The Astronaut Ice Cream is located in the Nerve Centre, the central door in the game's main hub, The Motherlobe. In here, you'll come across a room filled with monitors, and a raised platform in the middle which hosts a war table. You may notice some computers scattered around the platform - these are the key to obtaining the Astronaut Ice Cream.
You'll find that one of the computers has its screen lit to green, unlike the others. Simply interact with it and it will turn off. Now, look around at the other computer screens and you'll notice another is now lit up green. The aim is to keep interacting with the green monitors as they jump around the circle before a final one appears.
This final one is actually not on the pedestal but to the left of the room between the main door and the elevator. Once this is lit up green, interact with it and voila! An Astronaut Ice Cream will be dispensed.
It's not particularly hard to find once you know, but if you're not sure where to look it can stump you a bit. At least you can relax now you've got one of the most hidden items down in your log!
We hope you find this Psychonauts 2 guide useful while playing on Xbox Game Pass for console or PC!