Games like Astronomics
Games like Astronomics include No Man's Sky, Stellaris, Kerbal Space Program, Hardspace: Shipbreaker, and Kerbal Space Program 2. We matched them by the tags players give Astronomics on Steam (Space, Procedural Generation, Exploration, Top-Down, and Physics): closest matches first, and among equally close ones the better-known games.

No Man's Sky
Shared: Space · Exploration · Procedural Generation

Stellaris
Shared: Space · Exploration · Sci-fi

Kerbal Space Program
Shared: Space · Physics · Sandbox

Hardspace: Shipbreaker
Shared: Space · Physics · Sci-fi

Kerbal Space Program 2
Shared: Space · Exploration · Physics

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

X4: Foundations
Shared: Space · Exploration · Sandbox

Elite Dangerous
Shared: Space · Exploration · Sci-fi

FTL: Faster Than Light
Shared: Space · Sci-fi · Procedural Generation

Space Engineers
Shared: Space · Physics · Sandbox

Avorion
Shared: Exploration · Space · Sandbox

PEAK
Shared: Exploration · Physics · Procedural Generation

Deep Rock Galactic
Shared: Procedural Generation · Exploration · PvE

Space Engineers 2
Shared: Space · Sandbox · Physics

Star Valor
Shared: Space · Exploration · Sandbox

Reassembly
Shared: Space · Sandbox · Top-Down

SPORE™ Galactic Adventures
Shared: Space · Exploration · Sandbox

Space Pirates and Zombies
Shared: Space · Top-Down · Sci-fi

Universe Sandbox
Shared: Space · Physics · Sandbox

Empyrion - Galactic Survival
Shared: Space · Exploration · Simulation

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

Heat Signature
Shared: Space · Top-Down · Procedural Generation

SPORE™
Shared: Space · Exploration · Sandbox

Spaceflight Simulator
Shared: Space · Exploration · Sandbox