Despite its store classification, SpaceSim explicitly describes itself as software rather than a game: it has no game mechanics, progression, or sandbox elements. Its purpose is to make scientific simulation more accessible, letting users explore astrophysical events on a desktop PC or laptop without extensive knowledge of mathematics, physics, or programming.
The central activity is building and running particle-based simulations. Deformable objects interact through collisions and gravity, while rigid objects retain their shape. Users can adjust the properties of planets, stars, asteroids, disks, clouds, and galaxies, and create custom objects with Lua. Example investigations include the Moon-forming impact, Saturn’s ring system, and the DART impactor, alongside hypothetical scenarios. The software also offers visual tools such as particle coloring, gravity-field displays, and black-hole gravitational lensing.
SpaceSim is non-realtime: some lower-resolution simulations may run in real time, while simulations with millions of particles can take several hours. Its workflow is therefore centered on configuring, computing, and examining or replaying a simulation, rather than progressing through a conventional game loop.
