Ariane 5 Generic

The Ariane 5G launcher is the first version of Ariane 5. This version is the only one which was used from the first launch in June 1996 up to the launch of the first Ariane 5 ECA version in December 2002.

Ariane 5G launchers consist of a main cryogenic stage, two boosters and an upper stage. This relatively simple structure (Ariane 1 to 4 launcher had an extra stage) limits the number of engines which means the launcher is somewhat more robust.

First launch : 4 June 1996 – Flight 88

Maximum mass for a geostationary transfer orbit (GTO) :
6.9 tonnes for a simple launch
5.9 tonnes for a dual launch

Ariane 5G launcher components :

Main cryogenic stage (EPC)
Booster stage (EAP)
Storable propellant stage (EPS)
Vehicle Equipment Bay (VEB)
Fairing
External payload structure for multiple Ariane launches – Speltra
Ariane 5 dual launch system - Sylda 5
Ariane Structure for Auxiliary Payloads - ASAP

Ariane 5G launcher elements

The Main cryogenic stage (EPC)

The EPC is the main launcher element. It consists of an aluminium alloy tank with two compartments filled with 157 tonnes of non-toxic cryogenic propellant kept at a very low temperature. The thrust is provided by the Vulcain engine which can swivel along two axes. This is ignited seven seconds before lift-off in order to be able to monitor it during the ignition phase.

This stage provides most of the power necessary for orbiting the payload. When it stops, the launcher is at an altitude of between 130 and 420 kilometres depending on the type of mission. It then falls back towards the Earth and disintegrates above the ocean.

Height: 30.53 metres
Diameter: 5.46 metres (including thermal shielding)
Dry mass: 12.5 tonnes
Propellant :
132.37 tonnes of LOX (liquid oxygen)
25.84 tonnes of LH2 (liquid hydrogen)
Engine: Vulcain
Thrust: 1,114 kN
Combustion duration: 589 seconds

The booster stage (EAP)

This stage consists of two boosters attached to the main cryogenic stage. Their function is to provide the rocket with an acceleration of 0.5 G at lift-off. Each booster contains 238 tonnes of solid propellant and provides a thrust equivalent to that of an Ariane 4 rocket. They are equipped with an MPS motor. The nozzle axis can be changed to correct the thrust direction.

The EAP are ignited a few seconds after the EPC in order to ensure correct operation of the Vulcain engine. They then function for approximately 130 seconds before being jettisoned at an altitude of 55 to 70 kilometres. They then continue their trajectory up to an altitude of 80 to 140 kilometres following which they fall back into the sea at about 150 kilometres from the launch base. They may later be retrieved for inspection or analyses.

Height: 31.61 metres
Diameter: 3 metres
Dry mass: 40 tonnes each
Propellant: 237 tonnes of solid propellant each
68 % of ammonium perchlorate
18% of polybutadiene
14% aluminium
Motor: MPS
Thrust: 6,709 kN each
Combustion duration: 129 seconds

The storable propellant stage (EPS)

This stage is used to adjust the orbits on which satellites are placed. It is also used to separate satellites from the launcher and orientate them. The EPS has a set of four tanks containing up to 9.7 tonnes of conventional propellant (MMH and N2O4). Its engine can be reignited twice, thus enabling it to optimise the orbit positioning according to the type of satellite and the target orbit and to move away from the orbit after separation.

Height: 3.35 metres
Diameter: 5.4 metres
Dry mass: 1.2 tonnes
Propellant: :
3.2 tonnes of MMH (monomethylhydrazine)
6.5 tonnes of N2O4 (nitrogen tetroxide)
Engine: Aestus
Thrust: 29 kN
Combustion duration: up to 1,100 seconds

Vehicle Equipment Bay (VEB)

The vehicle equipment bay contains the two computers (the main computer and the back-up computer) used for flight control. It also includes the attitude control system (SCA) using hydrazine for controlling roll after separation of the boosters and three-axis orientation of the rocket during ballistic flight.

Height: 1.56 metres
Diameter: 5.4 metres
Mass: 1.5 tonnes

The fairing

The fairing in the form of a cone protects the satellites while travelling through the atmosphere. It is jettisoned about 200 seconds after lift-off at an altitude of about 110 kilometres.

Different fairing sizes are possible. The biggest one (17 metres) is used to install payloads up to a height of 15.5 metres.

Height: 12.7 to 17 metres
Mass: 2,027 to 2,900 kg
Inner working diameter: 4.57 metres

The external payload structure for multiple Ariane launches - Speltra

The Speltra structure fits between the upper EPS stage and the fairing. It enables Ariane to carry two satellites for a single launch. The first is installed in the Speltra structure while the second is installed under the fairing just above the Speltra.

First use on Ariane 5 : 4 June 1996 - Flight 88
Height: 5.5 to 7 metres
Mass: 704 to 820 kg
Inner working Diameter : 4.57 metres
Inner working Height : 6 metres

The Ariane 5 dual launch system - Sylda 5

As for the Speltra structure, the Sylda 5 structure is used to launch two satellites for a single launch. However, unlike the Speltra structure which is located between the fairing and the upper EPS stage, the Sylda 5 is located within the fairing.

Sylda 5 is lighter than Speltra but cannot carry satellites as big as those carried by the Speltra.

First use on Ariane 5 : 21 March 2000 - Flight 128
Height: 4.9 metres
Mass: 440 kg
Inner working Diameter : 4 metres
Inner working Height : 2.9 to 4.4 metres

Ariane Structure for Auxiliary Payloads - ASAP

The ASAP platform is used to launch several mini or microsatellites. The platform can be placed directly above the upper stage or in a Sylda 5 or Speltra structure.

When the ASAP is assembled as the main payload, it can contain up to eight satellites with a mass of 120 kilos each. Placed within a Sylda structure, the ASAP can carry four 300 kilo satellites or two satellites of 300 kilos and six of 120 kilos.

First use on Ariane 5: 16 November 2000 - Flight 135

Source : esa.int ; arianespace.com ; cnes.fr