Chapter 10. Introduction to Mods

Kerbal Space Program by itself is a fascinating and engrossing game, but you may have had times when you wish there were features that simply weren’t there — such as more action groups; a tool to help calculate the delta-v of each stage; or more realism for things like reentry, life support, or communications.

Luckily, KSP has a vibrant and active modding community, and many of the most wanted features have been implemented with mods. In fact, many of the game’s core features — including resource mining, and many parts and contracts — were once community-provided mods that have since been integrated into the base game. Mods can greatly increase the depth of the game, by expanding extraplanetary resource collection, future technologies, or mapping and communication features so that satellites become truly useful.

In this chapter, we’ll cover some of the best mods KSP has to offer, how to install and manage them, and even how to write your own.

Note

In this part, you’ll see the word stock appear quite often. Stock simply means the unmodified version of KSP — that is, KSP just after you’ve downloaded and installed it. Up until this part, we haven’t been using any mods at all.

Installing Mods Using the CKAN

In the dark ages, mods for Kerbal Space Program had to be installed by hand. Players needed to ensure their mod was compiled for the game version they were using, had any required dependencies, and did not conflict with other mods installed. Chaos ruled the land, players had to watch the forums to see when their favorite mods were updated, Kerbals lived in fear, and KSP upgrades meant manually reinstalling new versions of everything (a much more harrowing task than most space missions). A heavily modded setup was hard to maintain, and krakens lurked in the shadows.

In late 2014 came the englightenment, and the Comprehensive Kerbal Archive Network (CKAN) was born. At its core, the CKAN uses a strong metadata format to describe not only which mods were available, but also their incompatibilities, requirements, and how they could be installed by machine.

Today, the CKAN (see Figure 10-1 ) is used by tens of thousands of KSP users and has delivered cumulative decades of joy by reducing the effort needed to install mods.

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Figure 10-1. The CKAN completely rocks for mod management

Installing the CKAN

The CKAN is free, open source, and cross-platform; it uses the same executable and runs the same way on Mac, Linux, and Windows machines. To begin, you should visit the CKAN release page and download the ckan.exe file from the most recent release. The release notes will also mention any other dependencies required; for example, you may need to install libcurl under Linux.

On Windows, you can download and start the client like any other program by double-clicking on it. For Linux and Mac, you can launch the CKAN using mono :

    $ mono ckan.exe

($ is the terminal prompt; do not type it.) The CKAN client has both a GUI and a command-line mode. While most players choose to use the GUI functionality, we’ll also mention the command-line options to install each mod. For example, ckan.exe install DogeCoinFlag will install a flag with one of the world’s most popular crypto currencies, suitable for any craft going to Mun!

Tip

Place the ckan.exe file in the same directory as Kerbal Space Program, and it will automatically find your game install.

In this book, we’ll always install mods via the CKAN, as it provides a repeatable, reliable, and upgradable way to manage them. The CKAN is used by tens of thousands of KSP players worldwide.

Note

The CKAN was started as a direct result of this book, because one of the authors (Paul Fenwick) didn’t want to explain how to install mods by hand.

Installing a Mod

Installing a mod using the CKAN couldn’t be easier! Simply scroll to or search for the mod you want, and select the box saying you wish to install it. Once you’ve got the mods you want, head over to the Changeset tab to see what’s scheduled (see Figure 10-2 ).

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Figure 10-2. The CKAN with a set of changes scheduled

As you can see, the CKAN doesn’t select just the mods you requested, but any mods they depend upon as well. Mods can also recommend or suggest other mods that might work well with them, or declare known incompatibilities.

Best of all, there’s no need to download mods manually, unzip them, or read install instructions; the CKAN does all this for you! You can see this in action in Figure 10-3 .

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Figure 10-3. The CKAN fetches and installs your mods automatically

Uninstalling and upgrading mods are similarly straightforward, meaning that installing mods for Kerbal Space Program and keeping them up to date is much easier than for most games!

Why Is the CKAN Such a Big Deal?

A tool that automatically downloads and installs mods is pretty handy, but one of the reasons the CKAN is so popular is its design methodology. Traditional mod managers take the files from a mod and install them in your game directory, and remove them should you choose to uninstall the mod. However, users have to make sure that they have the right version, have all the dependencies the mod requires, and haven’t installed any conflicting mods. If the mod gets upgraded, it’s up to the user to notice the upgrade, make sure it’s still compatible with their other mods, and ensure that it’s been compiled for the correct game version. Consequently, it’s easy for mistakes to be made, especially if a user has dozens or hundreds of mods installed!

The CKAN is special because it has strong metadata for all the mods it works with. This metadata includes dependencies and conflicts, recommendations and suggestions, which version of KSP the mod was designed to work with, and exactly how to install the mod in question. This means that the CKAN can fulfill its primary goal of consistency — that the same mod will be installed the same way every time, and that it can guarantee it will work with the other mods and KSP version the user has installed.

The CKAN metadata is maintained by hundreds of volunteers, as well as a network of indexing bots, to make sure things are kept up to date. It’s also very complete; at the time of writing, the CKAN has over 650 mods indexed, more than the total number on any individual KSP modding site. You can find more about the CKAN at http://ksp-ckan.org/ .

Note

For readers with a Linux background, the CKAN spec is based upon the Debian spec, making it the equivalent of apt-get for Kerbal Space Program.

Mods and Saved Games

In general, it’s reasonably safe to add most mods to an existing game. However, it’s reasonably safe in the same way that Jeb considers climbing into a tin can on the top of 2,000 tons of explosive, liquified gas reasonably safe.

Note

Jeb and Valentina only consider climbing into poorly designed and highly unstable space cars to be safe because they have their badS parameter set to True in your persistent.sfs save file. This makes them incapable of experiencing fear, and is why it always looks like they’re having an amazing time shortly before the commencement of lithobraking.

However, as we all know, things can and will go wrong. Mods that only add parts or that don’t change gameplay are often safe, but mods that make sweeping changes (such as “Realism Overhaul and Real Solar System” ) will almost certainly break any saves you have. More important, removing mods can also break saves, especially if they affect parts that are used on active vessels.

Tip

If you truly care about a saved game, make a backup before you go modding. (Search for the Kerbal Space Program/saves folder on your system.)

Summary

At this point, you now have everything you need to know in order to install and play with mods. In the next several chapters, we’ll introduce some specific mods that will become indispensable to you; indeed, many dedicated players of Kerbal Space Program never play without some of these mods.