Tim Furniss/PARIS

The critical demonstration flight of the Ariane 502 launch vehicle has been delayed to 30 September, or later, by the need to change its Vulcain first-stage engine. The launch schedule is now "very tight", says the European Space Agency (ESA), and further delays are possible.

A 600s acceptance test of the Vulcain engine, due to power the 504, the first fully commercial flight to be operated by Arianespace in late 1998, was stopped after 300s when a component in the liquid-oxygen turbopump failed.

Because the engine for the 502 has the same type of component, mission managers from ESA and French space agency CNES, which manages the programme, have decided to replace the 502 engine with that of the 503. The 503 engine has a similar component, but provided by a new supplier.

ESA is taking no chances with the 502 and it will "-resist pressure" to meet the flight date if it will compromise the mission's success.

The delay may cause funding problems for the programme, which will force ESA to go back to its participating members to request further finance.

Source: Flight International