PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 2019-01-15 NOTE = "This file describes the files in the extras/orbnum directory of this volume." END_OBJECT = TEXT END Orbit Number Files for the DAWN Mission to Vesta and Ceres ========================================================== This directory contains the orbit number files generated by NAIF's ORBNUM utility program using the final merged spacecraft trajectory SPK files for the orbital phases of the mission. The orbit number files are plain ASCII text files that have lines terminated with a line feed character, LF (ASCII 10). The orbit number files with the ``.nrb'' extension contain data that follow the ``node-to-node'' orbit numbering scheme -- with the orbit number changing at the ascending node. DAWN Orbit Number Kernels Provided in This Data Set =================================================== The following DAWN orbit number files are provided in this data set: Final versions: dawn_vesta_iau_v05.nrb orbit number file providing the orbit numbers and other time and geometric values for the whole DAWN Vesta mission, covering from July 16, 2011 to August 31, 2012, generated using the PCK file ``dawn_vesta_v06.tpc'', with the subsolar and subspacecraft longitudes and latitudes in the ``Claudia Double-Prime'' coordinate system. dawn_ceres_v04.nrb orbit number file providing the orbit numbers and other time and geometric values for the whole DAWN Ceres primary mission and most of the DAWN Ceres Extended Mission 1 (XM1) covering from March 6, 2015 to April 23, 2018, generated using the PCK file ``dawn_ceres_v06.tpc''. dawn_ceres_xm2_v01.nrb orbit number file providing the orbit numbers and other time and geometric values for the end of the DAWN Ceres Extended Mission 1 (XM1) and the whole DAWN Ceres Extended Mission 2 (XM2), covering from April 23, 2018 to October 31, 2018 generated using the PCK file ``dawn_ceres_v06.tpc''. Earlier, superseded versions: dawn_vesta_iau_v04.nrb orbit number file providing the orbit numbers and other time and geometric values for the part of the DAWN Vesta mission, covering from July 16, 2011 to June 11, 2012, generated using the PCK file ``dawn_vesta_v06.tpc'', with the subsolar and subspacecraft longitudes and latitudes in the ``Claudia Double-Prime'' coordinate system. This file is obsolete and superseded by ``dawn_vesta_iau_v05.nrb''. dawn_vesta_iau_v03.nrb orbit number file providing the orbit numbers and other time and geometric values for the part of the DAWN Vesta mission, covering from July 16, 2011 to June 11, 2012, generated using the PCK file ``dawn_vesta_v05.tpc'', with the subsolar and subspacecraft longitudes and latitudes in the ``Claudia Prime'' coordinate system. This file is obsolete and superseded by ``dawn_vesta_iau_v05.nrb''. dawn_ceres_v03.nrb orbit number file providing the orbit numbers and other time and geometric values for the whole DAWN Ceres primary mission, covering from March 6, 2015 to June 18, 2016, generated using the PCK file ``dawn_ceres_v05.tpc''. This file is obsolete and superseded by ``dawn_ceres_v04.nrb''. dawn_ceres_v02.nrb orbit number file providing the orbit numbers and other time and geometric values for the part of the DAWN Ceres mission, covering from March 6, 2015 to October 23, 2015, generated using the PCK file ``dawn_ceres_v05.tpc''. This file is obsolete and superseded by ``dawn_ceres_v04.nrb''. dawn_ceres_v01.nrb orbit number file providing the orbit numbers and other time and geometric values for the part of the DAWN Ceres mission, covering from March 6, 2015 to June 30, 2015, generated using the PCK file ``dawn_ceres_v05.tpc''. This file is obsolete and superseded by ``dawn_ceres_v04.nrb''. For the DAWN Vesta mission, the orbit number is changing at the ascending node crossings with the first orbit starting at the first crossing after July 16, 2011. From that point the orbits are numbered continuously till the end of the Vesta mission without resets at the orbit phase boundaries. All ``dawn_vesta_iau_vXX.nrb'' files implement this numbering scheme. For the DAWN Ceres Primary mission and Extended Mission 1 (XM1), the orbit number is changing at the ascending node crossings with the first orbit starting at the first crossing after March 6, 2015. From that point on the orbits are numbered continuously till approximately two months before the end of XM1, April 23, 2018. All ``dawn_ceres_vXX.nrb'' files implement this numbering scheme. For the DAWN Ceres Extended Mission 2 (XM1), the orbit number is changing at the descending node crossings with the first orbit starting at the first crossing after April 23, 2018. From that point on the orbits are numbered continuously till the end of the mission, October 31, 2018. All ``dawn_ceres_xm2_vVV.nrb'' file implement this numbering scheme. The information contained in the orbit number files includes the following in which the "Column Title" entries are along the top of the orbit number file and "Meaning" describes what the column represents. Column Title Meaning --------------------- ----------------------------------- No. orbit number Event UTC *-NODE orbit start UTC time; A-NODE for ascending node numbering, D-NODE for descending node numbering Event SCLK *-NODE orbit start SCLK time; A-NODE for ascending node numbering, D-NODE for descending node numbering OP-Event UTC *-NODE opposite event UTC time; D-NODE or A-NODE SolLon & SolLat planetocentric subsolar longitude and latitude in the body-fixed frame defined by the asteroid rotation constants provided in the PCK file used to generate the orbit number file, at the orbit start time SC Lon, SC Lat, & Alt planetocentric subspacecraft longitude, latitude, and altitude relative to the reference ellipsoid in the body-fixed frame defined by the asteroid shape and rotation models provided in the PCK file used to generate the orbit number file, at the orbit start time Sol Dist Distance between Sun and asteroid, at the orbit start time Contact Information =================== Regarding DAWN project-specific information provided in this data set and for general information about the SPICE system: Boris Semenov (818)-354-8136 Boris.Semenov@jpl.nasa.gov address: Navigation and Ancillary Information Facility (NAIF) Jet Propulsion Laboratory MS 301-125L 4800 Oak Grove Drive Pasadena CA 91109 USA