The science tier tree can be a little wonky in Kerbal as the game does not let you know what you're getting next. Consult the game's wiki for a full view on what's available or play around in the sandbox version of the game.
Space in KSP is frighteningly big. Not only are there huge planets to explore, asteroids, spaceship wreckage and other anomalities, but there's also distant moons. You can interact and land at any of them, given that you have the right space ship for the job.
The game's UI does quite a good job. When in doubt, simply hold your mouse over things and It will almost always explain.
If you want to screw around in the Kerbal Space Program universe, hold down LEFT ALT and press F12 to open up the cheat menu.
As this game is still in development and constantly expanding as time goes by, there is only so much I can teach you in this guide. For more information, visit the Kerbal Space Program wiki at
The community does a very good job at keeping it up to date, but unfortunately, this signals the end of our guide to KSP. I hope this helped you and I wish you the best of luck in the space adventures to come!