As far I know, in the time of the MIR + Space Shuttle dockings it was a problem to solve.

Are their docking systems compatible?

  • $\begingroup$ Strongly related: space.stackexchange.com/questions/4980/… $\endgroup$
    – Mark
    Apr 2, 2018 at 5:37
  • $\begingroup$ @peterh do you mean APAS-95? $\endgroup$
    – zephyr0110
    Apr 2, 2018 at 6:31
  • $\begingroup$ @Mark Yes, although that post doesn't say, are the Tiangong-2 and the ISS compatible. Although likely they are, because Tiangong-1 used APAS-95 and also the ISS has APAS-95 ports, and it is unlikely that the Chinese would use different docking ports for their space stations. $\endgroup$
    – peterh
    Apr 2, 2018 at 6:59
  • $\begingroup$ @Prakhar Yes. I improved my comment. :-) $\endgroup$
    – peterh
    Apr 2, 2018 at 7:00
  • $\begingroup$ @peterh, actually, they're probably not compatible. ISS and Tiangong-1 both have passive APAS-95 ports, and to dock two APAS-95 ports, at least one needs to be an active port. $\endgroup$
    – Mark
    Apr 2, 2018 at 21:25

1 Answer 1


One of the docking systems in use on the ISS is a passive APAS-95 system. Tiangong-2 is believed to also have a passive APAS-95 system or something mechanically compatible. In order for two APAS-95 adapters to connect, at least one of them needs to be an active adapter, so Tiangong-2 can't dock with the ISS, but a Shenzhou spacecraft could probably dock with either.

  • 2
    $\begingroup$ Only one of the APAS systems on ISS is presently available, and only for another year or so. They are (or will be) all permanently covered. The APAS on PMA-1 is used to connect Node 1 (Unity) to the FGB (Zarya), the APAS on PMA-2 already has an international docking adapter attached, and the APAS on PMA-3 will have such an adapter installed in about a year. $\endgroup$
    – Tristan
    Apr 5, 2018 at 14:00

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