The thrusters on the Soyuz capsule to be used to return the two filmmakers and one Russian astronaut back to Earth on October 17th would not stop firing when they were supposed to during routine testing in preparation for undocking.
From the NASA announcement, which by the way buried this event in the announcement’s eighth paragraph:
At 5:02 a.m. EDT today, Russian flight controllers conducted a scheduled thruster firing test on the Soyuz MS-18 spacecraft that is scheduled to return to Earth Saturday night with three crew members aboard. The thruster firing unexpectedly continued after the end of the test window, resulting in a loss of attitude control for the International Space Station at 5:13 a.m. Within 30 minutes, flight controllers regained attitude control of the space station, which is now in a stable configuration. The crew was awake at the time of the event and was not in any danger.
Flight controllers are continuing to evaluate data on the station’s brief attitude change due to the thruster firing. NASA and Roscosmos are collaborating to understand the root cause.
According to the first link, the thrusters tilted the entire station 57 degrees from its correct orientation.
Not only do they not know why the thrusters did not shut down when commanded, they do not know why they eventually stopped firing. They suspect it was because the thrusters ran out of fuel, but this is not yet confirmed.
The Russians still plan to use this Soyuz to return the film crew in two days. The story does not say whether these thrusters are needed in any way to deorbit the capsule.
That’s the second uncontrolled thruster firing from a Russian spacecraft docked to ISS in less than three months. Yet, no such thing had occurred for many decades prior to this. In fact, the last such events that I can remember occurred in the 1960s.
Why such events are suddenly occurring now with such frequency is very concerning, to put it mildly. It brings to my mind the drilled hole in an earlier Soyuz capsule, a hole that was clearly drilled in Russia when the capsule was on the ground and then covered up so it was not detected until the capsule was docked to ISS. The Russians investigated, said they solved the mystery, but have never told anyone what that solution was.
To paraphrase Shakespeare, something is very rotten in Roscosmos.
