JUICE ORBNUM files ============================================================================== This "aareadme.txt" file describes the contents of the misc/orbnum directory of the JUICE SPICE data server. It also provides the file naming conventions used for the JUICE Orbit Number files, and it provides identification of the most current version of each kind of ORBNUM file. It was last modified on March 24, 2023 by Ricardo Valles Blanco, ESAC/ESA. Contact Information ----------------------------------------------------------------------------- If you have any questions regarding this file contact SPICE support at ESAC: Alfredo Escalante Lopez (+34) 91-8131-429 spice@sciops.esa.int or the JUICE Science Operations Center at ESAC: Marc Costa Sitja (+34) 646-746-711 Marc.Costa@ext.esa.int References and required readings ----------------------------------------------------------------------------- 1. ``ORBNUM User Guide'', NAIF Document Brief Summary ----------------------------------------------------------------------------- This directory contains the SPICE ORBNUM files for the JUICE mission. Please note that ORBNUM files are not considered SPICE kernels. The orbnum These are created from the SPK files converted from the Flight Dyamics Orbit Epehemeris Messages (OEM) files and the trajectory files provided by Mission Analysis. The Orbit Number files (*.ORB) contained in this directory are unix text files. These may be used in a non-compatible text environment by using the ASCII mode of FTP to port the files. Important Note Regarding Orbit Number Files ----------------------------------------------------------------------------- In the JUICE orbit number files produced by NAIF's ORBNUM utility program each of the records contains the time of THAT orbit's apocenter and the time of the NEXT orbit's pericenter. For example, the line for orbit '3' provide UTC and SCLK of orbit '3' apocenter and UTC of orbit '4' pericenter. Orbit number 1 corresponds to the first Jupiter tour phase orbit. All derived quantities provided on each record -- sub-solar lon/lat, sub-spacecraft lon/lat/alt, and orbital elements -- are computed for the time of apocenter. Example ~~~~~~~ This is an example of a JUICE orbit number file (spacing is altered to fit the page): No. Event UTC PERI ... Orbit Start Orbit End ... === ==================== ... ==================== ==================== ... 1 2031 JUL 21 20:50:26 ... 2031 NOV 02 03:22:04 2032 MAR 14 05:23:21 ... 2 2032 FEB 14 14:20:16 ... 2032 MAR 14 05:23:21 2032 APR 26 06:02:17 ... 3 2032 APR 11 22:47:30 ... 2032 APR 26 06:02:17 2032 MAY 21 20:12:46 ... 4 2032 MAY 10 14:44:32 ... 2032 MAY 21 20:12:46 2032 JUN 10 04:29:24 ... Given this example one can determine that: -- orbit 3 pericenter time is ``2032 APR 11 22:47:30'' -- orbit 3 time boundaries are from ``2032 APR 26 06:02:17'' to ``2032 MAY 21 20:12:46'' File naming conventions ----------------------------------------------------------------------------- Naming Scheme for JUICE ORBNUM files: The naming scheme for the JUICE spacecraft ORBNUM files is: juice_TYPE[_ID][_DESC]_[YYMMDD_YYMMDD]_vNN.orb where 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 of any particular of the original fule (optional); YYMMDD coverage start and stop times in TDB (optional); NN version number, starting from 01 (required; e.g. 01); Orbit Number Directory Structure ----------------------------------------------------------------------------- aareadme.txt This file. former_versions Subdirectory that contains obsolete versions of the ORBNUM files that have been updated in the Current ORBNUM File Set. juice_mat_crema_XXXXX_[YYMMDD_YYMMDD]_vNN.orb Contains JUICE orbit apocenter and pericenter times, orbital elements, and additional geometry parameters computed from the SPK long term file called: juice_mat_crema_XXXXX_[YYYYMMDD_YYYYMMDD]_vNN.bsp where XXXXX designates the reference to the Mission Analysis version number. YYYYMMDD_YYYYMMDD specifies the coverage of the original file and NN specifies the version of the file (optional). This is a mission analysis test file that corresponds to the latest CReMa release. Particulars ----------------------------------------------------------------------------- Nothing to report. Kernel File Details ----------------------------------------------------------------------------- The most detailed description of the data in a text ORBNUM file is provided in metadata included inside the descriptive text areas of the file. End of aareadme file.