An answer in the following mentions a free online calculator for long-distance space travel. https://worldbuilding.stackexchange.com/questions/33757/software-to-ease-my-interstellar-travel-calculations I'm looking for a 3d simulator that accurately and visually shows transition from orbit and other aspects of interplanetary (rather than interstellar) travel. I don't care about trading between planets or social interactions or wars - just the travel aspect. I'm thinking of purchasing Kerbal Space Program, https://www.kerbalspaceprogram.com/en/ which although it has cartoon green aliens as an extra, does, I've heard, have accurate physics. Does anyone have experience of this software? Will it serve my purpose? Does anyone have other recommendations? **Requirements** I'm hoping for software that shows heavenly bodies and spacecraft *visually* and in 3d from variable points of view, preferably with a zoom facility. The graphics don't have to be ultra-high-definition, just easy to recognise. I want to take account of amounts of thrust/fuel needed with realistic rocket equations built into the software (so I don't have to do them!) and to be able to travel from orbit around the home planet to orbit around the destination with course corrections where necessary. Takeoff from the planetary surface would be a bonus but not vital. NOTE: There is a tag especially for software-recommendations so I don't believe this question should be closed as 'opinion based'.