The State Commission
investigating the failure of a Proton/Block DM launch vehicle, which
left the ASTRA 1K satellite in a lower-than-planned orbit, has
submitted its final report to the Russian government, International
Launch Services (ILS) announced today.
The commission also provided a report to the ILS Failure Review
Oversight Board (FROB), which begins its review of the findings this
week in Moscow. The State Commission and the FROB were formed shortly
after the Nov. 26 launch from the Baikonur Cosmodrome in Kazakhstan.
The State Commission exonerated the Khrunichev-built, three-stage
Proton launch vehicle early in its investigation. “No fault has been
found with the implementation of the mission profile during the
powered flight of Proton’s Stages 1 through 3,” the final report
states.
The commission identified the Block DM upper stage as the source
of the failure. RSC Energia builds the Block DM. The commission noted
that the anomaly occurred at the start of the second Block DM main
engine burn, as did three other Block DM failures since 1996.
In the final report, the commission was unable to pinpoint a
single root cause for the failure. There was excessive fuel in the
main engine when it was ignited for the second burn, which led to
extraordinarily high temperatures that destroyed the engine, the
commission found. It identified two possible scenarios for the fuel
build-up, both attributed to “stray particles” that clogged the engine
components.
“The failure … to perform the second burn was caused by an
abnormal development of the start-up process in the course of which
ignition took place in the gas duct due to the excessive amount of the
fuel … present at the ignition time during the attempted second
burn,” the report states. “This in turn was caused by either 1) stray
particles clogging the manifolds through which (the fuel) is drained
from the starting-fluid feed line after the first burn or 2) loss of
air-tightness, due to stray particles, of the valve designed to supply
the fuel to the gas generator injector.”
Energia is developing a corrective action plan to submit to the
commission. The commission in turn will review the plan to determine
the validity and sufficiency of the proposed remedies. The commission
recommended seven areas to review for corrective action, including
Block DM testing and inspection, and processing of propellants, all to
be addressed by Energia.
ILS established the Failure Review Oversight Board to provide an
independent assessment of the State Commission findings and to ensure
that a robust corrective action plan is in place before commercial
flights are resumed. FROB Chairman Eric Laursen, ILS vice president
and chief engineer, and other members arrived in Moscow to begin their
review this week. The FROB process includes meeting with
representatives from the State Commission and from hardware
subcontractors.
“This incident shows similarities to other Block DM failures, and
we will take as much time as necessary to determine that the cause is
properly addressed,” Laursen said. “We won’t use this upper stage
until we are certain it is flight-worthy. ILS remains committed to
providing reliable, timely launch services for all our customers.”
Besides Laursen, FROB members include retired NASA and launch
industry experts, and representatives of SES-Global, owner of ASTRA
1K, and SES-Americom, the next scheduled ILS customer for Proton.
The Russian commission was led by Anatoli Koroteev, general
director of the Thermal Processes Institute of the Keldish Center, and
includes representatives of all organizations involved in the design,
manufacture, operation and support of the Proton/Block DM launch
vehicle.
