Ariane 5 is a European heavy lift launch vehicle that is part of the Ariane rocket family, an expendable launch system used to deliver payloads into geostationary transfer orbit (GTO) or low Earth orbit (LEO). Ariane 5 rockets are manufactured under the authority of the European Space Agency (ESA) and the Centre National d'Etudes Spatiales. Airbus Defence and Space is the prime contractor for the vehicles, leading a consortium of sub-contractors. Ariane 5 is operated and marketed by Arianespace as part of the Ariane programme. Astrium builds the rockets in Europe and Arianespace launches them from the Guiana Space Centre in French Guiana.
Ariane 5 succeeded Ariane 4, but was not derived from it directly. Ariane 5 has been refined since the first launch in successive versions, "G", "G+", "GS", "ECA", and most recently, "ES". ESA originally designed Ariane 5 to launch the Hermes spaceplane, and thus intended it to be human rated from the beginning.
Two satellites can be mounted using a SYLDA carrier (SYstème de Lancement Double Ariane). Three main satellites are possible depending on size using SPELTRA (Structure Porteuse Externe Lancement TRiple Ariane). Up to eight secondary payloads, usually small experiment packages or minisatellites, can be carried with an ASAP (Ariane Structure for Auxiliary Payloads) platform.
As of July 2015 Arianespace has signed contracts for Ariane 5 ECA launches up till 2023, after planned introduction of Ariane 6 in 2020.(Wikipedia)