Kitten Space Agency (currently referred to as a working title by Rocketwerkz, we’ll see if it sticks) is intended as a spiritual successor to Kerbal Space Program.

Rocketwerkz is a studio from New Zealand and were among the ones originally placing their bids with Take2 Interactive for developing a Kerbal Space Program successor, but after they lost the bid, any work was shelved.
However, after Take2 severely botched the sequel, Rocketwerkz revisited some of the early work, as well as its engine and framework, and decided to develop a spiritual successor instead.

Some of the developers from Kerbal Space Program as well as its massive modding community are onboard. Off the top of my head, this includes:

• HarvesteR - The original creator of KSP
• Blackrack - Known for various visual enhancement mods to KSP