NASA's Navigation and Ancillary Information Facility (NAIF) offers the SPICE (Spacecraft, Planet, Instrument, C-matrix, Events) observation geometry information system to assist in planning and interpreting scientific observations from space-based instruments aboard robotic planetary spacecraft, in support of engineering tasks associated with these missions, and for some heliophysics and earth science {missions.

The} SPICE Toolkit is offered in several languages. This port contains the toolkit for C.

WWW: https://naif.jpl.nasa.gov/naif/
