At what level of probability must a potential close approach generally be for active avoidance action to be taken?

Answer

Around one in 10,000 or higher

If the probability of impact exceeds a certain threshold, often cited as around one in 10,000 or higher, ground controllers must initiate avoidance protocols.

At what level of probability must a potential close approach generally be for active avoidance action to be taken?

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How ISS avoids collision with deadly debris & asteroids? - YouTube

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