The archive volumes contain ISS raw data products, with associated pointing, navigation and spacecraft orientation information, instrument documentation, calibration files, sample calibrated images, calibration algorithms, software and documentation necessary to produce calibrated ISS images.
The ISS archive is composed of four, multi-volume data sets.
- One data set devoted to calibration files. These volumes are numbered COISS_0nnn.
- One data set for all of the ISS raw images from launch through Saturn approach. These volumes are numbered COISS_1nnn.
- One data set for all of the ISS raw images from the Saturn tour. These volumes are numbered COISS_2nnn.
- One data set for cartographic map products. These volumes are numbered COISS_3nnn, and are available from Cassini cartographic volumes.
2. Directory and file naming.
The data directory on each volume contains the EDR image data files and accompanying detached PDS label files. These files are organized on the archive volumes in subdirectories in Spacecraft Clock (SCLK) order.
- Subdirectory names represent the SCLK time interval covered by the files in the subdirectory.
File names are sequential based on spacecraft clock time values (SCLK) corresponding to the time of shutter close, with an appended version number.
File names are in the form Annnnnnnnnn_v.IMG, where:
A can be one of the following indicators:
- N - Narrow Angle Camera.
- W - Wide Angle Camera.
nnnnnnnnn is the SCLK value at at time of shutter close.
v is the version number.
The ISS Users Guide, in PDF format, was updated September 2018. It provides a substantial amount of information reguarding the instrument and its data in a single document.
Users are strongly encouraged to review an ISS aareadme.txt file. This file appears in the root directory of every volume. (Some of the header information in the aareadme.txt files varies from one volume to the next, but the body of information in the files is the same.)
Further details of the ISS archive volumes can be found in the “Software Interface Specification” (SIS) Documents. These are found in the document directory on each data volume.
- The Data Product and Label SIS is available as documents/COISS_0xxx/Data-Product-SIS.pdf and documents/COISS_0xxx/Data-Product-SIS.txt.
The image files are archived in VICAR2 format. Each data volume contains a file COISS_xxxx/label/vicar2.txt providing the details of this file format.
The catalog subdirectory on each volume contains a wealth of information about the ISS instrument, team and data set. See, in particular:
- COISS_1xxx/catalog/jupiterds.cat: Description of the Jupiter data set.
- COISS_2xxx/catalog/saturnds.cat: Description of the Saturn data set.
- COISS_xxxx/catalog/issna_inst.cat: Description of the narrow-angle camera.
- COISS_xxxx/catalog/isswa_inst.cat: Description of the wide-angle camera.
- COISS_xxxx/catalog/insthost.cat: Description of the Cassini spacecraft.
- COISS_xxxx/catalog/mission.cat: Description of the Cassini mission.
A file, errata.txt, in the root directory of each volume documents any known anomalies or deviations from PDS standards, and identifies potential problems with the calibration files and their use.
Additional descriptions of the instrument can be found at the Cassini ISS web page.