Watching Dragon/Endeavour dock with the ISS, I was curious as to how they used thrusters to orient the spacecraft and “soft dock” with the ISS. The narrators didn’t mention what happened after the soft dock, but I imagine the “hard dock” was something like a convertible closing the roof where pins and hooks are used to lock both spacecraft together.

I was thinking it might be a simpler procedure for either Dragon or the ISS to extend a pole/boom like they use during aircraft in-flight-refueling where a boom is extended to catch a port. Once the boom is locked in, it could orient Dragon and pull it in for the soft dock. Has that ever been considered?

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    $\begingroup$ That sounds like the previously used berthing procedure where a ship (or "space barge" logistics module carried by the Shuttle in the past) parks near the ISS and the robotic arm grabs it and sticks it on a berthing port. $\endgroup$
    – ikrase
    Jun 1 '20 at 6:47
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    $\begingroup$ Or a bit like the probe and drogue docking mechanisms (albeit without booms) used by Apollo and Soyuz $\endgroup$
    – user20636
    Jun 1 '20 at 8:51

This is how Spacex's previous dragon spacecraft got docked to the ISS. Canadarm2 would grab dragon and pull it to dock to the ISS

See the Dragon Wikipedia page:

For the ISS Dragon cargo flights, the ISS's Canadarm2 grapples its Flight-Releasable Grapple Fixture and berths Dragon to the station's US Orbital Segment using a Common Berthing Mechanism.

Dragon grappled by Canadarm2

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    $\begingroup$ I thought I heard on the broadcast that the ISS went in to a different attitude adjustment mode for Dragon 2. Can you source your statement that it can remain in the same attitude? $\endgroup$
    – PearsonArtPhoto
    Jun 1 '20 at 13:21
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    $\begingroup$ @PearsonArtPhoto My statement was wrong so I removed it. Thank you for bringing it to my attention. Looking at space.stackexchange.com/questions/13425 it seems the ISS keeps rotating when docking, although it might change its attitude a bit. I got the idea that the ISS stopped its rotation for the Soyuz from an old article or answer about Dragon 2 (that said Dragon 2 would be able to match the ISS's rotation) but can't seem to find it anymore $\endgroup$ Jun 1 '20 at 13:39

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