PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "2006-06-21, RL, 2007-03-15, EME 2007-04-10, BSword, EN 2007-04-26, RL 2007-05-15, BSword 2007-09-20, RL" RECORD_TYPE = STREAM OBJECT = DATA_SET DATA_SET_ID = "MRO-M-HIRISE-2-EDR-V1.0" OBJECT = DATA_SET_INFORMATION DATA_SET_NAME = "MRO MARS HIGH RESOLUTION IMAGING SCIENCE EXPERIMENT EDR V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_OBJECT_TYPE = "IMAGE" START_TIME = 2006-09-29T15:16:33.333 STOP_TIME = "NULL" DATA_SET_RELEASE_DATE = "NULL" PRODUCER_FULL_NAME = "ALFRED MCEWEN" DETAILED_CATALOG_FLAG = "N" ARCHIVE_STATUS = "IN QUEUE" CITATION_DESC = "McEwen, A., Mars Reconnaissance Orbiter High Resolution Imaging Science Experiment, Experiment Data Record, MRO-M-HIRISE-2-EDR-V1.0, NASA Planetary Data System, 2007." DATA_SET_TERSE_DESC = "Experimental data records for MRO HiRISE (High Resolution Imaging Science Experiment)." ABSTRACT_DESC = "This data set includes the Experimental Data Records from the HiRISE instrument on MRO. These products are the permanent record of the raw images obtained by the HiRISE Instrument and contain the properties of unprocessed and unrectified imaging maintaining the original spacecraft viewing orientation and optical distortion properties. ." DATA_SET_DESC = " Data Set Overview ================= These Experimental Data Record (EDR) products are the permanent record of the raw images obtained by the HiRISE Instrument. The products contain the properties of unprocessed and unrectified imaging maintaining the original spacecraft viewing orientation and optical distortion properties. As part of the EDR generation process, FELICS- compressed images are decompressed and organized as raster images. EDRs are organized at the channel level with two EDRs needed for each operating CCD. As many as 28 EDR products are needed to capture a single HiRISE observation. Maintaining an archive of EDR products enables reprocessing of the raw science observations as calibration and geometry processing routines improve. Investigators interested in applying advanced calibration methods or needing to understand the properties of the raw imaging will find the EDRs a useful product. However, most science investigators will be interested in using the RDR products as geometry and radiometric processing has occurred on these products. Processing ========== EDR product creation is the resposibility of the HiRISE Operations Center (HiROC) at the Lunar and Planetary Laboratory, University of Arizona. The products are generated by an automated pipeline process called EDRgen. The pipeline is managed by the Conductor software (http://pirl.lpl.arizona.edu/software/Conductor.shtml) on as many HiROC systems simultaneously as seem appropriate to achieve the throughput and reliability needed to meet the HiRISE data production requirements. When the HiROC system detects that a new HiRISE observation data channel file is available at the JPL data distribution site it is automatically downloaded using the JPL File Exchange Interface (FEI) and the file is registered in the HiCat database as an EDRgen source ready for processing. A raw data file may also be manually submitted for processing, or reprocessing, by a HiROC operator. Each observation data channel file is subject to automated data verification. This includes consistency checks of data values and identification of spacecraft downlink data gaps noted in a JPL ground data system transaction log provided (and also automatically delivered) for each observation. Consistency checks include comparing the commanding parameters in the observation headers with the uplink commanding stored in the HiCat database. Other checks involve comparing the values against permitted values and ranges. Files with any data verification problems are automatically routed to a special processing pipeline of EDRgen. Here header data redundancy for an observation, and the original observation definition from the HiCat database, will be used to produce a PDS label with the best representation of the observation characteristics in the EDR product file. The inability to generate an acceptable PDS label is a failure condition that is automatically brought to the attention of a HiROC operator. The downlinked data will never be changed (except for FELICS decompression and even channel image data mirroring) and remains available in the EDR product file. All EDR data products are automatically queued for validation. Validation of a data product involves visual inspection by an operator and check-off against a set of acceptance criteria that are recorded in the HiCat database. The successful processing of an observation data channel file by EDRgen results in a PDS compliant EDR data product file and the update of the HiCat database with appropriate metadata from its ODL (Object Descriptor Language) label. Data ==== The format of the EDR data products is nearly identical to the original form of the data stream as produced by the instrument. Some processing was applied to the data for (1) FELICS decompressing an image (if the data were optionally compressed on the spacecraft), (2) identifying and filling gaps with 'no-data' values, (3) mirroring the pixel order of an image line for data read out in reverse order for channel 1 products only, and (4) adding a PDS label to the beginning of the file. The EDR products are processed to NASA data processing level-0. (This corresponds to level 2 for the Committee on Data Management and Computation (CODMAC) data level numbering system). NASA level- 0 products contain time-ordered raw instrument science data at full resolution with duplicate data removed and transmission anomalies identified and corrected whenever possible. An EDR is identified and described with PDS-labeling conventions with a PDS label located at the beginning of the file. Following the PDS label is the instrument data stream organized as objects each described by keywords in the PDS label area. The data objects store the raw image data and ancillary data needed to understand and process the image. The data objects contained in the EDR product were created by the HiRISE instrument flight software and remain in the original format except as noted above. The objects, describing various parts of the data stream, are summarized here. Pointer keywords in the PDS label, identified with a carat (^) as the first character, locate the objects in the file. The SCIENCE_CHANNEL_TABLE, LOOKUP_TABLE, and CPMM_ENGINEERING_TABLE objects contain metadata providing commanding, engineering, and instrument operating information related to the observation. The LINE_PREFIX_TABLE and LINE_SUFFIX_TABLE objects contain engineering and calibration data accompanying the observational data. The CALIBRATION_IMAGE contains image data useful for calibrating the instrument. The IMAGE object contains the observational image data. The GAP_TABLE locates gaps (missing data) in the observation. Gaps consisting of missing data in the observation data stream can occur whenever there is an interruption in the downlink communications systems between the MRO spacecraft and the MRO operations center at JPL. Data gaps in the HiRISE EDR products can be identified in two ways. First, the GAP_TABLE object identifies the data gap locations in the EDR products. The GAP_TABLE is a binary table of two columns that specify the starting and ending byte location of each gap. There is a row for each gap (see the PDS example label in section 6.1 for a label description of the GAP_TABLE). Additionally, gaps can be identified in the data by searching for consecutive bytes with the hexadecimal value FF (decimal 255). A gap is identified as any byte sequence containing more than four consecutive FF values. HiRISE 8-bit image pixels with the hexadecimal value FF will be a missing pixel. For 16-bit pixel data, the hexadecimal value FFFF identifies the pixel as missing. This is a reliable test because the HiRISE instrument can never create a FF 8-bit pixel or a FFFF 16-bit pixel. Time Standards ============== Two time-related standards are used in HiRISE EDR PDS labels: o Spacecraft clock; o Coordinated Universal time (UTC). The spacecraft clock (SCLK) is the fundamental system on MRO for initiating spacecraft events (such as starting an observation for one of the instruments). The SCLK has a counting unit of 1/(216) seconds for each tick of its sub-seconds field. Thus there are 65,536 SCLK ticks per second (a time interval of 15.2588 microseconds). The HiRISE expose-time command initiated by the spacecraft contains both the SCLK seconds and sub-seconds fields of that future moment in time at which the HiRISE exposure should begin. The HiRISE software will compute and store the corresponding future instant (converting SCLK sub-seconds notation to that of the HiRISE notation) at which time the exposure should begin. The HiRISE flight software will then set a 50-millisecond exposure- start software timer. Each time the expose-start timer elapses (every 50 milliseconds), the HiRISE flight software will check the current HiRISE time against the time at which the exposure should begin, and will start the exposure the first time it sees that current HiRISE time is later in time than the exposure time. The HiRISE flight software will time-stamp the actual start of an exposure (placed in the science channel header) to within 50 milliseconds of the actual start of the exposure. This time stamp, as well as all the other time stamps which the HiRISE flight software produces, will all be in units of the HiRISE clock (i.e. with the sub- seconds field counting in units of 16 milliseconds). HiROC ground data processing converts to SCLK units when computing the time at which various time-stamped HiRISE events occurred. The instrument sub- second field is converted back to the SCLK sub- second field and stored in the PDS labels. This conversion occurs in order to allow the SPICE NAIF toolkit (see http://pds- naif.jpl.nasa.gov/) to be used to process time fields. UTC times can be derived from the SCLK using the NAIF toolkit time routines and the SCLK kernel maintained by the MRO project. Data Storage Conventions ======================== The HiRISE EDR products contain binary data. Image pixel values are stored as either unsigned 8-bit or unsigned 16-bit pixel values depending on the operating mode of the instrument. The PDS label sections are stored as ASCII character strings conforming to the requirements defined in the PDS Standards Reference. The storage order is most significant byte (MSB) first. MSB ordering is the order used on the MRO spacecraft and the HiRISE instrument. " CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview This is a TBD data set. Known problems are TBD. Review ====== This archival data set has been examined by a peer review panel and has been accepted by the Planetary Data System (PDS). The peer review will be conducted in accordance with PDS procedures. Data Coverage and Quality ========================= EDR products are the permanennt record of raw and unprocessed images stored in a raster format as described by the IMAGE object defined in the PDS Standards Document. The EDR contain all of the inherent properties and unprocessed and unrectified imaging. " END_OBJECT = DATA_SET_INFORMATION OBJECT = DATA_SET_TARGET TARGET_NAME = "MARS" END_OBJECT = DATA_SET_TARGET OBJECT = DATA_SET_HOST INSTRUMENT_HOST_ID = "MRO" INSTRUMENT_ID = "HIRISE" END_OBJECT = DATA_SET_HOST OBJECT = DATA_SET_MISSION MISSION_NAME = "MARS RECONNAISSANCE ORBITER" END_OBJECT = DATA_SET_MISSION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = ELIAISONETAL2006 END_OBJECT = DATA_SET_REFERENCE_INFORMATION OBJECT = DATA_SET_REFERENCE_INFORMATION REFERENCE_KEY_ID = ELIAISON2006B END_OBJECT = DATA_SET_REFERENCE_INFORMATION END_OBJECT = DATA_SET END