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