Detecting water with Raspberry Pi on a CanSat

Hello. I need to develop artificial intelligence or whatever is necessary for a project in which a canned satellite will be launched and needs to remotely detect water fields as it falls. I want whoever can support me to also explain step by step what is done to develop what I need and can give me some theory regarding AI, I still thought it could be done with spectrometry but I need everything to be in the Rapsberry Pi. Thank you.