Mods can not only add utilities to the game to make your life easier but can also entirely change the way the game plays. In this chapter, we’ll look at several mods that make Kerbal Space Program significantly more realistic; as a result of these changes, the game is also made much more challenging.
In an unmodified game of Kerbal Space Program, many things behave in an unrealistic way. Almost all engines can be throttled, shut down, and relit, and any spacecraft can be sent instructions that take effect immediately—effectively, commands to even your unmanned probes are sent faster than the speed of light!
Kerbal Space Program simplifies a lot of things in comparison to real space programs. All engines use the same fuel and the same oxidizer, they can all be throttled as much as you like, and they can be restarted on demand. Kerbals can last indefinitely without food or water, and many planetary bodies are politely lined up on the ecliptic. Kerbin itself is a tiny world, getting into orbit is surprisingly straightforward, and the Kerbol system is about one-tenth the size of our own. All of these changes mean that KSP is fun, and the game provides the player with much room for error.
But what if you wanted to imagine you’re running a space program on Earth? What if you wanted to re-create the Apollo missions of the 1960s and 1970s, or what if you wanted to see what could be done with current or future technology ...