I didn't read the whole thing (and my planetary physics is pretty basic), but how would one protect infrastructure from getting struck by small bodies (asteroid

I didn't read the whole thing (and my planetary physics is pretty basic), but how would one protect infrastructure from getting struck by small bodies (asteroids I guess?)? Or are they a much rarer occurrence than I thought (I'm basing this off the fact that the moon is famously full of craters, and we were taught that in school that the moon "protects" earth)!