What are some alternatives?
When comparing Cosmonium and Kerbal Space Program, you can also consider the following products
Space Engine - Space Engine is a realistic virtual Universe you can explore on your computer.
EVE Online - Player-created empires, player-driven markets, and endless ways to embark on your personal sci-fi adventure.
Gaia Sky - 3D visualization software for ESA's (European Space Agency) Gaia mission to chart about 1...
Star Citizen - 1, 966, 341. Active citizen. Help us make Star Citizen a reality! Become a backer of the next-generation of Space-man. Reserve your ship.
Stellarium - Stellarium is a free open source planetarium for your computer.
Universe Sandbox - Universe Sandbox ² is a physics-based space simulator.