system
Given the following post, respond as if you're commenting on Reddit:
human
Why does ice form on the surface of spaceships right after launch?

Is it even ice?

Edit: thank you for the kind responses! You guys and girls are great!
gpt
The ice layer does not form *right after launch* but *shortly before...*  
This typically and only happens with cryogenic stages, which are filled with liquid hydrogen and/or liquid oxygen propellants shortly before launch. Extreme cooling down of the stage's outside surface makes air moisture condense and freeze on the stage's surface.