The long-awaited launch of the Ariane 502 test-flight, from the Guiana Space Centre, Kourou, French Guiana, on 30 October - 16 months after the failure of the first launch - has boosted the morale of the European space industry, despite the slightly premature shutdown of the first-stage engine, which resulted in the booster's payloads entering a lower-than-intended orbit.
The 502, which had a flawless lift-off after a 38min hold called at T-48s caused by an electrical-connection problem, should have placed two technological demonstration payloads into a 581 x 36,000km elliptical geostationary transfer orbit, demonstrating a commercial launch of communications satellites.
The Maqsat H payload, including the Teamsat spacecraft, was placed into a 524 x 27,000km orbit, with a perfect inclination after the slightly premature shutdown of the first-stage engine created a 200m/s velocity shortfall which could not be corrected, even with a longer-than-planned burn of the second stage ending at T+27min 32s. Deployment of the Teamsat satellite in its Speltra container was delayed until T+31min, the official end of the 502 mission. Another Maqsat technology payload remained attached to the first stage as planned.
The Vulcain shutdown resulted from fuel moving about in the tank which caused propellant levels to fall below the "empty" mark. This "slopping" resulted from a higher-than-expected roll of the first stage which, as a result of its lack of speed, landed in the Pacific Ocean, near New Guinea, 8,000km short of its intended point.
Mission managers, however, stress that the 502 was a qualification flight intended to iron out potential problems.
The launch success was greeted with relief by the European space community, particularly the Aerospatiale-led European consortium which builds the booster.
Antonio Rodota, director of the European Space Agency (ESA), which funded the flight, praised the success, but emphasised that it is "just the beginning". Another ESA-funded flight, the 503 - originally to have been Arianespace's first commercial vehicle - will be launched in March 1998, carrying an as-yet-unidentified commercial communications satellite on Arianespace's orderbook. The satellite customer is likely to be charged a discounted price of about $40 million.
The 503 will also carry the ESA Atmospheric Re-entry Demonstrator. This craft may be cancelled, however, because of the expected confirmation by France that it no longer intends to contribute the majority of funding for the intended ESA programme to develop jointly with NASA a Crew Rescue Vehicle for the International Space Station.
If the 503 is successful, Arianespace's Ariane 504 will be used for commercial operations, the vehicle flying one or two satellites from the organisation's 43-strong orderbook. This will probably be flown in September 1998, with the 505 and 506 following by August 1999.
The transition from Ariane 4 to Ariane 5 operations will be extended by about three years until at least 2003, when the Ariane 4 will be phased out, five years later than intended originally.
To maintain the longer transition period, Arianespace will order 20 more Ariane 4s, bringing the number of Ariane 4s available to 45, confirms Jean-Marie Luton, the new chief of Arianespace.
Luton says that the order is not just a reaction to the delay in the Ariane 5 becoming operational, but also a reflection of the growing launcher market and increasing competition.
There are 13 Ariane 5s on order for Arianespace and a bulk order of 50 is expected to be ordered later, says Luton, with the delivery probably being called for in batches of 20 and 30.
Once operational, the Ariane 5 is expected to reduce launch costs by 10%, compared with those of Ariane 4.
Although ten satellites are already manifested for Ariane 5 missions, only three are so large that they have to fly on the more- powerful booster.
Five Ariane 5s a year are expected to be launched from 1999 to 2001, increasing to between eight and ten a year after this.
Source: Flight International
