Sea Launch rocket failure blamed on hydraulic pump
BY STEPHEN CLARK
Posted: April 27, 2013
Sea Launch closed the investigation into a Feb. 1 rocket failure Thursday, concurring with the conclusion of Russian and Ukrainian experts that the mishap was caused by a faulty hydraulic pump used to steer the Zenit 3SL booster in flight.
The rocket's on-board computer detected the launcher veering from the planned flight path, triggering an emergency engine shutdown sequence designed to safely terminate the launch in the event of a problem.
The Zenit 3SL and its payload - the Intelsat 27 communications satellite - were lost when the rocket crashed into the Pacific Ocean a few miles from the launch site.
The hydraulic power supply unit, known by its Russian acronym BIM, failed approximately 3.9 seconds after liftoff due to "abnormal performance" of the pump, which is supposed to pressurize the hydraulic oil supplied to the Zenit rocket's first stage engine gimbal actuators.
During launch, the actuators pivot the Zenit's four-nozzle RD-171M first stage engine, directing the engine's thrust to guide the rocket on the proper trajectory.
"The pump failure was the result of contributing factors associated with a pump manufacturing process that proved difficult to control," Sea Launch said in a statement.
The company said no other contributing causes were found.
The rocket's RD-171M main engine was built by NPO Energomash in Russia, and the Zenit's two main stages are manufactured by Yuzhmash in Ukraine.
The Feb. 1 failure marked the fourth problematic launch in 35 flights from Sea Launch's ocean pad, and it was the first anomaly since the company emerged from Chapter 11 bankruptcy proceedings in 2010.
Sea Launch reorganized under majority Russian ownership after the bankruptcy, shedding debt and jettisoning much of the equity interest held by firms in the United States, Norway and Ukraine.
The company is headquartered in Bern, Switzerland.
Soon after the February mishap, Sea Launch's majority shareholder - RSC Energia - vowed to resume launching satellites using the ocean-based system.
The earliest Sea Launch could launch another Zenit 3SL rocket is at the end of 2013, according to Peter Stier, a Sea Launch spokesperson.
Stier said Sea Launch will receive its next batch of Zenit rocket hardware at the company's home port in Long Beach, Calif., in the fourth quarter of this year in shipments from Ukraine and Russia. Sea Launch assembles the Zenit rocket and Block DM upper stage with a satellite payload in Long Beach, then sails the command ship and launch platform to the launch site in the Pacific Ocean.
The Zenit rocket components will undergo modifications to address the issue that caused the Feb. 1 launch failure, Stier said. He declined to disclose what corrective actions are planned for the hardware.
The launch provider, which has seen its market share dwindle after bankruptcy, announced a deal in March for the launch of an unnamed communications satellite for EchoStar Corp. in 2015. The EchoStar launch was the exercise of an existing contract option with the satellite operator, which owns the DISH Network direct-to-home television service.
Sea Launch also has a contract option with AsiaSat of Hong Kong.
Sea Launch takes advantage of a performance boost from the higher speed of Earth's rotation on the equator, allowing the Zenit rocket to place heavier satellites into geostationary orbit, a common destination for communications spacecraft.
The company uses the Odyssey platform, a converted North Sea oil drilling rig, and a command and control ship to support its launches.
One or two launches of Zenit rockets are planned this year from the Baikonur Cosmodrome in Kazakhstan, Stier said. The return-to-flight mission is currently set to loft the Amos 4 communications satellite for Israel Aerospace Industries and Space Communication Ltd. of Tel Aviv.
The commercial launch from Baikonur, arranged through Space International Services Ltd. of Moscow under the Land Launch marketing banner, is not affiliated with the Sea Launch venture.
Another Zenit launch this year or next year will haul the Lybid communications satellite into orbit for Ukraine, officials said.