Astra is the brand name for a number of geostationary communication satellites, both individually and as a group, which are owned and operated by SES, a global satellite operator based in Betzdorf, in eastern

Luxembourg Luxembourg, officially the Grand Duchy of Luxembourg, is a landlocked country in Western Europe. It is bordered by Belgium to the west and north, Germany to the east, and France on the south. Its capital and most populous city, Luxembour ...

. The name is also used to describe the pan-European broadcasting system provided by these satellites, the channels carried on them, and even the reception equipment. At the time of the launch of the first Astra satellite, Astra 1A in 1988, the satellite's operator was known as Société Européenne des Satellites ("European Satellite Company"). In 2001 SES Astra, a newly formed subsidiary of SES, operated the Astra satellites and in September 2011, SES Astra was consolidated back into the parent company, which by this time also operated other satellite families such as AMC, and NSS. Astra satellites broadcast 2,600 digital

television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...

channels (675 in high definition) via five main satellite orbital positions to households across

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

Middle East The Middle East (term originally coined in English language) is a geopolitical region encompassing the Arabian Peninsula, the Levant, Turkey, Egypt, Iran, and Iraq. The term came into widespread usage by the United Kingdom and western Eur ...

and

North Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

. The satellites have been instrumental in the establishment of satellite TV and the introduction of digital TV,

HDTV High-definition television (HDTV) describes a television or video system which provides a substantially higher image resolution than the previous generation of technologies. The term has been used since at least 1933; in more recent times, it ref ...

, 3D TV, and Hybrid Broadcast Broadband TV (HbbTV) in Europe. A book, '' High Above'', telling the story of the creation and development of the Astra satellites and their contribution to developments in the European TV and media industry, was published in April 2010 to mark the 25th anniversary of SES.

Satellites

There are 10 fully-operational Astra satellites and another 3 as backup/reserve, the majority in four orbital locations - Astra 19.2°E, Astra 28.2°E, Astra 23.5°E, Astra 5°E. Astra's principle of "co-location" (several satellites are maintained close to each other, all within a cube with a size of .) increases flexibility and redundancy. Orbital data for the active satellites can be accesse
''here''

Manufacture and launch

Astra satellites have been designed by Boeing Satellite Systems (formerly Hughes Space and Communications), Airbus Defence and Space (formerly Astrium), Alcatel Space,

Lockheed Martin The Lockheed Martin Corporation is an American Arms industry, defense and aerospace manufacturer with worldwide interests. It was formed by the merger of Lockheed Corporation with Martin Marietta on March 15, 1995. It is headquartered in North ...

and Thales Alenia Space. The Astra satellites within a family are not necessarily identical. For example, of the Astra 2 satellites; Astra 2A and Astra 2C were BSS 601HPs, Astra 2B an Astrium Eurostar E2000+, Astra 2D a BSS 376 and Astra 2E, Astra 2F and Astra 2G are all Eurostar E3000s. The satellites have been launched by Arianespace by Ariane launch vehicles from Kourou, French Guiana, International Launch Services (ILS) Proton launch vehicles from

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Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a landlocked country primarily in Central Asia, with a European Kazakhstan, small portion in Eastern Europe. It borders Russia to the Kazakhstan–Russia border, north and west, China to th ...

, ILS

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launch vehicles from Cape Canaveral,

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and

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Falcon 9 Block 5 rockets also from Cape Canaveral. The satellites are launched into an elliptical "temporary transfer orbit" from where they use onboard propulsion to reach their final circular geostationary orbits, at nearly altitude. Proton launch vehicles fitted with a fourth stage propulsion unit are capable of launching the satellites several thousand kilometres higher (at the closest point of the elliptical orbit) than Ariane launch vehicles, and so most satellites launched in this way use less fuel to reach their geostationary orbit. More recent Astra satellites are built with an all-electric propulsion system for orbit raising and in-orbit manoeuvres to save weight.

Sirius and Astra 4A

The Sirius series of satellites (not connected with the North American Sirius Satellite Radio service) was started in 1993 with the purchase of the BSB Marcopolo 1 satellite (renamed Sirius 1) by Nordic Satellite AB (NSAB) for direct to home broadcasts to the Nordic and Baltic regions from the 5°East orbital position. Subsequent satellites launched to this location include Sirius 2 (1997), Sirius 3 (1998) and Sirius 4 (2007) and the position's coverage has been expanded to include

Eastern Europe Eastern Europe is a subregion of the Europe, European continent. As a largely ambiguous term, it has a wide range of geopolitical, geographical, ethnic, cultural and socio-economic connotations. Its eastern boundary is marked by the Ural Mountain ...

and

. In 2000, SES (then SES Astra) bought the 50% shareholding in NSAB owned by Teracom and Tele Danmark and in 2003 increased that holding to 75%, renaming the company SES Sirius AB. In 2008, Astra acquired further shares to take its shareholding in SES Sirius to 90% and in March 2010 took full control of the company. In June 2010, the affiliate company was renamed SES Astra and the Sirius 4 satellite renamed Astra 4A. The Astra 4A designation was originally given in 2005 to part of the NSS-10 craft (33 transponders) owned by another subsidiary of SES, SES New Skies, and positioned at 37.5°W for broadcast, data, and telecommunications into Africa, and in 2007 to part of the Sirius 4 satellite (six transponders of the FSS Africa beam) owned and operated by SES Sirius. From June 2010, the Astra 4A designation has applied to the entire satellite previously known as Sirius 4.

Failures

Astra 1K, the largest commercial communications satellite ever built at the time, was ordered by SES in 1997. It was launched by Proton rocket on 26 November 2002. The launch vehicle lifted off as planned and reached its parking orbit at which point the final stage of the launch vehicle was to initiate a second burn to transfer the satellite to its geostationary orbit. This did not occur and the satellite was released into the parking orbit, making it unusable. The only way to recover the satellite would have been the use of a

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

, however this was rejected. On 10 December 2002, SES instructed Alcatel Space (the manufacturer) and the French Space Agency CNES to deorbit the satellite, it broke up on re-entry over the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five Borders of the oceans, oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is ...

. On 16 January 2009, Astra 5A at Astra 31.5°E "experienced a technical anomaly leading to the end of the spacecraft's mission", some four years ahead of the spacecraft's expected end of life. Traffic carried by the satellite (especially channels for German cable service, Kabel Deutschland) was transferred to Astra 23.5°E. In March 2009, SES (then SES Astra) announced that in April, the Astra 2C satellite was to be moved from the Astra 28.2°E position to 31.5°E to temporarily take over Astra 5A's mission until Astra 3B is launched to Astra 23.5°E, when another craft currently there can be released to 31.5°E. The move of Astra 2C was started in May 2009 and completed on 11 May 2009, with the first transponders coming into use at the new position in the subsequent two weeks.

Broadcasting statistics

At the end of 2021, Astra satellite broadcasts were received in 170 million households in Europe. In Germany, the largest market for Astra broadcasts, 17 million households receive TV via satellite (15.93 million receiving satellite channels in HD) out of 37.22 million TV households (33.76 million HD TV households) in the country with take-up of other TV delivery methods as follows:''ASTRA TV monitor 2021: Satellite supplies most TV households in Germany''
SES. 26 April 2022. Accessed 29 April 2022

References

External links

SES fleet information and map

Official SES site

SES first maritime Ka-band service

* * * *

SES Broadband website

SES Techcom Services
- Official site {{SES World Skies SES (company) Telecommunications companies of Luxembourg Direct broadcast satellite services Communications satellite operators Betzdorf, Luxembourg