You can cheat a bit by making use of laser propulsion[0] to propel a rocket that contains the necessary fuel for deceleration. To almost completely eliminate f

You can cheat a bit by making use of laser propulsion[0] to propel a rocket that contains the necessary fuel for deceleration. To almost completely eliminate fuel requirements in subsequent trips you would bring the self-replicating equipment necessary to scale up the industrial capacity to build an complimentary laser system in the destination star system. This would allow you to propel ships on return voyages and slow down ships coming to the planet. The downside of course is that you've now built a death laser in each star system that could be used to wreak havoc. But then again in this scenario you've also built self-replicating space bots that can turn asteroids into stuff or planets into asteroids into stuff. [0] https://en.wikipedia.org/wiki/Laser_propulsion https://en.wikipedia.org/wiki/Laser_propulsion