Okay, I've been thinking of writing a story and I have a few questions. First, the idea is that a cargo ship on the way back to Earth from the outer solar system is sabotaged or has an accident, leading to a loss of communication with the rest of the solar system and, more importantly, their fusion reactor has been damaged and they cannot accelerate or decelerate. And to make matters worse, I was considering having them be on a collision course with Earth unless they can get their ship working again. (If feasible) Ship specifications: Some type of ion engine to provide propulsion. Fusion Reactor for power. Spinning ring where the crew live/work. No cryogenics or anything like that. Designed to haul large, bulky cargo. At least 1000 tons worth. Cannot enter the atmosphere of a planet. Now, specific questions. 1. What kind of minimum mass would a ship like this have? 2. What kind of velocity could they realistically reach given ship mass, engine, and fuel constraints? Would 0.01c be feasible? 3. Without primary power, what kind of problems would they have to deal with? I've thought of things like shortage of fresh water, ship temperature regulation, oxygen generation, and difficulty repairing the ship. What else? That's it for now. If anyone has any suggestions please feel free to comment.