The various Ariane 5 versions
The different versions of the Ariane 5 launcher
Just as for Ariane 5G, all the versions of the Ariane 5 launcher consist of a main cryogenic stage, two boosters and an upper stage.
ESA and CNES undertook the Ariane 5 Evolution programme in order to keep up with developments in satellites. This programme should make it possible to increase the launch capability of Ariane 5 by improving the performance of the lower components of the launcher (cryogenic stage and boosters).
A second programme, Ariane 5 Plus, was also undertaken to improve performances and develop the versatility of the upper stage.
Ariane 5G+
There were only three versions of this transition launcher ordered (Ariane 518 to 520).
First launch : 2 March 2004 - Flight 158
Maximum mass for a geostationary transfer orbit (GTO) :
5.9 tonnes for a dual launch
Main cryogenic stage (EPC)
Similar to the Ariane 5G EPC, the only changes made concern the electronics but not the stage performance.
Booster stage (EAP)
Similar to the Ariane 5G EAPs. A few minor changes were made to the onboard electronics and nozzles were lightened by 540 kg. This new type of EAP was used on Flight 162 on an Ariane 5G launcher.
‘Versatile’ storable propellant stage (EPS-V)
In this version of Ariane 5, the Ariane 5G EPS stage was replaced by the EPS-V stage developed as part of the Ariane 5 Evolution programme.
Ariane 5 ECA – the ‘10 tonnes’ Ariane 5
This version of Ariane 5 incorporates the improvements made as part of the Ariane 5 Evolution programme such as the new Vulcain 2 engine.
The ESC-A upper stage developed as part of the Ariane 5 Plus programme replaces the storable propellant stage (EPS) of Ariane 5G.
The first launch of an Ariane 5 ECA launcher was a failure. This was due to the failure of the Vulcain 2 engine. A leak in the cooling system led to an imbalance in the engine thrust and the rocket went out of control.
First launch : December 2002 – Flight 157 (failure) - Return to flight 12 February 2005
Maximum mass for a geostationary transfer orbit (GTO) :
About 10 tonnes for a single launch
About 9.4 tonnes for a dual launch
Main cryogenic stage (EPC)
Several improvements were made to the EPC with respect to Ariane 5G. The Vulcain engine was replaced by the Vulcain 2 engine. This new engine enables 20% more thrust due to a change in the mixture ratio. The bottom of the tank was lowered in order to increase the volume of liquid oxygen carried by about 15 tonnes.
Booster (EAP)
The amount of propellant in the boosters was increased by 2,430 kilos. This change led to an increase in 400 kilos of payload.
Vehicle Equipment Bay (VEB)
The Vehicle Equipment Bay was lightened and its electronics were upgraded. Changes also had to be made so that it could be adapted to the new upper stage.
Type A cryogenic upper stage (ESC-A)
This new stage replaces the storable propellant stage (EPS). It is based on the third stage of Ariane 4. Several components of this stage including the HM-7B engine were again used on ECS-A. However, some of its components such as the hydrogen tank have a completely new design.
The ESC-A carries 14.4 tonnes of cryogenic propellant (oxygen and hydrogen as for EPS) kept at a very low temperature.
Ariane 5 ES - ATV
This version of the Ariane 5 ES is mainly intended for the Automated Transfer Vehicle (ATV) missions to the International Space Station (ISS), but also for launching satellite constellations and interplanetary flights.
First launch : the first launch of ATV is being planned for sometime in 2006
Maximum mass for a geostationary transfer orbit (GTO) :
7.1 tonnes for a dual launch
Main cryogenic stage (EPC)
Stage identical to that of Ariane 5 ECA
Booster (EAP)
Changes made to the booster structure will make it possible to lighten the launcher by 2 tonnes per EAP. The EAPs, as for Ariane 5 ECA, will carry 2,430 kilos more propellant.
‘Versatile’ storable propellant stage (EPS-V)
In addition to the lengthening of the nozzle and the increase of the monometal hydrazine (MMH) tank capacity by 250 kg (identical changes to that of the Ariane 5 E/S EPS), this stage has a re-ignitable Aestus engine. Thanks to its new engine, this new version of the EPS is capable of making a 6-hour ballistic flight and may be reignited 5 times which will enable it to reach the ISS orbit, to launch a satellite constellation or to launch probes onto interplanetary trajectories.
It was used for the first time in 2004 to launch the Rosetta probe (on an Ariane 5G+ type launcher)
Source : esa.int ; arianespace.com ; cnes.fr
