Data Set Overview : This volume contains the results of the early cruise images of the Stardust Navigation Camera. These images are of no clear scientific or engineering use. They were acquired to ascertain the state of the camera during a time of successive contaminations and decontamination actions, as described in detail below. None are considered useful for calibration of future scientific images, given the nearly continuous changes in the state of the camera during this period.  A total of 203 images have been acquired by the STARDUST mission as of 29 October 2001. Some of these were taken for geometric and photometric calibration, but the majority were acquired to check on the state of the camera during decontamination procedures made necessary by contamination from unknown sources near the time of launch. As of this date, the camera is exhibiting near theoretical performance, except for a filter wheel failure. On February 26, 2001, the filter wheel suddenly failed to advance on command, remaining in the OpNav (#0) position. Fortunately OpNav is one of the two broadband filters, and >95% of the mission can still be accomplished without difficulty. There simply will be no composite color images of the comet nucleus.  One or more images have been acquired on 31 different dates. A very brief description of the rationale for each session and the results obtained follows.  #1 - 3/19/99 A series of 27 images was planned to thoroughly check out the camera. The spacecraft safed itself after three images, a bias (zero exposure) frame and two narrow band frames taken at 100 ms exposure. None showed anything, which seemed strange. (Images 1-3)  #2 - 10/21/99 Various spacecraft software conflicts having been resolved, it became possible to attempt a new camera checkout, this time consisting of a bias frame and one image through each of the eight filters, the latter taken with a 500 ms exposure time. Only the two broadband images showed stars, and these were weak and very diffuse. (Images 100-108)  #3 - 2/22/00 Two 200 ms calibration lamp images were taken through the OpNav filter. These were saturated, proving there was nothing wrong with the exposure times and the problem was probably more one of diffusion than absorption. (Images 110-111)  #4 - 2/29/00 Two additional calibration lamp images were acquired through the OpNav filter, this time with a 20 ms exposure. The intensity was all there, but the lamp images were severely diffused, like from the effect of a frost-covered windshield. These images gave information only about conditions downstream from the lamp, telling nothing about the condition of the scan mirror or the periscope. (Images 112-113)  #5 - 5/30/00 Twenty-eight windowed images (351x351 pixels) were acquired, six of them bias frames and 20 of them through the two wide band filters. Of those 20, 18 were of the 0 magnitude star Vega and two of the calibration lamp. The Vega images were taken half through the periscope and half not, using various exposure times. The periscope frames showed severe scattered light but no Vega images, very possibly because the geometrically uncalibrated system missed the star. The frames off the periscope showed huge diffuse images of Vega near the edge of the field. The calibration lamp images looked identical to those taken in February. (Images 114-141)  #6 - 8/8/00 A single windowed bias frame was acquired to check upon the effects, if any, of a large solar flare the previous week. There were no obvious effects. (Image 142)  #7 - 8/16/00 It was decided to turn on the CCD heater to see if that would remove any of the contamination on the optics. Images of the calibration lamp were taken in pairs, a full frame using the OpNav filter and a windowed frame using the HiRes (#7) filter, at zero hours, 1, 2, 4, 8, 16, 32, 56, 100, and 143 hours, 20 images in all. The temperature of the CCD was about 9C during this period. Each image showed changes, but contamination clearly remained at the conclusion of the heating. (Images 143-162)  #8 - 8/30/00 A final pair of calibration lamp frames was acquired after the CCD had cooled back to its normal operating temperature near -35C. The images were different, but still diffuse. (Images 163-164)  #9 - 9/12/00 Five star fields were obtained using the OpNav filter and different scan mirror angles. One spacecraft axis was not properly clamped, so there was smear on all images. (Images 165-169)  #10 - 9/26/00 Sequence #9 was repeated with three identical star field and two new ones. The images appeared somewhat more diffuse than those taken pre-heating, but the transmission seemed better, frame limits being about one magnitude fainter. (Images 170-174)  #11 - 10/17/00 Sixteen frames were taken of the Pleiades (M45) open cluster to attempt to determine the uniformity of the contamination and to see if the smaller intrinsic point spread of the HiRes filter would help us go fainter. Unfortunately there were high drift rates on the three HiRes images and no conclusion was reached. Contamination across the frame varied by no more than half a magnitude, but huge scattered light halos dominated every star image. One compressed frame was acquired, and it showed the compressor chip was working properly. (Images 175-190)  #12 - 11/27/00 A single OpNav frame of the calibration lamp was taken as a baseline for a new heating test. This time, both CCD and scan mechanism heaters were turned on and brought the CCD up to about 12C (the spacecraft was now much nearer perihelion). On December 5 the Sun was turned directly on the CCD radiator for about 30 minutes, bringing the CCD temperature up to 24C. This was done as part of a scheduled trajectory correction maneuver. All heaters were turned off on December 18, but navigation studies prevented any further image acquisition until January. (Image 191)  #13 - 1/5/01 One calibration lamp and four star field frames were acquired using the OpNav filter and 1000 ms exposures. The cal lamp frame showed the lamp filament for the first time since launch. The star frames showed sharper images and reached at least magnitude 9.0. There was still a very shallow skirt of scattered light around star images, however, and we were at least one full magnitude from the performance expected of the camera. (Images 192-196)  #14 - 1/16/01 Some 16 hours after Earth Gravity Assist we acquired 25 frames, five Lunar and two bias frames uncompressed and 16 Lunar and two bias frames compressed. These were taken at about 100,000 km from the Moon while flying nearly over its north pole, seeing about two- thirds front side and one-third back side in a half illuminated image. The wide band filters gave partially saturated images even at the minimum possible 5 ms exposure. The narrow band images were sharp but showed a halo of scattered light, as expected from the results of the previous sequence. It was intended that these Lunar images be used to recalibrate the camera. (Images 197-221)  #15 - 2/26/01 A series of 21 compressed full frame images were taken for the purpose of geometric calibration of the scan mirror. Nineteen were OpNav images taken at 10 degree intervals from 0 degrees to 180 degrees. Two were HiRes images taken at 80 degrees and 90 degrees, again to attempt a comparison of performance of OpNav and HiRes filters. It was immediately obvious that recontamination had occurred and we were back to the level of the previous Fall as far as scattered light was concerned. The images were useless for calibration, and any attempt at photometric calibration from the lunar images taken in January had been rendered moot. EVRs received, when the filter wheel was commanded back to its stowed position, said that it had not moved and still was in the OpNav position. (Images 222-242)  #16 - 3/1/01 Three frames were taken at this time, an uncompressed cal lamp frame and compressed and uncompressed star fields, the former to verify the filter wheel position and the later the contamination state. The first showed that indeed we had not moved from the OpNav filter position and that the cal lamp filament had once again disappeared. The later indeed showed renewed contamination. (Images 243-245)  #17 - 3/13/01 A series of nine images had already been planned to determine exactly where we come off the periscope and the extent of periscope contamination. A tenth was added as final verification that we were stuck in the OpNav position (confirmed), and this resulted in an absolute flight rule forbidding any further attempts to move the filter wheel, since getting stick in a narrow band filter would severely damage the mission by causing both a greater flyby distance and loss of all useful nucleus images. Images of a bright star (Spica) showed that we were getting about half the expected light through the periscope, so indeed there is additional contamination on the periscope mirrors. These also showed that we are fully off the periscope at a 20 degree mirror angle but not 15 degrees and that there was a great deal of scattered light into the periscope at the spacecraft attitude at which the images were acquired. (Images 246-255)  #18 - 3/22/01 On this date one cal lamp and one star field were taken as baseline for a third heating cycle. Immediately following these exposures, the CCD heater was turned on and the scan mechanism heater was turned up once again. (Images 256-257)  #19 - 3/27/01 One set of images, cal lamp plus star field, was taken immediately prior to performing a maneuver to once again point the CCD radiator at the Sun. This was a hot pair taken at 12C. The camera reached about 21C, and 45 minutes later, while still at 21C, a further pair of images was taken. A final pair was taken 12 hours later when the camera was back at 12C. To everyone's surprise, the first pair, taken BEFORE the camera radiator was pointed at the Sun, was noisy, as one would expect with the camera hot, but very clean. There was in fact no significant difference in the three pairs of images. All looked very good except for the hot pixels. (Images 258-263)  #20 - 4/2/01 The CCD and scan mechanism heaters were left on following the March 27 heating cycle. A pair of images was taken during this and each successive DSN pass. No change was seen. (Images 264-265)  #21 - 4/10/01 Another pair of images was acquired. (Images 266-267)  #22 - 4/18/01 Another pair of images was acquired. (Images 268-269)  #23 - 4/25/01 Another pair of images was acquired, and the heaters were returned to their normal state on April 29, CCD off and scan mechanism heating as needed for operation. (Images 270-271)  #24 - 4/30/01 Another pair of images was acquired, this time with the CCD back down to its normal operating temperature at -36C. Without all of the hot pixels, we could now see that we were in our cleanest state since launch, reaching somewhere near 10th magnitude without special filtering. Since this state was reached immediately after heating to only 8C, it appears that this recontamination was of a different nature than the original contamination, perhaps simply water vapor released when the spacecraft was hottest near perihelion. (Images 272-273)  #25 - 5/7/01 Another pair of images was acquired to check for any recontamination. (Images 274-275)  #26 - 5/17/01 Another pair of images was acquired to check for any recontamination. (Images 276-277)  #27 - 5/25/01 Another pair of images was acquired to check for any recontamination. (Images 278-279)  #28 - 5/31/01 Another pair of images was acquired to check for any recontamination. (Images 280-281)  #29 - 6/8/01 Sixteen full frame uncompressed images were taken of the encounter background field with exposures of one, three, and five seconds, at various mirror settings, and with the spacecraft in encounter attitude for periscope images, to check for scattered light. With a 0 degree mirror angle, there was about 200 dn /s of scattered light in the upper left corner, the worst part of the frame. With a 10 degree mirror angle, there was about 100 dn/s of scattered light in the upper left corner. At 20 degrees, and clear of the periscope, there was no scattered light detected. Processing of a five second exposure clear of the periscope indicated we reached magnitude 11.7 with a signal to noise ratio of three. There has been no further evidence of contamination since the third heating cycle began on March 22. (Images 282-297)  #30 - 8/29/01 Two images (298,299) were acquired to check for any recontamination of the camera and to furnish additional geometric calibrations. Both proved excellent, showing no new contamination for the past four months. No additional imaging is planned until the windowing software patch is available or until standard maintenance requires a camera status check (in about six months). Useful unwindowed imaging will not be possible for a year or more, that is, until we have more power and higher data rate as we begin to approach Sun and Earth once again. (Images 298-299)  #31 - 10/29/01 In anticipation of a long period with no imaging while the spacecraft was near aphelion, a final check was made on the state of the camera. This was used as an opportunity to place the spacecraft in the attitude relative to the Sun that it will have on approach, if an engineering readiness test is performed on the asteroid Annefrank in November 2002, as a check for scattered light. The single 1000 ms image remained free of significant contamination and showed no scattered light. (Image 300)  The images on this calibration volume are in standard PDS format. Each file includes an attached PDS label at the beginning of the file, followed by a histogram, and ending with the image itself. The PDS label contains two OBJECT definitions, which describe the storage requirements for both the histogram and image objects. The label also describes the circumstances surrounding the collection of the calibration image. This meta-data is in keyword and value pairs and each of these keywords is described at the end of this document.  Camera Description ------------------ The camera has a 1024x1024 array as the active portion of the CCD. The images that are stored on this volume, however, contain more than just the active portion of the CCD. Each line contains a sync pattern, a line counter, 12 baseline stabilization pixels, the 1024 pixels from the active portion of the CCD, and finally 8 over-clock pixels used to measure the quantum efficiency. The number of rows for each image is always 1024, no matter what compression mode is used, but the number of columns for each image depends on the compression mode used.  Compression Modes ----------------- The NAVCAM images can be either 8-bit or 12-bit data. The 12-bit data is commonly referred to as 'uncompressed data', while the 8-bit is referred to as 'compressed data'. This compression is accomplished by a 12-bit to 8-bit square-root look-up-table compression method, which is implemented in the hardware of the camera electronics. This compression is lossy and the estimate of the 12-bit image can be recovered using the look-up table mentioned in Appendix 3 of the Calibration Document. Both the image and histogram portions of the data file require different amounts of storage space, dependent on the compression mode used.  Pixel storage requirements -------------------------- In uncompressed mode with 12-bit data, the pixels are expressed in two bytes, as 16 bits per pixel. The upper nibble of the most significant byte is always zero for these images. In compressed mode with 8-bit data, the pixels are expressed in a single byte.   Number of Columns within each Row --------------------------------- The general form of each line for each image is fixed. The row of data from the camera can be categorized into five different regions:  1. Sync Pattern Always 2 bytes, with value 0x0000 2. Line Counter Always 2 bytes, values from 0 to 1023 3. 8 BLS pixels *Baseline Stabilization pixels, either 1 or 2 bytes per pixel 4. 1024 image pixels *Either 1 or 2 bytes per pixel 5. 12 over-clock pixels *Used to measure quantum efficiency, either 1 or 2 bytes per pixel  * The pixels are either 1 or 2 bytes per pixel dependent on the compression mode. Uncompressed, 12-bit images require 2 bytes per pixel, while compressed 8-bit images require 1 byte per pixel.  For the uncompressed, 12-bit data, each row contains 1046 'pixels' of data, which is exactly 2092 bytes. This is 2 bytes for the sync, 2 bytes for the line counter, 8 pixels at 2 bytes per pixel, 1024 pixels at 2 bytes per pixel and, finally, 12 pixels at 2 bytes per pixel. In equation form:  bytes_per_uncompressed_line : 2 + 2 + 2 * ( 8 + 1024 + 12 ) : 2092  For the compressed, 8-bit data, each row contains 1048 'pixels' of data, which is exactly 1048 bytes. This is 2 bytes for the sync, 2 bytes for the line counter, 8 pixels at 1 byte per pixel, 1024 pixels at 1 bytes per pixel and, finally, 12 pixels at 1 bytes per pixel. In equation form:  bytes_per_compressed_line : 2 + 2 + 1 * ( 8 + 1024 + 12 ) : 1048  Reading with RAW image readers ------------------------------ When using any of the supported PDS readers, this extra data at the beginning and end of the line is not displayed, but when reading these images with a raw raster-scan style reader, this extra data at the beginning and ending of each line must be taken into account.  Values to use when reading images with a RAW readers ---------------------------------------------------- Compression Mode # Rows # Columns Data Type ----------------- ------ --------- ------------------------------ Compressed 1024 1048 BYTE data Uncompressed 1024 1046 MSB_Unsigned_integer (16-bit)  Finding the offset to the data within the file ---------------------------------------------- When trying to read the histogram or image arrays from the file using a RAW reader, the reader must first skip all of the information before the object to be read. As an example, to read the image object using a raw reader, the reader must first skip the PDS attached header, as well as the histogram data. To determine the amount of data to skip, examine two keyword pairs from the attached label.  To advance to the beginning of the histogram data, examine the following keywords: RECORD_BYTES : 2092 ^IMAGE_HISTOGRAM : 3 The first keyword defines the number of bytes within each record, while the second keyword indicates at which record the data begins. In this example, the data starts in record #3. This indicates that 2 other records contain data prior to the start of the histogram data. To compute the data offset, account for 2 records of data: in this example, the offset is (3-1)*2092 : 4184.  To advance to the beginning of the image data, examine the following keywords: RECORD_BYTES : 2092 ^IMAGE : 11 As in the previous example, the first keyword defines the number of bytes within each record. The second keyword indicates the record at which the image data begins. To compute the data offset, follow the example above: Offset : ( ^image_histogram - 1 ) * record_bytes. Ex: Offset : ( 11 - 1) * 2092 : 20920  Flip Required to Achieve ``As Seen By Observer'' Display -------------------------------------------------------- Since the optical path of the camera includes a mirror and the flight and image production s/w do not compensate for the flip that this mirror introduces, the images displayed in normal left-to-right sample, top-to-bottom line fashion have to be transposed (flipped about left- top/right-bottom diagonal) in order to appear ``as observer located on the s/c would see it''.  A Sample PDS Attached Image Label --------------------------------- PDS_VERSION_ID : PDS3 /*** FILE FORMAT ***/ RECORD_TYPE : FIXED_LENGTH RECORD_BYTES : 2092 FILE_RECORDS : 1032 /*** POINTERS TO OBJECTS IN FILE ***/ ^IMAGE_HISTOGRAM : ('N0164C171.RAW',1) ^IMAGE : ('N0164C171.RAW',9) /*** GENERAL DATA DESCRIPTION PARAMETERS ***/ MISSION_NAME : 'STARDUST' SPACECRAFT_NAME : 'STARDUST' DATA_SET_ID : 'STARDUST-C/E/L-NC-2-EDR-V1.0' PRODUCT_ID : 'N0164C171.IMG' PRODUCER_INSTITUTION_NAME : 'JPL/ACT' PRODUCT_TYPE : 'EDR' SOFTWARE_NAME : 'ACT DMAPKTDECOM 1.0' MISSION_PHASE_NAME : 'Cruise 1' TARGET_NAME : 'N/A' FRAME_SEQUENCE_NUMBER : 164 /*** TIME PARAMETERS ***/ PRODUCT_CREATION_TIME : 2000-09-15T01:26:31 START_TIME : 2000-08-30T17:30:53.994 STOP_TIME : 'N/A' SPACECRAFT_CLOCK_START_COUNT : '0652123932:172' SPACECRAFT_CLOCK_STOP_COUNT : 'N/A' TIME_FROM_CLOSEST_APPROACH : -1220.075  /*** CAMERA RELATED PARAMETERS ***/ INSTRUMENT_NAME : 'NAVIGATION CAMERA' INSTRUMENT_HOST_NAME : 'STARDUST' INSTRUMENT_ID : 'NC' DATA_STREAM_TYPE : 'CRUISE' TELEMETRY_MUX_MODE_ID : 1 FILTER_WHEEL_IN_MOTION_MODE_ID : 0 EXPOSURE_ENABLE_MODE_ID : 0 EXPOSURE_DURATION : 150  CCD_HEATER_MODE_ID : 0 SLEEP_MODE_ID : 0 CAL_LAMP_MODE_ID : 1 QUANTIZATION_MODE_ID : 0 FIFO_EMPTY_MODE_ID : 1 FIFO_FULL_MODE_ID : 0 BULB_MODE_ID : 0 FILTER_STEPS : 7 FILTER_PARITY : 0 FILTER_NUMBER : 7 FILTER_NAME : 'HiRes' CENTER_FILTER_WAVELENGTH : 596.4  FILTER_FWHM : 200  NAVCAM_DIGITAL_TELEMETRY : 16#849ea1b0c0d5e7f7# SCAN_MIRROR_ANGLE : -0.012817  SCAN_MIRROR_LAST_COMMANDED_VELOCITY : 0  SCAN_MIRROR_MOTOR_MODE_ID : 0 /*** TEMPERATURE PARAMETERS IN  ***/ FOCAL_PLANE_TEMPERATURE : 234.713  SCAN_MIRROR_TEMPERATURE : 265.614  NOTE : ' EARTH MEAN EQUATOR AND VERNAL EQUINOX J2000 COORDINATES ARE THE INTERTIAL REFERENCE SYSTEM USED TO SPECIFY OBSERVATIONAL GEOMETRY. LATITUDE AND LONGITUDE COORDINATES OF TARGET ARE GEOCENTRIC. GEOMETRIC PARAMETERS ARE BASED ON BEST AVAILABLE DATA AT TIME OF PRODUCT CREATION. REFER TO EDR SPICE DATA BASE FOR THE MOST CURRENT OBSERVATIONAL GEOMETRY DATA.' /*** LINE-OF-SITE ON CELESTIAL SPHERE: Angles in  ***/ RIGHT_ASCENSION : 325.41  DECLINATION : -12.7562  TWIST_ANGLE : 1E+32  RETICLE_POINT_RA : ( 324.357, 323.094, 326.444, 327.744) RETICLE_POINT_DEC : (-15.0215,-11.7291,-10.4868, -13.763) EMEJ2000_SC_QUATERNION : ( 0.79995, -0.18296, -0.25495, 0.51148) /*** TARGET PARAMETERS: Position , Velocity  ***/ SC_TARGET_POSITION_VECTOR : ( -1E+32, -1E+32, -1E+32) SC_TARGET_VELOCITY_VECTOR : ( -1E+32, -1E+32, -1E+32) TARGET_CENTER_DISTANCE : -1E+32  SUN_TARGET_POSITION_VECTOR : ( -1E+32, -1E+32, -1E+32) SUN_TARGET_VELOCITY_VECTOR : ( -1E+32, -1E+32, -1E+32) SUN_TARGET_CENTER_DISTANCE : -1E+32  /*** TARGET WITHIN SENSOR FOV: Angles  ***/ CENTER_LATITUDE : -1E+32  CENTER_LONGITUDE : -1E+32  HORIZONTAL_PIXEL_SCALE : -1E+32  VERTICAL_PIXEL_SCALE : -1E+32  SMEAR_MAGNITUDE : 0.0749415  SMEAR_AZIMUTH : 59.2858  RETICLE_POINT_LATITUDE : ( -1E+32, -1E+32, -1E+32, -1E+32) RETICLE_POINT_LONGITUDE : ( -1E+32, -1E+32, -1E+32, -1E+32) /*** SPACECRAFT POSITION WITH RESPECT TO BODY ***/ SUB_SPACECRAFT_LATITUDE : -1E+32  SUB_SPACECRAFT_LONGITUDE : -1E+32  SPACECRAFT_ALTITUDE : -1E+32  SUB_SPACECRAFT_AZIMUTH : -1E+32  /*** VIEWING AND LIGHTING GEOMETRY (SUN ON TARGET) ***/ PHASE_ANGLE : -1E+32  INCIDENCE_ANGLE : -1E+32  EMISSION_ANGLE : -1E+32  /*** DESCRIPTION OF OBJECTS CONTAINED IN THE FILE ***/ OBJECT : IMAGE_HISTOGRAM ITEMS : 4096 DATA_TYPE : MSB_UNSIGNED_INTEGER ITEM_BITS : 32 END_OBJECT : IMAGE_HISTOGRAM OBJECT : IMAGE LINES : 1024 LINE_SAMPLES : 1024 SAMPLE_TYPE : MSB_UNSIGNED_INTEGER SAMPLE_BITS : 16 SAMPLE_BIT_MASK : 2#0000111111111111# MAXIMUM : 3994 MINIMUM : 0 LINE_PREFIX_BYTES : 20 LINE_SUFFIX_BYTES : 24 MEAN : 243.533 STANDARD_DEVIATION : 670.976 SATURATED_PIXELS : 0 CHECKSUM : 255362468 OBJECT : WINDOW WINDOW_DESC : 'HEATING TEST' TARGET_NAME : 'COLD AGAIN IMAGE' FIRST_LINE : 336 FIRST_LINE_SAMPLE : 336 LINES : 351 LINE_SAMPLES : 351 END_OBJECT : WINDOW END_OBJECT : IMAGE END  General notes regarding label ----------------------------- * Strings appear in quotes. * Integers and PDS Times do not take quotes. * Lists are enclosed within {} type brackets. * If a field is unknown, 'UNK' may be entered. * If a field is not applicable, 'N/A' may be entered. * Fields can spill freely, with or without white space, onto following lines. * Not all images contain the WINDOW object as part of the image object. This subobject is only present when windowed data is present in the image. Images which are full-frame do not have the WINDOW subobject.  Definition of Keywords/Values from the PDS Data Dictionary ---------------------------------------------------------- PDS_VERSION_ID The pds_version_id Keywords indicates the version number of the PDS standards documents that is valid when a data product label is created. Values for the PDS_VERSION_ID are formed by appending the integer for the latest version number to the letters 'PDS'. Examples: PDS3, PDS4.  RECORD_TYPE The record_type keyword indicates the record format of a file. Note: In the PDS, when record_type is used in a detached label file it always describes its corresponding detached data file, not the label file itself. The use of record_type along with other file-related data elements is fully described in the PDS Standards Reference.  RECORD_BYTES The record_bytes keyword indicates the number of bytes in a physical file record, including record terminators and separators.  FILE_RECORDS The file_records keyword indicates the number of physical file records, including both label records and data records.  ^IMAGE_HISTOGRAM The image_histogram object represents a pointer to the image histogram. The value is in 'RECORD_BYTE' units. This represents the record at which the histogram data begins. Because of this fact, account for one less than the number of records shown. As an example, if the pointer value is 4, and the bytes per record is 2092, the image histogram data starts at (4-1)*2092 : 6276 bytes.  ^IMAGE The ^image pointer represents a byte offset to the image data. The value is in 'RECORD_BYTE' units. This represents the record at which the image data begins. Because of this fact, account for one less than the number of records shown. As an example, if the pointer value is 11, and the bytes per record is 2092, the image histogram data starts at byte 29020.  MISSION_NAME The mission_name element identifies a major planetary mission or project. A given planetary mission may be associated with one or more spacecraft.  SPACECRAFT_NAME The spacecraft_name element provides the full, unabbreviated name of a spacecraft.  DATA_SET_ID The data_set_id element is a unique alphanumeric identifier for a data set or a data product. The data_set_id value for a given data set or product is constructed according to flight project naming conventions. In most cases the data_set_id is an abbreviation of the data_set_name. Example value: STARDUST-C/E/L-NC-2-EDR-V1.0. Note: In the PDS, the values for both data_set_id and data_set_name are constructed according to standards outlined in the Standards Reference.  PRODUCT_ID The product_id data element represents a permanent, unique identifier assigned to a data product by its producer. Note: In the PDS, the value assigned to product_id must be unique within its data set. This value represents the actual name of the image file on the archive. The output directory is also available.  PRODUCER_INSTITUTION_NAME The producer_institution_name element identifies a university, research center, NASA center or other institution associated with the production of a data set. This would generally be an institution associated with the element producer_full_name. In this dataset, this field has the value 'JPL/ACT', described as: JPL : Jet Propulsion Laboratory. ACT : Applied Coherent Technology Corp  PRODUCT_TYPE The product_type data element identifies the type or category of a data product within a data set. Examples: EDR, UDR.  SOFTWARE_NAME The software_name element identifies data processing software such as a program or a program library.  MISSION_PHASE_NAME The mission_phase_name element provides the commonly-used identifier of a mission phase.  TARGET_NAME The target_name element identifies a target. The target may be a planet, satellite, ring, region, feature, asteroid or comet. See target_type.  FRAME_SEQUENCE_NUMBER The frame_sequence_number element indicates the location within a cycle at which a specific frame occurs. Frames are repeated in a specific order within each cycle. In this dataset, this value represents a uniquely sequential identifier assigned to each image of the archive.  PRODUCT_CREATION_TIME The product_creation_time element defines the UTC system format time when a product was created. Formation rule: YYYY-MM-DDThh:mm:ss.  START_TIME The start_time element provides the date and time of the beginning of an event or observation (whether it be a spacecraft, ground-based, or system event) in UTC system format. Formation rule: YYYY-MM-DDThh:mm:ss.  STOP_TIME The stop_time element provides the date and time of the end of an observation or event (whether it be a spacecraft, ground-based, or system event) in UTC system format. Formation rule: YYYY-MM-DDThh:mm:ss.  SPACECRAFT_CLOCK_START_COUNT The spacecraft_clock_start_count element provides the value of the spacecraft clock at the beginning of a time period of interest.  SPACECRAFT_CLOCK_STOP_COUNT The spacecraft_clock_stop_count element provides the value of the spacecraft clock at the end of a time period of interest.  TIME_FROM_CLOSEST_APPROACH The time_from_closest_approach element provides the time with respect to periapsis or closest approach.  INSTRUMENT_NAME The instrument_name element provides the full name of an instrument. Note: that the associated instrument_id element provides an abbreviated name or acronym for the instrument.  INSTRUMENT_HOST_NAME The instrument_host_name element provides the full name of the host on which an instrument is based. This host can be either a spacecraft or an earth base. Thus, the instrument_host_name element can contain values which are either spacecraft_name values or earth_base_name values.  INSTRUMENT_ID The instrument_id element provides an abbreviated name or acronym which identifies an instrument. Note: The instrument_id is not a unique identifier for a given instrument. Note also that the associated instrument_name element provides the full name of the instrument.  DATA_STREAM_TYPE The data_stream_type element identifies a particular type of data stream to which the given data product is related. The images on this archive will be categorized as either 'Cruise' or 'Encounter' images, indicating the configuration of the spacecraft when the images were acquired.   EXPOSURE_DURATION The exposure_duration element provides the value of the time interval between the opening and closing of an instrument aperture (such as a camera shutter).  TELEMETRY_MUX_MODE_ID The telemetry_mux_mode_id element indicates that the NAVCAM telemetry multiplexor has sampled all digital engineering measurements. This value should always be 1 by the nature of the timing of the sampling of the multiplexor.  FILTER_WHEEL_IN_MOTION_MODE_ID The filter_wheel_in_motion_mode_id indicates that the filter wheel is in motion. Upon completion of the movement of the filter wheel, this value is set to a 0.  EXPOSURE_ENABLE_MODE_ID The exposure_enable_mode_id element indicates that the shutter has been enabled to open, and if successfully closed, should have a value of 0.  EXPOSURE_DURATION Exposure duration (integration time) of the image observation expressed in milliseconds.  CCD_HEATER_MODE_ID The ccd_heater_mode_id element indicates if the CCD heater is on, with a value of 1, or off, with a value of 0. This value is controlled independently by spacecraft commands.  SLEEP_MODE_ID The sleep_mode_id element indicates if the camera is in sleep mode, or in a low- power state. A value of 1 indicates that sleep mode is enables and a value of 0 indicates that sleep mode is disables. Once sleep mode has been enabled, it can only be disabled by cycling power to the NAVCAM.  CAL_LAMP_MODE_ID The cal_lam_mode_id element provides the value of the calibration lamp mode at the time the image was acquired. This value indicates whether the calibration lamp was on or off at the time the image was acquired.  QUANTIZATION_MODE_ID The quantization_mode_id element provides the identifier for the quantization mode used when the image was acquired. This value indicates if the original data was quantized at the time the data was acquired. A value of 'off' indicates that the data was not quantized, while a value of 'on' indicates that the data was quantized. In this dataset, this value indicates that the image was compressed with a hardware square-root compression technique prior to transmission.  FIFO_EMPTY_MODE_ID The fifo_empty_mode_id indicates if the readout FIFO is empty or not. When this value is set to 1, the FIFO is empty and when it is 0, the FIFO is not empty.  FIFO_FULL_MODE_ID The fifo_full_mode_id indicates if the readout FIFO is full or not. When this value is set to 1, the FIFO is full and when it is 0, the FIFO is not full. When the FIFO becomes full, pixel data is overwritten in the NAVCAM's FIFO. This value represents the state of the FIFO just before the new image was taken and represents the previous image's success.  BULB_MODE_ID The bulb_mode_id element indicates if the shutter has been commanded open. As long as this value remains a 1, the shutter will remain open. This value is controlled only by spacecraft commands. When a command is received from the spacecraft to set the bulb_mode value to 0, the shutter is closed. No image is acquired as a result of a bulb_mode off command. This value is used to take images whose exposure duration must be longer than 20 seconds.  FILTER_STEPS The filter_steps element indicates how many filters were traversed to reach the filter of interest. To move from one filter to the next takes one second, so a three step move would take three seconds.  FILTER_PARITY The filter_parity element is an odd parity bit to allow for identification of a faulty bit amongst one of the three bits needed to represent the filter number.  FILTER_NUMBER The filter_number element provides the number of an instrument filter through which an image or measurement was acquired or which is associated with a given instrument mode. Note: that the filter_number is unique, while the filter_name is not.  FILTER_NAME The filter_name element provides the commonly-used name of the instrument filter through which an image or measurement was acquired or which is associated with a given instrument mode. Example values: RED, GREEN. See also filter_number.  CENTER_FILTER_WAVELENGTH The center_filter_wavelength element provides the mid_point wavelength value between the minimum and maximum instrument filter wavelength values.  FILTER_FWHM The filter_fwhm element provides the measurement for the Full-width, half-max value associated with the filter. This is the width of the filter transmission curve at the point of half of the maximum transmission value.  NAVCAM_DIGITAL_TELEMETRY The navcam_digital_telemetry element is used to indicate the eight bytes returned from the camera at the completion of the acquisition of an image. The upper nibbles of each of the eight bytes should follow the pattern of 0x89abcdef. This is a check that can be used to determine if the camera is functioning properly. The lower nibbles of each of the eight bytes were used in determining many of the other parameters given in the other columns of data.  SCAN_MIRROR_ANGLE The scan_mirror_angle element indicates the angle of the scan mirror at the instant the image was taken. The mirror sweeps through the plane formed by the spacecraft X and Z axes. When the mirror is at 0 degrees, the light path is essentially from the +X axis. As the mirror rotates to +90 degrees, the light path is from the -Z axis. When the mirror moves on to +180 degrees, the light path is in the direction of the -X axis. The range of the mirror is approximately 0 degrees to +200 degrees.  SCAN_MIRROR_LAST_COMMANDED_VELOCITY The scan_mirror_last_commanded_velocity element indicates the last commanded velocity for the scan mirror. The scan mirror is not commanded to a position, but rather is reset to an initial position and is then commanded at a specific velocity for a specific amount of time. The value given here is that commanded velocity.  SCAN_MIRROR_MOTOR_MODE_ID The scan_mirror_motor_mode_id indicates if the scan mirror motor is either on or off. When the value is a 1, the motor is on. When the value is a 0, the motor is off.  FOCAL_PLANE_TEMPERATURE The focal_plane_temperature element provides the temperature of the focal plane array in degrees Kelvin at the time the observation was made.  SCAN_MIRROR_TEMPERATURE The scan_mirror_temperature element provides the temperature of the scan mirror in degrees Kelvin at the time the observation was made.  RIGHT_ASCENSION The right_ascension element provides the right ascension value. Right_ascension is defined as the arc of the celestial equator between the vernal equinox and the point where the hour circle through the given body intersects the Earth's mean equator (reckoned eastward).  DECLINATION The declination element provides the value of an angle, corresponding to latitude, used to fix position on the celestial sphere. Declination is measured positive north and negative south of the celestial equator, and is defined relative to a specified reference period or epoch.  TWIST_ANGLE The twist_angle element provides the angle of rotation about an optical axis relative to celestial coordinates. The RIGHT_ASCENSION, DECLINATION and TWIST_ANGLE elements define the pointing direction and orientation of an image or scan platform.  RETICLE_POINT_RA These parameters refer to the right ascension of the principal points of the camera. For the left pixel of the camera (line 1, sample 1), the upper right pixel (line 1 , last sample), lower left (last line, sample 1), and lower right(last line, last sample).  RETICLE_POINT_DEC These parameters refer to the declination of the principal points of the camera. For the left pixel of the camera (line 1, sample 1), the upper right pixel (line 1, last sample), lower left (last line, sample 1), and lower right(last line, last sample).  EMEJ2000_SC_QUATERNION The emej2000_sc_quaternion element identifies the quaternion required to rotate a vector in Earth-Mean-Equator J2000 coordinates into the spacecraft frame.  SC_TARGET_POSITION_VECTOR The sc_target_position_vector element indicates the x-, y-, z- components of the position vector from observer to target center expressed in J2000 coordinates, and corrected for light time and stellar aberration, evaluated at epoch at which image was taken.  SC_TARGET_VELOCITY_VECTOR The sc_target_velocity_vector element indicates the x-, y-, z- components of the velocity vector from observer to target center expressed in J2000 coordinates, and corrected for light time and stellar aberration, evaluated at epoch at which image was taken.  TARGET_CENTER_DISTANCE The target_center_distance element provides the distance between an instrument and the center of mass of the named target.  SUN_TARGET_POSITION_VECTOR The sun_target_position_vector element indicates the x-, y-, z- components of the position vector from sun to target center expressed in J2000 coordinates, and corrected for light time and stellar aberration, evaluated at epoch at which image was taken.  SUN_TARGET_VELOCITY_VECTOR The sun_target_velocity_vector element indicates the x-, y-, z- components of the velocity vector from sun to target center expressed in J2000 coordinates, and corrected for light time and stellar aberration, evaluated at epoch at which image was taken.  SUN_TARGET_CENTER_DISTANCE The sun_target_center_distance element provides the distance between the sun and the center of mass of the named target.  CENTER_LATITUDE The center_latitude element provides the latitude of the surface intercept point of the boresight of the camera.  CENTER_LONGITUDE The center_longitude element provides the longitude of the surface intercept point of the boresight of the camera.  HORIZONTAL_PIXEL_SCALE The horizontal_pixel_scale element indicates the horizontal picture scale.  VERTICAL_PIXEL_SCALE The vertical_pixel_scale element indicates the vertical picture scale.  SMEAR_MAGNITUDE The smear_magnitude element indicates how far an image was smeared during an exposure.  SMEAR_AZIMUTH The smear_azimuth element indicates the direction in which an image was smeared. The values of this angle increment in a clockwise direction from a horizontal reference line.  RETICLE_POINT_LATITUDE The reticle_point_latitude element provides the latitude of the surface intercept points of the principle points of the camera, defined as the upper left pixel of the camera (line 1,sample 1), the upper right pixel (line 1, last sample), lower left (last line, sample 1), and lower right (last line, last sample).  RETICLE_POINT_LONGITUDE The reticle_point_longitude element provides the longitude of the surface intercept points of the principle points of the camera, defined as the upper left pixel of the camera (line 1, sample 1), the upper right pixel (line 1, last sample), lower left (last line, sample 1), and lower right (last line, last sample).  SUB_SPACECRAFT_LATITUDE The sub_spacecraft_latitude element provides the latitude of the sub-spacecraft point. The sub-spacecraft point is that point on a body which lies directly beneath the spacecraft.  SUB_SPACECRAFT_LONGITUDE The sub_spacecraft_longitude element provides the longitude of the sub-spacecraft point. The sub-spacecraft point is that point on a body which lies directly beneath the spacecraft.  SPACECRAFT_ALTITUDE The sub_spacecraft_azimuth element provides the value of the angle between the line from the center of an image to the sub-spacecraft point and a horizontal reference line (in the image plane) extending from the image center to the middle right edge of the image. The values of this angle increase in a clockwise direction.  SUB_SPACECRAFT_AZIMUTH The spacecraft_altitude element provides the distance from the spacecraft to a reference surface of the target body measured normal to that surface.  PHASE_ANGLE The phase_angle element provides a measure of the relationship between the instrument viewing position and incident illumination (such as solar light). Phase_angle is measured at the target; it is the angle between a vector to the illumination source and a vector to the instrument. If not specified, the target is assumed to be at the center of the instrument field of view. If illumination is from behind the instrument, phase_angle will be small.  INCIDENCE_ANGLE The incidence_angle element provides a measure of the lighting condition at the intercept point. Incidence angle is the angle between the local vertical at the intercept point (surface) and a vector from the intercept point to the sun. The incidence_angle varies from 0 degrees when the intercept point coincides with the sub_solar point to 90 degrees when the intercept point is at the terminator (i.e., in the shadowed or dark portion of the target body). Thus, higher values to the middle right edge of the image. The values of this angle increase in a clockwise direction. of incidence_angle indicate the existence of a greater number of surface shadows.  EMISSION_ANGLE The emission_angle element provides the value of the angle between the surface normal vector at the intercept point and a vector from the intercept point to the spacecraft. The emission_angle varies from 0 degrees when the spacecraft is viewing the sub-spacecraft point (nadir viewing) to 90 degrees when the intercept is tangent to the surface of the target body. Thus, higher values of emission_angle indicate more oblique viewing of the target. Values in the range of 90 to 180 degrees are possible for ring data.  OBJECT : IMAGE_HISTOGRAM The histogram object is a sequence of numeric values that provides the number of occurrences of a data value or a range of data values in a data object. The number of items in a histogram will normally be equal to the number of distinct values allowed in a field of the data object. (For example, an 8-bit integer field can have 256 values. This would result in a 256-item histogram.) Histograms may be used to bin data, in which case an offset and scaling factor indicate the dynamic range of the data represented. The following equation allows the calculation of the range of each 'bin' in the histogram. 'bin lower boundary' : ('bin element' * scaling_factor) + offset.  ITEMS The items element defines the number of multiple, identical occurrences of an single object, such as a column. See also: repetitions. Note: In the PDS, the data element ITEMS is used for multiple occurrences of a single object, such as a column. REPETITIONS is used for multiple occurrences of a repeating group of objects, such as a container. For a fuller description of the use of these data elements, please refer to the Standards Reference.  DATA_TYPE The data_type element supplies the internal representation and/or mathematical properties of a value being stored. See also: bit_data_type, general_data_type. Note: In the PDS, users may find a bit-level description of each data type in the Standards Reference document.  ITEM_BITS The item_bits element indicates the number of bits allocated for a particular bit data item. Note: In the PDS, the item_bits element is used when the items element specifies multiple occurrences of an implied item within a BIT_COLUMN object definition.  END_OBJECT The end_object element terminates the object  OBJECT : IMAGE A regular array of sample values. Image objects are normally processed with special display tools to produce a visual representation of the sample values. This is done by assigning brightness levels or display colors to the various sample values. Images are composed of LINES and SAMPLES. They may contain multiple bands, in one of several storage orders.  Note: Additional engineering values may be prepended or appended to each LINE of an image, and are stored as concatenated TABLE objects, which must be named LINE_PREFIX and LINE_SUFFIX. IMAGE objects may be associated with other objects, including HISTOGRAMs, PALETTEs, HISTORY, and TABLEs which contain statistics, display parameters, engineering values, or other ancillary data.  LINES The lines element indicates the total number of data instances along the vertical axis of an image. Note: In PDS label convention, the number of lines is stored in a 32-bit integer field. The minimum value of 0 indicates no data received.  LINE_SAMPLES The line_samples element indicates the total number of data instances along the horizontal axis of an image.  SAMPLE_TYPE The sample_type element indicates the data storage representation of sample value.  SAMPLE_BITS The sample_bits element indicates the stored number of bits, or units of binary information, contained in a line_sample value.  SAMPLE_BIT_MASK The sample_bit_mask element identifies the active bits in a sample. Note: In the PDS, the domain of sample_bit_mask is dependent upon the currently-described value in the sample_bits element and only applies to integer values. For an 8-bit sample where all bits are active the sample_bit_mask would be 2#11111111#.  MAXIMUM The maximum element indicates the largest value occurring in a given instance of the data object.  MINIMUM The minimum element indicates the smallest value occurring in a given instance of the data object.  LINE_PREFIX_BYTES The line_prefix_bytes element indicates the number of non-image bytes at the beginning of each line. The value must represent an integral number of bytes.  LINE_SUFFIX_BYTES The line_suffix_bytes element indicates the number of non-image bytes at the end of each line. This value must be an integral number of bytes.  MEAN The mean element provides the average of the DN values in the image array.  STANDARD_DEVIATION The standard_deviation element provides the standard deviation of the DN values in the image array.  SATURATED_PIXELS The saturated_pixels element provides a count of the number of pixels in the array which at the maximum DN value. For this dataset, the non-quantized data has a maximum value of 4095, while the quantized data has a maximum value of 255.  OBJECT : WINDOW This object is a subobject of the image object and indicates that this image contains only a small portion of the original image. The small portion was transmitted to the ground, most likely, in an attempt to conserve bandwidth. The windowed data allows for the inspection of certain conditions on the spacecraft without the need to transmit the entire image to the ground.  WINDOW_DESC The window_desc value is the description of the windowed data. It attempts to describe the circumstances around which this image data was collected.  TARGET_NAME The target_name element attempts to describe the item that was being observed at the time the image was acquired.  FIRST_LINE The first_line element indicates the first line where valid data begins in the image. The full image was first padded with zeros and then this window of data was overlaid, forming an image of normal dimensions.  FIRST_LINE_SAMPLE The first_line_sample element indicates the leftmost column that contains valid data. This value, paired with the first_line element create the upper-leftmost pixel of valid image data.  LINES The lines element indicates the number of rows of image data associated with this window.  LINE_SAMPLES The line_samples element indicates the number of columns of image data associated with this window.  END_OBJECT The end_object element terminates the object.  CHECKSUM The checksum element represents an unsigned 32-bit sum of all data values in a data object.  END End of the PDS Label.   Contact Information : For any questions regarding the data format of the archive, contact:  Christopher Hash Applied Coherent Technology Corp 112 Elden Street, Suite K Herndon, VA 20170 (703) 742-0294 chash@actgate.com

Confidence Level Note Overview : The data collected here has been prepared with the highest concern for the perfectness of the data delivered. During the processing of the image data in preparation for delivery with this volume, the structure of each image was verified. This verification included detection of both the sync word and the line count bytes at the beginning of each line.