PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2005-07-01 NAIF:Elson original; ... 2021-04-12 NAIF:Costa updated cITATION_DESC with DOI; " 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. https://doi.org/10.17189/1520114" 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 releases of this data set, or to contact the NAIF node of the Planetary Data System for possible further information. SPK Files ========= The following kinds of SPK files are provided in this archive: - SPK files containing reconstructed spacecraft trajectory and ephemeris information for the Solar system planets and major Saturnian satellites produced by the Cassini Navigation team - SPK files containing ephemeris information for minor Saturnian satellites. produced by the Gravity Science team . 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 ========= The following kinds of CK files are provided in this archive: - regular operational reconstructed spacecraft orientation CKs produced the Cassini Attitude Articulation Control Subsystem team (AACS). The absolute accuracy of the orientation provided in these CKs is no better than 40-microradians due to quantization granularity resulting from raw telemetry quaternions downlinked as a 16-bit signed integers. - special high-fidelity reconstructed spacecraft orientation CKs produced by AACS, available only for a few short periods. The orientation in the CKs does not suffer from the quantization granularity issue. - predicted spacecraft orientation CKs produced AACS, including latest regular versions delivered during operations and, superseding them, the final post-mission versions created in 2018, intended to provide orientation for periods when reconstructed CK files have gaps in coverage - predicted gap-filler spacecraft orientation CKs created by NAIF, intended to close small gaps between predicted CKs to achieve fully continuous orientation coverage for the whole mission - image navigated (C-smithed) spacecraft orientation CKs produced by the Imaging Science Subsystem (ISS) team, covering only short intervals corresponding to the ISS image exposure - CDA instrument orientation CKs created by NAIF using the instrument articulation data from the CDA team, providing orientation of the CDA instrument relative to the spacecraft bus. - MIMI/LEMMS instrument orientation CKs created by the MIMI team, APL using the instrument articulation telemetry data, providing orientation of the MIMI/LEMMS instrument relative to the spacecraft bus. - custom Saturn frames orientation CKs created by the MIMI team, APL based on custom Saturn rotation models, providing support data for the corresponding frames defined in the MIMI FK files. For more information, see the files ``data/ck/ckinfo.txt''. This data set also includes two kinds of supplementary files with the information either derived from or describing CK 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 comparison reports showing differences between predicted and reconstructed C-Kernels produced by AACS. These files are provided in the ``extras/ckxtra/cknav'' directory. For more information about them, see the file ``extras/ckxtra/cknav/navinfo.txt''. The second kind of supplementary files are related to the ISS image navigated CKs providing logs of angular differences between image navigated and reconstructed CKs, and graphic images that resulted from the image navigation process. These files are provided in the `extras/ckxtra/ckiss'' directory. For more information about them, see the file ``extras/ckxtra/ckiss/issinfo.txt''. PCK Files ========= The following kinds of PCK files are provided in this archive: - generic text PCK files based on the IAU reports, created by NAIF - Cassini-specific text PCK files with data for planets and major satellites, created by the Cassini Instrument Operations team (IOT) - Cassini-specific text PCK files containing data for the small satellites (rocks) of Saturn, created by IOT - Cassini-specific binary PCK files containing orientation data for selected satellites, based on rotation models by M.S. Tiscareno, SETI. A description of these data items and references to their source is provided inside each PCK file's comments. For more information, see the file ``data/pck/pckinfo.txt''. FK Files ======== The following kinds of FK files are provided in this archive: - main Cassini project FK files defining the spacecraft, structures, and instrument frames, created by NAIF - rocks FK files defining body-fixed frames for the small satellites (rocks) of Saturn, created by IOT - dynamic frames FK files defining dynamic frames used by various project science and engineering teams, created by NAIF - MIMI FK files defining frames used by the MIMI team, created by the MIMI team, APL. 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. For more information, see the file ``data/fk/fkinfo.txt''. IK Files ======== IK files providing specifications for field-of-view size, shape and orientation, and other of relevant instrument geometric parameters for each of the Cassini instruments, created by NAIF are included in this archive. Metadata describing these parameters are provided in each IK file comments. For more information, see the file ``data/ik/ikinfo.txt''. SCLK Files ========== Spacecraft Clock kernel files providing a tabulation of data needed for converting time measurements between ephemeris time (ET) and spacecraft clock time (SCLK)for the Cassini on-board clock, created by the Spacecraft Team (SCT) are included in this archive. The report provided with the final post-mission reconstructed SCLK kernel created in 2018 stated that the fit limits were set to +/- 10 msec during periods when the s/c was using the CDS-A clock and to +/- 5 msec when the spacecraft was using the CDS-B clock. For more information, see the file ``data/sclk/sclkinfo.txt''. LSK Files ========= Generic Leapseconds kernel files providing a tabulation of ``leapseconds'' and some other terms used in converting time measurements between ephemeris time (ET) and Universal Time (UTC), created by NAIF are included in this archive. 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. For more information, see the file ``data/lsk/lskinfo.txt''. EK Files ========= The following kinds of Events kernel (EK) files are included in this archive: - Command Database EKs containing containing command and parameter descriptions, created by IOT - Science Plan EKs containing detailed science requests and high-level observation plans, created by IOT - Sequence EKs containing commands, ground events, subsystem status and notes taken from the integrated sequence Predicted Events Files, as well as ISS mechanical events (shutter and filter wheel movements) derived from the Multi-mission Image Processing Laboratory database used to process images, created by IOT. For a complete description of the EK 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