Mariner 2 Trajectory SPK file, Solution by Dr. John Anderson =========================================================================== Trajectory determined by Dr. John Anderson, (JPL, Retired), October 16, 2012. SPK created and comments added by Boris Semenov, NAIF/JPL, October 17, 2012. Objects in the Ephemeris -------------------------------------------------------- This file contains ephemeris data for the Mariner 2 (M2) spacecraft (NAIF ID -2) with respect to the Solar System Barycenter (NAIF ID 0) in the J2000 inertial reference frame. Time Coverage -------------------------------------------------------- This file covers the following time period: Start of Coverage (ET) End of Coverage (ET) ------------------------ ------------------------ 1962 AUG 27 07:20:00.000 1963 JAN 01 00:00:00.000 Pedigree -------------------------------------------------------- This SPK file created by packaging M2 trajectory data by Dr. John Anderson (see Appendix 1 for the mission and trajectory descriptions) provided as TDB JD -tagged M2 states relative to the Solar System Barycenter in the J2000 reference frame in five separate text files with the following coverages and time steps: Text files Interval Start ET Interval Stop ET Step, sec ---------- ------------------- ------------------- --------- Ephem1.dat 1962-08-27/07:20:00 1962-08-28/07:11:19 60 Ephem2.dat 1962-08-28/07:12:00 1962-09-04/23:59:19 8640 Ephem3.dat 1962-09-05/00:00:00 1962-12-13/19:11:19 8640 Ephem4.dat 1962-12-13/19:12:00 1962-12-15/19:11:19 60 Ephem5.dat 1962-12-15/19:12:00 1962-12-31/23:59:19 8640 into individual Type 13/Degree 7 SPK files using MKSPK (see Appendix 2 for MKSPK setup parameters) and then merging these individual SPKs with the DE 405 planetary ephemerides using SPKMERGE (see Appendix 2 for SPKMERGE log) to produce a single SPK. Contacts -------------------------------------------------------- If you have questions regarding this data contact Dr. John Anderson jdandy@earthlink.net or Boris V. Semenov (818)-354-8136, Boris.Semenov@jpl.nasa.gov Appendix 1: Mariner 2 Mission and Spacecraft Trajectory Description ============================================================================ The following Mariner 2 mission and spacecraft trajectory descriptions were provided by Dr. John Anderson: Mariner 2 was the first spacecraft to successfully encounter another planet. It was launched from Cape Canaveral on August 27, 1962 by a two-stage Atlas-Agena B rocket. A trajectory correction maneuver (TCM) was performed on September 4, 1962, and encounter with Venus occurred on December 14, 1962. The spacecraft was tracked at L-Band (960 MHz) from the DSN Goldstone complex in three-way Doppler mode, with DSS 12 transmitting and DSS 11 receiving, except for two data acquisitions in October with DSS 12 transmitting and receiving. The only archive for the Doppler data exists in printed form in JPL Technical Report 32-816, July 1, 1967, by John D. Anderson. Data between orbital injection at Earth and the TCM are not included and are presumably lost. A summary of scientific results from the mission, both in cruise phase and encounter phase, can be found in "A Summary Review of the Scientific Findings of the Mariner Venus Mission," C. P. Sonett, Space Science Reviews, Volume 2, Issue 6, pp.751-777, 1963. Results from the Doppler tracking can be found in "The Evaluation of Certain Astronomical Constants from the Radio Tracking of Mariner II," John D. Anderson, George W. Null, and Catherine T. Thornton, Progress in Astronautics and Aeronautics, Vol. 14, Academic Press, 1964. Launched: 1962-08-27 at 06:53:14 UTC On-orbit dry mass: 202.8 kg Nominal Power: 220.0 W SPACECRAFT TRAJECTORY: Trajectory was provided by John D. Anderson (JPL, Retired) as five ASCII files, based on a fit to the encounter data with planetary positions and masses from JPL DE405. A perturbation from solar-radiation pressure was included in the trajectory integration, but no account was taken of translational forces from outgassing of the attitude control subsystem, which were significant. The trajectory is intended for general historical purposes, but should be used cautiously for high-precision applications. Cruise data were not fit. The fitted encounter trajectory was integrated backwards to the TCM, an instantaneous velocity maneuver was calculated, and the trajectory was integrated backwards from the time of the TCM to Earth encounter at a constrained perigee altitude of 118 km, the altitude of the parking orbit at injection into Earth Venus transfer. No other constraints were imposed on the parking orbit, and the change of instantaneous velocity at the TCM was optimized to fit this one altitude constraint. The magnitude of the resulting velocity change for the TCM is 467.5 meters per second in a direction given by right ascension 154.63 degrees and declination 14.97 degrees, in the ICRF/J2000.0 reference frame.The Doppler residuals in the fitted Venus-encounter trajectory have a standard deviation of 34 mm per second, typical for L-Band data of the Mariner 2 era, before the implementation of atomic frequency and timing systems by the DSN. The distance at Venus encounter for the fitted trajectory is 40948 km, in good agreement with distance estimates by JPL Navigation at the time of the flyby. The time of closest approach to Venus from the fitted trajectory is 1962-Dec-14 19:55:19 CT at Venus and 19:57:57 UTC at Earth. The time of the TCM was adopted as 1962-Sep-05 00:00:00 CT, although the actual maneuver lasted about 34 minutes and ended a few minutes earlier. All time scales from the historical records are in UTC. For purposes of the trajectory calculations, these times were converted to CT (TDB as currently defined by the IAU) by means of HORIZONS tables for CT-UT. The light times between the spacecraft and geocenter were obtained by iterating on the fitted trajectory. Appendix 2: MKSPK Setup ============================================================================ \begindata LEAPSECONDS_FILE = '/kernels/gen/lsk/naif0010.tls' INPUT_DATA_TYPE = 'STATES' DATA_ORDER = 'EPOCH X Y Z VX VY VZ' INPUT_DATA_UNITS = ( 'ANGLES = degrees' 'DISTANCES= km' ) DATA_DELIMITER = ',' LINES_PER_RECORD = 1 TIME_WRAPPER = '# JD TDB' OUTPUT_SPK_TYPE = 13 POLYNOM_DEGREE = 7 OBJECT_ID = -2 CENTER_ID = 0 REF_FRAME_NAME = 'J2000' SEGMENT_ID = 'Mariner 2 by Dr. John Anderson' PRODUCER_ID = 'NAIF' \begintext Appendix 3: SPKMERGE Log ============================================================================ ; m2_620827_621231_ja_v1.bsp LOG FILE ; Created 2012-10-17/11:07:02.84. ; ; BEGIN SPKMERGE COMMANDS LEAPSECONDS_KERNEL = /kernels/gen/lsk/naif0010.tls SPK_KERNEL = m2_620827_621231_ja_v1.bsp SOURCE_SPK_KERNEL = m2_620827_620828_ja_v1.bsp INCLUDE_COMMENTS = NO BODIES = -2 BEGIN_TIME = 1962 AUG 27 07:19:18.817 END_TIME = 1962 AUG 28 07:11:18.817 SOURCE_SPK_KERNEL = m2_620828_620904_ja_v1.bsp INCLUDE_COMMENTS = NO BODIES = -2 BEGIN_TIME = 1962 AUG 28 07:11:18.817 END_TIME = 1962 SEP 04 23:59:18.817 SOURCE_SPK_KERNEL = m2_620904_621213_ja_v1.bsp INCLUDE_COMMENTS = NO BODIES = -2 BEGIN_TIME = 1962 SEP 04 23:59:18.817 END_TIME = 1962 DEC 13 19:11:18.817 SOURCE_SPK_KERNEL = m2_621213_621215_ja_v1.bsp INCLUDE_COMMENTS = NO BODIES = -2 BEGIN_TIME = 1962 DEC 13 19:11:18.817 END_TIME = 1962 DEC 15 19:11:18.817 SOURCE_SPK_KERNEL = m2_621215_621231_ja_v1.bsp INCLUDE_COMMENTS = NO BODIES = -2 BEGIN_TIME = 1962 DEC 15 19:11:18.817 END_TIME = 1962 DEC 31 23:59:18.816 SOURCE_SPK_KERNEL = /kernels/gen/spk/de405.bsp INCLUDE_COMMENTS = NO BODIES = 499, 299, 199, 399, 301, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 BEGIN_TIME = 1962 AUG 27 07:19:18.817 END_TIME = 1962 DEC 31 23:59:18.816 ; END SPKMERGE COMMANDS End of comments.