Russian specialists are stepping up quality control inspections at engine factories after investigators determined a production defect triggered the Aug. 24 failure of a Soyuz U rocket, effectively grounding the only spacecraft capable of flying astronauts and cosmonauts to the International Space Station.
The entire inventory of Russian rocket propulsion systems will be re-inspected as part of a program recommended by a special commission that traced the third-stage engine failure -- and the resulting loss of a supply-filled Progress cargo carrier -- to a clogged propellant line.
The finding was posted on the Facebook site of Roscosmos, the Russian Federal Space Agency. A status update there says telemetry data beamed back from the rocket shows a reduction in the amount of fuel being consumed by a gas generator shortly after ignition of the third-stage engine, or about 325 seconds into flight.
The engine automatically shut down, and the Soyuz U rocket and its payload made a destructive plunge back into the atmosphere. Any surviving wreckage rained down in remote, heavily forested mountains in the Republic of Altai.
The commission came to the conclusion that the clogged fuel line was specific to the failed engine and not a fleet-wide problem. "However, the decision to qualify the accident as a single occurrence should be taken only following additional checks and a special quality control program reviewing the entire inventory of the already manufactured propulsion systems," the Roscosmos update said.
Russian Prime Minister Vladimir Putin ordered an industry-wide quality control review after the Aug 24 launch failure, which was the second in a week and the fourth in the previous nine months for the Russian space program.
The third-stage of the Soyuz FG used to ferry Soyuz space capsules and crews to the International Space Station is very similar to the third stage of the failed Soyuz U rocket. The planned Sept. 21 launch of the next three station crew members was indefinitely delayed, raising the possibility that the outpost might have to be evacuated.
Two cosmonauts and American astronaut Ron Garan are scheduled to return to Earth on Thursday. The three remaining on the station -- including U.S. astronaut Mike Fossum -- are scheduled to return in mid-November.
The next station trio -- which includes NASA astronaut Dan Burbank -- now are tentatively scheduled for launch around Nov. 12 -- just four days before the planned Nov. 16 return of Fossum and his crewmates. Fossum's crew needs to depart the station by Nov 19 to avoid a prohibited nighttime landing in Kazakhstan.
Another three-member crew that includes US astronaut Don Pettit is scheduled to launch Dec 20.