Data Set Overview  :   This data set contains Calibrated data taken by New Horizons  Linear Etalon Imaging Spectral Array  instrument during the PLUTO mission phase.   LEISA is an infrared imaging spectrometer. The two-dimensional (2-D)  detector is a 256x256-pixel array. Spectral separation is done with a  wedged optical etalon filter, which comprises high (2.1-2.25 micron) and low (1.225-2.5 micron) spectral resolution segments. The optics and  filter arrangement configure one detector dimension as spatial at  constant wavelength and the other dimension as both spectral and  spatial. Multiple frames (images) may be taken in sequence, while  scanning the Field Of View (FOV) in the spatial+spectral dimension, such that each pixel-sized piece of the observed target will be observed at  all wavelengths across multiple frames. The resulting data products in  this data set are three-dimensional image cubes, which dimensions are  spatial, spatial+spectral, and spatial+time and which shall be convolved into spatial, spatial, and spectral image cubes at a later date.   During the Pluto mission phase starting in January, 2015, there were  several sub-phases: three Approach sub-phases, (AP1, AP2 and AP3); a  CORE sequence for the Pluto flyby on 14.July, 2015 (Day Of Year 195),  sometimes also referred to as NEP (Near-Encounter Phase); three  Departure sub-phases (DP1, DP2, DP3). For this first Ralph-LEISA  delivery for the Pluto mission phase, this data set includes only the  Approach data plus the subset of the CORE sequence data that was  downlinked through the end of July, 2015. The rest of the Pluto data  will be delivered in future versions of this data set according to the  schedule worked out by the Project and NASA.   On Approach during April, May and June of 2015, LEISA operations  included the following: functional testsincluding a scan test; and  observations of Pluto, Charon and the other Plutonian satellites.   This dataset includes the first 3 P-LEISA scans of Pluto taken at 28,  26, and 24 days before the Pluto closest approach, to look for changes  in surface color and composition over multiple rotations. It also  includes three of the PC_VISUV_MAP observations at 18, 17, and 15 days  before encounter, with the same goal as P-LEISA. At 13 days,  PC_LEISA_VAR looks at the IR variability of Pluto and Charon.   The dataset also has a series of PC_MULTI_MAP observations, from 11  days and 2 days before closest approach. The PC_MULTI_MAPs met multiple  objectives as measurements coordinated with the P-Alice, LORRI, and  MVIC instruments. For LEISA, these objectives included determining  Pluto and Charon phase integrals, as LEISA offers another alternative  to visible wavelength imaging to get the angular dependence of  scattering by Pluto. They also are the primary method of performing  global temperature mapping of Pluto's surface ices, based on LEISA  near-IR spectral-imaging. The measurements support further goals for IR  spectroscopic maps of Pluto and Charon, searching for changes over  multiple rotations, looking at the composition of low albedo areas of  Pluto, and investigating the composition of non-encounter hemispheres  of Pluto and Charon. Also, using LEISA to observe various regions of  Pluto at or near the approach and departure asymptote phase angles  supports the determination of the bolometric albedos of various  regions. Finally, LEISA spectral studies of Pluto at multiple phase  angles helps to learn about surface processing and structure in various  regions.   The remainder of the LEISA dataset has 2 observations on the day of  closest approach: (1) P_LEISA_Alice_1a, which is a backup for scans of  whole disk at 7-10 km/pix to get a global infrared spectral map of  Pluto; and (2) C_LEISA_LORRI_1, which gives the Charon resolved IR  surface map and phase integral, and spectral studies of Charon at  multiple phase angles to learn about surface processing and structure  in various regions. Both also fulfill the objectives of the MULTI_MAPs.   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_LEISA_PLUTO.TAB.  N.B. Some sequences provided may have no corresponding observations.   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  observation.    Version  :   This is VERSION 1.0 of this data set.    Processing  :   The data in this data set were created by a software data  processing pipeline on the Science Operation Center (SOC) at  the Southwest Research Institute (SwRI), Department of Space Studies.  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.    Calibration  :    Detailed information about calibration of LEISA data is available  in the SOC Instrument Interface Control Document (ICD) in the  DOCUMENT section of this data set. The LEISA calibration will only  be briefly summarized here; refer to the ICD for details about  what is summarized here.   The calibration of MVIC images comprises the following steps:   1) Remove electronics-induced and flat-field signal  2) Apply calibration offset and gain  3) Adjust for integration time, filter width, and pixel solid angle  4) Correct for gain   In addition, the calibration procedure calculates various quantities  such as error (see note below) and a data quality flag for each pixel  and includes those results in the calibrated data product as additional  PDS OBJECTs (FITS extensions) appended to the main OBJECT with the data  image. The quality flag PDS OBJECT is an image of values of the same  size as the main IMAGE product, with each quality flag pixel mapped to  the corresponding pixel in the main product. A quality flag value of  zero indicates a valid pixel; a non-zero value indicates an invalid  pixel.   Note that for windowed products, all pixels in an image are not  returned in the downlink telemetry. In the raw data, the pipeline  sets such pixels to zero DN (Data Number); the calibration processes  those zero-DN pixels as if they were real raw values may result in a  confusing result with the majority of the displayed image appearing as  an inverse of the calibration (calibration of zero values); therefore  the windowed status of the image, as recorded in the value for the NOTE  keyword of the PDS label should be considered when looking at these  data.   Calibration and data characteristics  ------------------------------------   i) Error estimates are all zero. As of late 2014, the code to calculate the values for the Error estimates extension has not been deployed to the SOC, and placeholder code sets all pixel error estimates to zero. When the updated code is deployed to the SOC, some reprocessed  observations may be delivered to PDS (e.g. Jupiter encounter data);  note that observations from the Launch and Pluto Cruise mission  phases have little if any science utility, so there is no incentive  to reprocess those data just to provide error estimates.   ii) Fixed-pattern noise. There is usually fixed-pattern noise (FPN) in  the data that cannot be removed by the flat-field correction. Users need to generate an average of a few run-up frames containing  background sky and the FPN, and subtract that average from every  frame with a target source present. The number of frames to use  will vary by observation, so this operation is not part of the  automated pipeline.   iii) Scattered light. Although some observations have been taken to  characterize scattered light, no photometric modeling of the stray  light has been made or applied to the data. Those observations have only been used to optimize the planned imaging at Pluto encounter to minimize the effect of stray light.   Ongoing in-flight calibration observations will be analyzed to  assess the long term stability of the calibration.    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.   LSB_0123456789_0X53C_ENG.FIT  ^^^ ^^^^^^^^^^ ^^^^^ ^^^\__/  | | | | ^^  | | | | |  | | | | +--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  | |  | +--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  * SPACECRAFT_CLOCK_START_COUNT  * SPACECRAFT_CLOCK_STOP_COUNT    Instrument Instrument designators ApIDs  : : :  LEISA LSB, LRW 0X53C - 0X54E *   * Not all values in this range are in this data set   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 meanings of each instrument designator:   Instr  Dsgn. Description  : :  LSB LEISA, Read minus Reset data  LRW LEISA, Raw Read and Reset data   See SOC Instrument ICD (/DOCUMENT/SOC_INST_ICD.*) for details    Here is a summary of the types of files generated by each ApID  along with the instrument designator that go with each ApID:    ApIDs Data product description/Prefix(es)  : :  0x53c - LEISA Lossless (CDH 1)/LRW,LSB  0x54b - LEISA Lossless (CDH 2)/LRW,LSB  0x53d - LEISA Packetized (CDH 1)/LRW,LSB  0x54c - LEISA Packetized (CDH 2)/LRW,LSB  0x53e - LEISA Lossy (CDH 1)/LRW,LSB  0x54d - LEISA Lossy (CDH 2)/LRW,LSB    Instrument description  ----------------------   Refer to the following files for a description of this instrument.   CATALOG   LEISA.CAT   DOCUMENTS   RALPH_SSR.*  SOC_INST_ICD.*  NH_RALPH_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   RALPH Field Of View definitions:   /DOCUMENT/NH_FOV.*  /DOCUMENT/NH_RALPH_V###_TI.TXT     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 either that the target was either a star, or that 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. The PDS  standards 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.    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-X-SPICE-6-PLUTO-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_LEISA_PLUTO.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; that is,  some sequences may have failed to execute due to spacecraft events  (e.g. safing) and there will be observations associated with those  sequences. No attempt has been made during the preparation of this  data set to identify if any, or how many, such empty sequences there  are, so it is up to the user to compare the times of the sequences  to the times of the available observations from the INDEX/INDEX.TAB  table to identify such sequences.    Time  :   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  http://naif.jpl.nasa.gov/).   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   or   JD2453755.256337 TDB.   The leapsecond adjustment (DELTA_ET : ET - UTC) over this dataset  is 65.184s.   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.     Software  :   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,  contact   New Horizons RALPH Principal Investigator:   Alan Stern, Southwest Research Institute   S. Alan Stern   Southwest Research Institute  Department of Space Studies  1050 Walnut Street, Suite 400  Boulder, CO 80302  USA

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,   NH-P-LEISA-2-PLUTO-V1.0,   may not have corresponding data products in the calibrated data set,   NH-P-LEISA-3-PLUTO-V1.0.    Data coverage and quality  :    Caveat about TARGET_NAME in PDS labels and observational intent  :    A fundamental truth of managing data from some spacecraft missions  is that the intent of any observation is not suitable for insertion  into the command stream sent to the spacecraft to execute that  observation. As a result, re-attaching that intent to the data  that are later downlinked is problematic at best. For New Horizons  that task is made even more difficult as the only meta-data that  come down with the observation is the unpredictable time of the  observation. The task is made yet even more difficult because  uplink personnel, who generate the command sequences and initially  know the intent of each observation, are perpetually under  deadlines imposed by orbital mechanics and can rarely be spared for  the time-intensive task of resolving this issue.   To make a long story short, 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 point to be made is that 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  instrument. Furthermore, for pointing instruments with one or more  spatial components to their detectors, a table has been provided  in the DOCUMENT/ area with XY (two-dimensional) positions of each  inferred target in the primary data products. If those values are  several thousand pixels off of a detector array, it is a strong  indication that the actual target of that observation is something  other than the inferred target, or no target at all e.g. dark sky.    Review  :  This dataset was peer reviewed and certified for scientific use on  TBD.