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Ariane 5 returns to flight after two-month delay caused by steering thruster concerns
By Frederic Castel
Special to SPACE.com
posted: 07:00 am ET
14 September 2000
ET
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PARIS -- Following a two-month delay in operations while six small thrusters in the rocket's steering system could be replaced, Arianespace managers have declared their Ariane 5 rocket is free from technical concerns and ready to fly again.
A close up view of an Ariane 5 rocket as it sits on its launch pad at the Guiana Space Center near Kourou, French Guiana. Image from Arianespace, used with permission.
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That clears the way for an Ariane 5 launch tonight from the Guiana Space Center in South America. Liftoff from near Kourou, French Guiana is expected between 5:54 p.m. and 6:49 p.m. Eastern Daylight Time (22:54 to 23:49 GMT). The giant rocket will be carrying a pair of communications satellites: Astra 2B from Luxembourg and GE Americom GE-7 from the United States. The satellite-delivery mission is expected to last about 38 minutes. The sixth launch of the Ariane 5 was initially set for July 25 but engineers at Astrium, which built the thrusters in Germany, wanted to fully understand why a leak happened last May during a test of a new upper-stage booster. The new booster is to fly on a more powerful version of the Ariane 5 in 2002."Technically, nothing was changed. The thrusters are identical to the previous ones, but since an anomaly was detected during an attitude control system ground-test firing in Europe on another version, it took almost two months to ensure that this problem would not occur on the next Ariane 5 launch," Eric Dautriat, director of launchers at the French space agency CNES, told SPACE.com. CNES is the prime contractor for the Ariane 5 upgrades that will create a new model known as ESV, short for the French words Etage Superieur Versatile. ~Thruster troubles The six small thrusters, located in an equipment bay atop the launcher, are designed to prevent the rocket from rolling during launch. Because the design of the thrusters used on the new upper stage was sufficiently similar to those that will be used on Ariane 5 rockets to be launched this year, Arianespace officials decided to ground the launcher until the situation could be resolved.
A pair of Astrium workers examine the steering thrusters used on the Ariane 5 rocket to keep it aimed in the correct direction during launch. Image from Astrium.
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Adding to the delay was the fact that welds on the thrusters could not be tested at the Kourou launch site, so the equipment had to be removed and shipped to Astrium's engine test center in Lampoldshausen, Germany. "This postponement shows Arianespace's very strict quality control policy, which is the only way to guarantee the highest possible reliability for customers," said Claude Sanchez, Arianespace senior spokesman. The Ariane 5 launcher has flown only once this year, last February. The European commercial launch firm sent an Ariane 4 rocket up just last week, continuing what is expected to be a rapid fire of missions that are to include three more Ariane 5 shots before the end of the year. "Of course, customers don't like postponement and delays to launch their satellites, but it's part of the space business. We try to accommodate the customer as well as we can," Francoise Bouzitat, Arianespace secretary general, told SPACE.com.
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