PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2014-10-01 SwRI:Carcich Release 0002 Added item 8. 2014-10-31 SwRI:Carcich Release 0002 Added to item 6 2014-10-31 SwRI:Carcich Release 0002 Added items 9 to 14. 2014-10-31 SwRI:Carcich Release 0002 Added ALICE UV correction. 2016-05-04 NAIF:Semenov Release 0003 Added items 15 and 16. 2021-01-21 SwRI:Enke Release 0005 Updated item 15. " RECORD_TYPE = STREAM OBJECT = TEXT NOTE = "Comments on the New Horizons SPICE Archive" PUBLICATION_DATE = 2016-04-30 END_OBJECT = TEXT END Comments on the New Horizons SPICE Data Archive =============================================== This document contains comments and errata concerning the New Horizons SPICE Data Archive. 1. Text Kernel File Format -------------------------- All SPICE text kernel files (LSK, PCK, SCLK, IK, FK) provided in this data set have lines terminated by only (UNIX convention.) This is dictated by NAIF's archiving approach to include a consistent set of UNIX binary (IEEE architecture) and text ( only for end of line marker) kernels in the archived data sets. However, the format of the text kernels is specified in their associated labels as ASCII (INTERCHANGE_FORMAT = ASCII.) This is a violation of the PDS standard stating that lines in ASCII files must be delimited by the combination of . This line termination treatment is standard practice for SPICE data sets in the PDS. 2. Use of SPACECRAFT_NAME in the Labels --------------------------------------- PDS labels for SPICE kernels provided in this data set contain the deprecated keyword SPACECRAFT_NAME instead of the keyword INSTRUMENT_HOST_NAME. This is standard practice for SPICE data sets in the PDS and is dictated by NAIF's archiving approach to make SPICE archives for more recent missions consistent with SPICE archives for older missions, for which use of SPACECRAFT_NAME was legitimate. 3. Values of INSTRUMENT_NAME in the Labels ------------------------------------------ PDS labels for SPICE kernels provided in this data do not set the keyword INSTRUMENT_NAME to "SPICE KERNELS", that is the name of the instrument described by the instrument catalog file SPICE_INST.CAT provided in the data set. Instead this keyword is set to either "N/A" or the name(s) of the instrument(s) or structure(s), the geometric parameters of which a particular kernel file provides. While this error does prevent the individual data products from being associated with the "SPICE KERNELS" instrument, it does not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS label to access the data. The other side of this error is that the data set does not include instrument catalog files for the following instruments named in the INSTRUMENT_NAME keyword in the PDS labels: "ALICE UV IMAGER" "ALICE ULTRAVIOLET IMAGING SPECTROGRAPH" "LONG RANGE RECONNAISSANCE IMAGER" "MULTISPECTRAL VISIBLE IMAGING CAMERA" "PLUTO ENERGETIC PARTICLE SPECTROMETER SCIENCE INVESTIGATION" "LINEAR ETALON IMAGING SPECTRAL ARRAY" "RADIO SCIENCE EXPERIMENT" "STUDENT DUST COUNTER" "SOLAR WIND AROUND PLUTO" 4. Missing FILE_RECORDS Keyword in the Binary Kernel Labels ----------------------------------------------------------- All labels for binary SPICE kernels provided in this data set are missing the FILE_RECORDS keyword, which is required because these labels have the RECORD_TYPE keyword set to FIXED_LENGTH. While this error violates the PDS standards, it does not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS labels to access the data. 5. Misleading name of the Alice instrument ----------------------------------------------------------- The value of the INSTRUMENT_NAME keyword for the ALICE UV instrument is "ALICE UV IMAGER", while the actual instrument is an imaging spectrograph. For reasons both historical and technical, this name cannot be easily changed. 6. Incomplete FOV Definition in ``nh_ralph_v100.ti'' ----------------------------------------------------------- The ``nh_ralph_v100.ti'' IK file contains an incomplete FOV definition for the instrument ID -98200. This definition includes only the ``FOV_FRAME'' and ``BORESIGHT'' keywords. A subsequent version of this file has been added as ``nh_ralph_v100u.ti'', in Release 0002 with the FOV_FRAME and BORESIGHT definitions removed. 7. Incorrect SCLK Values in the Comment Area of CK Files -------------------------------------------------------- The values of the SPACECRAFT_CLOCK_START_COUNT and/or SPACECRAFT_CLOCK_STOP_COUNT keywords in the copy of the PDS label embedded at the top of the comment area of CK files are incorrect for all CK files that contain more than one segment. The values of these keywords provided in the detached PDS labels are correct. The following errata were added ca. October, 2014 as part of the Release 0002 delivery and lien resolution: 8. Typos in the Comment Area and labels of 2006 and 2007 CK Files ----------------------------------------------------------------- 8.1) In CK files merged_nhpc_2006_v011.bc and merged_nhpc_2007_v006.bc, this phrase: Attitude informatrion in the New Horizons spacacraft flows should be this: Attitude information in the New Horizons spacecraft flows 8.2) In the label for CK file merged_nhpc_2007_v006.bc, the value for MISSION_PHASE_NAME only has one value, JUPITER, and is should have two values: JUPITER ENCOUNTER PLUTO CRUISE See also item 10 below. These errors do not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS label or CK Comment Area to access the data. 9. Typo in the Comment Area of ``nh_alice_v120.ti'' --------------------------------------------------- A TAB character was found in this file; a new version of this file has been added as ``nh_alice_v120u.ti''. 10. New MISSION_PHASE_NAME invalidates value in Release 0001 CKs ---------------------------------------------------------------- The formal name of mission phase JUPITER changed to JUPITER ENCOUNTER between Release 0001 and Release 0002. This means that some kernel-internal labels delivered with Release 0001 have invalid values for MISSION_PHASE_NAME. This error does not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS label to access the data. 11. Long interpolation intervals in Type 2 CK segments ------------------------------------------------------ Some pointing instances in type 2 segments cover tens of thousands of seconds (e.g. 2008-10-25, 2008-11-15, 2008-11-20). 12. Type 3 CK segments with calculated velocities used for spinning mode ------------------------------------------------------------------------ When modeling the transition from 5RPM spinning attitude mode using Type 2 CK segments to non-spinning 3-axis stabilization mode using Type 3 CK segments, the point at which the CK-writing process switched from Type 2 segments to Type 3 segments was too early i.e. while the spacecraft was still spinning. As a result, the Type 3 attitude telemetry was too sparse to accurately model the spinning spacecraft; in some cases look-ups into such Type 3 segments will return modeled angular velocities that are inverted (flipped sign) from the actual behavior. An analogous situation occurs during some transitions from 3-axis mode to spin mode, with the transition from Type 3 to Type 2 segments occurring too late. 13. Typo in the Comment Area and Label of nh_pepssi_v110.ti ----------------------------------------------------------- The DESCRIPTION values in the Comment Area and Label of IK file nh_pepssi_v110.ti have DESCRIPTION = "NH Alice instrument kernel " instead of DESCRIPTION = "NH PEPSSI instrument kernel " This error does not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS label to access the data. 14. Typo in the Comment Area and Label of nh_alice_v110.ti ----------------------------------------------------------- The INSTRUMENT_NAME values in the Comment Area and Label of IK file nh_alice_v100.ti have INSTRUMENT_NAME = "ALICE UV IMAGER" instead of INSTRUMENT_NAME = "ALICE ULTRAVIOLET IMAGING SPECTROGRAPH" This error does not affect usability of the SPICE data provided in this data set in any way because the SPICE toolkit does not use any information from the PDS label to access the data. The following errata were added ca. May, 2016 as part of the Release 0003 delivery and lien resolution: 15. Lack of planetary constants in release 0005 ----------------------------------------------------------- At the time of release 0005 (January 2021), the radius of all Pluto system bodies has been updated, as well as rotation and shape constants for Nix and Hydra. Updates to other constants for Pluto and Charon, and rotation and shape constants for Kerberos and Styx, were not yet available beyond the generic data provided in the 2009 IAU report in PCK pck00010.tpc . 16. Missing "Executive Summary" section in CK comments ----------------------------------------------------------- The internal comments of the CKs files data/ck/merged_nhpc_2014_v001.bc data/ck/merged_nhpc_2015_v001.bc do not include the "Executive summary" section provided in the comments of other telemetry-based spacecraft orientation CK files.