GSAT-7

GSAT-7
Mission type	Communication
Operator	ISRO
COSPAR ID	2013-044B
SATCAT no.	39234
Mission duration	Planned: 7 years; Elapsed: 11 years, 3 months, 20 days
Spacecraft properties
Bus	I-2K
Manufacturer	ISRO Satellite Centre; Space Applications Centre
Launch mass	2,650 kilograms (5,840 lb)
Power	3 kilowatts
Start of mission
Launch date	29 August 2013, 20:30 UTC
Rocket	Ariane 5ECA
Launch site	Kourou ELA-3
Contractor	Arianespace
Orbital parameters
Reference system	Geocentric
Regime	Geostationary
Longitude	74° East
Perigee altitude	35,779 kilometres (22,232 mi)
Apogee altitude	35,806 kilometres (22,249 mi)
Inclination	0.06 degrees
Period	23.93 hours
Epoch	7 November 2013, 23:12:49 UTC
Transponders
Band	UHF; C-band; Ku-band
	GSAT ← GSAT-10 GSAT-14 →

GSAT-7 or INSAT-4F is a multi-band military communications satellite developed by the Indian Space Research Organisation. The Indian Navy is the user of the multi-band communication spacecraft, which has been operational since September 2013. According to defense experts, the satellite will enable the navy to extend its blue water capabilities and stop relying on foreign satellites like Inmarsat, which provide communication services to its ships.^[2]^[3]

Satellite

GSAT-7, the multi-band communication satellite named Rukmini^[4] carries the payloads in UHF, C band and K_u band. It is the first dedicated military communication satellite (unlike earlier dual use satellites) built by ISRO that will provide services to the Indian Armed Forces^[5] with the main user being the Indian Navy.^[6] Its procured launch cost has been put at ₹480 crore, with the satellite costing ₹185 crore.^[7] Cost of whole project per Memorandum of Understanding with ISRO was ₹950 crores.^[8]

The multiple-band spacecraft will be used exclusively by the Navy to shore up secure, real-time communications among its warships, submarines, aircraft and land systems. GSAT-7/ INSAT-4F is said to significantly improve the country's naval operations around the world.

GSAT 7 satellite carrying payloads operating in UHF, S, C and Ku bands, had a lift-off mass of 2,650 kilograms (5,840 lb) and is based on ISRO's 2,000 kilograms (4,400 lb) class satellite bus I-2K with some new technological elements, including the antennae.^[9] After a flight of almost 34 minutes, the satellite was injected into a geosynchronous transfer orbit (GTO) of 249-kilometre (155 mi) perigee, 35,929-kilometre (22,325 mi) apogee and an inclination of 3.5 degree with respect to the equator.^[10]

ISRO launched a second satellite, GSAT-7A for Indian Air Force on 19 December 2018 on its Geosynchronous Satellite Launch Vehicle (GSLV-F11).^[11]^[12]

Launch

The satellite was launched early on 30 August 2013 atop an Ariane 5 ECA rocket from Kourou, French Guiana.^[13]

India's first dedicated military satellite was put into a geosynchronous orbit, about 36,000 kilometres (22,000 mi) above Earth, five days after it was launched after three orbit-raising manoeuvres from ISRO's Master Control Facility at Hassan in Karnataka.^[14] The 2.5-tonne spacecraft's antennae, including the ultra high frequency Helix antenna were deployed before it was stabilised on its three-axis in the orbit.^[15] All of the on-board transponders were switched on successfully on September 18, 2013^[16]

Capability

Rukmini will provide networking capabilities to various Indian Naval assets. During Theater-level Readiness and Operational Exercise (Tropex) in the Bay of Bengal in 2014, Rukmini was able to network about 60 ships and 75 aircraft seamlessly. Rukmini has a nearly 2,000 nautical mile 'footprint' over the Indian Ocean Region.^[17]