Space Journey (Steam key).

http://store.steampowered.com/app/535250/
Space Journey - is an open world Space Simulator; Where you could explore different planets, fly spaceships, land vehicles, robots and more! All of the current scenes are in a sandbox mode, meaning that they might be unfinished and have issues.
Current Features:
Universal sandbox Mode:
Try out five different scenes. Whether it is space station, planet, moon, vehicle or procedural generated sandboxes!

Spacecrafts:
Whether you choose a fighter or a carrier spacecraft, your choice! We currently have five different types of spaceships for you to try.

Land vehicles:
Hover-bike & Moon Explorer

Basic AI System & More!

Important: Once again, all of the scenes are currently in a sandbox mode, meaning that they might be unfinished and have some performance issues. For example, our moon terrain represents a portion of the planet, not the whole rounded surface. Although, you could experience our procedural generated planets, where you could fly over and see them built*. Basic AI system means that NPC´s that are currently in game has no interaction with a player. Everything is going to get improved within weekly updates.
Features to come (Q1-Q2 2017):
Online Multiplayer
Aggressive & Passive AI
AI Trading System
Quests & Missions
Procedural Universe
Steam Achievements
Mac & Linux Support
And more!