An Israeli communications satellite successfully launched Saturday from the Baikonur Cosmodrome on the first flight of a Zenit rocket since the same type of launcher lost control and crashed into the Pacific Ocean moments after liftoff in February.

Credit: TsENKI TV
 
The Zenit 3SLB rocket blasted off at 2005 GMT (4:05 p.m. EDT) Saturday from the Baikonur Cosmodrome in Kazakhstan. After getting a boost to space from two Ukrainian-built stages, the launcher's Russian kerosene-fueled Block DM upper stage fired three times before releasing the Amos 4 communications satellite into orbit at 0250 GMT Sunday (10:50 p.m. EDT Saturday).

Saturday's launch was the first flight of a Zenit rocket since a doomed Feb. 1 mission under the auspices of Sea Launch destroyed the Intelsat 27 communications satellite seconds after liftoff from Sea Launch's ocean-going launch platform in the Pacific Ocean.

Investigators blamed the Feb. 1 failure on a component inside the Zenit first stage's hydraulic steering system.

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 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 Block DM upper stage comes from Moscow-based Energia.

The launch of Amos 4 was conducted under the Land Launch banner managed by Space International Services Ltd., a Russian launch provider. Sea Launch was not affiliated with the Amos 4 mission, but the Land Launch and Sea Launch services use same type of rocket with minimal changes.

Photo of Amos 4 with its antennas and solar array deployed. Credit: IAI
 
Amos 4, described by its operator as Israel's largest and most sophisticated communications satellite, will provide direct-to-home television broadcasting, multimedia, broadband Internet and mobile communications services for 12 years.

With a launch mass of nearly 9,500 pounds, Amos 4 was built by Israel Aerospace Industries for Spacecom, Israel's Tel Aviv-based communications satellite operator.

IAI and Spacecom announced ground controllers established communications with the Amos 4 satellite shortly after its deployment from the Zenit's Block DM upper stage, indicating the craft was healthy following launch.

"We feel very proud of Amos 4, which reaffirms IAI's position as a world class satellite provider with industry leading capabilities in observation and communication satellites," said Joseph Weiss, IAI president and CEO.

Amos 4 will extend Spaceom's coverage footprint to Russia and Asia, along with improving service in the Middle East and Europe with Ku-band and Ka-band transponders.

"Amos 4 continues Spacecom's tradition of providing top quality satellite solutions primarily for emerging markets and is another milestone for the company," said David Pollack, Spacecom's president and CEO. "We are continuing to maintain our fast growth as we push to become a major player in our markets and expand and extend our reach in becoming a global satellite operator. Working with IAI throughout the process has been a blessing and we look forward to further cooperation with them."

The satellite will be positioned in geostationary orbit 22,300 miles over the equator at 65 degrees east longitude, but Amos 4 will initially operate from 67.25 degrees east longitude for in-orbit testing.