Kerbal Space Program is described as 'Create and manage your own space program, build and fly spacecraft, and try to conquer space' and is a simulation games in the education & reference category. There are more than 10 alternatives to Kerbal Space Program for a variety of platforms, including Windows, Steam, Mac, iPad and Android apps. The best Kerbal Space Program alternative is Orbiter, which is both free and Open Source. Other great apps like Kerbal Space Program are Space Simulator, Space Agency 2138, Kitten Space Agency and Juno: New Origins.
Orbiter is a realistic 3D real-time space flight simulator program.
Fed up with space games that insult your intelligence and violate every law of physics? Orbiter is a simulator that gives you an idea what space flight really feels like - today and in the not so distant future.
looks like it i think it's a clone
Space Simulator is a realistic space flight simulator for iOS and Android. It is an open-ended simulation where players can free roam Solar System or reenact historical NASA space program missions.
Built from the ground up with the spirit of discovery, Kitten Space Agency invites players and supporters to join a community pushing the boundaries of what a spaceflight program can be.
Bring to life anything you can imagine from rockets and airplanes to cars and more. Automate them with a visual programming language. Explore 3D planets and download more from the community. Share your creations online.
In Spaceflight Simulator, you will get to build your rockets, plan launches and flights, attempt landings, deploy payloads and explore new worlds.
Take part in a space program. Design spacecrafts and send them off to explore the vast expanses of space. Experience the real scale of the Solar system and the size of its celestial bodies.
Unscripted, living and thriving universe. First person action from the ground to the stars and beyond. You is always yourself, scavenging your first fruit from the tree or standing on the bridge of your flagship.
Pioneer is a space adventure game set in the Milky Way galaxy at the turn of the 31st century. The game is open-ended, and you are free to explore the millions of star systems in the game. You can land on planets, slingshot past gas giants, and burn yourself to a crisp flying...
Pioneer is not a game of simulation or building. It's more like Elite II, or Oolite.
A game of missions, trade and space combat in the 31st century using the Pioneer Space Sim engine with many additions and improvements.
Reentry is a space flight simulator based on real life spacecrafts. You create a new astronaut, gain levels and experience for every move you make by completing missions in space.
United Kingdom
United States
Russia
In no way is orbiter a KSP clone... it's a realistic simulator in continuous development for 21 years and counting. Orbiter is a flight simulator, not a game. When KSP just doesn't satisfy you anymore and you can calculate Hohmann transfers in your head, try this.