General information about SPICE LS-kernels
==========================================

   In the SPICE system, the Leapsecond (or LS) -kernel contains a
   tabulation of the leapseconds and other data required to perform a
   transformation between Universal Time Coordinated (UTC) and
   Ephemeris time (ET, also called Barycentric Dynamic Time, or TDB).
   Leapseconds may occur at the New Year or the end of June.

   The information in an LSK file can be manipulated by a collection of
   subroutines to provide required time system transformations. These
   subroutines are part of the SPICE library, the principal component
   of the SPICE Toolkit, and can be integrated into a user's
   application program. For information on the SPICE Toolkit and/or how
   to obtain it, please consult SPICE_INST.CAT and SOFT.CAT.

   Refer to the TIME.REQ document provided with the Toolkit to get more
   information about time conversions supported within the SPICE
   system.


ROSETTA LSK Files
=================

   This file describes the contents of the DATA/LSK directory. It also
   provides the file naming conventions used for the ROSETTA LSK kernels,
   and it provides identification of the most current version of LSK
   files.

   The LSK file is modified every time a new Leapsecond is announced by the
   International Earth Rotation Service (IERS).

   All LSK files (*.TLS) contained in this directory are UNIX text files
   with lines terminated by <LF> only.


ROSETTA Leap Seconds Kernels Contained in this Data Set
=======================================================

   The following generic LS-kernels are provided in this data set:

      NAIF0008.TLS
      NAIF0009.TLS
      NAIF0011.TLS   Contain parameters specifying the relationship
                     between the Barycentric Dynamical Time (TDB, also
                     called Ephemeris Time, ET) and Coordinated
                     Universal Time (UTC). The file with the latest
                     version supersedes all previous versions.


Kernel file details
===================

   The most detailed description of the data in a text LSK file is
   provided in metadata included inside the description area of the
   file. This information can be viewed using any text editor program.

   At least a basic knowledge of the SPICE system is needed in order to
   use these kernels. The SPICE Toolkit provides versions in Fortran
   (SPICELIB), C (CSPICE), IDL (Icy), Matlab (Mice), and Java
   (JNISpice) and the user can choose any one that suits him/her.

   The SPICE routine FURNSH can be used to load a kernel file into a
   SPICE-based application to make kernel data usable with SPICE
   APIs.

   If two (or more) text kernels assign value(s) using the '=' operator
   to identical keywords, the data value(s) associated with the last
   loaded occurrence of the keyword are used -all earlier values have
   been replaced with the last loaded value(s).