PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2005-07-01 NAIF:Elson original; ... 2017-12-28 NAIF:Semenov reset sTOP_TIME; updated CK subsection; " RECORD_TYPE = STREAM OBJECT = DATA_SET DATA_SET_ID = "CO-S/J/E/V-SPICE-6-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "CASSINI SPICE KERNELS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" START_TIME = 1997-10-15T09:26:08 STOP_TIME = 2017-09-15T10:31:48 DATA_SET_RELEASE_DATE = 2002-11-01 PRODUCER_FULL_NAME = "LEE ELSON" DATA_OBJECT_TYPE = "SPICE KERNEL" DETAILED_CATALOG_FLAG = "Y" DATA_SET_TERSE_DESC = "This data set contains navigation and ancillary data in the form of SPICE kernel files for the Cassini spacecraft." ABSTRACT_DESC = " This data set includes the complete set of Cassini SPICE data files (``kernel files''), which can be accessed using SPICE software. The SPICE data contains geometric and other ancillary information needed to recover the full value of science instrument data. In particular SPICE kernels provide spacecraft and planetary ephemerides, instrument mounting alignments, spacecraft orientation, spacecraft sequences of events, and data needed for relevant time conversions. " CITATION_DESC = " Elson, L.S., C.H. Acton, D.L. Conner and B.V. Semenov, Cassini SPICE Kernels V1.0, CO-S/J/E/V-SPICE-6-V1.0, NASA Planetary Data System, 2005. " DATA_SET_DESC = " Data Set Overview ================= This data set includes the complete set of SPICE data for Cassini in the form of SPICE kernels, which can be accessed using SPICE software available to read these files. The SPICE data contains geometric and other ancillary information needed to recover the full value of science instrument data. In particular SPICE kernels provide spacecraft and planetary ephemerides, instrument mounting alignments, spacecraft orientation and spacecraft sequences of events. Data needed for relevant time conversions is also included. This data set is contained on a single virtual volume, cosp_1000, including data from all mission phases and covering from launch, 1997-10-15, through the end time of the latest spacecraft trajectory file supplied in the data set. Until the end of the spacecraft lifespan this data set is accumulating with new data added approximately every three to six months. In addition, old data may be revised and added to the data set over time. Users are urged to be sure that they use the most recent data available by selecting files from the latest release, where appropriate. Data Types (SPICE kernel types) =============================== SPK kernels contain ephemerides for spacecraft, planets, satellites, comets and asteroids as well as for moving or fixed spacecraft and instrument structures. They provide position and velocity, given in a Cartesian reference frame. SPK files are located under the ``data/spk'' directory on the volumes comprising this data set. PCK kernels contain certain physical, dynamical and cartographic constants for target bodies, such as size and shape specifications, and orientation of the spin axis and prime meridian, that are meant to be used with applications that incorporate the SPICE Toolkit. PCK files are located under the ``data/pck'' directory on the volumes comprising this data set. IK kernels (Instrument description kernels) give descriptive and operational data peculiar to a particular scientific instrument, such as internal timing relative to the spacecraft clock and field-of-view model parameters. IK files are located under the ``data/ik'' directory on the volumes comprising this data set. CK kernels describe pointing, containing a transformation traditionally called the C-matrix which is used to determine time-tagged pointing (orientation) angles for a spacecraft structure upon which science instruments are mounted. CK files are located under the ``data/ck'' directory on the volumes comprising this data set. EK (Events) kernels contain spacecraft and science instrument event related information. EK files are located under the ``data/ek'' directory on the volumes comprising this data set. LSK (Leapseconds) kernels contain the leapseconds and the values of other constants required to perform a transformation between Universal Time Coordinated (UTC) and Ephemeris time (ET). LSK files are located under the ``data/lsk'' directory on the volumes comprising this data set. SCLK (Spacecraft Clock) kernels contain on-board clock calibration data required to perform a mapping between Ephemeris time (ET) and spacecraft on-board time (SCLK.) SCLK files are located under the ``data/sclk'' directory on the volumes comprising this data set. FK (Frame Definitions) kernels contain information required to define reference frames, sources of frame orientation data and inter-connections between these frames and other frames supported within the SPICE system. This includes mounting alignment information for each instrument. FK files are located under the ``data/fk'' directory on the volumes comprising this data set. Kernel File Details =================== Details specific to individual files are found in the ``*info.txt'' files in the corresponding data directory. The most detailed description of the data in each file is provided in metadata included inside the file -- in the description area of text kernels or in the comment area of binary kernels. Software ======== The SPICE Toolkit contains software modules needed to read SPICE kernel files. SPICELIB software is highly documented via internal headers. Additional documentation is available in separate ASCII text files called Required Reading files. For example, the S- and P- Kernel (SPK) Required Reading File, named SPK.REQ, describes use of the SPK kernel file readers and contains sample programs. The latest SPICE Toolkit for a variety of computer platforms such as PC, Mac, SUN, HP, SGI, VAX, DEC Alpha, etc. is available at the NAIF Node of PDS electronically (via anonymous FTP and WWW servers). Refer to information in ``software/softinfo.txt''. Each version of the Toolkit is also archived at the NASA National Space Science Data Center. Loading Kernel Files into a SPICE-based Application =================================================== The easiest way to make data from a collection of SPICE kernels available to a SPICE-based application is to list these kernels in a meta-kernel and load it into the program using the high level SPICE data loader routine FURNSH. This data set provides such meta-kernel(s) under the ``extras/mk'' directory. For more information about the CASSINI meta-kernel(s), see the file ``extras/mk/mkinfo.txt''. " CONFIDENCE_LEVEL_NOTE = " This volume contains SPICE kernel files created during mission operations and after mission data reconstruction and analysis. Some general information about this collection follows here, but the prospective user is also referred to extensive descriptions about each file that are stored inside each kernel file. These metadata provide detailed information regarding the information source from which the data were derived, the type of processing applied to the source data, applicability of the data, etc. Metadata are located in the ``comment area'' for binary kernel types (SPK, CK, EK), accessible using either the COMMNT or SPACIT utility program found in the NAIF Toolkit. Metadata are located after ``\begintext'' markers within the text kernel types (PCK, IK, FK, LSK, SCLK), accessible by using any available text file display tool such as a word processor, text editor, or the unix ``more'' or ``cat'' commands. In some cases data accuracy information does not exist, or may be estimated after mission completion. Where there are questions about data accuracy or ``confidence'' not addressed herein the reader is invited to examine subsequent SPICE archive volumes associated with this data set collection (if such exist), or to contact the NAIF node of the Planetary Data System for possible further information. SPK Files ========= Two kinds of SPK files are provided in this archive: SPK files produced by the Cassini Navigation team containing reconstructed spacecraft trajectory and ephemeris information for the Solar system planets and major Saturnian satellites, and SPK files produced by the Gravity Science team containing ephemeris information for minor Saturnian satellites. For more information, see the file ``data/spk/spkinfo.txt''. This data set also includes two kinds of supplementary files with the information either derived from or describing the reconstructed SPK files. These files are not SPICE kernels; for this reason they are provided in subdirectories under the ``extras'' directory. The first kind of supplementary files is the orbit number files generated at the archive preparation time using the NAIF's ORBNUM utility program for the NAV SPK files covering the orbital phases of the mission. These files are provided in the ``extras/orbnum'' directory. For more information about the orbit number files, see the file ``extras/orbnum/orbinfo.txt''. The second kind of supplementary files is the covariance table files containing the formal position uncertainties of Cassini's reconstructed ephemeris provided in the SPK files produced by the CASSINI NAV Team. These files are provided in the ``extras/spkxtra/covtab'' directory. For more information about these files, see the file ``extras/spkxtra/covtab/covinfo.txt''. CK Files ========= Seven kinds of CK files are provided in this archive. The Cassini Attitude Articulation Control Subsystem (AACS) has provided predicted (kind 1), reconstructed (2), and high-fidelity reconstructed (3) CK files for the spacecraft. NAIF created predicted gap-filler (4) CKs for the spacecraft to close small gaps between predicted CKs produced by AACS. The Imaging Science Subsystem (ISS) has produced image navigated CK files (5) containing the spacecraft attitude for certain image exposure times. Using data from the CDA team NAIF has created CK files (6) providing orientation of the CDA instrument relative to the spacecraft bus. Using data from telemetry MIMI/LEMMS team, APL has created CK files (7) providing orientation of the MIMI/LEMMS instrument relative to the spacecraft bus. For more information, see the file ``data/ck/ckinfo.txt''. This data also contains auxiliary files with information relevant to image navigated C-Kernels as well as comparisons between predicted and reconstructed C-Kernels produced by AACS. Because these files are outside the scope of the PDS archive requirements they are provided in the ``extras'' directory of this data set. For more detailed information, see the file ``extras/ckxtra/ckxtinfo.txt''. Caution on Using CK Files ------------------------- While not a data accuracy issue, the CK user is nevertheless cautioned to understand and properly use the data found and tolerance arguments that are inputs to the CK reader provided in the SPICE Toolkit. Descriptions about how to read CK files are found in the CK reader routine headers (top of the source code files) and in the ``CK Required Reading'' document; these are contained in each SPICE Toolkit package. The user is also referred to the Cassini CK Tutorial in the ``document/ck'' directory. In addition, it is not unusual for CK files to be revised. The user is urged to be sure that CK data have not been superseded by searching the latest data releases for appropriate coverage. PCK Files ========= PCK files provide size, shape and orientation data for ``target'' bodies such as Jupiter, Saturn and their major satellites. A description of these data items and references to their source is provided inside each PCK file, which is a simple text file that can be viewed using any word processor, text editor or text display utility. For more information, see the file ``data/pck/pckinfo.txt''. FK Files ========= Frames kernel files provide specifications for how one reference frame is defined relative to another frame. A description of each reference frame is provided inside each FK file, which is a simple text file that can be viewed using any word processor, text editor or text display utility. The Cassini frames kernel contains reference frames for the orbiter instruments and subsystems including communications antennae. For more information, see the file ``data/fk/fkinfo.txt''. IK Files ========= Instrument kernel files provide specifications for the mounting alignment and, where applicable, field-of-view size, shape and orientation for the named instrument. Metadata describing these estimates are provided in each IK file included in this archive. For more information, see the file ``data/ik/ikinfo.txt''. SCLK Files ========= Spacecraft Clock kernel files provide a tabulation of data needed for converting time measurements between ephemeris time (ET) and spacecraft clock time (SCLK). A SPICE SCLK file is made from a similar file produced by the Cassini AACS Team. Each newly made SCLK file fully replaces the previous SCLK file. For more information, see the file ``data/sclk/sclkinfo.txt''. SPICE software does not prohibit an SCLK file from being used for time conversions occurring for ``future times'' (or more accurately, for epochs that occur later than the epoch of the last telemetry data used in producing the last correlation coefficients found in the SCLK file). Such ``predict'' time conversions are likely to be inaccurate (changed somewhat) once the epoch of interest has been passed. LSK Files ========= Leapseconds kernel files provide a tabulation of ``leapseconds'' and some other terms used in converting time measurements between ephemeris time (ET) and Universal Time (UTC). ``Spacecraft Event Time'' (SCET) is the commonly used name for UTC events measured at the spacecraft. For more information, see the file ``data/lsk/lskinfo.txt''. Metadata describing how the LSK data are obtained or computed is contained inside the LSK text file. The time conversion provided by SPICE LSK files is accurate to approximately 0.000030 seconds. EK Files ========= Three kinds of Events kernel (EK) files are included in this archive: Command Database, Science Plan and Sequence EKs. Command database E-Kernels contain command and parameter descriptive information used with Sequence EK files (see below). Science Plan EKs contain detailed science requests and high-level observation plans. Sequence EKs contain commands, ground events, subsystem status and notes taken from the integrated sequence Predicted Events Files. They also contain ISS mechanical events (shutter and filter wheel movements) derived from the Multi-mission Image Processing Laboratory database used to process images. For a complete description of the files see the files ``document/ek/sis_ek_001_revc.pdf'', ``data/ek/ekinfo.txt'', and comments within the files. " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = SATURN END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_MISSION MISSION_NAME = "CASSINI-HUYGENS" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = CO INSTRUMENT_ID = "SPICE" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = UNK END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END