[Spice_announce] Some announcements and questions

Charles H. Acton Charles.H.Acton at jpl.nasa.gov
Fri Jul 18 17:08:56 PDT 2008

This message contains several announcements and questions.

Merged SPICE Tutorials
A few of you have asked for an integrated package of the SPICE 
tutorials. We took this to mean a single PDF file. That is now 
available under the Tutorials web page (see the bottom entry, 
SPICE_Tutorials_Merged") at the NAIF website:  
http://naif.jpl.nasa.gov/naif/tutorials.html. This is an 800+ page 
PDF file.

FURNSH Kernels for Archived SPICE Data Sets
A few months ago NAIF began providing so-called FURNSH kernels for 
the PDS archived SPICE data sets. A FURNSH kernel, sometimes called a 
meta-kernel, provides a convenient listing of all* the SPICE kernels 
that should be used together for a stated mission period. For some 
missions the breakdown is by calender year, while for others there is 
a single FURNSH kernel covering the entire mission.

Your application program need "load" only the FURNSH kernel(s) for 
the period(s) of interest and this will automatically load all of the 
individual SPKs, CKs, etc. that apply to that period. (This assumes 
you have downloaded the entire SPICE data set and have modified the 
value assigned to the PATH_VALUES keyword to point to the actual 
location of the SPICE data set's /data directory on your computer!)

These FURNSH kernels are placed in the /extras/mk folder within each 
archived data set. For instance, for the SPICE data that have been 
formally archived for the Cassini-Huygens mission, the collection of 
FURNSH kernels is found here:  

Should circumstances require a given FURNSH kernel be updated, a new 
version is created. An improved trajectory file is an example of such 
an update.

If you are unfamiliar with the notion of a FURNSH kernel, please 
download and read pages 13-15 of the "Introduction to Kernels" 
tutorial. This is a capability with which all SPICE users should be 

*NOTE: Cassini-Huygens is a special case. Only for this mission (so 
far) was NAIF unable to select a complete set of kernels for a given 
period of time. For Cassini it is not clear to NAIF which PCK a 
particular customer would want to use, given that Cassini updated the 
PCK with every new spacecraft trajectory solution.

Improved Information about PDS Archived SPICE Data Sets
Until now anyone wishing to access the formally archived SPICE data 
for a given mission had to either know where to find it on the NAIF 
server using the FTP protocol, or, get to it through a Planetary Data 
System central catalog interface that turns out not to be very 
convenient for acquiring a complete archived SPICE data set.

A new web page has been added that improves the connection to all 
archived SPICE data sets, including providing information about the 
dates covered and the size of the data set in Mbytes.

This change is part of a broader set of changes to the NAIF "Data" 
web pages aimed at better explaining what data are available.

If you have occasion to try these web pages, we're interested in your 
feedback on what works and what doesn't--how might we further improve 
your access to SPICE kernels?

Interoperability of Ancillary Data on an International Scale?
This week it is possible that the international group known as 
Committee on Space Research (COSPAR) will have endorsed the 
activities of the fledgling International Planetary Data Alliance 
(IPDA) http://www.planetarydata.org/, which is aimed at establishing 
interoperability among planetary science data archive systems. The 
primary focus of the IPDA will understandably be on science 
instrument data... images, spectra, particle counts, etc.  But should 
the IPDA be encouraged at some future date to take up the question of 
standards and mechanisms for achieving interoperability across 
whatever ancillary data systems are used by the various participating 
nations/agencies? Should you have any thoughts on this topic you are 
encouraged to contact the current IPDA chairperson, Maria Teresa 
Capria, or any of the IPDA members. Contact information for these 
people may be found at:  http://www.planetarydata.org/Members. 
Consider sending a copy of your thoughts to the NAIF manager 
(charles.acton at jpl.nasa.gov).

A Public SPICE Tools Repository?
If you are reading this text you are probably rather familiar with 
the kinds of tools (application and utility programs) the NAIF Group 
provides in the SPICE Toolkits, and the few extra tools available 
only from the utilities link on the NAIF webpage. This rather tightly 
controlled situation is not likely to change, other than NAIF will 
slowly add hopefully useful new tools as time permits.

Perhaps some of you SPICE users have developed, or might develop, 
tools you'd be willing to share with other SPICE users, either as 
supported code or in an "you're-on-your-own" basis. Anyone have any 
thoughts on this topic?

   Might it be useful?
   Portability issues?
   Accuracy/correctness issues?
   How maintain compatibility with SPICE Toolkits?
   ITAR issues?
   Liability concerns?
   Intellectual property rights issues?
   Where hosted? (Is there an existing site that would work?)
   How would it work?
   Might such a repository also include APIs (subroutines)?

If you have comments/ideas either send them to the NAIF manager 
(charles.acton at jpl.nasa.gov) or, for broader viewing and feedback, to 
the spice_discussion Mailman list 
(spice_discussion at naif.jpl.nasa.gov).

Finally, don't forget....
See the NAIF home page (http://naif.jpl.nasa.gov/naif/pds.html) for 
announcements about the new leapseconds kernels (LSK) and the 
upcoming SPICE training class.
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