The following are five games that are quite similar to Universe Sandbox.

Space Engine

Space Engine is a simulator that allows players to explore the universe in 3D. The game has a lot of features that allow players to both explore and recreate the universe. For example, players can create and edit their own solar systems and even influence how the simulation progresses.

Outer Wilds

Outer Wilds is a space exploration and adventure game. Players take on the role of a spacecraft and set out to discover the secrets of the Sagittarius Arm of the Milky Way. There are no limits to what the player can do in the game and many of the options lead to interesting and sometimes surprising results.

Astroneer

Astroneer is a sandbox game in which players explore the galaxy and collect resources to fuel the company’s growth. Players can use these resources to craft items and vehicles to assist in exploration and combat. The game is focused on providing the player with a sense of exploration and discovery.

Kerbal Space Program

Kerbal Space Program is a realistic space flight simulator. Players must build rockets and fly them into space. The game is designed to be as realistic as possible and aims to create a sense of wonder and accomplishment.