Questions about Ariane
Is Ariane a rocket or a launcher ?
Technically, Ariane is a launcher. As the name implies, it ‘launches’ a satellite into space so it can reach its orbiting position. But this term is not very explicit for the layman and so Ariane is usually referred to as a rocket. This allows more freedom of the imagination and evokes the conquest of Space and the adventures of Tintin! Rocket or launcher, it hardly matters. The main thing to remember is the amazing technical performance of its engines, capable of getting it off the ground and carrying it into Space. Some facts: Ariane is as tall as a 15 storey building and at the moment of lift-off weighs over 700 tonnes – about one tenth of the weight of the
What's it for ?
Ariane 5 is a very sophisticated ‘Space lorry’ that carries satellites under the protection of its fairing. It places these satellites on low, geostationary or other orbits, from where they carry out their missions. Their applications are wide-ranging and play a strategic role in today’s world: telecommunications, Earth observation, planetology, weather forecasting, military use etc.
Ariane 5 specialises in large geostationary satellites, such as those used for multimedia and mobile telephony. It really has come a long way since the first flight!
In 1979 Ariane 1 could handle a payload of 1.6 tonnes. Today, Ariane 5 can carry almost 10 tonnes into geostationary orbit.
It is one of the world’s most powerful launchers
Who contributes to this European saga ?
5,000 people from all the member countries of the ESA contribute to the production of launchers directly or through sub-contracting. There are small contributors and larger ones, such asWhat is so complicated about a launcher ?
Exerting the energy needed to go into space demands exceptionally high-performance fuel. Being able to develop this energy is Ariane 5’s strength… but it is also why it is so complicated! Just think: Ariane 5’s turbo-pump is as powerful as two high-speed trains, yet it would fit on a table. It turns at 30,000 rpm, i.e. ten times faster than a car engine! Add to that the restrictions related to the materials used. The liquid Hydrogen that powers the Vulcain engine is at -250°C: air turns to ice on contact with it. Fuel like this cannot be transported, so there needs to be a factory at the launch site to produce it! Furthermore, it is 14 times lighter than water so requires an enormous storage tank. The last but not the least of its complexities is the ignition phase of the cryogenic engine at the moment of lift-off. Only 4 countries in the world have mastered this delicate procedure –
And what are the specific problems with this type of project compared with the A 380?
A new model of an aircraft can be tested in stages. First, on the ground. Then it has hundreds of test flights. When the engineers are sure of its capabilities, it can be declared flight-worthy. In the Space domain, there is no dress rehearsal before D-day. Obviously we test the launcher, but ground conditions are not representative of those experienced in Space. To start with, there is no vacuum. Nor can we subject the launcher to the range of temperatures it will encounter when it goes from the cold of Space (-150°C, in the shadow of the Earth) to 200-300°C in the full force of the Sun’s rays. Lastly, with a launcher there’s no going back once the order to ignite the solid fuel boosters has been given. Nothing more can be done… other than hope that all goes according to plan. For these reasons, and also because the Space industry is continually pushing the technological barriers to their limits, we cannot exclude the possibility of technical incidents: although rare, their consequences can be serious.
Why is Ariane lauched from Guiana : beacause the wether is good there ?
Watching an Ariane lift-off in the tropical sunshine does add a festive feeling to the event, it’s true… However, the Kourou site was chosen for its three advantages, somewhat more serious than the weather. Its geographical position allows launches to the East and to the North in maximum conditions of safety: the launcher doesn’t fly over land for the first 2,500 miles! Second advantage? Its latitude. For launching into geostationary orbit, the nearer the site is to the equator, the stronger the catapult effect of the rotation of the Earth. This gives the Kourou site an advantage over both theHow would you describe Ariane 5 in relation to other launchers : is it the little sister or the distant cousin ?
The different versions of Ariane may all have the same first name, but Ariane 5 doesn’t have a lot in common with previous models. Firstly there are no longer three separate stages, as there were for Ariane 4. From now on, Ariane 5 is made of a 2-stage structure: the lower stage is identical for all missions and the upper stage can be adapted to the needs of each contract. Technologically, apart from the engine in the upper stage, which is the same in Ariane 4 and 5, everything else is different. The cryogenic engine in Ariane 5 is 10 times more powerful than the one in Ariane 4; Ariane’s solid fuel boosters weighed 10 tonnes, whereas Ariane 5’s are now 237 tonnes each. To sum up, Ariane 5 is a new generation of launchers, conceived after 10 years of research and development, months of construction and 22 days of planning, for a launch resulting in one short hour of life in Space.
