Hera SPK files =========================================================================== This ``aareadme.txt'' file describes the contents of the kernels/spk directory of the Hera SPICE Kernel Dataset. It was last modified on April 26, 2024 by Alfredo Escalante, ESAC/ESA. Brief Summary ----------------------------------------------------------------------------- This directory contains the SPICE SP-Kernel files for the Hera mission, including mission analysis, nominal and operational spacecraft trajectory SPKs, generic planetary and satellite ephemeris SPKs. File naming conventions ----------------------------------------------------------------------------- Naming Scheme for Hera mission SPKs: The naming scheme for the Hera spacecraft and its cubesats SPKs is: hera_SC_TYPE[_ID][_DESC]_YYYYMMDD_YYYYMMDD_vNN.bsp where SC acronym of the spacecraft: hera: for Hera; milani: for Milani cubesat; juventas: for Juventas cubesat TYPE Data type, where a reference to the originator of the data, the type of data and the and the reference period is provided. This is a three letter acronym. The first letter defines the file originator: s: Science Operations Center; m: Mission Analysis; f: Flight Dynamics; the second letter defines the reference period of the data: c: Cruise phase; l: Science phase Long term; m: Science phase Medium term; s: Science phase Short term; o: Undefined; the third letter indicates the type of data p: Predicted data; r: Reconstructed data; t: Test data; ID mapping to the original file product IDs as defined per an ICD document (optional); DESC description of the original reference file of any particular of the original file (optional); YYYYMMDD coverage start and stop times in TDB (required); NN version number, starting from 01 (required; e.g. 01); Current SPK Kernels Set ----------------------------------------------------------------------------- hera_sc_crema_2_0_DESCR.bsp SPICE SPK file that contains Hera spacecraft CReMA 2.0 trajectories covering from launch to arrival to Didymos for the following scenario. Where DESCR: LPO: Launch Period Open. LPC: Launch Period Close. ECP: Early Characterization Phase. PDP: Payload Deployment Phase. hera_sc_PO_DESCR.bsp SPICE SPK file that contains Hera spacecraft trajectory covering from launch to arrival to Didymos for the following scenario. Where DESCR: LPC_EMA_2024c: LPO and LPC of 2024 Earth-Mars-Didymos transfer with constraints on departure Vinf <= 5.1 km/s and arrival no later than 2026/12/28. Launch period has been shortened to 18 days in order to keep total Delta-V < 1100 m/s. LPC_EEA_2025a64: LPO and LPC of 2025 Earth-Earth-Didymos transfer with constraints on departure Vinf <= 6.0 km/s, departure declination fixed to 18 deg and arrival no later than 2031/01/31. a64 stands for Arianne 64. LPO_EA_2026a64: LPO and LPC of 2026 Earth-Didymos transfer with constraints on departure Vinf <= 6.0 km/s and arrival no later than 2031/01/31. a64 stands for Arianne 64. PO: Proximity Operations based on the trajectories reported on RD27. Created by the GMV. de432s.bsp SPICE SPK file containing JPL planetary ephemerides version DE432, created by NAIF, JPL. mar097_YYYYMMDD_YYYYMMDD.bsp SPICE SPK file containing JPL Martian satellite ephemerides version MAR097. Created by NAIF, JPL. estrack_vNN.bsp SPICE SPK file that defines the position for each of the ESA ESTRACK ground stations, as seen from the center of the Earth, in the topocentric frame defined in the corresponding ESTRACK FK. Created by the ESA SPICE Service (ESS). hera_sci_vNN.bsp SPICE SPK file that defines the position of some relevant points for science purposes. Created by the ESA SPICE Service (ESS). hera_dart_impact_site_vNN.bsp SPICE SPK file that defines the position of the DART impact site from last DART reconstructed trajectory. Created by the ESA SPICE Service (ESS). hera_struct_vNN.bsp SPICE SPK file that contains Hera spacecraft structures positions that apply during all the mission. Created by the ESA SPICE Service (ESS). Other directory contents ----------------------------------------------------------------------------- aareadme.txt This file. coverage.txt File that contains a summary of the coverage of all the SPK files present in the directory. Particulars ----------------------------------------------------------------------------- Trajectory data is consistent with planetary ephemeris DE-432 and with the leapseconds kernel naif0010.tls The detailed manoeuvre sequence for arrival to Didymos is not modelled in the provided orbit files. An operationally robust arrival sequence implies a delay of about 1-2 months of the arrival date. Kernel File Details ----------------------------------------------------------------------------- The most detailed description of the data in a binary SPK file is provided in metadata included inside the comment area of the file. This information can be viewed using the utility programs COMMNT and SPACIT included in the NAIF Toolkit. Contact Information ----------------------------------------------------------------------------- If you have any questions regarding this directory or its contents, please contact SPICE support at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int or NAIF at JPL: Boris Semenov (818) 354-8136 Boris.Semenov@jpl.nasa.gov References and required readings ----------------------------------------------------------------------------- 1. ``SPK Required Reading'', NAIF Document End of aareadme file.