Ariane 5
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Date: 2018-12-23

Ariane 5, by Wikipedia https://en.wikipedia.org/wiki?curid=3111 / CC BY SA 3.0

Ariane 5

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 French spatial agency Centre National d'Etudes Spatiales. Airbus Defence and Space is the prime contractor for the vehicles, leading a consortium of other European contractors.

Ariane 5 is operated and marketed by Arianespace as part of the "Ariane" programme. The rockets are launched by Arianespace from the Guiana Space Centre in French Guiana.

Ariane 5 succeeded Ariane 4, but was not derived from it directly as Ariane 5 was developed from scratch. 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," "Ariane Double-Launch System"). Three main satellites are possible depending on size using SPELTRA ("Structure Porteuse Externe Lancement TRiple Ariane," "Ariane Triple-Launch External Carrier Structure"). Up to eight secondary payloads, usually small experiment packages or minisatellites, can be carried with an ASAP ("Ariane Structure for Auxiliary Payloads") platform.

Ariane 5’s cryogenic H173 main stage (H158 for Ariane 5 G, G+, and GS) is called the EPC ("Étage Principal Cryotechnique"—Cryotechnic Main Stage). It consists of a large tank 30.5 metres high with two compartments, one for liquid oxygen and one for liquid hydrogen, and a Vulcain 2 engine at the base with a vacuum thrust of . The H173 EPC weighs about 189 tonnes, including 175 tonnes of propellant. After the main cryogenic stage runs out of fuel, it re-enters the atmosphere for an ocean splashdown.

Attached to the sides are two P241 (P238 for Ariane 5 G and G+) solid rocket boosters (SRBs or EAPs from the French "Étages d’Accélération à Poudre"), each weighing about 277 tonnes full and delivering a thrust of about . They are fueled by a mix of ammonium perchlorate (68%) and aluminum fuel (18%) and HTPB (14%). They each burn for 130 seconds before being dropped into the ocean. The SRBs are usually allowed to sink to the bottom of the ocean, but, like the Space Shuttle Solid Rocket Boosters, they can be recovered with parachutes, and this has occasionally been done for post-flight analysis. (Unlike Space Shuttle SRBs, Ariane 5 boosters are not reused.) The most recent attempt was for the first Ariane 5 ECA mission. One of the two boosters was successfully recovered and returned to the Guiana Space Center for analysis. Prior to that mission, the last such recovery and testing was done in 2003.

The French M51 SLBM shares a substantial amount of technology with these boosters.

In February 2000 the suspected nose cone of an Ariane 5 booster washed ashore on the South Texas coast, and was recovered by beachcombers before the government could get to it.

The second stage is on top of the main stage and below the payload. The Ariane 5 G used the EPS ("Étage à Propergols Stockables"—Storable Propellant Stage), which is fueled by monomethylhydrazine (MMH) and nitrogen tetroxide. It also has 10 tonnes of stora...