GSAT-18
Indian communications satellite
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GSAT-18 is an Indian communications satellite. Built by ISRO and operated by INSAT, it carries 24 C-band, 12 extended C-band, and 12 Ku-band transponders.As of 2025, 6 transponders in the spacecraft are kept in idle, as GSAT-14 covers their spectrum.they are expected to be online in early 2027.[5]
| |
| Mission type | Communications |
|---|---|
| Operator | INSAT |
| COSPAR ID | 2016-060A |
| SATCAT no. | 41793 |
| Website | GSAT-18 |
| Mission duration | Planned: 15 years Elapsed: 9 years, 5 months, 10 days |
| Spacecraft properties | |
| Bus | I-3K[1] |
| Manufacturer | ISRO Satellite Centre Space Applications Centre |
| Launch mass | 3,404 kg (7,505 lb)[2] |
| Dry mass | 1,480 kg (3,263 lb)[2] |
| Power | 6,474 watts[2] |
| Start of mission | |
| Launch date | 5 October 2016, ≈20:30 UTC[3] |
| Rocket | Ariane 5 ECA, VA-231[1] |
| Launch site | Guiana Space Centre ELA-3[1] |
| Contractor | Arianespace[1] |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Geostationary |
| Longitude | 74° E |
| Perigee altitude | 35,750 km (22,214 mi) |
| Apogee altitude | 35,822 km (22,259 mi) |
| Inclination | 0.0616° |
| Epoch | 11 June 2017 01:46:00 UTC[4] |
| Transponders | |
| Band | 24 × C band 12 × extended C band 12 × Ku band 2 × Ku beacon |
The satellite was launched on 5 October 2016 at approximately 20:30 UTC aboard an Ariane 5 ECA rocket from the Guiana Space Centre in Kourou, French Guiana.[3][6] The launch vehicle inserted the satellite into a geosynchronous transfer orbit, and once in service it will occupy the orbital slot at 74° East longitude.[1][7] The total cost of the satellite and launch services was about US$153 million.[8]
GSAT-18 was originally scheduled to launch on 12 July 2016 alongside Japan's Superbird-8 satellite, but a shipping mishap which damaged Superbird-8 forced a delay in the launch schedule.[9][10] Arianespace later paired GSAT-18 with Australia's Sky Muster II for a 4 October 2016 launch.[11] The launch was delayed 24 hours to 5 October due to excessively high crosswinds at the launch site.[12]
Orbit raising and station keeping
Orbit raising operations were made using an on-board LAM and chemical thrusters[2] to place the satellite in the intended geostationary orbital slot.
| Op # | Date/ Time (UTC) |
LAM burn time | Height achieved | Inclination achieved |
Orbital period | References | |
|---|---|---|---|---|---|---|---|
| Apogee | Perigee | ||||||
| 1 | 6 October 2016 10:16 | 6040.6 sec | 35,802 km (22,246 mi) | 14,843 km (9,223 mi) | 1.325° | 15 hrs, 36 mins | [13] |
| 2 | 8 October 2016 05:59 | - | 35,840 km (22,270 mi) | 32,518 km (20,206 mi) | 0.129° | 22 hrs, 34 mins | [14] |
| 3 | 9 October 2016 04:51 | 256.17 sec | 35,802 km (22,246 mi) | 35,294 km (21,931 mi) | 0.136° | 23 hrs, 44 mins | [15][16] |
