Reading the question about which modules of the ISS are provided by which partner and in light of the discussion about the future of the ISS the following question came to my mind.

From a technical standpoint, would it be possible to split the ISS into two fully functional space stations? That is, decouple (for example) the Russian segment from the US segment and replace the missing functionality of each segment by new modules.

And if possible, would it be economically more efficient than building two completely new space stations (e.g. one US, one Russian) that fulfill the same tasks as the ISS today?

Note: Of course, on a higher level the ISS is more than the combination of its segments and the collaboration between the different nations is the biggest achievement itself, but I am more interested in the technical aspects here.

  • $\begingroup$ It would be very funny as the U.S. explains in its custom positivist happy-sunshine style, how wonderful is that they let fall their modules down. It will be probably a PR disaster, it should be done in the shadow of another major win. For example, the first human Mars landing, or similar. The problem is that these cost far more as the ISS. $\endgroup$
    – peterh
    Jun 1, 2018 at 11:05
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    $\begingroup$ It's possible if you are not constrained by petty matters such as funding and schedule. Big picture, the US segment needs a propulsion module and a crew escape method. The Russian segment needs a power supply. $\endgroup$ Jun 1, 2018 at 11:39
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    $\begingroup$ ...and obviously the latter is much easier to make. The Russian segment functioned on small solar panels long before the big ones were deployed. US should get human spaceflight certified Dragon soon'ish, but there's no propulsion module anywhere in sight. $\endgroup$
    – SF.
    Jun 1, 2018 at 12:01
  • $\begingroup$ What happened to the ICM? I assume it was somewhat completed before being abandonded. $\endgroup$
    – geoffc
    Jun 1, 2018 at 13:19
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    $\begingroup$ It's partially completed and in storage. Emphasis on partially. Last I heard it would take a couple of years to complete. It was only supposed to be a stopgap anyway, no clue if it could maneuver the US segment as it is today. $\endgroup$ Jun 1, 2018 at 14:20

1 Answer 1


Would it be possible to split the International Space Station (ISS)? Absolutely. The ISS is entirely modular and can be broken down into individual components, but you propose to split the ISS along the US/Russian line and have two functional space stations. That is harder.

Presently, the Russian Zvezda module contains the guidance, navigation, control, and propulsion capabilities of the ISS. Without Zvezda, a separated US station would be in trouble. The US does have the Interim Control Module which would take around two and a half years to complete and launch, assuming a Falcon could be retrofitted to launch it. However, this module was designed to be a temporary solution, and in the long term a more mature solution would need to be designed.

A separated Russian station would be in slightly less trouble. Currently, the Russian segment depends on the US segment for supplemental power, but Russia has already prepared the Science Power Module, which is scheduled to arrive at the ISS in December 2019. The Russian segment also relies on the US segment for communications when not in line of sight of Russian ground stations, but this would not necessarily be a show stopper.

For more information:

  • $\begingroup$ Was there ever an answer focusing on how much it would cost to replace the Zvezda module? $\endgroup$ Jul 3, 2018 at 17:23
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    $\begingroup$ @MagicOctopusUrn No, but the budget to replace could easily exceed a billion dollars. $\endgroup$
    – called2voyage
    Jul 3, 2018 at 17:32

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