Kerbal Space Program, the unlikely success success story from Squad, a Mexican marketing agency turned game studio, will launch its first expansion on March 13. Called Kerbal Space Program: Making History Expansion, it’s the first add-on for the PC version of the game since it entered Steam Early Access in 2013.

Kerbal Space Program (or KSP) has been in development since 2010 and left Early Access in 2015. Since then it’s also come to PlayStation 4 and Xbox One. In May of 2017 it was acquired by Take-Two Interactive, and in March 2017, Squad announced the Making History Expansion.

In a press release, Take-Two said that the expansion would include a new Mission Builder that will allow players to create and edit missions.

“Players can customize their own missions to include launches, landings, rescues, malfunctions, explosions, repairs, and much more,” Take-Two said. “Unique victory conditions, exciting challenges, and unexpected obstacles provide an array of complexity in these missions. Players can challenge others to complete their missions by sharing them with the Kerbal Space Program community.”

The DLC will also include the History Pack, which will include a set of missions “inspired by humankind’s own space exploration.” They will include a spacewalk and a crash landing, and allow players to “attempt to recreate moments inspired by historic events, but with a unique Kerbal twist.”

The DLC has not been announced for any other platforms. So far, Making History is PC only.

Update: The team reached out to add that the DLC will sell for $14.99.