Is it a solid, liquid, gas, or plasma?
Fly to Mars
Launch a spacecraft from Earth to Mars and back again.
Build a solar system (original 2D version).
Look at the Sun in different ways.
Film yourself on the Moon, Mars, and more!
Save the Earth from asteroids.
Drive a Mars rover.
Planet Families 2
Build a solar system in 3d.
Be a photon, escape the sun.
Resize objects until they're the correct relative size.