Kerbals will be back for more launch failures in 2020 when Kerbal Space Program 2 launches, possibly on Steam but it's not set in stone. The game will be developed from ground up by Star Theory Games and published by Private Division.
Kerbal Space Program 2 will be developed by Star Theory Games rather than Squad since the latter sold the rights to the franchise to Take Two Interactive back in 2017. The publisher, Private Division, is Take Two's subsidiary that also published the first game.
According to the official website , the game has been "redesigned from the ground up to meet the demands of modern and next-generation space exploration" hinting that Kerbals sequel will be on PS5 and Project Scarlett. Devs did state they are keeping an eye on the "monumental foundations of the first game" in order to keep the sequel in the spirit of the original.
Players will still be able to build a space program and construct spacecraft while also designing resource-gathering colonies while attempting to learn the secrets of the galaxy. Yes, the sequel will take players outside Kerbolar System.
One topic that may prove to be controversial is regarding the revamped assembly and flight instructions that will allow both veterans and newcomers to "quickly put their creativity to the test" which sounds an awful lot like streamlining that would undercut some of the original KSP's charms. Star Theory assures players that is not the case but time will tell.
As previously mentioned, one of the new mechanics will be the colonies that gather resources. These colonies will have the derpy physics failures just like the space programs which will most likely result in horrific and hilarious accidents.
Star Theory Games
Interstellar travel will include going to planets outside the Kerbolar System. Some of them have been mentioned already - Ovin is a "ringer super-Earth with relentless gravity" while Rask and Rusk are a binary pair of celestial bodies. There are more, yet unannounced planets to be uncovered apparently.
Furthermore, Star Theory are looking to add multiplayer to KSP 2 due to not being technologically limited and they are working to incorporate some of the mods that are available for the original game.
The trailer above ends with a list of platforms that KSP 2 will be available on but doesn't specifically mention whether it will be available on Steam or Epic Games Store. The game currently has a Steam page but that is not much of a guarantee since games were previously taken from there and converted into Epic exclusives.