Electron beam welding of ARIANE 5 booster cases

摘要

Since 1980 more than 150 satellites have been launched by the European launch operating company ARIANESPACE at Kourou, French Guyana. Most of them have been successfully launched by the former versions ARIANE 1 to ARIANE 4. The new European launcher system ARIANE 5, Fig. 1, is available for transportation of satellites after the qualification flights, since 1999. In its basic version, ARIANE 5 is able to transport 6.8 tons payload into geostationary transfer orbit (GTO) in a dual-launch mode (2 satellite platforms per launch). During the first two minutes of lift-off, the two eccentric boosters provide a thrust of about 1300 tons, while the Vulcain engine of the central stage contributes only with 100 tons; the lift-off mass of the launcher is roughly 800 tons. For the ARIANE 5 launcher, MAN Technologie, Augsburg, has been responsible for design, analysis, testing and production of the booster cases, the EPC front skirt, the EPS tanks, the EPC and ESC bulkheads, the cardan, the thermal protections EPC and EAP and the GAT/GAM pressure vessels. Each booster case, total length 25 m and diameter 3 m roughly, is composed of three segments and filled with 240 tons of solid propellant. The forward segment S1 consists of a front dome and a short cylinder, the central segment S2 of three cylinders each 3.4 m in length, similar as rear segment S3, which has additionally an aft dome with a flange for the nozzle cone. With the generic Clevis/Tang connections for all single parts, each booster case weighs 19.8 tons.