PDS_VERSION_ID = PDS3 RECORD_TYPE = "STREAM" LABEL_REVISION_NOTE = " 2006-12-05 S.McLaughlin Created from version 1.0 of this data set. 2007-07-06 S.McLaughlin Resolved liens from Apr 2007 review for version 2.0 of this dataset, as calibrated by the final Deep Impact pipeline. 2014-01-31 EPOXI:McLaughlin Copied from V2.0; HRII Tempel1 encounter spectra V3.0, as calibrated by the EPOXI pipeline. 2014-03-30 EPOXI:McLaughlin Resolved liens from Mar 2014 review. " OBJECT = DATA_SET DATA_SET_ID = "DIF-C-HRII-3/4-9P-ENCOUNTER-V3.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "DEEP IMPACT 9P/TEMPEL ENCOUNTER - REDUCED HRII SPECTRA V3.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" START_TIME = 2005-06-20T21:08:55.422 STOP_TIME = 2005-07-06T18:17:45.282 DATA_SET_RELEASE_DATE = 2014-01-31 PRODUCER_FULL_NAME = "STEPHANIE MCLAUGHLIN" DETAILED_CATALOG_FLAG = "N" DATA_OBJECT_TYPE = "IMAGE" DATA_SET_TERSE_DESC = "Calibrated 1.05- to 4.8-micron spectral images of comet 9P/Tempel 1 acquired by the High Res. Infrared Spectrometer from 20 June through 6 July 2005 during the encounter phase of the Deep Impact mission. V3.0 was calibrated by the EPOXI mission pipeline." ABSTRACT_DESC = " This dataset contains calibrated, 1.05- to 4.8-micron spectral images of comet 9P/Tempel 1 the acquired by the High Resolution Infrared Spectrometer (HRII) from 20 June through 06 July 2005 during the encounter phase of the Deep Impact mission. Version 3.0 was calibrated by the EPOXI mission pipeline and corrects observation times with a maximum difference of about 40 milliseconds, corrects an error in the IR absolute calibration that previously inflated all spectra by a factor of 2, and upgrades the ALTFF line-dependent integration time. Version 3.0 also includes a new flat-field file derived from EPOXI lunar calibrations, improved quadrant-averaged linearity coefficients, and a refinement in the absolute spectral calibration curve. " CITATION_DESC = " McLaughlin, S.A., B. Carcich, S.E. Sackett, T. McCarthy, M. Desnoyer, K.P. Klaasen, L.M. Feaga, and S. Protopapa, DEEP IMPACT 9P/TEMPEL ENCOUNTER - REDUCED HRII SPECTRA V3.0, DIF-C-HRII-3/4-9P-ENCOUNTER-V3.0, NASA Planetary Data System, 2014." DATA_SET_DESC = " Data Set Overview ================= This dataset contains calibrated, 1.05- to 4.8-micron spectral images of comet 9P/Tempel 1 the acquired by the High Resolution Infrared Spectrometer (HRII) from 20 June through 06 July 2005 during the encounter phase of the Deep Impact mission. Version 3.0 was calibrated by the EPOXI mission pipeline and includes the correct interpretation of microsecond counter of the spacecraft clocks that previously introduced maximum errors of about 40 milliseconds in the earlier observation times, a corrected IR absolute spectral calibration step that previously inflated all spectra by a factor of 2, and an upgrade to the ALTFF line-dependent integration time. Version 3.0 also includes a new flat-field file derived from EPOXI lunar calibrations, improved quadrant-averaged linearity coefficients, and a refinement in the absolute spectral calibration curve. For Version 3.0, the EPOXI convention for constructing PRODUCT_IDs and data file names was used. For more information see the EPOXI Calibration Pipeline Summary document in this dataset and Klaasen, et al. (2013) [KLAASENETAL2011]. A summary of the comet observations in this dataset is provided here: Mid-Obs Exposure IDs Date DOY Minimum Maximum Mission Activity ---------- --- ------- ------- -------------------------- 2005-06-20 171 6002005 6002005 Daily comet imaging 2005-06-21 172 6002100 6002105 Daily comet imaging 2005-06-22 173 6002200 6002205 Daily comet imaging 2005-06-23 174 6002300 6002305 Daily comet imaging 2005-06-24 175 6002400 6002405 Daily comet imaging 2005-06-25 176 6002500 6002504 Daily comet imaging 2005-06-26 177 6002600 6002603 Daily comet imaging 2005-06-27 178 8000000 8000004 Continuous comet imaging 2005-06-28 179 8000005 8100004 Continuous comet imaging 2005-06-29 180 8100005 8300000 Continuous comet imaging 2005-06-30 181 8400000 8400005 Continuous comet imaging 2005-07-01 182 8400006 8500009 Continuous comet imaging 2005-07-02 183 8500009 8800003 Continuous comet imaging 2005-07-03 184 9000000 9000021 Continuous comet imaging 2005-07-04 185 9000022 9000029 Continuous comet imaging 9000030 9000039 Pre-impact scans 9000040 9000068 Impact imaging 9010000 9070002 Lookback imaging 2005-07-05 186 9080000 9110002 Lookback imaging 2005-07-06 187 9120000 9150002 Lookback imaging The 9P/Tempel 1 data are described in 'Deep Impact: The Anticipated Flight Data' by Klaasen, et al. (2005) [KLAASENETAL2005]. Initial results from the encounter and impact were presented in 'Deep Impact: Excavating Comet Tempel 1' by by A'Hearn, et al. (2005) [AHEARNETAL2005A]. Required Reading --------------- The documents listed below are essential for the understanding and interpretation of this dataset. Although a copy of each document is provided in the DOCUMENT directory of this dataset, the most recent version is archived in the Deep Impact and EPOXI documentation set, DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V4.0, available online at http://pds.nasa.gov. EPOXI_SIS.PDF - The Archive Volume and Data Product Software Interface Specifications document (SIS) describes the EPOXI datasets including this Deep Impact dataset recalibrated by the EPOXI pipeline, the science data products, and defines keywords in the PDS labels. EPOXI_CAL_PIPELINE_SUMM.PDF - The EPOXI Calibration Pipeline Summary provides an overview of the final version of the calibration pipeline that generated the data products in this dataset. For a thorough discussion of the pipeline, see 'EPOXI Instrument Calibration' by Klaasen, et al. (2013) [KLAASENETAL2011]. CALIBRATION_PAPER_DRAFT.PDF - This incomplete draft of 'Deep Impact Instrument Calibration' by Klaasen, et al. (2008) [KLAASENETAL2006] explains how the instruments were calibrated for the Deep Impact mission. It also describes the Deep Impact calibration pipeline, which was the basis for the EPOXI calibration pipeline. INSTRUMENTS_HAMPTON.PDF - The Deep Impact instruments paper by Hampton, et al. (2005) [HAMPTONETAL2005] provides very detailed descriptions of the instruments. HRII_ENCOUNTER_DATA_SUMMARY.PDF - This log provides notes and data quality recorded by the science team for each HRII exposure, beginning 28 hours before impact and continuing through the lookback period. HRII_ENCOUNTER_POINTING.PDF - This log provides general pointing and scanning information for each set of exposure IDs commanded for the HRII spectrometer from 20 June through 07 July 2005. HRII_3_4_DI_TEMPEL1.TAB - This ASCII table provides image parameters such as the mid-obs Julian date, exposure time, image mode, mission activity type, and description or purpose for each observation (i.e., data product) in this dataset. This file is very useful for determining which data files to work with. Related Data Sets ----------------- The following PDS datasets are related to this one and may be useful for research: DIF-CAL-HRII-2-GROUND-TV1-V1.0 DIF-CAL-HRII/HRIV-2-GROUND-TV2-V1.0 DIF-CAL-HRII/HRIV/MRI-2-GROUND-TV4-V1.0 - Raw HRII pre-flight calibration spectra from the first and second thermal vacuum tests in 2002 and the fourth one in 2003 DIF-CAL-HRII-2-9P-CRUISE-V1.0 - Raw HRII cruise calibration spectra DIF-C-HRII-2-9P-ENCOUNTER-V1.0 - Raw HRII spectra of comet Tempel 1 and calibration sources DIF-C-HRII/HRIV/MRI-6-TEMPS-V1.0 - HRII, HRIV, and MRI instrument thermal telemetry data from the Deep Impact mission which may be useful for determining how temperature fluctuations affect the science instruments, in particular the HRII spectrometer DI-C-SPICE-6-V1.0 - Deep Impact SPICE kernels DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V4.0 - Deep Impact and EPOXI documentation set Processing ========== The calibrated two-dimensional (wavelength and spatial/along-slit) FITS spectral images and PDS labels in this dataset were generated in late 2013 by the EPOXI data pipeline, maintained by the project's Science Data Center (SDC) at Cornell University. Known limitations and deficiencies of the pipeline and the resulting data are discussed in the EPOXI Calibration Pipeline Summary document in this dataset and by Klaasen, et al. (2013) [KLAASENETAL2011] and in 'Deep Impact Instrument Calibration' by Klaasen, et al. (2008) [KLAASENETAL2006]. For HRII spectra, the pipeline generates two types of calibrated products: - Uncleaned radiance data provided in units of Watts/(meter**2 steradian micron) and identified by the mnemonic 'RADREV'. The RADREV data are considered to be reversible because the calibration steps can be backed out to return to the original, raw data numbers. - Irreversibly cleaned radiance data provided in units of Watts/(meter**2 steradian micron) and identified by the mnemonic 'RAD'. The RAD data are considered to be irreversible because the calibration steps, such as smoothing over bad pixels, cannot easily be backed out to return to the original, raw data numbers. The calibration pipeline performed the following processes, in the order listed, on the raw HRII FITS data to produce the RADREV and RAD products found in this data set (the process uses the image mode to select the appropriate set of calibration files): - Calibration of temperatures and voltages in the FITS header - Quadrant-averaged linearization of raw data numbers - Subtraction of dark noise, derived using quadrant-averaged linearization of either in scene dark frames, specific exposure-ID darks, or optimized mode- dependent master dark frames (the prisms/spectral imaging module and IR focal plane array temperatures, OPTBENT and IRFPAT in the FITS header, are used for scaling if dark modeling is required) - Division by a flat field, derived from quadrant-averaged linearization - Determine spectral registration and bandwidth for each pixel (using OPTBENT from FITS headers) - Conversion of data numbers to units of radiance for an absolute, radiometric calibration that is reversible (RADREV) and that was derived from quadrant-based linearization - Interpolation over bad and missing pixels identified in the RADREV data to make a partially cleaned, irreversible, radiometric calibration with units of radiance (RAD); Steps for despiking (i.e., cosmic ray removal) and denoising the data which are part of the RAD stream were not performed because the existing routines are not robust. - Set non-image pixels at the left, right, and bottom edges to zero in the RADREV and RAD products. The 'real data' window of an image is given by CALWINDW in the FITS header. If edge pixels need to be analyzed, the original DN values can be found in the raw products located in the PDS dataset, DIF-C-HRII-2-9P-ENCOUNTER-V1.0. As part of the calibration process, the pipeline updated the per-pixel image quality map, the first FITS extension, to identify: - Pixels where the raw value was saturated, - Pixels where the analog-to-digital converter was saturated, - Pixels that were ultra-compressed and thus contain very little information, and - Pixels considered to be anomalous as indicated by bad pixel maps derived for per-pixel linearity (missing pixels were identified when the raw FITS files were created). The pipeline also created FITS image extensions for a spectral registration (wavelength) map, a spectral resolution (bandwidth) map, and a signal-to-noise ratio map, which are briefly described in the next section. The calibration steps and files applied to each raw image are listed in the PROCESSING_HISTORY_TEXT keyword in the PDS data label. Data ==== FITS Images and PDS Labels -------------------------- Each calibrated spectral image is stored as FITS. The primary data unit contains the two-dimensional spectral image, with the fastest varying axis corresponding to increasing wavelengths from about 1.05 to 4.8 microns and the slowest varying axis corresponding to the spatial or along-slit dimension. The primary image is followed by four image extensions that are two-dimensional pixel-by-pixel maps providing additional information about the spectral image: - The first extension uses one byte consisting of eight, single-bit flags to describe the quality of each pixel in the primary image. The PDS data label defines the purpose of each single-bit flag. - The second extension provides the spectral registration or wavelength for each pixel in the primary image. This extension is required because the wavelength for each pixel changes as the temperature of the instrument increased or decreased. - The third extension provides the spectral bandwidth for each pixel in the primary image. This extension is required because the bandwidth for each pixel changes as the temperature of the instrument increased or decreased. - The fourth extension provides a signal-to-noise ratio for each pixel in the primary image. Each FITS file is accompanied by a detached PDS data label. The EPOXI SIS document provides definitions for the keywords found in a data label and provides more information about the FITS primary image and the extensions. Many values in a data label were extracted from FITS image header keywords which are defined in the document EPOXI_FITS_KEYWORD_DESC.ASC found in the Deep Impact and EPOXI documentation dataset, DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V4.0. File Naming Convention ---------------------- The naming convention for the data labels and FITS files is HIyymmddhh_eeeeeee_nnn_rr.LBL or FIT where 'HI' identifies the HRII instrument, yymmddhh provides the UTC year, month, day, and hour at the mid-point of the observation, eeeeeee is the exposure ID (OBSERVATION_ID in data labels), nnn provides the image number (IMAGE_NUMBER in the data labels) within the exposure ID, and rr identifies the type of reduction: RR for RADREV data (reversibly calibrated, radiance units) R for RAD data (partially cleaned RADREV data, radiance units) Up to 999 individual images or frames can be commanded for one exposure ID. Spectral scans often had 32 or more frames for one specific exposure. Therefore, nnn in the file name provides the sequentially increasing frame number within an exposure ID and corresponds to IMAGE_NUMBER in the data labels. For example, if 50 frames were commanded for a scan with an exposure ID of 9000028, the first FITS file name would be HI05070404_9000028_001_RR.FIT and the last would be HI05070404_9000028_050_RR.FIT. This convention is the one used by the EPOXI pipeline to construct data product file names and PRODUCT_IDs. To translate between the EPOXI and Deep Impact conventions, refer to the HRII_TRANSLATE_PRODUCT_ID.LBL and HRII_TRANSLATE_PRODUCT_ID.TAB files located in the DOCUMENT directory of this dataset. Image Compression ----------------- All calibrated data products are uncompressed. If an associated raw data product was compressed on board the flyby spacecraft (and thus received on the ground and archived as compressed) then the calibration pipeline used one of four 8-bit lookup tables to decompress the raw image. For more information, see the EPOXI Calibration Pipeline Summary document as well as Hampton, et al. (2005) [HAMPTONETAL2005], Klaasen, et al. (2008) [KLAASENETAL2006] and Klaasen, et al. (2013) [KLAASENETAL2011]. Image Orientation ----------------- A true-sky 'as seen by the observer' view is achieved by displaying the image using the standard FITS convention: the fastest-varying axis (samples or wavelength) increasing to the right in the display window and the slowest-varying axis (lines or spatial/along-slit) increasing to the top. This convention is identified in the data labels: the SAMPLE_DISPLAY_DIRECTION keyword is set to RIGHT and LINE_DISPLAY_DIRECTION to UP. The direction to celestial north, ecliptic north, and the Sun is provided in data labels by CELESTIAL_NORTH_CLOCK_ANGLE, ECLIPTIC_NORTH_CLOCK_ANGLE, and SUN_DIRECTION_CLOCK_ANGLE keywords and are measured clockwise from the top of the image when it is displayed in the correct orientation as defined by SAMPLE_DISPLAY_DIRECTION and LINE_DISPLAY_DIRECTION. Please note the aspect of the North celestial pole in an image can be computed by adding 90 degrees to the boresight declination given by DECLINATION in the data labels. Using this convention to display an approach image of Tempel 1, ecliptic North is toward the right and the Sun is down. After impact, the Flyby spacecraft came out of shield mode and turned back to observe at the comet. For lookback images, ecliptic North is toward the left and the Sun is down. For a comparison of the orientation of HRII flight images with those from ground-based calibrations as well as those from the Medium Resolution Instrument CCD (MRI) and the High Resolution Instrument CCD (HRIV) CCD (ITS), see the quadrant nomenclature section in Klaasen, et al. (2008) [KLAASENETAL2006] and Klaasen, et al. (2013) [KLAASENETAL2011]. Spectral Scans -------------- Each HRII scan of Tempel consists of multiple frames within one exposure ID (OBSERVATION_ID in the data labels). To work with these spectral scans, it is recommended that all frames for one exposure ID be stacked into a three-dimensional cube. Then, a spatial-spatial map can be produced for a specific wavelength by selecting the appropriate spectral column from the image cube. Spectral wavelengths are provided by the second FITS extension, the spectral registration (wavelength) map. IR Slit Location ---------------- For a comparison of the relative locations of the IR slit with respect to the fields of view of the Medium Resolution Instrument CCD (MRI) and the High Resolution Instrument CCD (HRI), see the instrument alignment section of Klaasen, et al. (2008) [KLAASENETAL2006]. To visually inspect where the IR slit was estimated to be on the nucleus of Tempel 1 during impact and lookback, see the HRII/HRIV context maps included Deep Impact and EPOXI documentation dataset, DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V4.0. Timing for Spectra ------------------ It is important to note that the readout order of the IR detector affects the timing of the spectra. When a HRII spectral image is displayed using the true-sky convention, the wavelength increases horizontally to the right and the spatial or along-slit direction is vertical. In this orientation, the IR detector was read out from the left and right edges and toward the center and starting with the first row at the bottom and ending with the last row at the top of the display. Since the detector is reset and read out on a pixel-by-pixel basis, the read out order affects the time at which each pixel is exposed although each pixel has the same exposure duration -- except for the ALTFF mode that has different read and reset causing the effective exposure time to vary with line number, i.e., along the slit in the spatial direction. Additionally, the end of the spectrometer slit that always points roughly towards the sun is the first line to be readout and the last line to be read out is furthest from the sun, assuming the spacecraft is in its usual orientation with the solar panels pointing roughly toward the sun. For more information about the timing of the spectra, see the zero exposure background section of the EPOXI instrument calibration paper by Klaasen, et al. (2013) [KLAASENETAL2011]. A brief discussion about how the calibration pipeline handles the ALTFF mode is included in the EPOXI Calibration Pipeline Summary document. Parameters ========== Data Units ---------- The calibrated RADREV and RAD image data have units of radiance, W/(m**2 steradian micron). Imaging Modes ------------- A summary of the imaging modes is provided here. For more information see Hampton, et al. (2005) [HAMPTONETAL2005], Klaasen, et al. (2008) [KLAASENETAL2006] and Klaasen, et al. (2013) [KLAASENETAL2011]. In the table below, X-Size is the spectral dimension and Y-Size is the spatial dimension along the slit. X-Size Y-Size Bin Mode Name (pix) (pix) Type Comments ---- ------ ------ ----- ----- ------------------------------------ 1 BINFF 512 256 2x2 Binned full frame 2 BINSF1 512 126 2x2 Binned sub-frame 3 BINSF2 512 64 2x2 Binned sub-frame 4 UBFF 1024 512 1x1 Unbinned full frame 5 ALTFF 512 256 2x2 Alternate mode 1 (min. exposure time is 1/2 of mode 1) 6 DIAG 1024 512 1x1 Diagnostic, one reset frame followed by a separate read frame such that odd IMAGE_NUMBERs are reset frames and even IMAGE_NUMBERs are read frames 7 MEMCK 1024 512 1x1 Memory Check By utilizing the different imaging modes of the HRII instrument, the observational requirements for desired exposure times were met. Note, of the 7 modes, only modes 1-6 were used for the encounter with comet Hartley 2. Subframe modes are binned (2x2), reduce the spatial (LINE) extent of the image FOV, and have a shorter readout time which reduces the exposure time for bright objects and keeps the detector from saturating. Time- and Geometry-Related Keywords ----------------------------------- All time-related keywords in the data labels, except EARTH_OBSERVER_MID_TIME, are based on the clock on board the flyby spacecraft. EARTH_OBSERVER_MID_TIME provides the UTC when an Earth-based observer should have been able to see an event recorded by the instrument. The SDC pipeline was not able to automatically determine the proper geometric information for the target of choice in some cases. When these parameters could not be computed, the corresponding keywords in the data labels are set to a value of unknown, 'UNK'. Also if GEOMETRY_QUALITY_FLAG is set to 'BAD' or GEOMETRY_TYPE is set to 'PREDICTED' in the PDS labels, then this indicates the geometry values may not be accurate and should be used with caution. The value 'N/A' is used for some geometry-related keywords in the data labels because these parameters are not applicable. Observational geometry parameters provided in the data labels were computed at the epoch specified by the mid-obs UTC, IMAGE_MID_TIME, in the data labels. The exceptions are the target-to-sun values evaluated at the time light left the target that reached the spacecraft at mid-obs time, and the earth-observer-to-target values evaluated at the time the light that left the target, which reached the spacecraft at mid-obs time, reached Earth. Ancillary Data ============== The timing and geometric parameters included in the data labels and FITS headers were computed using the final version of the kernel files archived in the Deep Impact SPICE dataset DI-C-SPICE-6-V1.0. Coordinate System ================= Earth Mean Equator and Vernal Equinox of J2000 (EME J2000) is the inertial reference system used to specify observational geometry parameters in the data labels. Software ======== The observations in this dataset are in standard FITS format with PDS labels, and can be viewed by a number of PDS-provided and commercial programs. For this reason no special software is provided with this dataset. " CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview ========================= The data files in this dataset were reviewed internally by the EPOXI project. Review ====== This dataset was peer reviewed and certified for scientific use on 21 March 2014. Data Coverage and Quality ========================= There are no unexpected gaps in this dataset. All observations received on the ground were processed and included in this dataset. Transient anomalous pixels may be present in the data. Horizontal striping through some images indicates missing data. The image quality map extension identifies where pixels are missing. If the second most-significant bit of a pixel in the image quality map is turned on, then data for the corresponding image pixel is missing. For more information, refer to the EPOXI SIS document. Limitations =========== Timing ------ Geometry-related parameters in the PDS data labels are uncertain at a level of a few seconds because of a known 2-second discrepancy between the clocks on board the flyby and impactor spacecraft and between in-situ data and ground-based observations. After a detailed analysis of the timing problem in early 2006, improved self-consistent SPICE kernels were generated by the Deep Impact project to correlate the spacecraft clocks; there is still a 1-2 second uncertainty between the in-situ data and the ground- based observations and an uncertainty of about one half of a second between the clocks on the flyby and impactor spacecraft. These improved kernels were included in the DI SPICE data set and were used to calculate the geometric parameters in the PDS data labels. For more information about this discrepancy, see the Deep Impact Spacecraft Clock Correlation report, SCLK_CORRELATION.ASC, provided on the Deep Impact and EPOXI documentation dataset, DI-C-HRII/HRIV/MRI/ITS-6-DOC-SET-V4.0. The EPOXI project plans to generate a complete and highly accurate set of UTC correlations since launch. This will ultimately result in a future version of a SCLK that will retroactively change correlation for **all** Deep Impact and EPOXI data. When this kernel is available, it will be added to the SPICE data sets for the two missions and posted on the NAIF/SPICE web site at http://naif.jpl.nasa.gov/naif/. HRI Telescope Focus ------------------- Images of stars acquired early during the Deep Impact mission in 2005 indicated the HRI telescope was out of focus. However, this focus problem does not significantly affect the HRII instrument. For more details please see the Deep Impact instrument calibration paper by Klaasen, et al. (2008) [KLAASENETAL2006]. Displaying Images ----------------- Flight software writes an image header over the first 100 bytes of quadrant A. These image header pixels are included in the calibrated FITS images. Since the values in these pixels vary dramatically, it is recommended that the values of the EPOXI:MINIMUM and EPOXI:MAXIMUM keywords in the data label (or the MINPVAL and MAXPVAL in the FITS header) be used to scale an image for display because these values exclude the header bytes as well as the reference rows and columns located at the edges of the image. For more information, see the quadrant nomenclature section of the EPOXI SIS document. " END_OBJECT = DATA_SET_INFORMATION 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 = "HRII" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_MISSION MISSION_NAME = "DEEP IMPACT" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "AHEARNETAL2005A" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "AHEARNETAL2005B" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "HAMPTONETAL2005" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "KLAASENETAL2005" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "KLAASENETAL2006" END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = "KLAASENETAL2011" END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END