I've discovered another game (recently released) that offers the desired flight characteristics and navigational challenges, and it is free to play on steam. It is called Fly Dangerous and can be found here. https://store.steampowered.com/app/1781750/Fly_Dangerous/

It is an excellent game, however the full inertial/newtonian physics model is only available by adjusting the settings in the "dev tools" options menu. My preferred dev tools settings are included in the zip file of my custom level downloads. . Also, it's against the rules to use Flight Assist for vector and rotation , so make sure they are both off. The tunes are amazing and don't worry that there's no gravity on the planets, it's just a good way to have more scenery to keep you oriented.