The lower composite comprises two elements:
- A central cryogenic core, which burns cryogenic propellants combining liquid hydrogen and oxygen.
- A solid booster stage with 2 boosters delivering over 90% of the total thrust of the launcher at lift-off. After burning for 2 minutes, they separate from the central core 60 km above the Atlantic Ocean.
The highly complex Vulcain engine is the fruit of nearly 15 years of research. It forms the central cryogenic core of the lower section of Ariane 5.
Bottom view of the Vulcain engine. Credits: CNES/ESA/Arianespace/CSG Service optique, 2006.
Designed by Snecma Moteurs, Vulcain weighs 1,650 kg and delivers 20 times more thrust than the engine on Ariane 4.
New technologies were incorporated into its design, including a new copper alloy for the combustion chamber, high-strength materials for the turbopumps and high-power supersonic turbines.
Vulcain 2 is an upgraded version of the engine, designed for Ariane 5 ECA, providing a 20% performance gain.
Modular upper section
The upper section is adapted according to mission requirements. Whatever launcher variant is used, this section comprises:
- Fairing: made of 2 half-shells, the fairing protects the payloads on ascent through the atmosphere; it is jettisoned about 3 minutes into the flight.
- Vehicle equipment bay (VEB): this is the launcher’s electronic brain, containing all the instructions necessary for flight; it controls and corrects the launcher’s position if needed, commands engine cut-off, stage separation and so on.
- SYLDA 5: bearing structure accommodating 2 separate payloads; for some missions the ASAP platform is used and houses up to 8 microsatellites.
- Upper stage: housed inside the upper section, this is the only stage not ignited at lift-off; once above the dense atmosphere, it supplies the extra thrust necessary to place the payload in orbit.
Ariane 5’s fairing is closed. Credits: CNES/CSG Service optique.
Earlier generic versions of Ariane 5 were equipped with a storable propellant stage (EPS), replaced by the cryogenic upper stage (ESC-A) on Ariane 5 ECA.
ESC-A burns liquid oxygen and hydrogen, whereas EPS uses other liquid propellants (mono-methyl-hydrazine and nitrogen peroxide).
Different upper section configurations for Ariane 5. Credits: ESA/D.Ducros.
Did you know?
Kourou launch base
The Ariane launch site, owned by ESA, is located near Kourou, French Guiana, on the North-east coast of South America. The site’s ideal near-equatorial location at 5° North takes advantage of the Earth’s rotational speed to place satellites into geostationary orbit.
Ariane 5 is launched from the ELA 3 launch complex, which can handle 8 launches per year.
Industrial facilities working directly on launcher manufacture and integration were installed on site in French Guiana for ELA 3 for the first time since the creation of the Guiana Space Centre (CSG).
Between 1988 and 1996, a complete assembly line and launch facility was built in Kourou.
This facility comprises the factories and buildings for production of solid booster stages, as well as assembly of launcher elements and preparation of payloads, and ground tracking infrastructure (Jupiter control centre and TTC network).
Ariane 5 ECA is rolled out to the launch pad. Credits: CNES/ESA/Arianespace/CSG Service optique.