JacobJamison9 at 03:47, 19 July 2025

2025-07-19T03:47:09Z

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{{Short description|Indian communications satellite}}
{{Infobox spaceflight |auto=all
| name = GSAT-18
| image = File:GSAT-18.png
| mission_type = [[Communications satellite|Communications]]
| operator = [[Indian National Satellite System|INSAT]]
| COSPAR_ID = 2016-060A
| SATCAT = 41793
| website = [http://isro.gov.in/Spacecraft/gsat-18 GSAT-18]
| mission_duration = Planned: 15 years Elapsed: {{time interval|5 October 2016 20:30|show=ymd|sep=,}}

| spacecraft_bus = [[I-3K]]<ref name="AR2016">{{cite web |url=http://www.isro.gov.in/sites/default/files/article-files/right-to-information/annual_report-15-16.pdf |title=Annual Report 2015-2016 |publisher=Indian Space Research Organisation |format=PDF |page=28 |date=December 2015 |url-status=dead |archive-url=https://web.archive.org/web/20160705060034/http://www.isro.gov.in/sites/default/files/article-files/right-to-information/annual_report-15-16.pdf |archive-date=2016-07-05 }}</ref>
| manufacturer = [[Indian Space Research Organisation Satellite Centre|ISRO Satellite Centre]] [[Space Applications Centre]]
| launch_mass = {{convert|3404|kg|lb|abbr=on}}<ref name="brochure">{{cite web |url=http://www.isro.gov.in/sites/default/files/flipping_book/GSAT-18/files/assets/common/downloads/GSAT%2018%20-%20Brochure.pdf |title=GSAT-18 |publisher=Indian Space Research Organisation |access-date=2017-06-12 |archive-date=2016-12-13 |archive-url=https://web.archive.org/web/20161213050343/http://www.isro.gov.in/sites/default/files/flipping_book/GSAT-18/files/assets/common/downloads/GSAT%2018%20-%20Brochure.pdf |url-status=dead }}</ref>
| dry_mass = {{convert|1480|kg|lb|0|abbr=on}}<ref name="brochure" />
| dimensions =
| power = 6,474 watts<ref name="brochure" />

| launch_date = {{start-date|5 October 2016}}, ≈20:30 [[UTC]]<ref name="nasasf20161005">{{cite news |url=https://www.nasaspaceflight.com/2016/10/ariane-5-sky-muster-ii-gsat-18-launch/ |title=Ariane 5 launches Sky Muster II and GSAT-18 |work=NASA Spaceflight |first=Chris |last=Bergin |date=5 October 2016 |access-date=6 October 2016}}</ref>
| launch_rocket = [[Ariane 5 ECA]], VA-231<ref name="AR2016"/>
| launch_site = [[Guiana Space Centre]] [[ELA-3]]<ref name="AR2016"/>
| launch_contractor = [[Arianespace]]<ref name="AR2016"/>
| entered_service = 

| orbit_reference = [[Geocentric orbit|Geocentric]]
| orbit_regime = [[Geostationary orbit|Geostationary]]
| orbit_longitude = 74° E
| orbit_periapsis = {{convert|35750|km|mi|0|abbr=on}}
| orbit_apoapsis = {{convert|35822|km|mi|0|abbr=on}}
| orbit_inclination = 0.0616°
| orbit_epoch = 11 June 2017 01:46:00 UTC<ref name="heavens-above">{{cite web |url=http://heavens-above.com/orbit.aspx?satid=41793 |title=GSAT-18 - Orbit |work=Heavens-Above |date=11 June 2017 |access-date=12 June 2017}}</ref>
| apsis = gee

| trans_band = 24 × [[C band (IEEE)|C band]] 12 × extended C band 12 × [[Ku band|Ku band]] 2 × Ku beacon

| programme = [[GSAT]]
| previous_mission = [[GSAT-15]]
| next_mission = [[GSAT-9]]
}}

'''GSAT-18''' is an Indian communications satellite. Built by [[ISRO]] and operated by [[INSAT]], it carries 24 [[C band (IEEE)|C-band]], 12 extended C-band, and 12 [[Ku band|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.<ref>{{Cite web |date=2025-03-27 |title=GSAT-18 cost: PAC tells space dept to be economically prudent |url=https://indianexpress.com/article/india/gsat-18-cost-pac-tells-space-dept-to-be-economically-prudent-9908053/ |access-date=2025-06-09 |website=The Indian Express |language=en}}</ref>

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.<ref name="nasasf20161005" /><ref name="busistan20161006">{{cite news |url=http://www.business-standard.com/article/pti-stories/india-s-communication-satellite-gsat-18-launched-successfully-116100600381_1.html |title=India's communication satellite GSAT-18 launched successfully |work=Business Standard |agency=Press Trust of India |date=6 October 2016 |access-date=6 October 2016}}</ref> 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.<ref name="AR2016"/><ref name="sfn_ls">{{cite web|url=https://spaceflightnow.com/launch-schedule/ |title=Launch Schedule |work=Spaceflight Now |date=4 October 2016 |archive-url=https://web.archive.org/web/20161005082318/http://spaceflightnow.com/launch-schedule/ |archive-date=5 October 2016 |url-status=dead }}</ref> The total cost of the satellite and launch services was about {{US$|153 million}}.<ref name="sfnow20161005">{{cite news |url=https://spaceflightnow.com/2016/10/05/ariane-5-goes-on-test-run-after-launching-two-satellites/ |title=Ariane 5 goes on test run after launching two satellites |work=Spaceflight Now |first=Stephen |last=Clark |date=5 October 2016 |access-date=6 October 2016}}</ref>

GSAT-18 was originally scheduled to launch on 12 July 2016 alongside Japan's [[Superbird-B3|Superbird-8]] satellite, but a shipping mishap which damaged Superbird-8 forced a delay in the launch schedule.<ref name="sn20160620">{{cite news |url=http://spacenews.com/japans-dsn-1-military-communications-satellite-damaged-during-transport-to-launch-base/ |title=Japan's DSN-1 military communications satellite damaged during transport to launch base |work=Space News |first=Peter B. |last=de Selding |date=20 June 2016 |access-date=10 September 2016}}</ref><ref name="hindu20160710">{{cite news |url=http://www.thehindu.com/todays-paper/tp-national/deferred-gsat18-awaits-october-launch-at-kourou/article8829906.ece |title=Deferred GSAT-18 awaits October launch at Kourou |work=The Hindu |first=Madhumathi |last=D. S. |date=10 July 2016 |access-date=10 September 2016}}</ref> [[Arianespace]] later paired GSAT-18 with Australia's [[Sky Muster II]] for a 4 October 2016 launch.<ref>{{cite web |url=http://www.arianespace.com/mission-update/sky-muster-satellite-delivered-for-flight-va231/ |title=Sky Muster II comes to French Guiana for launch on Ariane 5 |publisher=Arianespace |date=31 August 2016 |access-date=10 September 2016}}</ref> The launch was delayed 24 hours to 5 October due to excessively high [[crosswind]]s at the launch site.<ref name="hindustan20161005">{{cite news |url=http://www.hindustantimes.com/india-news/bad-winds-delay-isro-s-launch-of-communications-satellite-gsat-18-by-a-day/story-edkq5GVmwYVTBl1t2xxp3M.html |title=Bad weather delays Isro's launch of communications satellite GSAT-18 |work=Hindustan Times |agency=Press Trust of India |date=5 October 2016 |access-date=5 October 2016}}</ref>

== Orbit raising and station keeping ==
Orbit raising operations were made using an on-board [[Liquid Apogee Motor|LAM]] and chemical thrusters<ref name="brochure" /> to place the satellite in the intended geostationary orbital slot.

{| cellpadding="2" style="margin:0 auto; text-align:center;" class="wikitable sortable"
|-
! rowspan="2"| Op #
! rowspan="2"| Date/ Time (UTC)
! rowspan="2"| LAM burn time
! colspan="2"| Height achieved
! rowspan="2"| Inclination achieved
! rowspan="2"| Orbital period
! rowspan="2"| References
|-
! Apogee || Perigee
|-
| 1 || 6 October 2016 10:16 || 6040.6 sec || {{convert|35802|km|mi|abbr=on}} || {{convert|14843|km|mi|abbr=on}} || 1.325° || 15 hrs, 36 mins || <ref>{{cite web |url=http://www.isro.gov.in/update/07-oct-2016/first-orbit-raising-manoeuvre-of-gsat-18-has-been-successffully-carried-out-lam |title=The first orbit raising manoeuvre... |publisher=Indian Space Research Organisation |date=7 October 2016 |access-date=12 June 2017 |archive-date=23 May 2017 |archive-url=https://web.archive.org/web/20170523164711/http://isro.gov.in/update/07-oct-2016/first-orbit-raising-manoeuvre-of-gsat-18-has-been-successffully-carried-out-lam |url-status=dead }}</ref>
|-
| 2 || 8 October 2016 05:59 || - || {{convert|35840|km|mi|abbr=on}} || {{convert|32518|km|mi|abbr=on}} || 0.129° || 22 hrs, 34 mins || <ref>{{cite web |url=http://www.isro.gov.in/update/08-oct-2016/second-orbit-raising-manoeuvre-of-gsat-18-has-been-successfully-carried-out-lam |title=The second orbit raising manoeuvre... |publisher=Indian Space Research Organisation |date=8 October 2016 |access-date=12 June 2017 |archive-date=23 May 2017 |archive-url=https://web.archive.org/web/20170523161611/http://isro.gov.in/update/08-oct-2016/second-orbit-raising-manoeuvre-of-gsat-18-has-been-successfully-carried-out-lam |url-status=dead }}</ref>
|-
| 3 || 9 October 2016 04:51 || 256.17 sec || {{convert|35802|km|mi|abbr=on}} || {{convert|35294|km|mi|abbr=on}} || 0.136° || 23 hrs, 44 mins || <ref>{{cite web |url=http://www.isro.gov.in/update/09-oct-2016/third-lam-firing-of-gsat-18-25617-sec-has-been-successfully-completed-october-9 |title=Third LAM firing of GSAT-18... |publisher=Indian Space Research Organisation |date=9 October 2016 |access-date=12 June 2017 |archive-date=23 May 2017 |archive-url=https://web.archive.org/web/20170523155756/http://isro.gov.in/update/09-oct-2016/third-lam-firing-of-gsat-18-25617-sec-has-been-successfully-completed-october-9 |url-status=dead }}</ref><ref>{{cite web |url=http://www.isro.gov.in/update/09-oct-2016/orbit-determination-results-third-lam-firing-are-apogee-x-perigee-height-was |title=Orbit Determination results... |publisher=Indian Space Research Organisation |date=9 October 2016 |access-date=12 June 2017 |archive-date=24 May 2017 |archive-url=https://web.archive.org/web/20170524210142/http://isro.gov.in/update/09-oct-2016/orbit-determination-results-third-lam-firing-are-apogee-x-perigee-height-was |url-status=dead }}</ref>
|-
|}

== References ==
{{Portal|Spaceflight}}
{{reflist}}

{{GSAT Satellites}}
{{Indian spacecraft}}
{{Orbital launches in 2016}}

[[Category:GSAT satellites]]
[[Category:Spacecraft launched by India in 2016]]
[[Category:Ariane commercial payloads]]

GSAT-18 - Revision history

JacobJamison9 at 03:47, 19 July 2025