Your Home Planet Counts As An Ice Planet, So All You Have To Do Is:
- Unlock Terraformer
- Build A Terraformer On Your Home World.
Achievement Pops Once It Turns On.
Edit: 2/9/2024
Might Not Work Anymore, If That's The Case, You Need To Go To An Ice Planet And Get The Temperature Up To Zero Celsius With A Terraformer.
Good Luck!