The need for an early growth version of Ariane 5, to meet the demand for higher launch weights, has been deemed essential by Arianespace if it is to compete with other launchers into the next century. A decision on development of the Evolution will probably be taken at the Toulouse meeting of European Space Agency ministers in October.

If approved, the first launch of the up-rated launcher would come in mid-2002. The cost of development would be around ECU 1,000 billion ($744 million).

The extra power will come from developments to both the Vulcain main engine and the solid boosters. There are four major changes:

increase of the main cryogenic-stage capacity, from 158t to 170t;

increase Vulcain thrust to 1,350kN;

welded booster factory joints (saving 2t);

the addition of a third stage carrying 15t of fuel instead of 9.7t, with an increase of thrust of the engine, from 26kN34kN.

Changes to the Vulcain centre on an increase in throat diameter and a new liquid-oxygen turbo-pump with a two-stage turbine. Further developments are in the pipeline and, if funded, could see thrust increases of up to 34% with a Vulcain Mk4. This could be available in 2014. The resulting Ariane 5 would be capable of launching up to 9t to GTO, or up to 28t to low orbit. A "super Ariane 5" has even been considered, with four solids and three cryogenic stages, the first using five Vulcains for the first stage and a single engine for the second. This would be capable of the lunar launches.

Source: Flight International