Found a site with worked numbers.
https://space.stackexchange.com/ques...-get-you-there
These are all from earth
The Moon / Luna:
Closest to Earth (Supermoon): 356,577 km
Travel time (at 9.80665 m/s2, no deceleration): 2h 22m 12s
Travel time (at 9.80665 m/s2, decelerating halfway): 3h 20m 24s
So turnover at 1h 40m gives you 42m to stop it. Should be doable if it isn't a warship with armor and point defenses.
Mars:
Closest to Earth: 65 million km
Travel time (at 9.80665 m/s2, no deceleration): 1d 7h 58m 5s
Travel time (at 9.80665 m/s2, decelerating halfway): 1d 21h 13m 1s
Turnover at 23h, gives about 9 h to stop it.
That all sounds like you can with procedures and pre planned interceptors deal with it.
Lots of possibility for complacency, budget cutting and such to make it a PC problem that they have to make do.