Tim Furniss/LONDON

The critical third European Space Agency-funded development flight of the Ariane 5 launcher is scheduled to take place from Kourou, French Guiana, on 20 October.

The 503 mission must succeed if the new launcher is to be handed over to Arianespace for commercial work (Flight International, 24-30 June). Its aim is to place a dummy communications satellite from Germany's Keyser Threde into geostationary transfer orbit (GTO).

The first flight failed in June 1996 as a result of a guidance system problem. If the 502 mission in October 1997 been a fully commercial flight, it too would have been classed as a failure by the insurance industry, because the payload was not placed into a perfect orbit.

Setting the date for the Ariane 5 launch was the most important of several developments in the commercial launcher industry as September came to a close.

Orbital Sciences successfully launched eight Orbcomm data communications satellites aboard a Pegasus XL booster on 23 September, bringing to 26 the number of spacecraft in orbit, providing the world's first global monitoring, tracking and messaging network. The company plans to undertake launches of a further two Pegasus and one Taurus before the end of the year. Globalstar has confirmed its recovery plan after the loss of 12 Globalstar satellites in the Zenit rocket failure on 12 September. Three Soyuz boosters will have carried four satellites into space by January 1999. There will be up to five additional Soyuz launches. Boeing Delta IIs are to be used for a further six launches, each carrying four satellites. The Zenit may be considered for two further launches next year. Sea Launch has confirmed that the first Zenit 3 booster will carry a dummy satellite representing the Hughes Galaxy XI which was to have flown the mission. The launch is being delayed until March 1999, following US Government investigations into technology transfer and the Zenit 2 failure which lost the Globalstar satellites (Flight International, 23-29 September). Lockheed Martin has postponed the launch of a Telesat communications satellite aboard a Russian Proton booster and returned the satellite from the Baikonur launch pad to its factory to check for possible defects that caused the recent failure of the Lockheed Martin Echostar 4 satellite in orbit.

Source: Flight International