Data Set Information
DATA_SET_NAME MESSENGER SPICE KERNELS V1.0
DATA_SET_ID MESS-E/V/H-SPICE-6-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : This data set includes the complete set of MESSENGER 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, and data needed for relevant time conversions. This data set is contained on a single virtual volume, MESSSP_1000, including data from all mission phases and covering from launch, 2004-08-03T00:00:00, 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 six months. Data are associated with the mission phases given below. These are defined in the MESSENGER DMAP. These may be updated periodically. Start time End time Phase Name Date (DOY) Date (DOY) ------------------- ----------------- ----------------- Launch 03 Aug 2004 (216) 12 Sep 2004 (256) Earth Cruise 13 Sep 2004 (257) 18 Jul 2005 (199) Earth Flyby 19 Jul 2005 (200) 16 Aug 2005 (228) Venus 1 Cruise 17 Aug 2005 (229) 09 Oct 2006 (282) Venus 1 Flyby 10 Oct 2006 (283) 07 Nov 2006 (311) Venus 2 Cruise 08 Nov 2006 (312) 22 May 2007 (142) Venus 2 Flyby 23 May 2007 (143) 20 Jun 2007 (171) Mercury 1 Cruise 21 Jun 2007 (172) 30 Dec 2007 (364) Mercury 1 Flyby 31 Dec 2007 (365) 28 Jan 2008 (028) Mercury 2 Cruise 29 Jan 2008 (029) 21 Sep 2008 (265) Mercury 2 Flyby 22 Sep 2008 (266) 20 Oct 2008 (294) Mercury 3 Cruise 21 Oct 2008 (295) 15 Sep 2009 (258) Mercury 3 Flyby 16 Sep 2009 (259) 14 Oct 2009 (287) Mercury 4 Cruise 15 Oct 2009 (288) 03 Mar 2011 (062) Mercury Orbit 04 Mar 2011 (063) 17 Mar 2012 (077) Mercury Orbit Year 2 18 Mar 2012 (078) 17 Mar 2013 (076) Mercury Orbit Year 3 18 Mar 2013 (077) 17 Mar 2014 (076) Mercury Orbit Year 4 18 Mar 2014 (077) 17 Mar 2015 (076) Mercury Orbit Year 5 18 Mar 2015 (077) 30 Apr 2015 (120) 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 not used by the MESSENGER program and are not included in this data set. LSK (Leap seconds) kernels contain the leap seconds 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 MESSENGER 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 MESSENGER meta-kernel(s), see the file ``extras/mk/mkinfo.txt''.
DATA_SET_RELEASE_DATE 2017-05-12T00:00:00.000Z
START_TIME 2004-08-03T07:13:35.000Z
STOP_TIME 2015-04-30T07:26:02.000Z
MISSION_NAME MESSENGER
MISSION_START_DATE 2004-08-03T12:00:00.000Z
MISSION_STOP_DATE 2015-04-30T12:00:00.000Z
TARGET_NAME EARTH
VENUS
MERCURY
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID MESS
INSTRUMENT_NAME SPICE KERNELS
INSTRUMENT_ID SPICE
INSTRUMENT_TYPE N/A
NODE_NAME Navigation and Ancillary Information Facility
ARCHIVE_STATUS LOCALLY ARCHIVED
CONFIDENCE_LEVEL_NOTE This data set contains SPICE kernel files created during mission operations. 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 : Four kinds of SPK files are provided in this archive: a planetary ephemerides SPK, merged spacecraft reference trajectory SPKs, a final mission SPK that contains both merged spacecraft reference trajectory and planetary ephemerides (msgr_040803_150430_150430_od431sc_2.bsp), and a set of five alternative on-orbit spacecraft SPKs produced from MLA instrument and radio science data provided by the MLA and Radio Science teams at GSFC. Each of these kinds is briefly described below; more information is available in the file ``data/spk/spkinfo.txt''. Planetary SPK ------------- The DE405 planetary ephemeris SPK file included in this data set contains ephemeris data for the Solar System planet barycenters, Sun, Mercury, Venus, Earth, Moon, and Mars. This version of ephemerides was officially used by the project during mission operations. The internal comments included this SPK file provide detailed accuracy information. A custom version of this file containing data from both DE405 and DE423, spk/msgr_de405_de423s.bsp, is included in this archive and used prior to the final release. It is deprecated in the final release since the data it contains are merged into the final spacecraft trajectory SPK. Merged Spacecraft Reference Trajectory SPKs ------------------------------------------- These SPKs are the latest official full-mission merged reference trajectory SPK files that contain only the spacecraft ephemeris. They were created by merging a series of reconstructions and short-term predictions onto the modeled whole-tour SPK. These files include extensive internal comments providing detailed information about reconstructed and predicted portions of the data. Final Mission Spacecraft Reference Trajectory SPK ------------------------------------------------- The final version of the full-mission merged trajectory SPK, msgr_040803_150430_150430_od431sc_2.bsp, also contains the required planetary ephemeris. As noted above, the DE405 planetary ephemeris and the custom planetary ephemeris, msgr_de405_de423s.bsp, should not be loaded when this SPK is loaded. See the final MKs for details. GSFC Spacecraft Trajectory SPKs ------------------------------- The MLA and radio science teams at Goddard Space Flight Center (GSFC) have produced a set of five SPKs that cover the on-orbit phases of the mission. These are produced from MLA instrument and radio science data. These provide a greater precision than the mission SPKs and can be used in place of the mission SPK in many situations. CK Files : Four kinds of C-kernel files are provided in this archive: the spacecraft bus and solar panel orientation CKs, the MDIS attitude history CKs, the MDIS Pivot Platform CKs, and the USGS MDIS c-Smithed CKs. Each of these kinds is briefly described below; more information is available in the file ``data/ck/ckinfo.txt''. These CK files, except for the USGS MDIS CKs, 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. Spacecraft Bus and Solar Panel Orientation CK Files --------------------------------------------------- These CK files providing the orientation of the spacecraft bus (``the spacecraft'') can be used to support interpretation of data obtained by all science experiments. These CK Files also contain the orientation of the +X to -X solar panels 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 1 Hz). The engineering telemetry that supplied the attitude history included a quality flag which was used during construction of the files to eliminate readings that do not meet science requirements. The spacecraft guidance and control telemetry from Oct 20, 2006 was interrupted when the spacecraft was demoted to earth acquisition mode. Due to the anomaly, data were missing. The CK file covering this day was ``patched'' with simulated data to provide coverage for the missing period. MDIS Attitude History CK Files ------------------------------ These CKs provide orientation of the spacecraft bus based on the 1-Hz spacecraft attitude data bracketing MDIS observations only. They represent the same information as the spacecraft bus orientation CKs, but at a different sampling frequency. These CK files store 16 bit ``compressed'' quaternions, unlike the spacecraft CK files, which use full 32 bit quaternions. The angular rate data included in the MDIS attitude history file did not come from Guidance and Control telemetry. Instead, this information was derived from the attitude information. Note that if the normal spacecraft bus orientation telemetry supports a 1-Hz rate, this data is not necessary and may not be down linked. Therefore the MDIS attitude history file may not cover all MDIS observations - just those for which sufficient coverage may not exist in the spacecraft bus CK's. MDIS Pivot Platform (Gimbal) CK Files ------------------------------------- These CKs provide pointing of the MDIS instrument over time. The MDIS stepper motor setting telemetry was used to calculate the pointing for each image taken. This information was included in the image header and was used to construct these CK files. Every set of MDIS exposures has related orientation information provided in these CKs. USGS MDIS c-Smithed CK Files ------------------------------------- The USGS MDIS CKs were produced at the US Geological Survey from MDIS data. They are intended primarily for use with the USGS Digital Elevation Model (DEM) products archived at the PDS Cartography and Imaging Sciences Node (data set ID: MESS-H-MDIS-5-DEM-ELEVATION-V1.0). 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. PCK Files : PCK files provide size, shape and orientation data for ``target'' bodies such as Earth, Venus and Mercury. 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. Two types of PCK file are provided in this data set: a type of PCK file containing the official IAU/IAG/COSPAR values as of 10/21/2011 and a type containing a MESSENGER specific file for the MESSENGER updates to Mercury parameters. This second type of PCK file was adopted by the MESSENGER Principle Investigator based on the recommendation of the MESSENGER science team concerning the best and most current data. It contains both the generic PCK provided by NAIF and the MESSENGER specific parameters. 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 specifications for how one reference frame is defined relative to another frame. This data set includes two kinds of FK files: FKs providing the complete set of frame definitions for the spacecraft, its structures such as solar array, and all of its science instruments and FKs defining a number of dynamic frames used in science data reduction. Meta information provided in the comments included in these files consists of the frame specifications, description of the frame relationships, source of and accuracy of the information, etc. More information about the MESSENGER FK files is available in 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. Parameter values were determined from pre-launch measurements and in-flight measurements. This data set includes IK files for the EPPS, GRNS, MAG, MASCS, MDIS, MLA, and XRS instruments. They represent the best available information at the present time and meet science requirements. More information about the MESSENGER 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). A SPICE SCLK file is made from a similar file--SCLK/SCET file, or SCLKvSCET file--produced by another mission entity. Each newly made SCLK file fully replaces the previous SCLK file. The time correlation accuracy of the SCLK files provided in this data set meet the science requirements for all phases of the mission. Note that the SCLK kernels provided in this data set have been determined to be in a relativistic solar system barycentric frame of reference. This has been verified through confirmation that the ephemerides used to compute the SCLK kernel correlations are in a solar barycentric frame. It is critically important that the users of these kernels for time applications be aware of this and that they properly interpret the time correlations in the SCLK kernels. The file ``sea_2007_010.pdf'' in the ``document'' directory should be consulted for information on how to do this. In addition, the file ``sea_2003_024.pdf'' in the ``document'' directory gives further information on the format and design of these kernels. More information about the SCLK files is available in the file ``data/sclk/sclkinfo.txt''. LSK Files : Leap seconds kernel files provide a tabulation of ``leap seconds'' 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 : Events kernel (EK) files are not used by the MESSENGER mission; therefore, no EKs are included in this data set.
CITATION_DESCRIPTION Turner, Scott, MESSENGER SPICE KERNELS V1.0, MESS-E/V/H-SPICE-6-V1.0, NASA Planetary Data System, 2007.
https://doi.org/10.17189/1520108
ABSTRACT_TEXT This data set includes the complete set of MESSENGER 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.
PRODUCER_FULL_NAME MIKE REID
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