SPICE system is a data system built by Navigation Ancillary Information Facility (NAIF), acting under the directions of NASA's Office of Space Science, to assist scientists in planning and interpreting scientific observations from space borne instruments. The principal objective of this information system is that it will contain the geometric and much other ancillary information needed to recover the full value of science instrument data, and that it will facilitate correlation of individual instrument data sets with data from other instruments on the same or other spacecraft.

The primary SPICE data sets, called kernels, contain-in a practical sense-the fundamental set of ancillary information of potential interest to scientists. SPICE kernels are composed of information which has been structured and formatted, without loss of information, for easy access and correct use by the science community. Kernels are produced by the most knowledgeable sources of such information, usually located at a mission operations center. They must include or be accompanied by metadata--consistent with flight project data system standards--that provide pedigree and other descriptive information needed by prospective users.

The SPICE system includes library of portable FORTRAN subroutines needed to read the kernel files and calculate most common observation geometry parameters. Users integrate these SPICE "Toolkit" subroutines into their own application programs to compute observation geometry parameters and related information where and as needed.

NAIF has designed the kernel file and software Toolkit architectures with portability and multimission application as principal goals. In addition, because extensive software documentation and examples are provided with the Toolkit, with a reasonable learning effort the software can be confidently used by the full spectrum of the NASA-supported space sciences community.

The SPICE system is or soon will be used on numerous international space missions in the planetary, astrophysics, space physics and earth science disciplines. Scientists in many countries may be counted as SPICE customers.

In addition to providing SPICE technology to NASA and international space missions the NAIF Group serves as the Ancillary Data Node of NASA's Planetary Data System. In this role NAIF provides a permanent archive and distribution and consultation functions for planetary project ancillary data sets.

SPICE files and NAIF Toolkit software may be requested by contacting the NAIF group located in the Navigation Systems Section of Caltech's Jet Propulsion Laboratory in Pasadena California. Orders are filled as resources permit and priority is given to scientists doing data analysis directly supported by NASA's Office of Space Science.