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Sea Launch Test Flight Downed by 2nd Stage Glitch

By Anatoly Zak Staff Writer posted: 07:05 pm EST 15 March 2000

Sea Launch Fails to Deliver ICO Satellite

The manufacturer of the Zenit 3-SL booster rocket, which failed on Sunday after takeoff from a platform in the Pacific, officially announced that an error in the prelaunch sequence caused the failure.

In todays statement, KB Yuzhnoe in Dnepropetrovsk said that the analysis of information from launch-sequence processing showed that shortly before takeoff, a necessary command to close the valve of a pneumatic system on the rockets second stage had not been sent.

By the time the second stage engine ignited in flight, its pneumatic system lost more than 60 percent of its pressure. As a result, the system could not function properly to provide automatic control of the propulsion unit, including its steering engine.

The Zenits second stage is equipped with a one-chamber RD 120 engine produced by Moscow-based Energomash, which provides most of the thrust for the stage, and a small, four-chamber 11D 513 engine, which allows steering the rocket in flight.

The second stage propulsion unit shut down at 7 minutes, 41 seconds into the flight, sending its commercial communications payload to plunge into the ocean around 2,672 miles (4,300 kilometers) downrange from the altitude of around 124 miles (200 kilometers). Nobody was hurt.

The performance of the first stage powered by a four-chamber RD 171 engine was nominal.

KB Yuzhnoe, which builds the first and second stage of the three-stage vehicle, said that the most probable cause of the failure was a logic error introduced into the automated launch sequence during the systems update after the second launch.

No other anomalies were reported in flight, and all the hardware already manufactured and delivered to the Sea Launch home port in the U.S. will not require upgrades, KB Yuzhnoe said.

The Zenit 3-SL rocket is based on a two-stage Zenit 2 launcher capable of delivering up to 13 tons (13.208 kilograms) of payload into the low Earth orbit. It is Russias newest and most advanced standard launcher.

The booster uses a highly automated prelaunch process, as well as ecologically friendly engines on all its stages that burn liquid oxygen and kerosene. These were major factors in its use by Sea Launch -- a multinational joint venture including Boeing of the U.S., KB Yuzhnoe of Ukraine, RKK Energia of Russia and Kvaerner Maritime of Norway.

Sea Launch employs a converted oil platform to conduct launch operations from the equator, where a rocket can carry an increased payload into orbit because it is maximizing the boost it receives from the force of Earth's rotation.

The Block DM SL upper stage, manufactured by RKKEnergia, was added to the rocket to form the Zenit 3-SL used by Sea Launch.

In September 1999, Sea Launch successfully delivered its first commercial payload into the orbit. The first demonstration launch of the Zenit 3-SL from the Sea Launch platform in March 1999 was also flawless.

In 1998, 12 Globalstar communications spacecraft were lost in the failure of a Zenit 2 rocket that lifted off from the Baikonur Cosmodrome. Three Zenit 2 launchers also failed to deliver military payloads between 1990 and 1992. A 1990 accident destroyed one of Zenits launch pads at Baikonur.

-- (, March 16, 2000

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