Viagenie MTI Systems Space Initiatives Inc Deep space communications involve long delays (e.g., Earth to Mars has one-way delays 4-24 minutes) and intermittent communications, mainly because of orbital dynamics. The IP protocol stack used on the Internet is based on the assumptions of shorter delays and mostly uninterrupted communications. This document describes the key characteristics, use cases, and requirements for deep space networking, intended to help when profiling IP protocols in such environment.