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Finding SPICE Components

An Introduction tothe NAIF Server

January 2009

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N IF Overview

• Many SPICE “products” are available from the NAIF server

– Access is via the http or ftp protocol– See next page for URLs

• SPICE products made outside of JPL are controlled by the producing organizations. Some may be available from the NAIF server, some may be available at other public servers, or on restricted servers, or not at all.

– Some of these SPICE products may eventually become accessible from the NAIF server after they are formally archived within NASA’s Planetary Data System.

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• NAIF home page http://naif.jpl.nasa.gov

• Here you may access nearly all SPICE products available to NAIF*- kernels (generic, mission ops, PDS archived)- software (Toolkits and individual application programs)- documents- tutorials- programming lessons- problem solving tips- rules about using SPICE- links to useful resources

• SPICE announcements (by NAIF) http://naif.jpl.nasa.gov/mailman/listinfo/spice_announce

• SPICE discussion (by anyone) http://naif.jpl.nasa.gov/mailman/listinfo/spice_discussion

NAIF Server Basics

* Note: some SPICE products made outside of JPL may not be available to NAIF until formally archived with the Planetary Data System (PDS), or perhaps never.

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N IF Getting SPICE Kernels

• The remaining charts discuss where to find the various categories of SPICE kernel files:

– Mission operations kernels, for (mostly JPL) active flight projects

– Archived kernels, those formally delivered to and accepted by NASA’s Planetary Data System

– Generic kernels, not tied to a specific flight project or other task

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N IF Mission Ops Kernels - 1

ftp://naif.jpl.nasa.gov/pub/naif/CASSINI/kernels/

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N IF Mission Ops Kernels - 2

Kernel file

Kernel file detached label (text)

aareadme.txt

•••

Kernel file naming conventions

…/CASSINI/kernels/spk

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N IF Archived Kernels - 1

• Two methods for obtaining PDS archived kernels are available.

– Directly from the NAIF server, using your browser» Recommended!» Unless you have reason to do otherwise, download the

entire archival data set using the ftp URL• You’ll get all the latest data, and you’ll get the associated “furnsh files”

– Using the PDS central catalog interface, using your browser

• Pictorial examples are shown on the next several pages

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N IF Archived Kernels - 2

If you select “PDS Archive Area” on the NAIF web page you can follow a path like this one. - You can use Unix “wget,” or the FileZilla tool, or some other equivalent with the ftp URL to download the entire data set (recommended!) - Or you can select specific kernels from the kernel folders, and/or “furnsh” meta- kernels and other items from the extras folder

Index of ftp://naif.jpl.nasa.gov/pub/naif/pds/data/co-s_j_e_v-spice-6-v1.0/cosp_1000/

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N IF Archived Kernels - 3If you select “PDS Central Catalog” on the NAIF web page you will be offered a query capability as shown here. However, this provides access only to individual kernels, which is generally not a recommended/useful approach.

“Spice Kernels” has been pre-selected for you.

Select a “Mission,” or an “Instrument Host” (they are not always identical).

Select START and STOP dates, if desired.

Finally, press “GO” and see what turns up!

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N IF Generic Kernels Example - 1

ftp://naif.jpl.nasa.gov/pub/naif/generic_kernels/

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QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Generic Kernels Example - 2

Typical SPK file

Comments about thefile, also placed insidethe SPK file

“brief -ct” summariesof all SPK files in the directory

Summary of all SPK files in the directory, ordered by alpha and by date placed on the server

Folder containing older(no longer current) files