Posted: Fri, Oct 8, 2004, 10:21 AM ET (1421 GMT)
An electrical short caused a Zenit 3SL booster to shut down its upper stage earlier than planned, placing its satellite into a low orbit, investigators said Thursday. The Zenit 3SL, operated by the international consortium Sea Launch, lifted off on June 28 to place the Telstar 18 satellite into geosynchronous transfer orbit, but the Block DM-SL upper stage engine shut down prematurely. Investigators concluded that a short in the stage's cable network caused interference in circuits that transfer propellant flow rate information to the main engine control system. The interference created distorted data that led the control system to have the engine consume more propellant than planned, leading to the premature shutdown. The problem has been corrected, officials said, and the booster is ready to return to flight later this year. The satellite itself was still able to reach its final orbit using additional onboard propellant; the extra propellant use will not reduce the spacecraft's designed 13-year lifetime.

Related Links:

•  Spaceflight Now article
•  Boeing press release