PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = " 2006-03-01 NAIF:Semenov original; 2006-03-06 NAIF:Semenov added required DATA_SET_MISSION object; 2006-03-28 PPI:Joy minor spelling and grammatical changes; 2006-12-18 NAIF:Semenov post peer-review update; 2007-01-02 NAIF:Semenov update for re-release of the DI SDC SPK with compliant name; 2007-02-27 NAIF:Semenov update for addition of extras; 2007-06-11 NAIF:Semenov removed ARCHIVE_STATUS keyword; 2011-09-09 NAIF:Semenov updated for v2 CKs and SCLK fractional part discrepancy; 2013-01-08 NAIF:Semenov reset STOP_TIME; " RECORD_TYPE = STREAM OBJECT = DATA_SET DATA_SET_ID = "DI-C-SPICE-6-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "DEEP IMPACT SPICE KERNELS V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_SET_TERSE_DESC = " Navigation and ancillary data in the form of SPICE System kernel files for the Deep Impact Flyby and Impactor spacecraft. " ABSTRACT_DESC = " This data set includes the complete set of Deep Impact SPICE data files (``kernel files''), which can be accessed using SPICE software. The SPICE data contains geometric and other ancillary information needed to recover the full value of the science instrument data. In particular SPICE kernels provide spacecraft and planetary ephemerides, instrument mounting alignments, spacecraft orientation, spacecraft sequences of events, and data needed for relevant time conversions. " CITATION_DESC = " Semenov, B.V., and C.H. Acton, DEEP IMPACT SPICE KERNELS V1.0, DI-C-SPICE-6-V1.0, NASA Planetary Data System, 2006. " START_TIME = 2005-01-12T19:22:28 STOP_TIME = 2005-08-09T21:19:51 DATA_SET_RELEASE_DATE = 2006-03-01 PRODUCER_FULL_NAME = "BORIS V. SEMENOV" DATA_OBJECT_TYPE = "SPICE KERNEL" DETAILED_CATALOG_FLAG = "Y" DATA_SET_DESC = " Data Set Overview ================= This data set includes the complete set of Deep Impact (DI) SPICE data files (``kernel files''), which can be accessed using SPICE software. The SPICE data contains geometric and other ancillary information needed to recover the full value of the science instrument data. In particular SPICE kernels provide spacecraft and planetary ephemerides, instrument mounting alignments, spacecraft orientation, spacecraft sequences of events, and data needed for relevant time conversions. Data Types (SPICE kernel types) =============================== SPK kernels contain ephemerides for spacecraft, planets, satellites, comets and asteroids as well as for moving or fixed spacecraft and instrument structures. They provide position and velocity, given in a Cartesian reference frame. SPK files are located under the ``data/spk'' directory of this data set. PCK kernels contain certain physical, dynamical and cartographic constants for target bodies, such as size and shape specifications, and the orientation of the spin axis and prime meridian. PCK files are located under the ``data/pck'' directory of this data set. IK kernels (Instrument description kernels) give descriptive and operational data peculiar to a particular scientific instrument, such as internal timing relative to the spacecraft clock and field-of-view model parameters. IK files are located under the ``data/ik'' directory of this data set. CK kernels describe pointing, containing a transformation traditionally called the C-matrix which is used to determine time-tagged pointing (orientation) angles for a spacecraft structure upon which science instruments are mounted. CK files are located under the ``data/ck'' directory of this data set. EK (Events) kernels are derived from the integrated sequence of events used to produce actual spacecraft commands. EK files are located under the ``data/ek'' directory of this data set. LSK (Leapseconds) kernels contain the leapseconds and the values of other constants required to perform a transformation between Universal Time Coordinated (UTC) and Ephemeris time (ET). LSK files are located under the ``data/lsk'' directory of this data set. SCLK (Spacecraft Clock) kernels contain on-board clock calibration data required to perform a mapping between Ephemeris time (ET) and spacecraft on-board time (SCLK.) SCLK files are located under the ``data/sclk'' directory of this data set. FK (Frame Definitions) kernels contain information required to define reference frames, sources of frame orientation data and inter-connections between these frames and other frames supported within the SPICE system. This includes mounting alignment information for each instrument. FK files are located under the ``data/fk'' directory of this data set. Kernel File Details =================== A brief overview of the different types of Deep Impact kernels included in this data set is provided in the CONFIDENCE_LEVEL_NOTE section of this file while details specific to individual files are found in the ``*info.txt'' files in the corresponding data directory. The most detailed description of the data in each file is provided in metadata included inside the file -- in the description area of text kernels or in the comment area of binary kernels. Software ======== The SPICE Toolkit contains software modules needed to read SPICE kernel files. SPICELIB software is highly documented via internal headers. Additional documentation is available in separate ASCII text files called Required Reading files. For example, the S- and P- Kernel (SPK) Required Reading File, named SPK.REQ, describes use of the SPK kernel file readers and contains sample programs. The latest SPICE Toolkit for a variety of computer platforms such as PC, Mac, SUN, etc. is available at the NAIF Node of PDS electronically (via anonymous FTP and WWW servers). Refer to information in ``software/softinfo.txt'' for details regarding obtaining this software. Each version of the Toolkit is also archived at the NASA National Space Science Data Center. Loading Kernel Files into a SPICE-based Application =================================================== The easiest way to make data from a collection of SPICE kernels available to a SPICE-based application is to list these kernels in a meta-kernel and load it into the program using the high level SPICE data loader routine FURNSH. This data set provides such meta-kernel(s) under the ``extras/mk'' directory. For more information about the Stardust meta-kernel(s), see the file ``extras/mk/mkinfo.txt''. " CONFIDENCE_LEVEL_NOTE = " This data set contains SPICE kernel files created during mission operations and after mission data reconstruction and analysis. Some general information about this collection follows here, but the prospective user is also referred to extensive descriptions about each file that are stored inside each kernel file. These metadata provide detailed information regarding the information source from which the data were derived, the type of processing applied to the source data, applicability of the data, etc. Metadata are located in the ``comment area'' for binary kernel types (SPK, CK, ESQ), accessible using either the COMMNT or SPACIT utility program found in the NAIF Toolkit. Metadata are located after ``\begintext'' markers within the text kernel types (PCK, IK, FK, LSK, SCLK), accessible by using any available text file display tool such as a word processor, text editor, or the unix ``more'' or ``cat'' commands. In some cases data accuracy information does not exist because could not be estimated even after mission completion. Where there are questions about data accuracy or ``confidence'' not addressed herein the reader is invited to examine subsequent SPICE archive releases associated with this data set (if such exist), or to contact the NAIF node of the Planetary Data System for possible further information. SPK Files ========= The SP-Kernel files included in this data set provide different versions of the trajectory of the Deep Impact Flyby (DIF) and Deep Impact Impactor (DII) spacecraft and ephemeris data for the mission target comet Tempel 1. Some of these SPKs also include ephemeris data for planets, the Sun, and a possible extended mission target comet Boethin. One version of the DIF and DII trajectories provided in this data set (dif_preenc174_nav_v1, dii_preenc174_nav_v1) was generated by merging regular orbit determination solutions based on radio tracking and far approach optical navigation data produced by the DI Navigation team, JPL during operations. This solution covers the whole primary mission, from launch to the beginning of August 2005, and extends four years past it, to January 2009. While this solution does not provide accurate trajectory for the close encounter because the encounter portion of it is based on predicted data generated pre-encounter, it provides sufficient coverage and accuracy for processing data taken at all other times during the mission. Another version of the DIF and DII trajectories provided in this data set was generated as the result of post-encounter processing of the close approach optical navigation data by Dan Kubitschek and Nick Mastrodemos of the DI Navigation Team, JPL. This solution covers only the two day period around the Tempel 1 encounter. While this solution provides much better accuracy for processing of the close encounter data, it was found to be inadequate for some applications because the spacecraft position provided in it was referenced to the impact site rather than the comet Tempel 1 center. Two SPKs files of this kind provide early (di_finalenc_nav_v1.bsp) and final (di_finalenc_nav_v3.bsp) versions of this solution with the earlier version being archived only because it was used in processing image data in November/December 2005. The last version of the DIF and DII trajectories provided in this data set (di_finalenc_nav_v3_to06048.bsp) was generated by adjusting the final close approach optical navigation solution mentioned above by Brian Carcich of the DI Science Data Center, Cornell University. This solution also covers only the two day period around the Tempel 1 encounter. The adjustment was done by incorporating the offset between the impact site and the comet center determined from the final optical navigation solution SPK (v3) and the latest Tempel 1 shape model provided by Peter Thomas. This solution was used to process the PDS archive images in February 2006. This data set also includes a separate, long-spanning SPK (di_tempel1_ssd_v1.bsp) providing the latest ephemeris data for comet Tempel 1 produced using all DI mission data by the Solar System Dynamics Group, JPL. The ``original'' and ``adjusted'' close approach solutions mentioned are consistent with and incorporate a portion of this file. Additional information about SPK files provided in this data set is available in the file ``data/spk/spkinfo.txt''. CK Files ======== C-kernel files included in this data set provide the orientation of the DIF and DII spacecraft buses and the DIF high gain antenna (HGA). Most of these CK files were produced from engineering telemetry downlinked from the spacecraft. As is often the case with spacecraft engineering telemetry-based measurements, considerable uncertainty exists as to the accuracy of such measurements, and, data quality (accuracy and completeness) can vary significantly. DIF Spacecraft Bus CK files --------------------------- Two kinds of the DIF spacecraft bus orientation CK files are included in this data set. The first kind, based on the low rate (1/8 Hz), provides coverage for the whole primary mission while the second kind, based on the high rate telemetry (5 Hz) provides coverage only for a short period in February 2005 and the for about 50 minutes around closest approach to Tempel 1. Both types of files need to be loaded to provide most complete coverage with the high rate CKs, providing superior attitude, loaded last so that data from them is accessed first. Also, while the low rate CK covers the whole mission, its coverage contains numerous gaps ranging from minutes to hours and, in some cases, even days. Due to these gaps this CK does not provide attitude data for about 20% of the DIF images, particularly those taken during some cruise calibration sequences and far approach. This lack of attitude can be alleviated to some extent by modifying interpolation intervals in the file by using the CKSPANIT program (as was done for processing of the images for archiving in PDS in February 2006 - see comments below on 'gap-filler CK files'.) The first archived versions of both the low rate and the high rate CKs had problems with internal time tags. The tags in the low rate CKs were ``compressed'' to the start of each second due to discrepancy in interpretation of the fractional SCLK part, causing timing error of up to 50 milliseconds and the end of each second (see additional information about this in the ``SCLK Files'' section below.) The tags in the high rate CKs were truncated by up to 2 milliseconds, introducing attitude errors of almost 20 microradians during the fastest spacecraft turn rates in the ~100 second interval before the closest approach to Tempel 1 (at other times attitude errors due to this truncation were negligible). These problems were fixed in the version 2 of these CKs. The accuracy of the DIF spacecraft bus orientation determined on-board varied significantly, from 50 micro-radians (~5 MRI pixels) at the times when the attitude was determined based on the star tracker measurements to a few hundreds of micro-radians (tens of MRI pixels) for the periods when the attitude was determined by propagating ACS gyro data without any star tracker updates for extended periods of time. For this reason, the actual nucleus center position in the images is different from the center position computed using the CK files provided in this data set by as many as 20-30 MRI pixels for a number of the early pre-encounter and post-encounter look-back images. Some of this discrepancy may also be attributed to fact that the linear interpolation done by the Type 3 CK readers between the rather sparse, 1/8th Hz attitude points stored in the low-rate CK file does not adequately represent the actual orientation between the points. A number of times during the mission the ACS system was reset due to a safe mode entry or an update to the flight software. At the time of each reset the attitude quaternion computed by the ACS software was re-initialized (in some cases to an identity quaternion, in other cases to a random quaternion) and for a period of time following the reset, until the ACS was able to re-estimated the actual orientation from the star tracker data, the attitude data sent down in the channelized telemetry was bogus. This table lists the times and reasons of the ACS resets during the mission: 2005 JAN 12 19:25:30.858 post-launch safe mode 2005 JAN 12 19:29:44.578 post-launch safe mode 2005 JAN 12 19:33:37.578 post-launch safe mode 2005 JAN 12 19:37:18.578 post-launch safe mode 2005 JAN 12 19:45:05.007 post-launch safe mode 2005 JAN 20 06:59:48.398 solar flare induced safe mode 2005 FEB 09 21:32:48.264 flight s/w 6.3.0 update 2005 MAR 16 08:28:18.000 SCU-A reset safe mode 2005 APR 12 23:27:45.377 flight s/w 7.0.0 update 2005 JUN 06 04:12:39.808 flight s/w 7.0.0 update DII Spacecraft Bus CK Files --------------------------- Two kinds of the DII spacecraft bus orientation CK files are included in this data set. The first kind provides DII attitude prior to its separation from DIF. This attitude -- constant with respect to DIF -- was determined as the result of processing instrument geometric calibration data. The second kind, based on telemetry, provides attitude from separation through impact. The coverage of this CK contains a number of gaps. Due to these gaps this CK does not provide attitude data for some of the post-separation DII images. This lack of coverage can be alleviated by modifying the interpolation intervals in the file by using the CKSPANIT program (as was done for processing of the images for archiving in PDS in February 2006.) It is important to note that during image archive preparation Science Data Center team observed a bias (of up to 20 ITS pixels, decreasing to zero at closer to the impact time) in image pointing solutions done using this CK. No explanation was found for and no correction was done to this bias at that time. DIF HGA CK Files ---------------- Two kinds of the DIF HGA orientation CK files are included in this data set. The first kind is based on the measured HGA gimbal angles provided in telemetry (``V-channels'') while the second kind is based on the commanded HGA gimbal angles provided in telemetry (``B-channels''). These files should be loaded together to provide the most complete coverage with the file based on measured angles loaded last (to be accessed first.) Even when loaded together, the combined coverage provided by the files is full of gaps, which can be alleviated by modifying the interpolation interval information by using the CKSPANIT program. Additional information about CK files provided in this data set is available in the file ``data/ck/ckinfo.txt''. PCK Files ========= PCK files provide size, shape and orientation data for ``target'' bodies such as planets, satellites, comets and asteroids. A description of these data items and reference to their source is provided inside the PCK file, which is a simple text file that can be viewed using any word processor, text editor or text display utility. This data set contains generic PCK file based on the official IAU/IAG/COSPAR values accepted in 2000 and PCK file for DI mission target -- Tempel 1 -- providing constants determined after the encounter. The PCK file for Tempel 1 contains both rotation and shape/size data derived by the DI science team during post encounter data analysis. Additional information about PCK files provided in this data set is available in the file ``data/pck/pckinfo.txt''. FK Files ======== Frames kernel files provide specifications for how one reference frame is defined relative to another frame. The DI FK provided in this data set contains a complete set of frame definitions for the both spacecraft, their structures such as antennas, and all of their science instruments. Comments in the FK file provide the frame definitions, a description of the frame relationships, the source of and accuracy of the mounting alignment information, etc. The instrument frame definitions provided in the file incorporate the latest mounting alignment data available at the end of the mission. Additional information about FK files provided in this data set is available in the file ``data/fk/fkinfo.txt''. IK Files ======== Instrument kernel files provide specifications for the optical and physical instrument parameters and -- where applicable -- field-of-view size, shape and orientation for the named instrument. Metadata describing these estimates are provided in each IK file included in this archive. While a majority of the of parameters included in the IK files archived in this data set are based on the nominal instrument data, the files incorporate the latest version of optical distortion model derived by the DI optical navigation team. Additional information about IK files provided in this data set is available in the file ``data/ik/ikinfo.txt''. SCLK Files ========== Spacecraft Clock kernel files provide a tabulation of data needed to convert time measurements between ephemeris time (ET) and spacecraft clock time (SCLK). A SPICE SCLK file is made from a similar file -- SCLK/SCET or SCLKvSCET file -- produced by another mission entity. Each newly made SCLK file fully replaces the previous SCLK file. This data set includes SCLK kernels providing the correlation between the DIF spacecraft primary (SCU-A) on-board clock, DIF spacecraft secondary (SCU-B) on-board clock, and DII spacecraft on-board clock. Two SCLK kernels -- the ``official'' version and ``science'' version -- are available for the DIF primary clock and DII clock while only one SCLK kernel -- ``official'' version -- is available for the DIF secondary clock. The main difference between the ``official'' versions of the SCLK kernels and the ``science'' versions is that ``official'' versions are based on the latest time correlations that were used by the project during mission operations while the ``science'' versions contain updated correlations that were used to process science data for archiving in PDS. The correlation updates for the DIF primary clock and for the DII clock were done for two different reasons. The DIF correlation was updated to eliminate ``artificial'' data points introduced by the tool-set that created source SCLKvSCET file and to adjust clock rates in order to connect actual data points in a continuous fashion. The DII correlation, on the other hand, was updated to simply enforce consistency between the DIF primary clock and the DII clock based on the SCLK times of the impact determined from the image data (DII SCLK = 1/173727875.105 +/-300ms per Dennis Wellnitz and DIF SCLK = 1/173727702.218 +/-25ms per image number 064 of ExpID 9000910) and DIF/DII trajectory solutions based on close approach optical navigation data (time of impact for DII trajectory at 2005-185T05:44:34.2 UTC). The ``science'' versions of the SCLKs and trajectory solutions based close approach optical navigation data were created in the following sequence: - correlation from ``official'' DIF primary clock SCLK kernel was modified to get ``science'' DIF primary clock SCLK kernel - ``science'' DIF primary clock SCLK kernel and ``official'' DII SCLK kernels were used to process close approach optical navigation images to generate trajectory solution - UTC of impact (2005-185T05:44:34.2) was determined by converting DIF SCLK of impact determined from DIF images (1/173727702.218) to UTC using ``science'' version of DIF primary clock SCLK kernel - correlation from ``official'' DII SCLK kernel was modified so that UTC mentioned above matched DII SCLK of impact determined from DII images (1/173727875.105) - DII trajectory was shifted so that impact happened at the UTC mentioned above. Because of the tight coupling between the SPK and SCLK kernels, the ``science'' SCLK must be used for encounter image processing. Unfortunately, the absolute accuracy of both ``official'' and ``science'' correlations is no better than 1 second as was determined by a DI Time Issues Working Group that included Ball and JPL engineers and members of the DI science team. This group was put together at the end 2005 with the goal to improve DIF and DII time correlation knowledge. The group concluded that getting improvement was not possible without substantial effort due a number of factors among which were the lack of correlation data during the last ten days before encounter, big changes in the thermal conditions and strong temperature dependency of the clock oscillators, and errors in the production of the time correlation packets. Note that the clock format defined by both ``official'' and ``science'' SCLK kernels (seconds with fractional seconds given as a count of 1/256 second ticks) does not match the format of on-board time tags in mission telemetry (seconds with fractional seconds given as top 8 or 16 or full 20 bits of a count of micro-seconds). For details on this discrepancy and the algorithm to fix it see ``sclk140.txt'' provided in Deep Impact and EPOXI documentation set (DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V3.0). While all science images sent to the ground contained SCLK time in the headers (spacecraft primary, SCU-A, SCLK for DIF and main SCLK for DII), optical- and auto-navigation image headers contain a different time. This time was so a called on-board Ephemeris Time (ET) that optical/auto navigation on-board software used internally to perform autonomous trajectory and attitude solutions. This on-board ET was computed from on-board clock by adding a constant delta to it to make it synchronous with the actual ET to the extent possible. Since the on-board clock was drifting throughout the mission, the delta had to be changed a number of times. The table below shows the delta, in seconds, that must be subtracted from the on-board ET to get corresponding SCLK (spacecraft primary, SCU-A, SCLK for DIF and main SCLK for DII) and the time when a particular delta had been uplinked and took effect in the on-board software (shown as UTC and on-board ET): DIF: Delta Applicability Start UTC Apl. Start on-board ET ------- ----------------------- ---------------------- 64.184 2005-014T02:50:20.1133 158943084.297 160.176 2005-083T11:14:00.1992 164934912.535 177.161 2005-103T02:14:28.7695 166630537.301 268.794 2005-157T04:17:00.0000 171303535.833 237.978 2005-175T03:58:33.1251 172857585.892 DII: Delta Applicability Start UTC Apl. Start on-board ET ------- ----------------------- ---------------------- 64.184 2005-014T02:50:20.1133 158943084.297 Additional information about SCLK files provided in this data set is available in the file ``data/sclk/sclkinfo.txt''. LSK Files ========= Leapseconds kernel files provide a tabulation of ``leapseconds'' and some other terms used in converting time measurements between ephemeris time (ET) and Universal Time (UTC). ``Spacecraft Event Time'' (SCET) is the commonly used name for UTC events measured at the spacecraft. Metadata describing how the LSK data are obtained or computed is contained inside the LSK text file. The time conversion provided by SPICE LSK files is accurate to approximately 0.000030 seconds. Additional information about LSK files provided in this data set is available in the file ``data/lsk/lskinfo.txt''. EK Files ======== Two Events kernel (EK) files are included in this archive: DIF Sequence EK and DIF Command Dictionary EK. DIF Sequence EK contains a summary of the commands sent to the spacecraft during the mission as well as instrument state (status) summaries as modeled by the sequence generation tools. This file was created from integrated sequence Predicted Events File (PEF) provided by Steve Wissler, DI Mission Operations Systems Engineer as the end of the primary mission. While significant effort was made to collect all necessary information for producing complete PEF file, command logs for some periods have not been available and the commands for these periods are missing from the EK. Also, because the PEF file was the result of sequence modeling process the EK records have times different from the actual command execution times (although very close in most cases). DIF Command Dictionary EK is based on the last version of the command dictionary available at the end of the primary mission. Additional information about EK files provided in this data set is available in the file ``data/ek/ekinfo.txt''. Kernel Files Not Included In This Data Set =========================================== A number of kernel files used to process image data archived in PDS and mentioned in the image labels were not included in this data set because they either were superseded by the files provided in this archive, or were known to contain incorrect or out-of-date information, or could be easily re-created from the data provided in this archive using utility program(s) available from NAIF. Among such files are: - predicted SPK files: spk_bet_050112_101_impactor.bsp spk_bet_050112_101_flyby.bsp spk_od023.bsp dif_ort11_dss_merged.bsp spk_diipredict_2005177_175028.bsp These SPKs were used for processing of the images for archiving in PDS during November/December 2005. They contained earlier versions of the spacecraft trajectory and comet ephemerides and were superseded by the SPKs included in this data set. - predicted CK files: dii_attached_v10.bc launch_bet050112_101_20050102t205819_att.bc dif_rec_ck_ort11_merged.bc dii_predict_2005177_175028.bc These CKs were used for processing of the images for archiving in PDS during November/December 2005. They contained predicted attitude data for DII and DIF spacecraft. The main purpose of using these files was to provide ``some'' orientation data for under 20% of the images, for which actual orientation data was not available in the reconstructed CKs provided in this archive. While they served this gap-filler purpose, the data provided by them was incorrect in most/all cases due to differences between planned and actual pointing profiles, timing issues, etc. For this reason they were not included into this data set. - nominal Tempel 1 PCK file: di_tempel1_v00.tpc This PCK was used for processing of the images for archiving in PDS during November/December 2005. It contained nominal, placeholder shape/size and rotation constants for comet Tempel 1. It was superseded by comet PCK ``di_tempel1_v01.tpc'' provided in this data set. For the record, the nominal constants provided in that PCK were: BODY1000093_POLE_RA = ( 0.0 0.0 0.0 ) BODY1000093_POLE_DEC = ( +90.0 0.0 0.0 ) BODY1000093_PM = ( 0.0 205.7142857142857 0.0 ) BODY1000093_RADII = ( 3.1 2.1 2.1 ) - star position SPK and PCK files: naifstarnames_2005321_v01.tpc stars_2005321_v01.bsp These SPK and PCK were used in the Science Data Center image processing pipeline to provide access via SPICE interfaces to positions of a few stars used for instrument calibration during the mission. While these kernels successfully served their purpose, they were not fully compliant with official NAIF practices. This reason they were not included into this data set. On the other hand, recognizing the importance of this data, it was decided to include the star positions stored in these files into this data set's documentation for the reference. The table below provides these positions. Each line contains J2000 RA (hours, arc-minutes, arc-seconds), J2000 DEC (degrees, arc-minutes, arc-seconds) and name. 10,24,23.71,-74,1,53.8,PRETEND I CAR HD90589 0,25,45.07,-77,15,15.3,BET HYI HD2151 10,2,42,-60,7,0,NGC3114 6,23,57.11,-52,41,44.4,CANOPUS HD45348 1,37,42.85,-57,14,12.3,ACHERNAR HD10144 21,7,6,42,14,0,NGC7027 19,41,48.95,50,31,30.2,16 CYG A HD186408 7,33,27.32,-50,35,3.3,HD60753 18,36,56.34,38,47,1.3,VEGA HD172167 0,24,5.22,-72,4,57.9,47 TUC NGC104 6,45,08.92,-16,42,58.0,SIRIUS HD48915 9,11,16.72,-62,19,1.1,I CAR HD79447 11,5,33,-58,43,48,NGC3532 18,51,6,-6,16,0,M11 10,36,16.079,-58,16,38.20,HD92044 08,40,36,-53,02,0,OMI VEL CLUSTER IC2391 - ``gap-filler'' CK files dii_predict_050703_050704.bc dif_predict_050112_050809.bc These CKs were used for processing of the images for archiving in PDS during February to fulfill the same purpose as the predicted CKs mentioned above -- to provide ``some'' orientation data for under 20% of the images, for which actual orientation data was not available in the reconstructed CKs. Unlike the other predicted CKs these two kernels did not provide truly predicted orientation. Instead they stored the same data as the reconstructed CKs but allowed interpolation across gaps of any size between actual attitude data points. These files were not included in this data set because they were created -- and can be recreated at any time -- from the reconstructed CKs provided in this data set using CKSPANIT application with the tolerance of 44236800 ticks (= 2 days). " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_MISSION MISSION_NAME = "DEEP IMPACT" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_TARGET TARGET_NAME = "9P/TEMPEL 1 (1867 G1)" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "DIF" INSTRUMENT_ID = "SPICE" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "DII" INSTRUMENT_ID = "SPICE" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = UNK END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END