Data Set Information
DATA_SET_TERSE_DESCRIPTION Calibrated data taken by New Horizons Solar Wind Around Pluto instrument during the KEM1 ENCOUNTER mission phase. This is VERSION 2.0 of this data set.
Data Set Overview

      This data set contains Calibrated data taken by
      the New Horizons Solar Wind Around Pluto instrument during the
      KEM1 ENCOUNTER mission phase.

      SWAP comprises electro-optics and detectors to obtain count rate
      measurements of the solar wind; measuring the solar wind before,
      during and after the Pluto encounter will allow characterization
      of the atmospheric escape rate of Pluto. The SWAP electro-optic
      elements select the angles and energies of the solar wind and
      pickup ions to be measured; ions thus selected are registered with
      a coincidence detector system. SWAP measures the energy spectrum
      of ions in its environment by varying (also called scanning or
      sweeping) voltages of the electro-optics over many steps during a
      short time period. SWAP can also immediately follow a sweep of
      coarse voltage steps with a sweep of finer steps, centered on the
      peak measurement of the coarse sweep, to obtain a higher
      resolution of that portion of the energy spectrum.

      There are three types of SWAP science data: real-time; summary;
      histogram. Real-time data, at rates up to 1Hz, provide the most
      detailed science measurements since they contain the full count
      rate distribution as a function of energy (speed). For science
      summary and science histogram modes, the full distribution is not
      recorded. Instead, parameters are derived from the count rate
      distribution stored by SWAP. These derived parameters require less
      memory than storing the whole distribution. The science summary
      and science histogram modes are primarily used during the cruise
      phase of the mission. For science data, the common data product is
      usually a binary table; for calibrated real-time data,
      spectrograms as images are also provided. Typically the tables
      have instrument parameters and measurements in the columns and
      measurement times in the rows, but the actual format depends on
      the type of data and the processing level (raw vs. calibrated).
      Other tables containing housekeeping and other parameters are also
      provided. This data set includes documentation for all data types
      and formats.

      For a list of observations, refer to the data set index table. This
      is typically INDEX.TAB initially in the INDEX/ area of the data set.
      There is also a file SLIMINDX.TAB in INDEX/ that summarizes key
      information relevant to each observation, including which sequence
      was in effect and what target was likely intended for the


      This is VERSION 2.0 of this data set.

      This version includes data acquired by the spacecraft between 08/14/2018
      and 01/31/2019. It only includes data downlinked before 02/01/2019.
      Future datasets may include more data acquired by the spacecraft
      after 08/13/2018 but downlinked after 01/31/2019.

      Two digits of precision have also been added to the EXPOSURE_DURATION
      value in all data labels after V1.0.

      General statement about data set versions after V1.0
      The pipeline (see Processing below) was re-run on these data for each
      version since the first (V1.0).  A pipeline rerun usually changes the
      FITS headers but not the FITS data of raw data sets.  In some cases
      calibrated FITS data may change because the calculated geometry of an
      observation has changed.  See data set version-specific sections below
      for significant exceptions to this general statement, i.e. changes to
      pipeline processing, calibration processing, and data delivered.

      Note that even if this is not a calibrated data set, calibration
      changes are listed as the data will have been re-run and there will be
      updates to the calibration files, to the documentation (Science
      Operations Center - Instrument Interface Control Document:
      SOC_INST_ICD) and to the steps required to calibrate the data.


      The data in this data set were created by a software data
      processing pipeline on the Science Operations Center (SOC) at
      the Southwest Research Institute (SwRI), Department of Space Operations.
      This SOC pipeline assembled data as FITS files from raw telemetry
      packets sent down by the spacecraft and populated the data labels
      with housekeeping and engineering values, and computed geometry
      parameters using SPICE kernels.  The pipeline did not resample
      the data.


      The observations in this data set are stored in data files using
      standard Flexible Image Transport System (FITS) format.  Each FITS
      file has a corresponding detached PDS label file, named according
      to a common convention.  The FITS files may have image and/or table
      extensions. See the PDS label plus the DOCUMENT files for a
      description of these extensions and their contents.

      This Data section comprises the following sub-topics:

      - Filename/Product IDs
      - Instrument description
      - Other sources of information useful in interpreting these Data
      - Visit Description, Visit Number, and Target in the Data Labels

      Filename/Product IDs

        The filenames and product IDs of observations adhere to a
        common convention e.g.

         ^^^ ^^^^^^^^^^ ^^^^^ ^^^\__/
         |        |       |    |  ^^
         |        |       |    |   |
         |        |       |    |   +--File type (includes dot)
         |        |       |    |      - .FIT for FITS file
         |        |       |    |      - .LBL for PDS label
         |        |       |    |      - not part of product ID
         |        |       |    |
         |        |       |    +--ENG for CODMAC Level 2 data
         |        |       |       SCI for CODMAC Level 3 data
         |        |       |
         |        |       +--Application ID (ApID) of the telemetry data
         |        |          packet from which the data come
         |        |          N.B. ApIDs are case-insensitive
         |        |
         |        +--MET (Mission Event Time) i.e. Spacecraft Clock
         +--Instrument designator

      Note that, depending on the observation, the MET in the data filename
      and in the Product ID may be similar to the Mission Event Time (MET)
      of the actual observation acquisition, but should not be used as an
      analog for the acquisition time.  The MET is the time that the data are
      transferred from the instrument to spacecraft memory and is therefore
      not a reliable indicator of the actual observation time.  The PDS label
      and the index tables are better sources to use for the actual timing of
      any observation.  The specific keywords and index table column names for
      which to look are

        * START_TIME
        * STOP_TIME

        Instrument   Instrument designators              ApIDs **
        ===========  ==================================  =============
         SWAP         SWA                                0X584 - 0X587 *

         * Not all values in this range are in this data set
         ** ApIDs are case insensitive

         There are other ApIDs that contain housekeeping values and
         other values.  See SOC Instrument ICD (/DOCUMENT/SOC_INST_ICD.*)
         for more details.

        Here is a summary of the types of files generated by each ApID
        (N.B. ApIDs are case-insensitive) along with the instrument
        designator that go with each ApID:

         ApIDs   Data product description/Prefix(es)
         =====   ===================================
         0x584 - SWAP Science Real-Time/SWA
         0x585 - SWAP Science Summary/SWA *
         0x586 - SWAP Science Histogram Header/SWA
         0x587 - SWAP Science Histogram Data/SWA

         * Level 3 NH SWAP data sets produced after April, 2016 do not have
         0x585 (Science Summary data); in-flight and in practice, 0x585
         data are used only for health and safety and not for science.

      Instrument description

        Refer to the following files for a description of this instrument.




          NH_SWAP_V###_TI.TXT  (### is a version number)

      Other sources of information useful in interpreting these Data

        Refer to the following files for more information about these data

          NH Trajectory tables:

            /DOCUMENT/NH_MISSION_TRAJECTORY.*   - Heliocentric

          SWAP Field Of View definitions:


          SWAP Data summary plots:


      Visit Description, Visit Number, and Target in the Data Labels

      The observation sequences were defined in Science Activity Planning
      (SAP) documents, and grouped by Visit Description and Visit Number.
      The SAPs are spreadsheets with one Visit Description & Number per row.
      A nominal target is also included on each row and included in the data
      labels, but does not always match with the TARGET_NAME field's value in
      the data labels.  In some cases, the target was designated as RA,DEC
      pointing values in the form ``RADEC=123.45,-12.34'' indicating Right
      Ascension and Declination, in degrees, of the target from the
      spacecraft in the Earth Equatorial J2000 inertial reference frame.
      This indicates that either the target was a star, or the
      target's ephemeris was not loaded into the spacecraft's attitude and
      control system which in turn meant the spacecraft could not be pointed
      at the target by a body identifier and an inertial pointing value had
      to be specified as Right Ascension and Declination values.  PDS-SBN
      practices do not allow putting a value like RADEC=... in the PDS
      TARGET_NAME keyword's value. In those cases the PDS TARGET_NAME value
      is set to CALIBRATION.  TARGET_NAME may be N/A (Not Available or Not
      Applicable) for a few observations in this data set; typically that
      means the observation is a functional test so N/A is an appropriate
      entry for those targets, but the PDS user should also check the
      the PDS label, plus the provided sequence list (see Ancillary Data
      below) to assess the possibility that there was an intended target.
      These two keywords are especially useful for STAR targets as often
      stars are used as part of instrument calibrations, and are
      included as part of the sequencing description which is captured
      in these keywords.

    Ancillary Data

      The geometry items included in the data labels were computed
      using the SPICE kernels archived in the New Horizons SPICE
      data set, NH-J/P/SS-SPICE-6-V1.0.

      Every observation provided in this data set was taken as a part of a
      particular sequence.  A list of these sequences has been provided in
      file DOCUMENT/SEQ_SWAP_*.TAB.  In addition, the
      sequence identifier (ID) and description are included in the PDS label
      for every observation.  N.B. While every observation has an associated
      sequence, every sequence may not have associated observations.  Some
      sequences may have failed to execute due to spacecraft events (e.g.
      safing).  No attempt has been made during the preparation of this data
      set to identify such empty sequences, so it is up to the user to
      compare the times of the sequences to the times of the available
      observations from INDEX/INDEX.TAB to identify such sequences.


      There are several time systems, or units, in use in this dataset:
      New Horizons spacecraft MET (Mission Event Time or Mission Elapsed
      Time), UTC (Coordinated Universal Time), and TDB Barycentric
      Dynamical Time.

      This section will give a summary description of the relationship
      between these time systems.  For a complete explanation of these
      time systems the reader is referred to the documentation
      distributed with the Navigation and Ancillary Information
      Facility (NAIF) SPICE toolkit from the PDS NAIF node, (see

      The most common time unit associated with the data is the spacecraft
      MET.  MET is a 32-bit counter on the New Horizons spacecraft that
      runs at a rate of about one increment per second starting from a
      value of zero at

        19.January, 2006 18:08:02 UTC


        JD2453755.256337 TDB.

      The leapsecond adjustment (DELTA_ET = ET - UTC) was 65.184s at
      NH launch, and the first four additional leapseconds occurred
      in at the ends of 12/2009, 06/2012, 06/2015, and 12/2016.
      Refer to the NH SPICE data set, NH-J/P/SS-SPICE-6-V1.0, and the
      SPICE toolkit documentation, for more details about leapseconds.

      The data labels for any given product in this dataset usually
      contain at least one pair of common UTC and MET representations
      of the time at the middle of the observation.  Other portions
      of the products, for example tables of data taken over periods
      of up to a day or more, will only have the MET time associated
      with a given row of the table.

      For the data user's use in interpreting these times, a reasonable
      approximation (+/- 1s) of the conversion between Julian Day (TDB)
      and MET is as follows:

        JD TDB = 2453755.256337 + ( MET / 86399.9998693 )

      For more accurate calculations the reader is referred to the
      NAIF/SPICE documentation as mentioned above.

    Reference Frame

      Geometric Parameter Reference Frame

      Earth Mean Equator and Vernal Equinox of J2000 (EMEJ2000) is the
      inertial reference frame used to specify observational geometry items
      provided in the data labels.  Geometric parameters are based on best
      available SPICE data at time of data creation.

      Epoch of Geometric Parameters

      All geometric parameters provided in the data labels were computed at
      the epoch midway between the START_TIME and STOP_TIME label fields.


      The observations in this data set are in standard FITS format
      with PDS labels, and can be viewed by a number of PDS-provided
      and commercial programs. For this reason no special software is
      provided with this data set.

    Contact Information

      For any questions regarding the data format of the archive,

      New Horizons SWAP Principal Investigator:

      David McComas

      Princeton University
      Princeton Plasma Physics Laboratory
      Peyton Hall
      Princeton, NJ   08544
DATA_SET_RELEASE_DATE 2019-10-18T00:00:00.000Z
START_TIME 2018-08-14T08:08:02.011Z
STOP_TIME 2019-01-30T06:08:02.177Z
MISSION_START_DATE 2016-10-26T12:00:00.000Z
MISSION_STOP_DATE 2021-09-30T12:00:00.000Z
NODE_NAME Small Bodies
Confidence Level Overview
      During the processing of the data in preparation for
      delivery with this volume, the packet data associated with each
      observation were used only if they passed a rigorous verification
      process including standard checksums.

      In addition, raw (Level 2) observation data for which adequate
      contemporary housekeeping and other ancillary data are not available
      may not be reduced to calibrated (Level 3) data.  This issue is raised
      here to explain why some data products in the raw data set,


      may not have corresponding data products in the calibrated data set,


    Data coverage and quality
      Every observation provided in this data set was taken as a part of a
      particular sequence.

      Refer to the Confidence Level Overview section above for a summary
      of steps taken to assure data quality.

      SWAP data product completeness at the end of a mission phase

      Downlink data several days beyond the end of the nominal end of
      mission phase* were included in this data set in an attempt to fill
      the products at the nominal end of mission phase*.  This was done in
      an attempt to ensure complete coverage of data up through the nominal
      end of the mission phase*.  This also means that for the SWAP
      last-in-time products in this data set, which include observations
      beyond the nominal end of the mission phase*, may be incomplete.
      The following paragraphs provide details about this issue.

      SWAP data product completeness - details

      SWAP data are taken more or less continuously, but telemetry downlinks
      are done in batches, so the SWAP data are stored on-board the
      spacecraft at least until they are downlinked, sometimes hours or days
      after they are taken.  Furthermore, SWAP PDS data are grouped into
      products, each covering approximately one day's worth of data,
      starting and ending at a time of day near 18:08 UTC.

      This data set comprises data downlinked through a fixed cutoff date*.
      The interaction between the downlink cutoff, the batch nature of
      downlink, and the grouping of SWAP data will result in the last day's,
      or few days', data products in this data set containing less than
      a full day's worth of data.  This applies to SWAP science and
      engineering data as well as housekeeping and thruster data stored in
      the data products.  For example, this has been most noticeable during
      the Pluto PDS data set deliveries, e.g. the last product in the V2.0
      delivery with ApID 0x585 had very little science data and neither
      housekeeping nor thruster data, whereas the same product in the V3.0
      delivery had the full expected day's worth of data; also, the V3.0
      delivery has a product with ApID 0x584 that was not present in the
      V2.0 delivery.

      The NH project is considering  delivering SWAP data sets as a single
      incrementing data set.  Beyond that and other than adding a few days
      of telemetry beyond the nominal mission phase end*, the NH project has
      no further plans to mitigate this minor issue.

      In summary, the choice to deliver New Horizon data sets by mission
      phase affects SWAP data set product completeness near those mission
      phase boundaries.

    Observation descriptions in this data set catalog

      Some users will expect to find descriptions of the observations
      in this data set here, in this Confidence Level Note.  This data
      set follows the more common convention of placing those
      descriptions under the Data Set Description (above, if the user is
      reading this in the DATASET.CAT file) of this data set catalog.

    Caveat about TARGET_NAME in PDS labels and observational intent

      The downlink team on New Horizons has
      created an automated system to take various uplink products, decode
      things like Chebyshev polynomials in command sequences representing
      celestial body ephemerides for use on the spacecraft to control
      pointing, and infer from those data what the most likely intended
      target was at any time during the mission.  This works well during
      flyby encounters and less so during cruise phases and hibernation.

      The user of these PDS data needs to
      be cautious when using the TARGET_NAME and other target-related
      parameters stored in this data set.  This is less an issue for the
      plasma and particle instruments, more so for pointing instruments.
      To this end, the heliocentric ephemeris of the spacecraft, the
      spacecraft-relative ephemeris of the inferred target, and the
      inertial attitude of the instrument reference frame are provided
      with all data, in the J2000 inertial reference frame, so the user
      can check where that target is in the Field Of View (FOV) of the

      Finally, note that, within the FITS headers of the data products,
      the sequence tables, and other NH Project-internal documents used
      in this data set and/or inserted into the data set catalog,
      informal names are often used for targets instead of the canonical
      names required for the TARGET_NAME keyword.  For example, during
      the Pluto mission phase, instead of the TARGET_NAME '15810 ARAWN
      (1994 JR1)' there might be found any of the following:  1994JR1;
      1994 JR1; JR1.  For all values where the PDS keyword TARGET_NAME
      is used (e.g. in PDS labels and in index tables), the canonical,
      PDS-approved names are used (if not, please bring this to the
      attention of PDS so it can be rectified).  However, within the
      context of this data set, these project abbreviations are not
      ambiguous (e.g. there is only one NH target with 'JR1' in its
      name), so there has been, and will be, no attempt to expand such
      abbreviations where they occur outside formal PDS keyword values.

      This dataset was peer reviewed and certified for scientific use by
      the PDS.
ABSTRACT_TEXT This data set contains Calibrated data taken by the New Horizons Solar Wind Around Pluto instrument during the KEM1 ENCOUNTER mission phase. This is VERSION 2.0 of this data set. This data set contains data acquired by the spacecraft between 08/14/2018 and 01/31/2019. It only includes data downlinked before 02/01/2019. Future datasets may include more data acquired by the spacecraft after 08/13/2018 but downlinked after 01/31/2019. The data includes SWAP observations and plasma rolls in the approach and departure of MU69. A gain test was also performed.
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