HYLAS-4
{{Short description|Telecommunications satellite}}
{{Infobox spaceflight
| name = HYLAS-4
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| operator = Avanti Communications
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| spacecraft =
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| spacecraft_bus = Star-3 Bus
| manufacturer = Orbital ATK
| launch_mass = 4,000 kg
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| launch_date = 5 April 2018, 21:34 UTC
| launch_rocket = Ariane 5 flight VA242
| launch_site = ELA-3, Guiana Space Centre
| launch_contractor = Arianespace
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| orbit_eccentricity = circular{{Cite news|url=https://www.space.com/29222-geosynchronous-orbit.html|title=What Is a Geosynchronous Orbit?|work=Space.com|access-date=2018-03-03}}
| orbit_inclination =
| orbit_period = 23h 56min{{Cite web|url=http://astronomy.swin.edu.au/cosmos/S/Sidereal+Day|title=Sidereal Day {{!}} COSMOS|website=astronomy.swin.edu.au|language=en|access-date=2018-03-03}}
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| apsis = apsis
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| trans_capacity = up to 28 GHz
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HYLAS-4 is a telecommunications satellite owned and operated by Avanti Communications and manufactured by Orbital ATK (now Northrop Grumman Innovation Systems) that was launched by an Ariane 5 rocket on 5 April 2018.{{Cite web|url=https://spaceflight101.com/events/ariane-5-va242/|title=Ariane 5 (VA242) • DSN-1 & Hylas 4|website=spaceflight101.com|language=en-US|access-date=2018-03-03}}
Mission
The satellite is built to provide high speed data transmission services to Africa, Latin America and Europe.{{Cite news|url=http://www.arianespace.com/press-release/hylas-4-satellite-to-be-launched-by-arianespace/|title=Hylas 4 satellite to be launched by Arianespace - Arianespace|work=Arianespace|access-date=2018-03-03|language=en-US}} It is based on Orbital ATK's Star-3 Bus, delivering 64 28 GHz fixed beams covering Africa and parts of Europe. There are also four independent steerable beams that can serve Africa, South America and Europe.{{Cite news|url=https://www.avantiplc.com/fleet-coverage/our-satellite-fleet/hylas-4/|title=Avanti Communications - Satellite Fleet - HYLAS 4|work=Avanti Communications|access-date=2018-10-25|language=en-GB|archive-date=2018-10-25|archive-url=https://web.archive.org/web/20181025150305/https://www.avantiplc.com/fleet-coverage/our-satellite-fleet/hylas-4/|url-status=dead}} The capacity will partially be used to allow Avanti to expand into new markets and provide growth for existing markets.{{Cite web|url=http://space.skyrocket.de/doc_sdat/hylas-4.htm|title=HYLAS 4|website=space.skyrocket.de|access-date=2018-03-03}}
Launch
The satellite was launched into geosynchronous orbit by Arianespace on an Ariane 5 rocket in its ECA variant from ELA-3 at Guiana Space Centre in French Guiana. The launch was originally planned in early 2017 but has been delayed to 21 March 2018, and then to 5 April 2018. The satellite reached its geostationary orbital position by 19 April 2018.{{Cite web|url=https://investor.avantiplc.com/news/hylas-4-reaches-geo-orbit/|title=Avanti Communications announces its HYLAS 4 satellite has successfully reached its geostationary orbital position | Investor Relations|date=10 July 2023 }}