From Starbounder - Starbound Wiki
It, along with the other set pieces, can be found inside chests inside the Erchius Facility mission.
For a full video guide see https://youtu.be/ANZQruhOmMY Spacesuit Set Location Video - Starbound 1.0
- Perturbed Koala: Added to game files
- Upbeat Giraffe: Implemented in game
- Cheerful Giraffe: Changed rarity from 'rare' to 'uncommon'