> Engine in development could cut Mars travel time to three months<p>Yes, and fusion power is right around the corner -- perpetually. The central problem is the same -- how to create and sustain a fusion reaction without melting the reactor's container. This engine project is in reality another effort to solve the key problem standing in the way of practical fusion power.<p>It will be terrific if it succeeds, but it's essential to avoid thinking of it as a conceptual alternative to mainstream fusion research. It's fusion research with a nozzle.<p>If mainstream fusion research succeeds, this project will borrow those results. If this project succeeds, mainstream research will borrow its results. They're two branches of a tree.<p>My favorite pipe-dream spacecraft engine generates an acceleration of one G continuously. With such an engine, we could get to Mars in 48 hours -- simply accelerate continuously toward Mars (when it's nearby in its orbit) for 24 hours at one G, then turn the spacecraft around and decelerate for the rest of the trip, arriving with zero velocity. All that remains is to solve the annoying problem that no such thing exists.