Data Set Overview
    =================
      The Lunar Reconnaissance Orbiter (LRO) Lunar Exploration
      Neutron Detector (LEND) that will act as large orbital neutron
      telescope for mapping the Moon's neutron albedo. LEND consists
      of eight 3He sensors for detecting thermal and epithermal
      neutrons, four of which are are collimated to improve spatial
      resolution. LEND also contains the Sensor for High Energy
      Neutrons (SHEN), which is a stilbene scintillator that produces
      a flash of light each time a high energy neutron in the energy
      range 0.3 - 15.0 MeV collides with a hydrogen nucleus and
      creates a recoil proton. A full description of the LRO LEND
      instrument can be found in [MITROFANOVETAL2008].
 
      The LRO LUNAR EXPLORATION NEUTRON DETECTOR 2 EDR data set
      is a time series collection of science and housekeeping data
      from the LRO spacecraft. Data are sorted by type and by time.
      Data are sorted by time, with each data file containing one
      day's worth of data from midnight to midnight UTC. Measurements
      are assigned to a particular day based on the end of the
      collection interval.
 
      LEND collects a new spectrum (frame) approximately every
      second. Approximately 86400 spectra are expected to be received
      every day. The collection interval can be changed in the middle
      of a time series file, which can be determined by noting the
      difference between record timestamps. The data (both science
      and housekeeping) are downloaded from the spacecraft. Data are
      output to a spooler that passes them to the University of
      Arizona (UA) database ingest process. The ingest process inputs
      raw data into the UA database. Data are retrieved from the UA
      database to build the LEND EDR data products.
 
      The LEND EDR data set is intended to be the lowest level
      (level 0) data available for LEND. It should be useful to those
      scientists who are experienced in neutron spectroscopy.
 
    Parameters
    ==========
       The LEND EDR data set is composed of two data types. The
       objective of compiling the LEND EDR is to create a record of
       the primary data collected by LEND. The following paragraphs
       discuss the parameters of interest in each of the data types.
 
       Science
       -------
         The LEND SCI data are time series science records taken over
         the course of a day. Data files are labeled with the date.
         Individual records are a single data collection interval,
         which lasts 1 second. Data includes spectra for all
         collimated and uncollimated 3He detectors as well as spectra
         for the stilbene high energy neutron detector.
 
       Housekeeping
       ------------
          The housekeeping data are time series records for each
          housekeeping parameter taken over the course of a day.
          Individual records are a single data collection interval.
          Data includes command, voltage and temperature information.
 
    Processing
    ==========
      A process termed 'ingest' occurs on the LEND Science Operations
      Center computer which receives data from the LRO Mission
      Operation Center. The ingest process verifies the consistency
      of the data. The LEND EDR data product is output by software
      that maps the stored relational data into the format described
      by the LEND EDR SIS. Both processes (ingest and output) are
      rigorously tested. Multiple versions of the data product may be
      made available if software bugs affecting the output data are
      uncovered and corrected. In the event of an error whose fix
      changes released data, it is expected the data will be
      reprocessed by the revised software and made available.
 
 
    Data
    ====
      The LEND EDR data product contains two types of data.
 
      LEND_SCI_DATA               Neutron Detector science data
      LEND_HK_DATA                Neutron Detector housekeeping data
 
      LEND_SCI_DATA is a time series of Neutron Detector science
      data. LEND_HK_DATA is a time series of Neutron Detector
      housekeeping data. Each product type is stored in a separate
      file with a detached PDS label. All the product types are stored
      as binary tables with fixed-length records.
 
 
    Coordinate System
    =================
      Not applicable for this data set.
 
    Software
    ========
      No LEND specific software is provided with this data set.
 
      PDS-labeled images and tables can be viewed with the program
      NASAView, developed by the PDS and available for a variety of
      computer platforms from the PDS web site
      http://pds.nasa.gov/tools/software_download.cfm. There is no
      charge for NASAView.
 
    Media/Format
    ============
      The LEND EDR will be delivered using DVD media. Formats will be
      based on standards for such products established by the
      Planetary Data System (PDS) [PDSSR2006].

Confidence Level Overview
    =========================
      The data presented in the LEND EDR is intended to be the least
      processed, most primitive data set released for LEND. Data
      presented here are an accurate representation of LEND data as
      received from the spacecraft.
 
 
    Review
    ======
      The LEND EDR was reviewed internally by the LEND team prior to
      release to the PDS. PDS will also performed an external peer
      review of the LEND EDR.
 
 
    Data Coverage and Quality
    =========================
      Data reported are the minimally processed data received from
      the orbiter during nominal LEND operations. All data received
      is reformatted into one of the EDR data types. Data are by
      definition of good quality, as damaged telemetry packets are
      sequestered upon receipt from the spacecraft. We do not expect
      to receive many (if any) damaged data packets.
 
 
  Limitations
  ===========
    The major limitation of this data set is that this is level 0,
    minimally processed data. The data are received from the
    spacecraft telemetry and ingested into a database. If gaps
    exist in the telemetry, data are lost.
 
  Data Compression
  ===============
    No data compression is used.