Aussie missile launcher seen by War Office marks major stage (6)

I believe the answer is:

womera

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'stage' is the definition.
Both the answer and definition are singular nouns.
Maybe there's a link between them I don't understand?

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Another definition for womera that I've seen is " stick in Australia".)

I've seen this clue in The Times and The Sunday Times.

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