Stephen Clark at SpaceFlight Now tells us the Russians have already run the Soyuz anomaly to ground:
In an announcement Monday, the Russian space agency said the investigation into the Soyuz launch failure Aug. 24 was focusing on a malfunction in the rocket’s third stage gas generator. The launch was carrying an automated Progress cargo ship to the International Space Station, and debris from the mission crashed in the Altai region of southern Russia.
"Off-nominal performance of [Soyuz third stage] propulsion system was found by the board to be due to the gas generator whose operating conditions were disrupted," the Russian announcement said.
The Soyuz investigation has not formally issued its findings or recommended corrective actions. A launch schedule for the next manned flight to the International Space Station will not be decided until the commission completes its work.
But a gas generator “whose operating conditions were disrupted” by… what? Programming error? Static discharge? Computer/chip fail? A workmanship issue?
Check out the Soyuz Users Manual which offers a bit more third stage detail:
The third-stage engine is powered by a single turbopump spun by gas from combustion of the main propellants in a gas generator. These combustion gases are recovered to feed four vernier thrusters that handle attitude control of the vehicle. For deorbitation and collision avoidance, a reaction nozzle is positioned on the side of the stage and vents the oxygen tank. The LOX tank is pressurized by the heating and evaporation of the oxygen, while the kerosene tank is pressurized by combustion products from the gas generator. An interstage truss structure connects the core stage with the third stage, thereby allowing for the ignition of the third stage before separation of the second. In fact, this ignition assists the separation of the second stage.
So even though the investigation hasn’t closed out, it appears the Russians are already in a full-court-press to return-to-flight. Again, at about $55 million per ride to the space station, as well as the monies from the resupply missions, the Russians certainly want the fees.