Games like Keplerian Space Discovery
Games like Keplerian Space Discovery include Kerbal Space Program, Universe Sandbox, SpaceEngine, Kerbal Space Program 2, and Spaceflight Simulator. We matched them by the tags players give Keplerian Space Discovery on Steam (Flight, Science, Space Sim, 3D Platformer, and Physics): closest matches first, and among equally close ones the better-known games.

Kerbal Space Program
Shared: Science · Space · Physics

Universe Sandbox
Shared: Space Sim · Space · Science

SpaceEngine
Shared: Space Sim · Space · Science

Kerbal Space Program 2
Shared: Space · Science · Physics

Spaceflight Simulator
Shared: Space Sim · Space · Science

Solar Expanse - Space Exploration Manager
Shared: Science · Space · Physics

Hardspace: Shipbreaker
Shared: Space · Physics · Simulation

Reentry - A Space Flight Simulator
Shared: Flight · Space Sim · Space

Exo One
Shared: Flight · Space · Physics

X4: Foundations
Shared: Space Sim · Space · Simulation

Microsoft Flight Simulator (2020) 40th Anniversary Edition
Shared: Flight · Simulation · Realistic

Uncrashed : FPV Drone Simulator
Shared: Flight · Simulation · Physics

STAR WARS™: Squadrons
Shared: Flight · Space · Simulation

Aviassembly
Shared: Flight · Physics · Science

V: Rings of Saturn
Shared: Space · Physics · Space Sim

Juno: New Origins
Shared: Science · Space Sim · Flight

Elite Dangerous
Shared: Space Sim · Space · Simulation

SpaceBourne 2
Shared: Flight · Space Sim · 3D

X-Plane 11
Shared: Flight · Simulation · Realistic

BeamNG.drive
Shared: Physics · Simulation · Realistic

Universe Sandbox
Shared: Science · Physics · Space

Children of a Dead Earth
Shared: Science · Space · Simulation

Flyout
Shared: Flight · Simulation · Physics

Avorion
Shared: Space Sim · Flight · Space