A spacecraft's engines are defined only by the amount of thrust they put out and amount of fuel they use, allowing anything from solar sails to conventional rocket engines to futuristic nuclear fission and fusion drives to be simulated.
A spacecraft's engines are defined only by the amount of thrust and amount of fuel they use. They put out thrust. Amount of fuel is allowing anything from solar sails to conventional rocket engines to futuristic nuclear fission and fusion drives. This is to be simulated. They use fuel.