[kanisae]

Fission is the way to go for this for its general simplicity of design and it can self start by manually moving control rods. I never see anyone talking about they are going to restart a fusion reactor if it ever goes offline for any reason.

My thought is to use fission for powering the ship, and fusion for the drive. The fission reactors can start the fusion drive as needed and you can have multiple portable fission reactors like the NASA kilopower designs in an offline/inert state that could be powered on in an emergency.