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. 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 channels (675 in high definition) via five main satellite orbital positions to households across Asia, Australia, Africa, Americas, Europe, New Zealand, Middle East and North Africa. The satellites have been instrumental in the establishment of satellite TV and the introduction of digital TV, HDTV, 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.

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 150 km (93 mi).) increases flexibility and redundancy. Orbital data for the active satellites can be accessed here

Astra satellites have been designed by Boeing Satellite Systems (formerly Hughes Space and Communications), Airbus Defence and Space (formerly Astrium), Alcatel Space, Lockheed Martin 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 Baikonur, Kazakhstan, ILS Atlas launch vehicles from Cape Canaveral, Florida, United States and SpaceX 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 36,000 km (22,000 mi) 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.

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 and Africa.