05-19-2019, 03:37 AM
I was torn between using frozen hydrogen in the Starlark and water.(This is a spaceship adapted from one I designed nearly fifty years ago, in my teens). I can change it to hydrogen, as this is more abundant than methane.
Either way the propellant needs to be heated before it can be used; the rocket motor isn't lit until the ship is far from the Sun, since most of the early acceleration is due to a boostbeam/magsail combo. When the ship is decelerating at the destination, once again it is far from any star (having used a magbrake to loose much of its momentum). In both cases the fuel and propellant will be very cold, and the initial heat from the rocket can be dumped into the fuel and propellant tanks.
Either way the propellant needs to be heated before it can be used; the rocket motor isn't lit until the ship is far from the Sun, since most of the early acceleration is due to a boostbeam/magsail combo. When the ship is decelerating at the destination, once again it is far from any star (having used a magbrake to loose much of its momentum). In both cases the fuel and propellant will be very cold, and the initial heat from the rocket can be dumped into the fuel and propellant tanks.