|
Mission SPICE kernels that have been archived by the NAIF Node
of the Planetary Data System are available directly
from the PDS SPICE Archive on the NAIF server.
For each mission the kernels and associated descriptive information are provided as a single PDS data set.
For a majority of the missions this is an
accumulating PDS data set, initially assembled with archival data
from the earliest portion of the mission and then increasing in size as the mission progresses and new "chunks"
of archival SPICE data are added, typically every three or six months.
For SPICE users who don't need the most recent flight operations data, acquiring archived kernels
using the PDS Archive link above is the best approach. This way you'll be sure to
get the entire collection of archived kernels available as of the current date, including all mission-appropriate
generic kernels. These archive collections are much easier to use than the "operational flight project kernels" available elsewhere on the NAIF web pages: many small files have been merged into a few longer ones, unneeded files have been eliminated, and you'll also receive
"furnsh kernels" that help you use consistent and complete kernel sets. Also you'll receive the best descriptive information (meta-data) that will help you understand important details about the specific kernels in the data set. For some (orbital) missions you'll also receive a
SPICE ORBNUM file.
Be aware that the end time of the period covered by an accumulating archived data set will lag behind real time,
usually by six to nine months.
An alternate means for obtaining SPICE data is to use the
PDS Central Catalog's
Data Search mechanism. This catalog provides access to archived SPICE data
for NASA missions no matter at which PDS node they are archived.
|
