Data Set Overview      =================      This data set includes the complete set of JUNO SPICE data files      (``kernel files''), which can be accessed using SPICE software.      The SPICE data contain 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 data needed for relevant time conversions.      This data set is contained on a single virtual volume,      JNOSP_1000, including data from all mission phases and covering      from launch through the end time of the latest spacecraft      attitude 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.      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 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. 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      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 JUNO 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. SPICE 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 JUNO meta-kernel(s), see the file      ``extras/mk/mkinfo.txt''.

This data set 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, ESQ), 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, MK), accessible by using any available      text file display tool such as a word processor, text editor, or      the unix ``more'' or ``cat'' commands.      Where there are questions about data accuracy or ``confidence''      not addressed herein the reader is invited to contact the NAIF      node of the Planetary Data System for possible further      information.      SPK Files      =========      SPK files contain ephemerides for spacecraft, planets,      satellites, comets and asteroids as well as for moving or fixed      spacecraft and instrument structures.      Three kinds of SPK files are provided in this archive: SPK files      for the spacecraft orbit, SPK files for the Solar System planets      and satellites, and SPK files for the relative locations of      selected spacecraft structures.      The spacecraft orbit SPK files contain the reconstructed      spacecraft trajectory determined by the JUNO Navigation (NAV)      Team, JPL. The informal 1-sigma uncertainty for the JUNO      spacecraft reconstruction during cruise is on the order of 25      kilometers while the informal 1-sigma uncertainty for the JUNO      spacecraft reconstruction during perijove passes is on the order      1 kilometer.      This data set also includes the orbit number files generated      during the mission using the NAIF's ORBNUM utility program. These      files are not SPICE kernels; for this reason they are provided in      the ``extras/orbnum'' directory. For more information about the      JUNO orbit number files, see the file      ``extras/orbnum/orbinfo.txt''.      The DE436 planetary ephemeris SPK file included in this data set      contains ephemeris data for the Solar System planet barycenters,      Sun, Mercury, Venus, Earth, and Moon. The JUP310 SPK file      included in this data set contain ephemeris data for the eight      largest Jovian satellites. These versions of ephemerides were      officially used by the project during mission operations. The      accuracy information for these ephemerides is provided in the      memos released with this data by the Solar System Dynamics (SSD)      group, JPL.      The JUNO structures SPK file included in this archive provides      relative locations of the High Gain Antenna (HGA) and MAG      sensors. The data included in the file are based of the      dimensions from the spacecraft engineering drawings.      More information about JUNO SPK files is available in the file      ``data/spk/spkinfo.txt''.      CK Files      ========      CK files provide time-varying orientation data for the      spacecraft, and its structures and science instruments.      Seven kinds of C-kernel files are provided in this archive: the      reconstructed spacecraft bus (SC) orientation CKs; the low-      accuracy reconstructed SC orientation CKs; the MAG Advanced      Stellar Compass (ASC) Camera Head Units (CHU) and Magnetometer      Optical Benches (MOB) reconstructed, inertially referenced      attitude CKs; the MAG ASC CHU and MOB averaged alignment,      spacecraft frame referenced CKs; the MAG MOB temperature-based      alignment, spacecraft frame referenced CKs; the MAG MOB fixed      alignment, spacecraft frame referenced CKs; and the merged UVS      reconstructed orientation CKs.      The reconstructed spacecraft bus orientation CKs were created by      NAIF from reconstructed attitude products (ATT_RECON DRFs)      generated by the Spacecraft Team, LMCO by post-processing on the      ground the attitude data from engineering telemetry. As reported      by the Spacecraft team, the attitude reconstruction accuracy as      applies to the reconstructed attitude quaternions in the      ATT_RECON DRFs, inside of PJ-14 hours to PJ+4 hours is 0.41 mrad      per axis, 3-sigma (note that long star outages could affect      this); outside perijove time periods -- 1.0 mrad per axis,      3-sigma, excluding any precessions activities, including repoints      and large precessions (e.g., to/from MWR attitudes) and any      delta-v maneuver activity (TCM, DSM, JOI, OTM, BTM, APO, BPO,      STM, etc); for the remainder of the time -- during any precession      or delta-v maneuver activity the errors can be much larger due to      thruster pulsing and nutation (based on maneuver performance up      to Jun 2017, accuracy is probably within 3 mrad/axis during these      delta-v maneuvers) and during precessions (and repoints) the      errors depend upon the size of the precession. The angular      momentum vector accuracy, as applies to the specific angular      momentum vectors in the ATT_RECON DRFs, is 0.15 mrad total angle,      3-sigma, excluding any precessions activities (repoints and large      precessions, e.g., to/from MWR attitudes) and any delta-v      maneuver activity (TCM, DSM, JOI, OTM, BTM, APO, BPO, STM, etc);      for the remainder of the time -- during any precession or delta-v      maneuver activity the errors can be much larger due to thruster      pulsing, which affect the angular momentum vector suddenly and      significantly while the available telemetry is not sufficient to      reconstruct these sudden shifts.      The low-accuracy reconstructed spacecraft bus orientation CKs      were created by NAIF from low-frequency channelized attitude      telemetry. They are provided only for anomaly periods not covered      by the reconstructed spacecraft CKs. During these periods the      attitude provided by these low-accuracy CKs is good to 0.1-0.25      degrees for ``quiet'' intervals with relatively dense data points      but has errors of many tens of degrees during spacecraft attitude      maneuvers (spin-ups, precession re-pointings, etc) and during      intervals with very sparse attitude data points (points spaced      hours or even days apart).      The reconstructed MAG ASC CHU/MOB CKs were created by NAIF from      CHU channelized telemetry. They provide inertially referenced      orientation for each of the four CHUs (A, B, C, and D) and two      MOBs (in-board and out-board). The accuracy and coverage of the      attitude stored in these CKs varies depending on downlinked data      frequency and CHU performance. When used in MAG data processing      these CKs occasionally introduce unfavorable oscillating      signatures.      The averaged alignment, spacecraft frame referenced MAG ASC      CHU/MOB CKs were created by NAIF by differencing comparing      inertially referenced spacecraft and CHU/MOB orientations      provided in their corresponding reconstructed CKs. The      time-varying CHU and MOB alignments eliminate oscillating      signatures seen when using the reconstructed MAG ASC CHU/MOB CKs      but due to the simplistic approach used to derive them might      introduce show changing biases in the inertially referenced MAG      attitude solutions. It is possible that better alignment CKs      resulting from more sophisticated modeling and superseding these      CKs will be added to the data set in a later release.      The temperature-based alignment, spacecraft frame referenced MAG      MOB CKs were created by the MAG Team, GSFC using the DTU solar      array and SRU bracket thermal distortion model. These CKs, more      accurate than the averaged alignment CKs but covering only few      day periods around perijoves, were used by the MAG Team to      process their perijove data.      The fixed alignment, spacecraft frame referenced MAG MOB CKs were      created by NAIF. These CKs do not contain actual alignment data.      Instead they contain zero-offset ``connection'' segments      providing access to fixed alignment data stored in the FK.      Together with the FK these CKs allow computing MAG sensors      orientation accurate to better than 0.5 milliradian between      perijoves but are in error of more than one milliradian around      perijoves. These CKs were used by the MAG Team to process their      data between perijoves.      The merged UVS reconstructed orientation CKs provide actual      telemetry-based orientation of the JUNO UVS instrument      observation frame. They were created by NAIF by merging      individual UVS CKs produced by the UVS Team, SWRI.      More information about JUNO CK files is available in the file      ``data/ck/ckinfo.txt''.      PCK Files      =========      PCK files provide size, shape and orientation data for ``target''      bodies such as Jupiter, Europa, and Earth. A description of these      data items and reference to their source is provided inside the      PCK file, which is a simple text file that can be viewed using      any word processor, text editor or text display utility.      The generic PCK file included in this data set is based on the      IAU/IAG/COSPAR values accepted in 2009.      More information about the PCK files included in this data set is      available in the file ``data/pck/pckinfo.txt''.      FK Files      ========      Frames kernel files provide definitions of the reference frames      specifying their names, types, and relationships to other frames.      The JUNO mission FK file provided in this data set contains the      complete set of frame definitions for the spacecraft, its      structures such as solar array and antennas, and all of its      science instruments. Meta information provided in the comments      included in this file consists of the frame definitions,      description of the frame relationships, source of and accuracy of      the mounting alignment information, etc.      More information about the JUNO FK files is available in the file      ``data/fk/fkinfo.txt''.      IK Files      ========      Instrument kernel files provide specifications for geometric      parameters and--where applicable--field-of-view size, shape and      orientation for the named instruments. Metadata describing these      estimates are provided in each IK file included in this archive.      Parameter values were determined from pre-launch measurements,      instrument parameters specification documents, and in some cases      from analysis of in-flight calibration data. The accuracy      estimates for these data vary from instrument to instrument and,      where available, are included in the IK internal comments.      This data set includes IK files for all instruments on the JUNO      spacecraft.      Because the sets of geometric parameters included in the IKs vary      from instrument to instrument users are encouraged to carefully      examine the IKs before using them.      More information about JUNO IK files is available in 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).      The JUNO SPICE SCLK files were made from similar files--SCLK/SCET      files, or SCLKvSCET files--produced by another mission entity.      Each newly made SCLK file fully replaces the previous SCLK file.      For JUNO, the time correlation accuracy provided in the SCLK      kernel files for the Jupiter orbital operations time period is      informally reported to be better than 10-20 milliseconds.      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.      More information about the JUNO SCLK files is available in the      file ``data/sclk/sclkinfo.txt''.      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.      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.      More information about the LSK files is available in the file      ``data/lsk/lskinfo.txt''.      EK Files      ========      The JUNO project did not produce any EK files; therefore, no EKs      are included in this data set.