Arianespace set to launch two telecom satellites in second Ariane 5 mission of 2017
Archive photo of an Ariane 5 ECA amidst launch preparations in Kourou, French Guiana. Photo Credit: Arianespace
Arianespace, the French multinational commercial launch provider, is gearing up to loft two communication satellites aboard its workhorse Ariane 5 rocket. Flight VA236 is set to launch from the spaceport in French Guiana in a nearly 3-hour launch window opening at 4:31 p.m. EDT (20:31 GMT) on Tuesday, March 21, 2017.
The Mission
Deploying two large satellites in a single mission is a hallmark capability of the Ariane 5, and Flight VA236 is no different. Though an Ariane 5 launch is, overall, more expensive than their competitors – predominately SpaceX – the Ariane’s ability to loft two heavy payloads on a single flight lowers the per-customer costs to comparable levels.
Coupled with Arianespace’s enviable success record and long history, this rideshare arrangement can be an attractive option for customers and has been employed throughout the vehicle’s nearly 20-year history.
The Ariane 5’s payload fairing, encompassing the SGDC satellite and SYLDA adapter, are lowered over the KOREASAT-7 satellite during integration. Photo Credit: Arianespace
Riding in the top slot of the SYLDA payload adapter is the 12,644-pound (5,735-kilogram) Brazilian Geostationary Satellite for Communications and Defense (SGDC) spacecraft. Built on Thales Alenia Space‘s Spacebus 4000C4 platform, the satellite will provide both civilian and governmental telecommunications services to the South American nation.
Sharing the flight, and mounted in the bottom slot of the payload adapter, is KOREASAT-7. Also built by Thales Alenia Space, but on the smaller Spacebus 4000B2 platform, the 8,113-pound (3,680-kilogram) satellite will supply communication services to a large area encompassing much of Southeast Asia.
Similar Functions, Different Hemispheres
Though the pair of satellites sitting atop the 165.7-foot (50.5-meter) tall rocket serve similar functions, and were both built by Thales Alenia Space, they will serve vastly different parts of the globe.
The SGDC satellite, operated by Telebras S.A. and managed by prime contractor VISIONA Tecnologia Espacial S.A., will be positioned above the equator at 75 degrees West longitude and is projected to have an operational on-orbit lifetime of more than 18 years.
The satellite will provide more than 57 gigabits per second (Gbps) communications service via 57 Ka-band spot beams and 5 X-band channels, and is part of the Brazilian government’s goal of providing broadband Internet services to its citizens via the National Broadband Plan.
SGDC will also provide secure communications for governmental and defense functions via the state-owned satellite.
Providing similar services, and nearly on the exact opposite side of Earth, is the KOREASAT-7 satellite. Once the satellite settles into its slot at 116 degrees East over the equator, it will provide data services – such as Internet access, video broadcast, and government communications – to South Korea, Indonesia, the Philippines, India, and the Indochinese Peninsula.
Operated by ktsat – a wholly-owned subsidiary of South Korea’s largest telecom provider, KT Corp. – the satellite will supply services via its Ku-band and Ka-band transponders and has a projected operational lifetime of more than 15 years.
The Rocket
Arianespace has tapped its reliable Ariane 5 to launch a pair of communication satellites to geosynchronous transfer orbit (GTO). The European launcher is one of only two active and mission-proven heavy-lift rockets in the world today and is capable of lofting 44,000 pounds (20,000 kilograms) to low-Earth orbit (LEO) or 23,667 pounds (10,735 kilograms) to GTO.
Ariane 5’s first stage is powered by a lone liquid-fueled Vulcain 2 engine and a pair of side-mounted P241 solid-fueled boosters. The trio of engines produces 3.4 million pounds-force (15,120 kilonewtons) of thrust at liftoff, with more than 92 percent of that coming from the P241 boosters.
The pair of boosters will operate for slightly more than 2 minutes, after which they will be jettisoned and fall into the Atlantic Ocean.
Supplying the remaining eight percent of liftoff power is the core stage’s Vulcain 2 cryogenic engine. Burning a mixture of liquid hydrogen and liquid oxygen, the hydrolox powerplant provides 220,000 pounds-force (960 kilonewtons) of sea-level thrust. That increases to 310,000 pounds-force (1,390 kilonewtons) as it climbs into the vacuum of space.
The second stage is outfitted with a single HM7B cryogenic engine. It supplies 15,000 pounds-force (67 kilonewtons) of vacuum thrust and can operate for 945 seconds.
Flight VA235 will feature the Ariane 5 in its ECA – Evolution Cryotechnique type A – configuration; it will mark the 61st overall launch of that variant of the Ariane 5 and the second of 2017. The mission will be broadcast live via Arianespace’s website. Coverage will begin 15 minutes before the scheduled liftoff.
Artist’s rendering of the SGDC satellite. Image Credit: Thales Alenia
Curt Godwin
Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.
