Craftily united in the conquest of space (6)

I believe the answer is:

docked

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'craftily united' is the definition.
Although both the answer and definition are past participle verbs, I can't see how they can define each other.

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for docked that I've seen before include "Cut short" , "Berthed" .)

I've seen this clue in the Evening Standard.

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