Press Release

Sea Launch Completes Investigation of In-Flight Anomaly

By SpaceRef Editor
October 8, 2004
Filed under , ,
Sea Launch Completes Investigation of In-Flight Anomaly

Preparations for Return to Flight Underway

LONG BEACH, Calif., October 7, 2004 – The Sea Launch Independent Review
Board (IRB) has concluded its review of the Telstar 18 mission on June 28,
which released the satellite short of its intended target apogee. Sea Launch
is now ready to return to flight.

Immediately following the mission, Sea Launch partner RSC Energia appointed
a commission in Moscow to investigate a premature shutdown of the Block
DM-SL upper stage. RSC Energia was able to recreate the anomaly on the
ground in full scope, matching the flight telemetry data from the Telstar 18

The commission identified the most probable cause as a short in the onboard
cable network. This short introduced electrical interference in the circuits
that transmit liquid oxygen and fuel flow rate data to the main engine
control system. The main engine control system performed nominally, given
the distorted data it received from the flow rate sensors. As a result of
the main engine control system acting upon the distorted data, the Block
DM-SL consumed more fuel than planned and prematurely shut down due to fuel
depletion. The shutdown was performed nominally based on the ability of the
robust Block DM-SL control system to handle contingency situations.

The IRB unanimously approved the commission’s findings and recommended
corrective actions. Kirk Pysher, vice president and chief systems engineer
for Sea Launch, chaired the IRB, which included the Sea Launch partners,
independent reviewers, subject matter experts and customer representatives.

The required corrective actions were developed and verified through test to
prevent a similar anomaly from occurring in future flights. The IRB has
confirmed the corrective actions are appropriate and will increase the
overall Block DM-SL reliability through increased fault tolerance during
flight and pre-launch screening for defects. It also confirmed the Block
DM-SL is ready for return to flight. Sea Launch remains highly confident in
the robust capability of the Zenit-3SL system, including the upper stage.
The Block DM-SL is one of the premiere upper stages in the industry, with
more than 220 successful flights and an overall reliability of approximately

Despite the early shutdown of the upper stage engine, spacecraft
manufacturer Space Systems/Loral raised the Telstar 18 satellite to its
final orbital position, where it is now fully operational. Loral says it
expects the spacecraft to meet or exceed its 13-year specified life.

Sea Launch Company, LLC, headquartered in Long Beach, Calif., and marketed
through Boeing Launch Services, is the world leader in providing heavy-lift
commercial launch services. The international partnership offers the most
direct and cost-effective route to geostationary orbit. With the advantage
of a launch site on the Equator, the reliable Zenit-3SL rocket can lift a
heavier spacecraft mass or provide longer life on orbit, providing best
value plus schedule assurance. For additional information, please visit the
Sea Launch website at:


Paula Korn

562.499.4729 or 562.254.5684 (mobile)

SpaceRef staff editor.