Today I used the phrase "retire that risk" and realized I didn't know what it meant. I've heard the phrase used by NASA, [for example here](https://www.nasa.gov/seh/6-4-technical-risk-management):

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> Systems engineers are involved in this process to help...determine if new risks arise or old risks can be retired...
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The usage sounds similar to "retire a debt", which I find to be another puzzling construction.

* Does "retiring a risk" simply mean eliminating it? Or does it require elimination by virtue of passage if time?
* What's the origin of this phrasing and is there an intuitive meaning behind it?