If you are not already familiar with how to use SPICE data, take a moment to read about using SPICE data.
Three categories of SPICE data, often referred to as kernels, are available from this website. You should carefully read about all three of these categories using the links below in order to find the best data for your needs.
It might be that a one-time effort to obtain some SPICE data will be sufficient for your science or engineering purposes. But be aware that, later on, new SPICE data might have been produced that would be of interest to you. We suggest you read Data Updates to learn more.
Selecting the appropriate kernels to use in your work might be straightforward, but it might require careful thought. We suggest you read Kernel Selection to learn more.
regarding accessing all three categories of SPICE data is available from the NAIF server.
Insufficient or missing data is often the cause of a user's problem when trying to use SPICE. Take a look at this note on missing data for some pointers.
CAUTION: always download needed text kernels--do not CUT/PASTE the text
kernel contents displayed in your browser into a text editor and save
that as your text kernel. (CUT/PASTE may insert extraneous, unseen
characters in your new text kernel that will render it unusable.)
All of the underlying folders are intentionally exposed to facilitate the SPICE customer selecting the data needed for the job at hand.
All "PDS Archived SPICE Data Sets" are suitable for use in research programs proposed in response
to NASA's ROSES and similar research opportunity announcements.