On the first mission, tracking stations have to be knocked out so the human convoy can pass undetected.

A web was set up through which not even a grain-of-sand meteorite could pass undetected.

To a surface dweller, he might have passed undetected only a foot away.

I think they are a long way from being able to pass undetected.

Both of them had passed undetected in the standard body scan the police had given him back on Earth.

Assume further that a test sometimes fails, allowing one in every thousand errors to pass undetected.

Given shelter, someone might pass undetected in this landscape for some time.

So much can go wrong - and pass undetected.

Behind closed doors: How could events in the house have passed undetected for so long?

How could events in the house, which is situated on a busy street, have passed undetected for so long?