1. PdcursesmodPublic Domain Curses - a curses library for environments that don't fit the termcap/terminfo model, modified and extended from the 'official' version
2. Sat codeCode for the SGP4/SDP4 satellite motion model, and for manipulating TLEs (Two-Line Elements).
3. jpl ephCode to read, use, and manipulate JPL DE ephemeris data.