What component, if any, would cause irreparable harm ("total") the ISS if it were to break or require replacement? If this component exists, when is it going to reach its end-of-life?

By "total", I mean that it would be cheaper to build a new space station rather than repair or replace the broken component. Also, since this hypothetical repair might go into Ship of Theseus territory, I would consider the ISS to have been "totaled" if it's given a new name afterwards, like ISS2 instead of ISS.


1 Answer 1


Speculative, but I'll nominate the S0 Truss.

This truss segment forms the center of the ISS truss structure and also connects the truss to the chain of pressurized modules. If the S0 suffered complete structural failure, the truss could separate into two sections and the chain of pressurized modules into a third. Since the majority of electrical power comes from, and the majority of heat rejection goes to, the truss, it would be catastrophic even if the modules remained pressurized.

The S0 is highlighted in gold here and pointed out by the red arrow. Image created by myself using DOUG.

enter image description here

The S0 truss is fairly old; it was added to the ISS in April 2002 during shuttle mission STS-110. I am aware of studies done back when I worked at JSC in the 2014 timeframe concerning extension of the station life to 2024, but I don't have any information about the results.

I am not advancing this as a credible failure; just what seems to me would be one of the failures with the worst impact.

  • 2
    $\begingroup$ what could a gyro do if it spontaneously broke into a few pieces at maximum angular velocity? $\endgroup$
    – uhoh
    Feb 24, 2020 at 3:13
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    $\begingroup$ Can we really consider a whole truss structure as a single “component”? $\endgroup$
    – Michael
    Feb 24, 2020 at 10:26
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    $\begingroup$ @Michael If so, I nominate the ISS. If the ISS required replacement, it could cause us to launch a new station instead of using the ISS. The gold highlight does appear to consist of two separate sections... $\endgroup$
    – user253751
    Feb 24, 2020 at 11:55
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    $\begingroup$ @fraxinus ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100021932.pdf 6600 rpm $\endgroup$ Feb 24, 2020 at 14:10
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    $\begingroup$ What if one of the central modules, like Node 1 suffered a large puncture? If one of the exterior modules gets a hole in it, then it can just be sealed off but damage to Unity or Destiny would cripple ISS operations imo $\endgroup$
    – Dragongeek
    Feb 24, 2020 at 18:24

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