Mars Horizon

File information

Last updated

Original upload

Created by


Uploaded by


Virus scan

Safe to use

Tags for this mod

About this mod

Add unlockable deep space mission slots.

Permissions and credits
This is an unofficial mod of Mars Horizon (2020 game).
It unlocks additional deep space slots for long duration missions, freeing up slots for more missions to help maintain game pace.

All old saves are compatible.  New saves made with this mod would still work without the mod.


A mod loader is required.  The step depends on the loader:

  • BepInEx : Extract package into a new subfolder under BepInEx\plugins.
  • Simple Mars Horizon Mod Loader : Extract package into a new subfolder under Mods.
  • Unity Mod Manager : Same as above, or install through the GUI.

To uninstall this mod, delete the extracted files.


By default, up to 3 deep space slots can be unlocked by these actions:

  • Launch The Grand Tour milestone mission and reach at least phase 2.
  • Construct the Space Science Library building. (Era 3 reward research)
  • Construct the Deep Space Network building.

Once unlocked, missions that meet the following requirements will be automatically
moved to the deep space network, freeing up normal mission slots.

  • The mission must take at least 30 months to complete, and has at least 3 phases.
  • At least 6 months and 2 phases have passed since launch.

This means, new deep space missions will not be transferred immediately.
A mission with a long phases 2 can occupy a normal slot for years.

The conditions are configurable (see below).
On a 1920x1080 screen, a UI scale of 86% or less is required to fit all three slots on the screen.

The slot unlocked by The Grand Tour is permanent and can be used by other deep space missions,
even if the tour later fails.


If a game is saved with mission(s) in deep space slot(s), and is later loaded without the mod,
all missions will still be alive and well, but you cannot launch new mission until the number
of missions drops to vanilla level.  The same may also happen if mod config is changed mid-game.