GSAT-7

Spacecraft nº:

Indian spacecraft nº: 71

Launch data: Designation  39234 / 13044B Launch date  29 Aug 2013 - 20:30 UT Launch site  Ko, ELA-3 Launch vehicle  Ariane-5ECA (VA215) Mission  Communications Geostationary orbit: Perigee / Apogee  35671 x 35792 km Eccentricity   Inclination  0.0 deg Period  1436.1 min

Spacecraft data: Prime manufacturer  ISRO Platform  I-2K (I-2000) Bus Operator  Indian Navy Mass at launch  2650 kg Dry Mass   kg Basic shape   Dimension (m)   Equipment  UHF, S-band, C-band and Ku-band transponders Solar array  2 deployable solar arrays Stabilization   Propulsion  440 Newton thrust liquid apogee motor DC power  2600 W Design lifetime  9 yrs

GSAT-7 at Kourou Island in French Guiana. Photo Credit: ISRO

Location:

Description:

• GSAT 7 will relay communications between Indian naval vessels and military commanders using UHF, S-band, C-band and Ku-band transponders. Positioned over the equator at 74 degrees longitude, GSAT 7 will cover the Indian subcontinent and neighboring waters. The satellite, also known as INSAT 4F, was the 17th Indian satellite launched by Arianespace.
• The satellite employs the standard 2.5 ton bus platform with power handling capability of around 2600 W and lift off mass of 2,550 kg.
• The Navy will use GSAT-7 to communicate with its submarines, frigates, destroyers and aircraft from its centers on the shore. Initially, the satellite will be used by the IAF and IA also.
  "This is the first time that the ISRO is building a dedicated satellite for the Navy. It is meant for defense requirements. The Navy and other agencies [the Army and the Indian Air Force] will use it for their communication," ISRO sources told.

Mission details:

• An Ariane 5ECA placed two communications satellites in a 238 x 35777 km x 3.5 deg geostationary transfer orbit on Aug 29, 2013. GSAT-7, also known as Insat-4F, will provide communications for the Indian Navy. Eutelsat-25B, also called Es'hail 1, is jointly owned by Eutelsat SA of Paris and Es'hailsat. Es'hailsat is a spinoff of ictQATAR, the Qatari Supreme Council of Information and Communications Technology. The satellite's name means Canopus (the star Alpha Car).
• The EPC 570 core stage flew a -969 x 161 km x 6.5 deg trajectory across the Atlantic and reentered; the ESC-A upper stage made a single burn to the lower inclination transfer orbit. The flight used launch vehicle L570 and the mission was designated VA215.
• On August 31, 2013 the apogee motor was used to place the satellite in an intermediate orbit with the following parameters:
  Perigee : 16803 km, Apogee : 35794 km, Inclination : 0.6 deg, Orbital Period : 16 hr 19 minutes.
• A second apogee motor on September 1, 2013 at 12:44 PM successfully raised its orbit to:
  Perigee : 31789 km, Apogee : 35794 km, Inclination : 0.14 deg, Orbital Period : 22 hr 12 minutes.
• On September 3, 2013, ISRO announced through a press release that GSAT-7 has been successfully placed in a geosynchronous orbit; it would reach its assigned Geostationary orbital slot of 74 degree East longitude within the next 10 days.
• On Sep 10 GSAT-7 was in a 35671 x 35792 km x 0.2 deg drifting east over 73E; Es'hail was in a 35784 x 35788 km x 0.1 deg orbit on station at 31.7E.
• On September 14, 2013, the communication transponders in UHF, S, C and Ku bands were planned to be switched on.
• On September 19, 2013, ISRO announced that all the 11 communication transponders (operating in UHF, S, C and Ku-bands) have been successfully switched on and their performance is found to be normal. GSAT-7 is now positioned at its designated orbital slot of 74 deg East longitude in the geostationary orbit and In Orbit Testing (IOT) of the 11 transponders is in progress.

Satellite tracking: