PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2017-02-06 Initial version by S. Murakami; 2017-04-15 Revised by S. Murakami; 2017-05-02 Revised by S. Murakami; 2017-05-19 Revised by S. Murakami; 2017-05-25 Updated by S. Murakami; 2018-04-05 Updated by S. Murakami; 2018-04-19 Updated by S. Murakami; 2019-01-29 Updated by S. Murakami; " RECORD_TYPE = STREAM OBJECT = DATA_SET DATA_SET_ID = "VCO-V-SPICE-6-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "VENUS CLIMATE ORBITER SPICE KERNELS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_SET_TERSE_DESC = " Navigation and ancillary data in the form of SPICE System kernel files for the Venus Climate Orbiter (VCO, also known as PLANET-C and AKATSUKI) mission. " ABSTRACT_DESC = " This data set includes the complete set of Venus Climate Orbiter (VCO, also known as PLANET-C and AKATSUKI) SPICE data files (``kernel files'') for the cruising, the sun orbiting, and the science phase(s) of the mission. The SPICE data files, which can be accessed using SPICE software, contain geometric and other ancillary information needed to recover the full value of the 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 = " Murakami, S., Y. Yamamoto, K. McGouldrick, G. L. Hashimoto, N. Hirata, VENUS CLIMATE ORBITER SPICE KERNELS V1.0, VCO-V-SPICE-6-V1.0, NASA Planetary Data System, 2017. " START_TIME = 2010-05-21T00:51:00 STOP_TIME = 2018-12-31T23:58:12 DATA_SET_RELEASE_DATE = 2017-07-01 PRODUCER_FULL_NAME = "SHIN-YA MURAKAMI" DATA_OBJECT_TYPE = "SPICE KERNEL" DETAILED_CATALOG_FLAG = "Y" DATA_SET_DESC = " Data Set Overview ================= This data set includes the complete set of Venus Climate Orbiter (VCO, also known as PLANET-C and AKATSUKI) SPICE data files (``kernel files'') for the cruising, the sun orbiting, and the science phase(s) of the mission. The SPICE data files, which can be accessed using SPICE software, contain geometric and other ancillary information needed to recover the full value of the 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. This data set is contained on a single virtual volume, VCOSP_1000, including data from all mission phases and covering from launch, 2010-05-20T21:58:22, through the end time of the latest reconstructed spacecraft orientation CK file supplied in the data set. Until the end of the spacecraft life span this data set is accumulating with new data added approximately once per year. Data are associated with the mission phases given below. These may be updated periodically. Start time End time Phase Name Date (DOY) Date (DOY) ------------------------ ----------------- ----------------- Cruise 20 May 2010 (140) 06 Dec 2010 (340) Sun Orbiting 07 Dec 2010 (341) 06 Dec 2015 (340) Primary Science Phase 07 Dec 2015 (341) 31 Mar 2018 (090) Extended Science Phase 1 01 Apr 2018 (091) 31 Mar 2021 (090) (planned) 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 of this data set. PCK kernels contain certain physical, dynamical and cartographic constants for target bodies, such as size and shape specifications, and the orientation of the spin axis and prime meridian. PCK files are located under the ``data/pck'' directory of 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 of 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 of this data set. EK (Events) kernels are derived from the integrated sequence of events used to produce actual spacecraft commands. In some cases EK files are used for storing database-type information such as parameter value tables, triangular shape model data, etc. EK files are located under the ``data/ek'' directory of 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 of 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 of 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 of this data set. Kernel File Details =================== A brief overview of the different types of Venus Climate Orbiter kernels included in this data set is provided in the CONFIDENCE_LEVEL_NOTE section of this file while 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, etc. is available at the NAIF Node of PDS electronically (via anonymous FTP and WWW servers). Refer to information in ``software/softinfo.txt'' for details regarding obtaining this software. 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 Venus Climate Orbiter meta-kernel(s), see the file ``extras/mk/mkinfo.txt''. " CONFIDENCE_LEVEL_NOTE = " This data set contains SPICE kernel files created during mission operations and analysis. Some general information about this collection follows here, but the prospective user is also referred to extensive descriptions (metadata) about each file that are stored inside each kernel file. Those 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, DBK), 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 because it could not be estimated even 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 associated with this data set (if such exist), or to contact C-SODA (Center for Science-satellite Operation and Data Archive) at ISAS/JAXA for possible further information. SPK Files ========= Two kinds of SPK files are provided in this archive: a planetary ephemeris SPK, spacecraft reference trajectory SPKs. Each of these kinds is briefly described below; more information is available in the file ``data/spk/spkinfo.txt''. Planetary SPK ------------- A custom version of planetary ephemeris SPK file containing data from both DE423 and DE430, spk/vco_de423_de430.bsp, is included in this archive. Spacecraft Reference Trajectory SPKs ------------------------------------ These SPKs are the latest official reference trajectory SPK files that contain only the spacecraft ephemeris. They were created by merging a series of reconstructions. These files include extensive internal comments providing detailed information. Additional information about SPK files provided in this data set is available in the file ``data/spk/spkinfo.txt''. Orbit number files ------------------ This data set also includes 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 supplementary files are 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''. CK Files ======== Five kinds of C-kernel files are provided in this archive: the reconstructed CKs for spacecraft attitude produced from telemetry, the predicted CKs for spacecraft attitude produced by data extracted from history of commands sent from the ground, the reconstructed CKs for orientation of the solar array paddles of the spacecraft produced from telemetry, the nominal CK for orientation of the solar array paddles of the spacecraft, and the predicted CKs for orientation of the two medium gain antennas of the spacecraft produced from history of commands sent from the ground. Each of these kinds is briefly described below; more information is available in the file ``data/ck/ckinfo.txt''. All reconstructed CK files were produced from engineering telemetry downlinked from the spacecraft. As is often the case with spacecraft engineering telemetry-based measurements, considerable uncertainty exists as to the accuracy of such measurements, and, data quality (accuracy and completeness) can vary significantly. All predicted CKs were produced from command history that describes commands sent from the ground. Spacecraft Bus reconstructed CK Files ------------------------------------- These CK files providing the orientation of the spacecraft bus (``vco_YYYY_vVV.bc'') can be used to support interpretation of data obtained by all science experiments. They were generated by mission operations at variable sampling resolutions depending on downlink availability and spacecraft configuration (can be up to 0.5 Hz). Spacecraft Bus predicted CK Files --------------------------------- These CK files providing the orientation of the spacecraft bus (``vco_YYYY_pred_vVV.bc'') can be used to support interpretation of data obtained by all science experiments. They were generated from history of attitude control commands. These CK files cover the gaps (i.e., the period without any data points) in the reconstructed CK files for spacecraft attitude. Solar Array Paddle Orientation reconstructed CK Files ----------------------------------------------------- These CK files (``vco_sap_YYYY_vVV.bc'') contain the orientation of the -Y to +Y solar array paddle (SAP1) and the +Y to -Y solar array paddle (SAP2) relative to the spacecraft bus. They were generated by mission operations at variable sampling resolutions depending on downlink availability and spacecraft configuration (can be up to 0.5 Hz). Solar Array Paddle Nominal Orientation CK Files ----------------------------------------------- These CK files (``vco_sap_nominal_vVV.bc'') contain the nominal orientation of the SAP1 and the SAP2 relative to the dynamic frame, ``VCO_SAP_NOMINAL''. X-band Medium Gain Antennas Orientation reconstructed CK Files -------------------------------------------------------------- These CK files (``vco_xmga_YYYY_vVV.bc'') contain the orientation of the X-band Medium Gain Antenna A (XMGA-A) and the X-band Medium Gain Antenna B (XMGA-B) relative to the spacecraft bus. They were generated from history of commands. PCK Files ========= The PCK files included in this data set provide size, shape and orientation data for the mission target, Venus, and for the Solar System planets and satellites. A description of these data items and reference to their source is provided inside the PCK files, which are simple text files that can be viewed using any word processor, text editor or text display utility. Two types of PCK file are provided in this data set: a type of the generic PCK file (``pck00010.tpc'') containing the official IAU/IAG/COSPAR values as of 10/21/2011 and a type containing a the Venus Climate Orbiter mission specific file (``vco_gm_de431_v01.tpc'') for the GM values used in the Venus a Climate Orbiter mission. It contains both the generic PCK provided by NAIF and the Venus Climate Orbiter mission specific parameters. Additional information about PCK files provided in this data set is available in the file ``data/pck/pckinfo.txt''. FK Files ======== The FK files included in this data set provide definitions for the Venus Climate Orbiter spacecraft frames, and the Venus body-fixed frame. Comments in the FK files provide the frame specifications, descriptions of the frame relationships, the source of and accuracy of the mounting alignment information, etc. The ``vco_spacecraft_vVV.tf'' FK defines the Venus Climate Orbiter spacecraft frame and frames for its engineering structures and science instruments. The ``rssd0002.tf'' FK is the generic frames definition kernel for ESA planetary missions and defines the body-fixed frame for Venus. Additional information about FK files provided in this data set is available in the file ``data/fk/fkinfo.txt''. IK Files ======== The IK files included in this data set provide specifications for the optical and physical instrument parameters and -- where applicable -- field-of-view size, shape and orientation for the Venus Climate Orbiter instruments. Each IK file contains comments providing descriptions of the included parameters and FOV and frame specifications. All IK files provided in the data set were created by the PLANET-C Project Team. There is one IK for each instrument (``vco_uvi_vVV.ti'', ``vco_ir1_vVV.ti'', ``vco_ir2_vVV.ti'', ``vco_lac_vVV.ti'', and ``vco_lir_vVV.ti'') except for Ultra Stable Oscillator (USO) used in Radio Science (RS) experiments. Additional information about IK files provided in this data set is available in the file ``data/ik/ikinfo.txt''. SCLK Files ========== The SCLK file included in this data set provides a tabulation of data needed to convert time measurements between ephemeris time (ET) and Venus Climate Orbiter spacecraft clock time (SCLK). This file was created by the PLANET-C Project Team and is named ``vco_vVV.tsc''. The accuracy of and issues with the correlation provided by this file are discussed in the comments. Additional information about SCLK files provided in this data set is available in the file ``data/sclk/sclkinfo.txt''. LSK Files ========= The LSK file included in this data set provides the most current tabulation of ``leapseconds'' and other terms used in converting time measurements between ephemeris time (ET) and Universal Time (UTC) at the time when this data set was assembled (February 2017). 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. Additional information about LSK files provided in this data set is available in the file ``data/lsk/lskinfo.txt''. EK Files ======== The PLANET-C Project Team did not produce any EK files; therefore, no EKs are included in this data set. " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_MISSION MISSION_NAME = "VENUS CLIMATE ORBITER" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_TARGET TARGET_NAME = "VENUS" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "VCO" 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