The second test flight of the European Space Agency's (ESA) Ariane 5 booster has been delayed from April to July 1997. ESA and French space agency CNES made the decision to ensure that "each individual operation" can be closely analysed.

The third qualification flight, Ariane 503, to be managed by Arianespace, the European commercial-launcher organisation, will be delayed from September to November. Arianespace plans to operate the Ariane 5 commercially from flight 504 in 1998 (Flight International, 9-15 October, 1996).

The 501 maiden flight failed on 4 June, 1996, after an untested Ariane 4-class inertial-reference unit used on the Ariane 5 caused the vehicle to pitch down and break apart 31s after lift-off, with the loss of four Cluster science satellites, costing about $500 million.

The 502 flight will carry dummy payloads representing two commercial-communications satellites, and possibly an amateur-radio satellite. Flight 503 will carry ESA's Atmospheric Re-entry Demonstrator spacecraft and a commercial satellite to be agreed between Arianespace and the customer.

Arianespace hopes to launch four Ariane 5s in 1998, with eight Ariane 4s, but has made provisional plans to order more Ariane 4s if there are further delays.

The cost of the Ariane 5 failure is put at about $360 million and is being paid for partly by the vehicle's contractors. Arianespace, which was originally to have flown the 503 as a fully commercial flight, will sell it back to ESA at a reduced price, making some additional revenue from the 503's commercial-customer charge.

ESA and its Ariane 5 participating member states will have to contribute additional funds and these may be raised by delaying work on potential upgrades to the booster and diverting funds from other programmes, including that of Earth observation.

The agency's problems have been made worse by the reluctance of some member states - led by France - to agree to fund new programmes until the Ariane 5 launcher has been proven. A decision as to whether to fly a new Cluster mission, costing $300 million, is adding to the dilemma.

Source: Flight International