Russian Thruster Misfire Incident Turned Out To Be More Dangerous

On July 29, the Russian module, Nauka, docked successfully at the International Space Station (ISS) and after a few hours, its thrusters began to fire autonomously. NASA had then reported that the incident had spun the ISS by 45 degrees. But a follow-up story has revealed that the incident was far more serious than that.  

Speaking to the New York Times, flight director, Zebulon Scoville, who was in charge when the mishap occurred, recounted the day when he had to declare a "spacecraft emergency" during his seven-year-long tenure. Had the situation not been brought under control, there was a serious risk that the spacecraft would be lost forever. But the quick thinking and rapid response of the team ensured that the worst-case scenario did not come to pass, rather the crew in the ISS, were hardly in any danger.   

Taking charge on an off-day so that his colleague could attend some meetings, Scoville received two messages that indicated that the ISS had lost "attitude control". Video feed from the ISS helped them recognize that the Nauka's thrusters had begun firing, after the successful dock. Scoville's team contacted Nauka's team to shut the thrusters off but were told that they could do so, only after 70 minutes, when the ISS was above Russian airspace, the NYT report said.   

As the thrusters continued to fire, the ISS began to spin at 0.56 degrees a second, not fast enough for astronauts aboard to even notice the spin. But the uncontrolled spinning put instruments and ISS at risk. NASA mission control alerted the astronauts declaring an emergency and then worked with Russian mission control to fire thrusters on two other spacecraft that were docked on the opposite end of the Nauka to balance the forces, according to NYT.

The Nauka thrusters then abruptly stopped firing and the ISS was flipped back into the correct orientation. The whole situation lasted an hour. While NASA had reported that the ISS had spun 45 degrees, Scoville said that the number was incorrectly reported and the flight had actually turned 540 degrees and even flipped on its back, before coming to a stop. Following the NYT report, NASA also tweeted an update confirming the same.  

Update: @space_station was 45° out of attitude when Nauka's thrusters were still firing & loss of control was discussed with the crew. Further analysis showed total attitude change before regaining normal attitude control was ~540°. Station is in good shape & operating normally.

— NASA (@NASA) August 3, 2021

In spite of the incident, Scoville had only good things to say about his Russian counterparts and called them "fantastic partners" in the ISS program. 

Life aboard the ISS is quite unpredictable. One day, you are holding your own Olympic Games and on another is an emergency like never before.