Space Station Did 540-Degree Tumble (Corrected)


The upset of the International Space Station a week ago was a lot more dramatic than was first revealed and there’s now a call for an independent investigation of the incident. As we reported last week the ISS was knocked off its normal attitude when a Russian module that had just docked with the station activated one of its thrusters. NASA officials initially said the mishap nudged the ISS to a bank angle of 45 degrees but they’ve since corrected that. The football-field-sized collection of modules connected by a spindly structure actually tumbled on three axes 540 degrees before systems on the station fired thrusters (ironically from another Russian structure docked to the ISS) to counter the errant maneuver. For the first time in the history of the program, an emergency was declared.

To right the flimsy collection of parts, the crew had to roll it back 180 degrees. The drama forced the cancellation of Boeing’s Starliner crew capsule as the ISS crew looked for potential damage. That process continues as a parade of spaceships line up to dock with the station in the next few weeks, including the Starliner. So far, NASA has issued statements saying the bond between U.S. and Russian space programs remains strong and the two agencies will sort it all out. A former NASA Mission Control scientist who now works as a TV network space consultant says a full independent investigation is warranted. In an op-ed in IEEE Spectrum, James Oberg said the statements coming from both organizations harken to a time when safety culture slipped at NASA in favor of political considerations. “While the proximate cause of the incident is still being unravelled, there are worrisome signs that NASA may be repeating some of the lapses that led to the loss of the Challenger and Columbia space shuttles and their crews,” he wrote. “And because political pressures seem to be driving much of the problem, only an independent investigation with serious political heft can reverse any erosion in safety culture.”

An earlier version of this story said the station rolled, indicating a single axis maneuver, but it actually tumbled on all three axes.

Russ Niles
Russ Niles is Editor-in-Chief of AVweb. He has been a pilot for 30 years and joined AVweb 22 years ago. He and his wife Marni live in southern British Columbia where they also operate a small winery.

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  1. So, are they advertising a sequel to “Space Cowboys”? The gee whiz aspect of that project has waned considerably, and we’re not getting any corresponding bang for our buck from the ISS. It’s time to reload the Manned Mars Mission funding, and focus NASA resources toward manned deep space exploration missions.

      • We do not even need manned deep space missions. Instrumentation is already better at sensing data than a human is that is wrapped up in a space suit. Using people as probes to deep space is a waste of the human.

        • Sensors are better than a human in a space suit at sensing. What spacecraft far away from Earth are not good at is thinking. Rovers and now helicopters on Mars would be getting a lot more science done if there were a human nearby – not 15 light minutes away which makes active control impossible from Earth. Driving a rover would certainly be faster if there were a human in the loop. Also, if humans were nearby, you wouldn’t have to be quite so careful in the design of the rovers. Now if something breaks, the mission is finished. With a human nearby, they could fix it and send the rover back out. There are lots of reasons a combined strategy of humans and robotics would be a great benefit.

          • Repair probes? For the money and resources that it takes to send a human along (and back), you can send a dozen probes for redundancy AND more coverage over an area.

            Probes are expendable; sending people will require crazy amounts of money and testing and resources and weight and systems AND a trip back home. More can be discovered if we don’t send people.

  2. Obviously operational quality is sliding. Getting a little “woke” there NASA? A full root cause analysis should have been done immediately after the incident, followed by corrective actions. “”Still being unraveled” status is code for we’re not saying and lack of transparency will doom any program. Rise and shine boys. QA is a discipline, not a department.

  3. Serious, apparently no interlock in the software to reduce/prevent thrusters firing when very close or docked.

  4. I guess it depends which MSM you pay attention to. I see in the Washington Post, for example, “Russian thruster misfire led to a ‘tug of war’ at the International Space Station as crew sought to regain control”, by By
    Dalvin Brown on July 30, 2021 at 4:08 p.m. EDT. (link, abbreviated in an attempt to evade the AvWeb moderation delay: technology/2021/07/30/boeing-starliner-launch-rescheduled/)

  5. So when they declared an emergency did the NASA controller ask them for the number of souls on board and fuel in pounds?

  6. My understanding from a different source is that it was a single-axis roll, but telemetry data gives a false impression that it was a multi-axis tumble due to the reference attitude used. And the ISS was “backwards” to begin with.

    • That is correct. The uncommanded thruster was firing constantly in a single direction, causing the rotation in one axis. Passing 45deg of rotation the rate was 1/2deg per second.
      As I understand it, this was about the point that other thrusters were brought online to counter the rotation, so rate probably didn’t get much more, though they were unable to stop it entirely until the fuel was depleted from the ‘bad’ module.
      So not any risk of tearing the station apart, but certainly a very serious event nonetheless.

      • At 1/2 degree per second, it took the station 12 minutes to do a complete roll. That’s fairly tame. It’s serious from a control perspective, as nothing should be firing uncommanded; but not serious as far as the lives of the crew or endangering the station.