What is the maximum final relative speed of two spacecraft docking? Say, a supply ship docking with the ISS.

I imagine the incoming ship would try to break as much as possible, but there must be some residual speed.

It's probably dependent on the kinds of the two spacecraft. I'm fine with just a rough idea, i.e. 1 m/s, 10 cm/s, etc

(question was inspired by answering How to plot a Clohessy Wiltshire trajectory on MATLAB?)


1 Answer 1


We can put an upper bound on this by looking at the requirements for relative velocity in the International Docking Standards.

Here is a screen shot of the relevant page. You can see the closing velocity upper limit is 0.1 m/s.

enter image description here

  • 2
    $\begingroup$ So, there actually is a website internationaldockingstandard.com . You live and learn. Thanks for the answer! $\endgroup$ Commented Feb 23, 2018 at 19:32
  • $\begingroup$ Huh. 0.1 m/s contact speed seems... bold. $\endgroup$ Commented Feb 23, 2018 at 21:57
  • $\begingroup$ If 0.1 m/s contact speed seems... bold, what is about 0.05 m/s? 0.05 m/s < contact speed < 0.1 m/s. $\endgroup$
    – Uwe
    Commented Feb 24, 2018 at 9:33
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    $\begingroup$ I think 0.05 is the lower bound. You have to get there, after all. $\endgroup$ Commented Feb 24, 2018 at 16:52
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    $\begingroup$ The lower bound is about ensuring the mechanism latches. Ish. I think the petals in particular depend on the incoming spacecraft having residual momentum so it can be guided into the proper ending position. (I've worked on the standard in question, though not on that part of it) $\endgroup$
    – Erin Anne
    Commented Feb 26, 2018 at 4:32

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