and nickname. These points help.

Role Naval links
Follow-ups Series
Space and defence Link

A Question You May Face

An original practice question, not a past paper question.

“Explain the role of dedicated military communication satellites like GSAT-7 in India’s maritime security.”

How to Answer

Satellite GSAT-7.
Role Network.
Series 7A, 7R.
Challenges Jamming.

GS Relevance

Prelims: GSAT-7 user, launch, bands, coverage, GSAT-7A. GS Paper 3: space technology, defence, maritime security.

Frequently Asked Questions

What is GSAT-7?

GSAT-7, nicknamed Rukmini, is India's first dedicated military communication satellite, built by ISRO for the Indian Navy and launched on 29 August 2013 on an Ariane-5 rocket from Kourou. It is a geostationary satellite with UHF, S, C and Ku band transponders covering the Indian Ocean Region.

What is the coverage of Rukmini?

GSAT-7 gives coverage of about 2,000 nautical miles from the Indian coast, which includes most of the Indian Ocean Region. It links warships, submarines, aircraft and shore stations to one another in real time, so the Navy can fight as a network and not as separate units.

What is GSAT-7A?

GSAT-7A, nicknamed Angry Bird, is a military communication satellite launched on 19 December 2018 by the GSLV-F11 rocket. It serves the Indian Air Force and the Army, linking ground radar stations, airbases, airborne warning aircraft and unmanned aerial vehicles through the Ku band.

What is GSAT-7R?

GSAT-7R, also known as CMS-03, is a newer, heavier naval communication satellite launched in November 2025 by an LVM3 rocket from Sriharikota to replace and expand the capacity of Rukmini. Its exact details are only partly public, so they should be confirmed from ISRO releases.

Why was GSAT-7 launched on a foreign rocket?

When GSAT-7 was launched in 2013, its mass of about 2.65 tonnes was beyond the capacity of India's operational rockets, as GSLV Mk III was not ready and GSLV Mk II had limited capacity, so ISRO used the Ariane-5 of Arianespace. Later heavy satellites have been launched on Indian rockets.

PYQ Practice — Statement Analysis

1 GSAT-7 is a communication satellite for the Indian Navy.

True

Nicknamed Rukmini.

2 GSAT-7 was launched on the PSLV.

False

On an Ariane-5.

3 GSAT-7A is nicknamed Angry Bird.