spacetoday.net: Zenit failure blamed on faulty hydraulic pump

Posted: Fri, May 3, 2013, 7:55 AM ET (1155 GMT)
Zenit-3SL launch of Intelsat 21 (Sea Launch)

The failure of a Sea Launch Zenit-3SL rocket earlier this year has been traced back to a faulty hydraulic pump in the rocket's first stage, the company recently announced. The Zenit-3SL failed 40 seconds after liftoff on February 1, resulting in the loss of its Intelsat-27 satellite payload. Investigators said a hydraulic pump used to pressurize oil used by the main engine gimbal actuators failed 3.9 seconds into the flight, leading to a loss of control of the vehicle and an emergency engine shutdown. Investigators blamed the pump failure on "contributing factors associated with a pump manufacturing process that proved difficult to control." That problem, Sea Launch officials said, should be straightforward to address, but they did not specify when they believed the rocket would return to flight.