DIF SPK file for the DIXI Part of the EPOXI Mission =========================================================================== Created by Boris Semenov, NAIF/JPL on April 1, 2011 using SPK files provided by Shyam Bhaskaran, DI NAV/JPL and Steve Chesley, SSD/JPL. Objects in the Ephemeris -------------------------------------------------------- This file contains ephemeris data for Deep Impact Flyby (DIF) spacecraft (NAIF ID -140), DIXI mission's target comet Hartley 2 (NAIF ID 1000041), Sun, and planets and planet barycenters. Approximate Time Coverage -------------------------------------------------------- The DIF trajectory and comet and planetary ephemerides provided in this file cover from the beginning of the DIXI part of the EPOXI mission to approximately ten years after the end of the EPOXI mission: COVERAGE BEGIN TIME (TDB): 2008 DEC 12 20:00:00.000 COVERAGE END TIME (TDB): 2021 JAN 31 00:01:06.184 Status -------------------------------------------------------- This file was created by merging into a single SPK file the reconstructed OD SPK files produced during the DIXI part (December 2008 to January 2011) of the EPOXI mission, the latest (as of January 2011) predicted post-DIXI spacecraft trajectory SPK, the best available (as of March 2011) Hartley 2 ephemeris solutions, and generic planetary ephemerides DE 405. This SPK is intended for archiving in the Planetary Data System (PDS). Pedigree -------------------------------------------------------- This file was created by Boris Semenov, NAIF/JPL on April 1, 2011 using SPK files provided by Shyam Bhaskaran, DI NAV/JPL and Steve Chesley, SSD/JPL using the SPKMERGE program (see Appendix 1 for SPKMERGE log). DIF Spacecraft Trajectory DIF spacecraft trajectory data from the following SPK files provided by Shyam Bhaskaran were merged to produce this SPK (coverage for the trajectory taken from each of the files is shown in the second and third columns of the table): SPK name Start UTC Stop UTC ---------------------------- ------------------- ------------------- spk_drm224_Burn-full.bsp 2008-12-12 19:58:54 2009-02-19 23:58:53 spk_drm225-full.bsp 2009-02-19 23:58:53 2009-10-15 10:23:53 spk_od227-full.bsp 2009-10-15 10:23:53 2010-03-28 23:58:53 spk_drm228_WithBurn-full.bsp 2010-03-28 23:58:53 2010-05-28 23:58:53 spk_drm230_WithBurn-full.bsp 2010-05-28 23:58:53 2010-07-19 23:58:53 spk_drm231_WithBurn-full.bsp 2010-07-19 23:58:53 2010-09-05 00:00:00 spk_drm234_WithBurn-full.bsp 2010-09-05 00:00:00 2010-09-29 19:00:00 spk_drm237_WithBurn-full.bsp 2010-09-29 19:00:00 2021-01-31 00:00:00 These SPK files contained the following OD solutions (the start and stop of the data arc for each solution is listed in the second and third columns of the table): SOLUTION Arc start Arc end ------- -------- ------- DRM224 09/02/08 12/02/08 DRM225 12/12/08 03/11/09 OD227 10/15/09 11/29/09 DRM228 03/29/10 05/17/10 DRM230 05/29/10 07/12/10 DRM231 07/20/10 09/23/10 DRM234 09/05/10 11/03/10 DRM237 09/29/10 12/03/10 The SPK file spk_drm225-full.bsp contained a large predicted part at the end of its coverage because no OD solutions were performed during the period between March and October 2009. Due to that these is a large (~600 km) discontinuity at boundary of this file and the next SPK, 2009-10-15T10:23:54, as seen in the segment boundary discontinuity summary provided in Appendix 2. The SPK spk_drm237_WithBurn-full.bsp contained the final reconstructed Hartley 2 flyby trajectory released by EPOXI NAV on January 6, 2011. A summary of discontinuities that exist at the boundaries of the spacecraft trajectory segments that came from these SPK files is provided in Appendix 2. Hartley 2 Trajectory Hartley 2 ephemeris data from the following SPKs provided by Shyam Bhaskaran (spk_* files) and Steve Chesley (sb-103p-* files) was merged to produce this SPK: SPK name Start UTC Stop UTC ---------------------------- ------------------- ------------------- sb-103p-252.bsp 2008-12-12 19:58:54 2010-08-01 00:00:00 sb-103p-253.bsp 2010-08-01 00:00:00 2010-11-03 13:59:31 spk_drm237_WithBurn-full.bsp 2010-11-03 13:59:31 2010-11-05 13:59:31 sb-103p-253.bsp 2010-11-05 13:59:31 2011-01-01 00:00:00 sb-103p-252.bsp 2011-01-01 00:00:00 2021-01-31 00:00:00 The SPK spk_drm237_WithBurn-full.bsp, produced by the DI NAV team, contained Hartley 2 ephemeris solution that was the best and most consistent with the spacecraft trajectory for the closest encounter time but not for far approach and departure. Hartley 2 ephemeris covering only the two day period around encounter was copied from that file in this SPK. The SPK sb-103p-253.bsp, produced by the SSD team, contained the best fit to all EPOXI time-frame observations but did not take into account earlier observations from the ground. Hartley 2 ephemeris covering only the four month period around encounter (except for two days around closest encounter) was copied from that file in this SPK. The rest of Hartley 2 ephemeris included in this SPK -- prior to 2010-08-01 and after 2011-01-01 -- came from the best long-term solution provided in the SPK sb-103p-252.bsp. Because the three source Hartley 2 SPKs contained independent solutions discontinuities exists at each of the boundaries between segments that came from these SPKs. These discontinuities are especially large -- ~1000 and ~600 km -- between the segments from sb-103p-252.bsp and sb-103p-253.bsp SPKs. A summary of the discontinuities is provided in Appendix 2. Internal comments from and README files included with the SPKs sb-103p-253.bsp and sb-103p-252.bsp are provided for the reference in the Appendix 3. Contacts -------------------------------------------------------- If you have questions regarding this data contact Boris V. Semenov (818)-354-8136 Boris.Semenov@jpl.nasa.gov Shyam Bhaskaran (818)-354-3152 Shyam.Bhaskaran@jpl.nasa.gov Steve Chesley (818)-354-9615 Steve.Chesley@jpl.nasa.gov Appendix 1: SPKMERGE Log -------------------------------------------------------- ; dif_dixi_nav_v1.bsp LOG FILE ; Created 2011-04-01/13:35:18.86. ; ; BEGIN SPKMERGE COMMANDS LEAPSECONDS_KERNEL = naif0009.tls SPK_KERNEL = dif_dixi_nav_v1.bsp SOURCE_SPK_KERNEL = de405.bsp INCLUDE_COMMENTS = NO BODIES = 499, 299, 199, 399, 301, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 BEGIN_TIME = 2008 DEC 12 19:58:54.817 END_TIME = 2021 JAN 31 00:00:00.000 SOURCE_SPK_KERNEL = sb-103p-252.bsp INCLUDE_COMMENTS = NO BODIES = 1000041 BEGIN_TIME = 2008 DEC 12 19:58:54.817 END_TIME = 2010 AUG 01 00:00:00.001 SOURCE_SPK_KERNEL = sb-103p-253.bsp INCLUDE_COMMENTS = NO BODIES = 1000041 BEGIN_TIME = 2010 AUG 01 00:00:00.001 END_TIME = 2010 NOV 03 13:59:31.001 SOURCE_SPK_KERNEL = spk_drm237_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = 1000041 BEGIN_TIME = 2010 NOV 03 13:59:31.001 END_TIME = 2010 NOV 05 13:59:31.001 SOURCE_SPK_KERNEL = sb-103p-253.bsp INCLUDE_COMMENTS = NO BODIES = 1000041 BEGIN_TIME = 2010 NOV 05 13:59:31.001 END_TIME = 2011 JAN 01 00:00:00.001 SOURCE_SPK_KERNEL = sb-103p-252.bsp INCLUDE_COMMENTS = NO BODIES = 1000041 BEGIN_TIME = 2011 JAN 01 00:00:00.001 END_TIME = 2021 JAN 31 00:00:00.000 SOURCE_SPK_KERNEL = spk_drm224_Burn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2008 DEC 12 19:58:54.817 END_TIME = 2009 FEB 19 23:58:53.815 SOURCE_SPK_KERNEL = spk_drm225-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2009 FEB 19 23:58:53.815 END_TIME = 2009 OCT 15 10:23:53.818 SOURCE_SPK_KERNEL = spk_od227-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2009 OCT 15 10:23:53.818 END_TIME = 2010 MAR 28 23:58:53.815 SOURCE_SPK_KERNEL = spk_drm228_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2010 MAR 28 23:58:53.815 END_TIME = 2010 MAY 28 23:58:53.816 SOURCE_SPK_KERNEL = spk_drm230_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2010 MAY 28 23:58:53.816 END_TIME = 2010 JUL 19 23:58:53.817 SOURCE_SPK_KERNEL = spk_drm231_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2010 JUL 19 23:58:53.817 END_TIME = 2010 SEP 05 00:00:00.001 SOURCE_SPK_KERNEL = spk_drm234_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2010 SEP 05 00:00:00.001 END_TIME = 2010 SEP 29 19:00:00.001 SOURCE_SPK_KERNEL = spk_drm237_WithBurn-full.bsp INCLUDE_COMMENTS = NO BODIES = -140 BEGIN_TIME = 2010 SEP 29 19:00:00.001 END_TIME = 2021 JAN 31 00:00:00.000 ; END SPKMERGE COMMANDS Appendix 2: Trajectory Segment Boundary Discontinuity Summary -------------------------------------------------------- This SPK file contains a number of spacecraft trajectory SPK segments and Hartley 2 ephemeris segments that came from original individual SPK files. Although, each segment provides continuous trajectory within the interval that it covers, in general a position and velocity discontinuity exists at the boundary of the segment and the segments whose coverage immediately precede and follow it. The times and magnitudes of discontinuities at the boundaries of the segments containing DIF and Hartley trajectories relative to the Sun are provided in the tables included in this Appendix. The top portion of the tables contains the name of this SPK file. All descriptive lines in the top portion of the file start with the ``#'' character to allow direct plotting of the data in the freeware ``gnuplot'' application. The tables consist of 4 columns. The first column contains the UTC time of that segment boundary. The last three columns (2..4) contain view coordinate frame components -- ``down track'' (this direction is parallel to the velocity vector), ``normal to plane'' (this direction is computed as cross product of position vector by velocity vector) and ``in plane'' (this direction is computed as a cross product of ``down track'' by ``normal to plane'') -- of the difference between the state vectors computed at that UTC time defining segment boundary at which a discontinuity exists. The pairs of segments and discontinuity times are determined using an algorithm that emulates the standard SPK loading priority -- ``last loaded segment takes precedence''. Therefore, the discontinuities summarized in the file are those which a user reading file would actually see. The difference components in the view coordinate frame were computed for each discontinuity using the following algorithm: -- A single state was computed from each pair of segment the J2000 frame at the time of discontinuity. -- For this pair of states, a position difference vector was computed by subtracting the state computed from the segment with higher priority from the state computed from segment with lower priority. Then, a frame transformation matrix rotating these difference vectors from J2000 to the view coordinate frame defined by the state obtained from the higher priority segment was computed, and the position difference vector was rotated to the view frame coordinates using this matrix. The heliocentric spacecraft trajectory segment boundary discontinuities for this file are: # # Summary of DIF spacecraft trajectory discontinuities at # segment boundaries for SPK file dif_dixi_nav_v1.bsp: # # BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #----------------------- ------- ------- ------- 2009-02-19T23:58:53.814 1.7009 -4.7796 0.2543 2009-10-15T10:23:53.818 587.2287 -302.6892 -0.5463 2010-03-28T23:58:53.814 -21.0830 1.1158 5.0040 2010-05-28T23:58:53.815 0.5206 -1.4494 0.3363 2010-07-19T23:58:53.817 0.4479 0.9030 -0.2571 2010-08-19T19:59:01.143 0.0000 -0.0000 -0.0000 2010-09-05T00:00:00.000 0.1965 1.1371 0.4684 2010-09-29T19:00:00.000 -0.0552 0.8481 -0.0636 2010-11-08T03:00:01.000 -0.0000 -0.0000 -0.0000 2011-01-31T00:00:00.000 8.7650 -12.0905 -33.5846 The heliocentric Hartley 2 trajectory segment boundary discontinuities for this file are: # # Summary of Hartley 2 trajectory discontinuities at segment # boundaries for # SPK file dif_dixi_nav_v1.bsp: # # BOUNDARY TIME (UTC) DOWNTRK INPLANE NORMAL #----------------------- ------- ------- ------- 2010-08-01T00:00:00.000 -254.8567 930.9927 220.5965 2010-11-03T13:59:31.000 -0.7465 -9.8984 1.4150 2010-11-05T13:59:31.000 2.4886 11.6045 -3.1201 2011-01-01T00:00:00.000 -390.6192 -583.6520 299.7221 Appendix 3: Internal Comments from Hartley 2 SPKs by SSD -------------------------------------------------------- Internal comments from and README files accompanying the SPKs sb-103p-253.bsp and sb-103p-252.bsp are provided below. ------------------------ sb-103p-252.bsp README ------------------------ ******* POSTFIT SUMMARY ******* Object: Comet 103P/Hartley 2 Ref. Solution: 252 Producer: Steven R. Chesley Planetary Ephemeris: DE405 Small Body Ephemeris: SB405-CPV-2 No. Observations: 5939 Observation Arc: 1997-May-02.5 to 2011-Mar-25.5 ---- Optical Residuals ---- RA Dec Total Maximum Residual Difference 0.001 0.000 Mean weighted residual -0.115 -0.068 0.133 Maximum weighted residual 3.310 at 2010-Oct-16.7 RMS, unweighted 0.625 0.510 0.570 RMS, weighted 0.570 Normalized RMS 0.570 No. optical observations: 5147 used and 661 deleted. --- Satellite Residuals --- RA Dec Total Opt+Sat Maximum Residual Difference 0.038 0.062 Mean weighted residual 0.035 0.031 0.047 Maximum weighted residual 2.337 at 2010 Nov 3.2 RMS, unweighted 0.944 0.411 0.728 RMS, weighted 0.667 Normalized RMS 0.425 0.553 No. satellite observations: 785 used and 66 deleted. ----- Radar Residuals ----- Delay Doppler Radar+Opt+Sat Maximum Residual Difference 0.006 0.000 Normalized RMS 0.658 0.512 0.553358 No. Delay observations: 6 used and 0 deleted. No. Doppler observations: 1 used and 0 deleted. Chi Squared: 3634.964 ---- Corrected Elements (J2000): Solution 252 Epoch 2455114.50000 = 2009 Oct 10.00000 Post-Fit Std.Dev. EC 0.6949978067505750 0.0000000136 QR 1.0584228682977570 0.0000000419 au TP 2455497.8020879362 0.0000023117 d 2010 Oct 28.30209 OM 219.77474878629240 0.0000031706 deg W 181.21260570794560 0.0000049074 deg IN 13.61750470043255 0.0000014089 deg AJ1 3.37623999229E-9 6.94400E-11 AJ2 3.67392070549E-9 3.99722E-11 ALF 100.617788682990 7.51385E-01 DEL 32.8537438952004 8.67353E-01 A 3.470213958206521 0.0000000990 au P 2361.200167407229 0.00010107 d 6.46450046435115 yr W~ 40.98735449423805 0.0000026096 deg NOTE: The above postfit standard deviations are scaled from the formal sigmas by a factor of 0.5536. ------------------------ sb-103p-252.bsp comments ------------------------ ; sb-103p-252.bsp LOG FILE ; ; Created 2011-04-01/13:31:05.41. ; ; BEGIN NIOSPK COMMANDS SPK_FILE = sb-103p-252.bsp SOURCE_NIO_FILE = sb-103p-252.nio BEGIN_TIME = CAL-ET 2008 JAN 01 00:00:00.000 END_TIME = CAL-ET 2021 APR 26 00:00:00.000 ; END NIOSPK COMMANDS SMALL BODY EPHEMERIS FILE HEADER Reader: NIOSPK File Name: sb-103p-252.nio File ID: SB-103P-252 File type: SMALL BODY EPHEMERIS FILE 2 Written by: SBGEN Equinox: J2000 DE-Used: DE-0405 Object Type: COMET Record Type: COMBINED Object Name: P/Hartley 2 Short Name: HARTLEY2 IAU Number: 103 ID Number: 1000041 Center: 10 Solution ID: 252 SBE Used: SB405-CPV-2 GM: 0.00 No. coefs: 13 No. coefs-sets: 1 Comments: EPOXI PDS delivery ------------------------ sb-103p-253.bsp README ------------------------ ******* POSTFIT SUMMARY ******* Object: Comet 103P/Hartley 2 Ref. Solution: 253 Producer: Steven R. Chesley Planetary Ephemeris: DE405 Small Body Ephemeris: SB405-CPV-2 No. Observations: 5441 Observation Arc: 2010-Mar-13.5 to 2011-Mar-25.5 ---- Optical Residuals ---- RA Dec Total Maximum Residual Difference 0.000 0.000 Mean weighted residual -0.159 0.014 0.160 Maximum weighted residual 3.344 at 2010-Oct-16.7 RMS, unweighted 0.564 0.480 0.524 RMS, weighted 0.524 Normalized RMS 0.524 No. optical observations: 4600 used and 646 deleted. --- Satellite Residuals --- RA Dec Total Opt+Sat Maximum Residual Difference 0.004 0.005 Mean weighted residual 0.148 -0.023 0.150 Maximum weighted residual 1.260 at 2010 Nov 4.7 RMS, unweighted 54.526 16.877 40.360 RMS, weighted 0.571 Normalized RMS 0.353 0.501 No. satellite observations: 834 used and 17 deleted. ----- Radar Residuals ----- Delay Doppler Radar+Opt+Sat Maximum Residual Difference 0.000 0.000 Normalized RMS 0.650 0.158 0.501362 No. Delay observations: 6 used and 0 deleted. No. Doppler observations: 1 used and 0 deleted. Chi Squared: 2733.583 ---- Corrected Elements (J2000): Solution 253 Epoch 2455489.50000 = 2010 Oct 20.00000 Post-Fit Std.Dev. EC 0.6950847764106027 0.0000000758 QR 1.0586739906565180 0.0000000045 au TP 2455497.7619517889 0.0000027232 d 2010 Oct 28.26195 OM 219.75906356266620 0.0000011076 deg W 181.20471631450180 0.0000031987 deg IN 13.61910219065841 0.0000017643 deg AJ1 7.08860369838E-9 1.15411E-10 AJ2 1.92175489127E-8 5.28488E-10 ALF 139.765219828912 5.34876E-01 DEL -7.14410622663265 7.12894E-01 A 3.472027333348700 0.0000008674 au P 2363.051192035434 0.00088556 d 6.46956820478829 yr W~ 40.96377987716801 0.0000031685 deg NOTE: The above postfit standard deviations are scaled from the formal sigmas by a factor of 0.5016. ------------------------ sb-103p-253.bsp comments ------------------------ ; sb-103p-253.bsp LOG FILE ; ; Created 2011-04-01/12:43:48.83. ; ; BEGIN NIOSPK COMMANDS SPK_FILE = sb-103p-253.bsp SOURCE_NIO_FILE = sb-103p-253.nio BEGIN_TIME = CAL-ET 2008 JAN 01 00:00:00.000 END_TIME = CAL-ET 2012 MAR 16 00:00:00.000 ; END NIOSPK COMMANDS SMALL BODY EPHEMERIS FILE HEADER Reader: NIOSPK File Name: sb-103p-253.nio File ID: SB-103P-253 File type: SMALL BODY EPHEMERIS FILE 2 Written by: SBGEN Equinox: J2000 DE-Used: DE-0405 Object Type: COMET Record Type: COMBINED Object Name: P/Hartley 2 Short Name: HARTLEY2 IAU Number: 103 ID Number: 1000041 Center: 10 Solution ID: 253 SBE Used: SB405-CPV-2 GM: 0.00 No. coefs: 13 No. coefs-sets: 1 Comments: EPOXI PDS delivery =========================================================================== End of dif_dixi_nav_v1.bsp comments.