In its broadest definition, a space simulation is any software that simulates space and/or space flight. This could include realistic or fanciful simulations. Realistic simulations could include astronomy programs.

Examples of realistic space simulations:

• Orbiter (sim)
• Celestia
• Eagle Lander 3D

Typically though, the term "space simulation" is spoken in the abbreviated form of "space sim" and refers to a genre of computer games.

Examples of "space sim" computer games:

• Descent: Freespace
• Elite (computer game)
• EVE Online (a massive multiplayer online game set in space)
• Freelancer (computer game)
• Homeworld
• I-War (Independence War)
• Noctis (simulates a galaxy's worth of stars, planets and moons for pure exploration)
• Starflight
• X: Beyond the Frontier and X2: The Threat