I'm currently in the early planning phase for a hard sci-fi campaign set solely within the Solar System. What I'd like to do is figure out some way to simplify orbital mechanics in a way that wouldn't require me to boot up Kerbal Space Program or manually figure out equations every time, if only because that ruins the pace of play. The Expanse RPG has some decent charts for communication times and brachistochrone trajectories but they rely on using torchships and I'd like to limit the use of those in-setting if possible. Has anyone here made or played with a ruleset or an external program that could allow for this? If not, any ideas as to how I could go about crafting one?