One idea I've had for a long time is to be able to configure the rocket by tuning variables like power, steering, weight and strength. That's just what I've done with this first version of the Rocket Configurator. You get to it from the Play screen:
Power is obvious. Steering effectively gives it more powerful steering jets, turning the ship more quickly. Weight makes the rocket lighter and direction changes easier. Strength is how well it handles collisions with rocks and planets.
The player can't max out all four variables. If each variable has a range of 0..1, the sum of all can only go up to 2 and the default is [0.5, 0.5, 0.5, 0.5].
It would possibly, maybe, be cool to have this configurator on the Apple watch and be able to change it at any time. But that's a stretch goal.