A rocket from or to mars is traveling for 9 months so plenty of time to shoot it out of the sky. But I think we will never colonize mars if we don't fix the anti-gravity over there. Last time I heard that ISS visitors decrease around 1% bone density per few days so to live there will be devestating for humans. We need a hybrid race or a big evolution first. Hopefully our war-thoughts evovle out of our systems with us