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Sea
Launch Failure May Have Been Due to Unclosed Valve
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Ukrainian
KB Yuzhnoe/PO Yuzhmash, which builds the first and second stage of
the three-stage Sea Launch vehicle, has suggested the most
probable cause of the failure was a logic error introduced into
the automated launch sequence during the system’s update after
the second launch. KB
Yuzhnoe said analysis of information from launch-sequence
processing showed that shortly before takeoff, a computer command
to close the valve of a pneumatic system on the rocket’s second
stage had not been sent. When the second stage engine ignited in
flight, its pneumatic system had 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. Sensing the rocket was not functioning
properly, an onboard safety system shut down the second
stage propulsion unit at 7 minutes, 41 seconds into the flight,
sending its commercial communications payload tumbling into the
ocean about 4,300 km (2,672 miles) downrange from an altitude of
approximately 200 km (124 miles). The Zenit’s 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 performance of the first stage powered by a
four-chamber RD 171 engine was nominal. During the launch phase intermittent
dropouts in data signals occurred, Sea Launch was using NASA's
Tracking and Data Relay Satellite System (TDRSS) to receive data
from the rocket. The information that was available showed the
rocket was losing altitude and not gaining enough speed to make it
into space. Sea Launch has named its chief engineer, Jim Maser, to
lead the Failure Oversight Review Board. The board will begin its
work when the U.S. State Department approves a Technical
Assistance Agreement to allow Sea Launch partners to share
information. Currently, the different companies are reviewing
their own data. Boeing has a 40 percent stake in Sea Launch,
RSC-Energia of Russia has a 25 percent share, Kvaerner Maritime of
Norway owns 20 percent, and KB Yuzhnoye/PO Yuzhmash, of Ukraine
owns 15 percent of the program. Recent filings with the U.S.
Securities and Exchange Commission report Boeing lost US$87
million on Sea Launch in 1998 and another US$57 million in 1999.
More
Information
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