The offer will only apply to users who currently own the game and those who buy the title before the end of April, studio Squad stated. The decision to introduce free expansions comes in response to the player outcry that followed Squad's mention of a possible paid-for expansion available after the release of the original game.
The company initially told fans that all updates would be available for free; however, at the time Squad defined updates in terms of bug fixes and not full expansions.
"[It's an] admittedly quite grey area concerning what constitutes an update or an expansion to KSP and, most importantly, what our promise of 'all future updates for free' actually means," executive producer Adrián Goya told Eurogamer.
"It's quite obvious now that we need to rephrase that statement so everyone knows exactly what they're getting when they purchase the game.
"Given that this was a point of confusion, and that we believe that no matter what, a promise is a promise, we are including expansions in what you can expect to get for free if you have already bought the game. Also, for those considering purchasing the game, we will maintain this promise for all purchases made until the end of this month."
It is currently unknown what this upcoming expansion will include; however, Goya adds that the studio's initial concepts for the game were broader than what was eventually developed. In order to avoid stretching the scope of the game entirely, the studio will offer these new features as optional expansions.
"Over the course of the two-and-a-half years we've been developing KSP, we've come across many ideas that we thought were very cool, but didn't really fit the original scope of the game. Those would have led us astray from our vision of the complete game, not to mention that they could take many months, if not years, to implement.
"Those ideas are massive undertakings, which is why we'd like to have them as optional additions, so we could have them without having to stretch the scope (and deadlines) for the main game."