... SPICE User's Guides . brief - User's Guide for BRIEF, a utility program that allows you to summarize the ephemeris contents and coverage for one or more SPK files. ? ... commnt - User's Guide for COMMNT, a utility program that is used to add comments, extract comments, read comments, or delete comments in SPICE SPK, CK and EK files. ? ... tobin - User's Guide for TOBIN, a command line utility program that converts transfer format SPK, CK and EK files to binary format. ? ...