ISS crew returns safely to Earth

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After their return was delayed because of the Progress launch failure, three astronauts today successfully returned to Earth from ISS, using the Soyuz capsule whose thrusters had fired by accident during radio checks several days ago.


  • BSJ

    “Although the incident sounds dramatic, former ISS commander Chris Hadfield took to Twitter to note such unexpected firings can take place in this manner.

    “While re-powering the Soyuz after six months, it’s possible to inadvertently activate its attitude control and fire the thrusters,” he wrote. “No real harm done, it happened during Expedition 7 too, just wastes a bit of fuel, and Soyuz has plenty.”

    And somebody once said that foam falling off the shuttle’s main tank was no problem at all. Happens all the time, so why worry…

  • Gealon

    Indeed, I don’t imagine the station it designed to withstand the kinds of load that would be generated if, oh let’s say, another thruster firing occurs and they can’t stop it. Putting the station into a rapid roll in any axis would likely destroy the main solar arrays and for all we know, rupture one or more modules from the increasing stress.

    Nope, I think you are spot on, that “No harm done” quote is just a bit of sugar coating to make us feel good about something that could have turned into a catastrophe.

  • Edward

    This reminds me of Gemini 8, when a thruster wouldn’t stop firing, spun up the spacecraft, and could have killed the crew.

    Any inadvertent action or operation in space should not be treated lightly or tolerated. As several crews could tell us, if they were still alive, space is a dangerous place, and it does not take much to go wrong to kill everyone on board. Ground testing has had tragically deadly accidents, too.

    I hope that the thruster problem was one of cosmonaut error and not some inherent electrical problem. However, that it happened before suggests that there is a procedural or systemic problem that has yet to be rectified, and that should frighten the space community, not reassure it.

    As you said, Gealon, if the thruster won’t stop, as it wouldn’t on Gemini 8, then all that “plenty” of fuel that Hadfield likes today could turn a small hiccough, tomorrow, into the catastrophe that Gemini 8 avoided and that Hadfield would not like.

    BSJ wrote, “And somebody once said that foam falling off the shuttle’s main tank was no problem at all. Happens all the time, so why worry…”

    Diane Vaughn used (or coined) the phrase “normalization of deviance” in her book “The Challenger Launch Decision,” meaning the same thing. A problem (deviance) wasn’t catastrophic any of the times that it happened before, so they started to think of it as normal operation (normalization).

  • PeterF

    Perhaps future habitats should be designed with a “vestibule” that can be cut loose if there is a problem like this in the future.

  • Right now the “vestibule” is called a Soyuz capsule. Two in fact, available all the time. Doesn’t that make you feel great!

    Soon however — in only a few years — we will have our own lifeboats, American-made, and thus I think far more reliable.

  • Gealon

    Edward, thank you for reminding me about Gemini 8. I recalled the thruster problem was from one of the early capsules but didn’t have the time to research the name yesterday.

  • PeterF

    No, no! I meant like an actual module that ferries/capsules can dock to. It would act as an airlock between the habitat and powered vehicles. Sort of a loading dock/ mudroom.
    I envision a large inflatable unit with multiple docking ports. Access to the habitat through a double hatch would remain sealed at most times. A flexible structure would be more forgiving during “sloppy” docking eliminating unnecessary stresses on the habitat. If there was a catastrophic accident during docking/ undocking, only the atmosphere in the bubble would be at risk.
    If a docked craft experienced an anomalous thruster event, the bubble would “break off” at the frangible connection. The vestibule wouldn’t be damaged and could then be recoverable.

    An alternative design would resemble an accordion. An arriving vessel would “park” at a specified distance. The accordion would be inflated so that the docking collar would extend to the vessel hatch. Powerful electromagnets would be energized for the initial connection to align the hatches to a matching “hard” connection. (These could also be used for a temporary “soft” dock to any smooth ferrous hull of a non-matching vessel’s docking port) Air pressure in the accordion would keep the vessel at a safe distance. The pleats in the accordion would enable large lateral motions while maintaining a fairly constant internal volume. The frangible connection of this system would then be located between the accordion and the vestibule. The only resource at risk would be the accordion and its atmosphere. And the accordion would also be recoverable.

  • Gealon

    The Russians actually do sort of have that on a few of their docking ports. Rasvet and the older Pirs docking compartment act as air locks. Though with all of the free floating cabling and ductwork, a quick disconnect isn’t exactly possible should another capsule malfunction, nor would be cutting the capsule loose. Cutting a misfiring capsule loose though could be even worse as it could come back and collide with another part of the station.

    I think the best bet to improve safety is A; for the Russians to take a good long look at their quality control issues and actually do something about them, and B; perhaps install a mechanism to cut off the fuel feeds to the thrusters for the duration of docked operations. If B has already been implemented and this was indeed just a confused step in their procedures, then simply rework the procedure or change the means by which the thrusters can be activated entirely so it cannot happen accidentally.

  • Edward

    PeterF’s suggested sounds similar to the jetways at airports. I think, however, the better solution is for the spacecraft to be made reasonably reliable and do not unexpectedly start their thrusters.

    Just as the engines on the jets at jetways do not suddenly start up and crash into their terminals, the spacecraft’s thrusters should not suddenly start up and wreak their havoc.

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