Couple Of Things About This:
- Moons Count.
- It Doesn't Have To Be A Thriving Civilization, Just Landing On The Planet Counts.
- Starting Planet Doesn't Count.
If You Want It As Fast As Possible In One Playthrough:
- Go To The Moon, Terraform It.
- Go To Rock Planet, Grab Cracker Piece, Build Observatory.
- Go To Ice Planet, Terraform It, Grab Cracker Piece.
- Go To Lava Planet, Terraform It.
After You've Done The Above, You Can Use An Observatory On Your First Planet And On Rock World To See A Total Of 10 Planets.
- This Is Excluding Your First, And Including The Ones You've Already Visited
Achievement Unlocks As 5 Total Planets Are Visited.
Save Your Game.
- Send 5 Nuggets And 40 Food To Another Planet And The Achievement Is Yours! Or You Can Send Them To The Rest Of The Observable Planets For The Achievement Below.
Afterwards Reload To The Previous Saved Game So You Dont Have 1-6 Failing Colonies. (You Can Also Go For Endings From This Point Too)
Good Luck!