File: aareadme.txt Creation Date: 2006-08-04 (NJB) Revised: 2008-03-18 (NJB) Revised: 2021-06-25 (NJB) Revised: 2022-09-30 (NJB) Revised: 2023-06-17 (BVS) Authors: Nat Bachman, Boris Semenov (JPL/NAIF) Contents of path pub/naif/generic_kernels/fk/satellites ======================================================= The text kernels discussed here moon_de440_220930.tf moon_080317.tf moon_071218.tf moon_assoc_me.tf moon_assoc_pa.tf *nameid*.tf are unix-style text files. They are suitable for use on all unix boxes, including PC/linux and MAC/OSX machines. Lunar frame kernel (FK) ----------------------- DE440 version ------------- This frame kernel contains specifications of lunar reference frames realizing the Lunar Principal Axis (PA) and Mean Earth/Polar Axis (ME) reference systems: moon_de440_220930.tf Reference: [1] Ryan S. Park, et al, "The JPL Planetary and Lunar Ephemerides DE440 and DE441," The Astronomical Journal, Volume 161, Number 3. 2021 AJ 161 105. URL: https://iopscience.iop.org/article/10.3847/1538-3881/abd414/meta The reference frames specified by this kernel are associated with the lunar libration data provided by JPL's DE440 planetary ephemeris. The ME frame is a variant that has been closely aligned with the DE421 ME frame. See [1] for details. This frame kernel contains extensive documentation; the kernel may by viewed with a text editor or web browser. The cited frame kernel is to be used with the binary lunar PCK moon_pa_de440_200625.bpc This PCK is located in the path pub/naif/generic_kernels/pck DE421 version ------------- This frame kernel contains specifications of lunar reference frames realizing the Lunar Principal Axis (PA) and Mean Earth/Polar Axis (ME) reference systems: moon_080317.tf The reference frames specified by this kernel are associated with the lunar libration data provided by JPL's DE-421 planetary ephemeris. This frame kernel contains extensive documentation; the kernel may by viewed with a text editor or web browser. The cited frame kernel is to be used with the binary lunar PCK moon_pa_de421_1900-2050.bpc This PCK is located in the path pub/naif/generic_kernels/pck Version preceding DE421 ----------------------- This frame kernel contains the latest specifications of lunar reference frames realizing the Lunar Principal Axis (PA) and Mean Earth/Polar Axis (ME) reference systems: moon_071218.tf The reference frames specified by this kernel are associated with the lunar libration data provided by JPL's DE-418 planetary ephemeris. This frame kernel contains extensive documentation; the kernel may by viewed with a text editor or web browser. The cited frame kernel is to be used with the binary lunar PCK moon_pa_de418_1950-2050.bpc This PCK is located in the path pub/naif/generic_kernels/pck A memo describing the PA to ME frame offset is available in this location. The document is named de418_ephemeris_and_lunar_orientation. Lunar body-fixed frame association kernels ------------------------------------------ By default, the SPICE system considers the body-fixed reference frame associated with the Moon to be the one named IAU_MOON. This body-frame association affects the outputs of the SPICE frame system routines CIDFRM CNMFRM and of the SPICE time conversion and geometry routines ET2LST ILLUM SRFXPT SUBPT SUBSOL Finally, any code that calls these routines to obtain results involving lunar body-fixed frames are affected. Within SPICE, the only higher-level system that is affected is the dynamic frame system. NAIF provides "frame association" kernels that simplify changing the body-fixed frame associated with the Moon. Using FURNSH to load either of the kernels named below sets the Moon's body-fixed frame to that shown in the right-hand column: Kernel name Lunar body-fixed frame ----------- ---------------------- moon_assoc_me.tf MOON_ME moon_assoc_pa.tf MOON_PA For further information see the in-line comments in the association kernels themselves. Also see the Frames Required Reading section titled "Connecting an Object to its Body-fixed Frame." Satellite NAIF name-ID mapping kernels -------------------------------------- The *nameid*.tf FK files provide NAIF name-ID mappings for satellites from specific satellite ephemeris SPK files which (satellites) do not have name-ID mappings built into the SPICE toolkit. For example, the FK jup344_nameid.tf provides mappings for a subset of satellites from the SPK jup344.bsp. Getting help ============ SPICE tutorials are available on the NAIF web site: http://naif.jpl.nasa.gov/naif/ The following tutorials may be of particular interest: Intro to Kernel Files PCK (Planetary cartographic and physical constants) FK (Reference frame specifications) Also see the following Required Reading documents provided with the SPICE Toolkit: Frames Kernel PCK Many SPICE kernels contain internal documentation. Text kernels may be viewed with a text editor or web browser. Comments in binary kernels may be viewed using the SPICE utility COMMNT. Coverage of binary PCKs may be viewed using the SPICE utility SPACIT. See the COMMNT and SPACIT User's Guides (provided with the SPICE Toolkit) for details.