OPSAT stands for "Operational Satellite Uplink", It is used by the main protagonist in the Splinter Cell series (Sam Fisher).
It receives information from the NSA
based on details about the mission. For example: Objectives, Notes, Pictures.
Sam Also uses it to store useful information received from dead bodies, Interrogation, or from computers. For example: emails, notes, Key Codes.
1: Lambert (after describing a mission objective): Details on your OPSAT.
2: Sam (after taking an email from a computer): I've uploaded some text to you using my OPSAT. This could be bad.