This is a list of all the puzzles you have to complete before you can do the final exhibit - Build a Universe.
Lobby: Where in the Universe
Exploratorium 1st floor:
Create an Aurora and Atmospheric Phenomena
Build a Rocket and Plot a Course
Planetary Pinball and Create a Ring
Dangers of Deep Space and Where Am I?
Exploratorium 2nd floor:
Create a Star and Spaceship Earth
Create an Eclipse and Types of Eclipses
Backwards Time Viewer and Time Dilation
Identify the Constellations and Observatories of the World
Planetarium: 8 Arcade Puzzles
Through the library: Build a Telescope
If you've completed all of those, then you can do the final exhibit. It's on the 1st floor of the Exploratorium. Look for the room that has a panorama of the constellations on the wall facing you when you enter.
I would suggest you save Gamestat this time before
you do the puzzle.