CAPS: the only driver for manned space
The problems of detecting approaching comets and their fragments are so formidable that only the largest Moon based systems will be adequate. An dhtese will have to be man tended, or men will be involved in their deployment.
Afterwards we can consider Mars.
But then what do I know about the impact hazard?
I only wrote the book which is the only survey of actual impact data for the Americas.
You can thank me later.
E.P. Grondine
Man and Impact in the Americas