PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM SPACECRAFT_NAME = "MARS GLOBAL SURVEYOR" TARGET_NAME = "MARS" OBJECT = TEXT INTERCHANGE_FORMAT = ASCII PUBLICATION_DATE = 1998-11-09 END_OBJECT = TEXT END Mars Orbital Camera Software Interface Specification MOC Narrow Angle and Wide Angle Decompressed Standard Data Products M. Caplinger Malin Space Science Systems, Inc. Approved by: _________________________ M. Malin, Principal Investigator September 1998 (formatted December 29, 1998) Contents 1. Introduction ...................................... 1 1.1. Purpose ........................................ 1 1.2. Scope .......................................... 1 1.3. Applicable Documents ........................... 1 1.4. Functional Description ......................... 1 1.4.1. Data Content Summary ........................ 1 1.4.2. Source and Transfer Method .................. 2 1.4.3. Recipients and Utilization .................. 2 1.4.4. Pertinent Relationships with Other Inter- faces ............................................ 2 1.5. Assumptions and Constraints .................... 2 2. Environment ....................................... 3 2.1. Hardware Characteristics and Limitations ....... 3 2.1.1. Special Equipment and Device Interfaces ..... 3 2.1.2. Special Setup Requirements .................. 3 2.2. Interface Medium Characteristics ............... 3 2.3. Failure Protection, Detection, and Recovery .... 3 2.4. End-of-File Conventions ........................ 3 3. Access ............................................ 3 3.1. Access Tools ................................... 3 3.2. Input/Output Protocols ......................... 3 3.3. Timing and Sequencing Characteristics .......... 3 3.4. PDB Information ................................ 3 4. Detailed Interface Specifications ................. 4 4.1. Labeling and Identification .................... 4 4.2. Structure and Organization Overview ............ 4 4.3. Substructure Definition and Format ............. 5 4.3.1. Header/Trailer Description Details .......... 9 4.4. Volume, Size, and Frequency Estimates .......... 9 September 1998 iii 1. Introduction _ ____________ 1.1. Purpose _ _ _______ This document describes the format of the Mars Orbiter Cam- era (MOC, previously known as the Mars Observer Camera) Decompressed Standard Data Product for the Narrow Angle (NA) and Wide Angle (WA) systems. Note that this product is explicitly not called an Experi- ment Data Record (EDR), because it has undergone more pro- cessing (decompression and error correction) than an EDR traditionally sees. The closest thing to an EDR product which will be archived are the raw MOC instrument packets. 1.2. Scope _ _ _____ The format and content specifications in this SIS apply to all phases of the project for which this product is avail- able. 1.3. Applicable Documents _ _ __________ _________ Mars Global Surveyor Science Data Management Plan (JPL 542- 310) Mars Global Surveyor Project Archive Generation, Validation and Transfer Plan (JPL 542-312) Mars Global Surveyor Project Data Management Plan (JPL 542- 403) Mars Observer Camera Software User's Guide (Part 1: Flight Software) Mars Observer Camera Instrument Template (I-Kernel PDS docu- ment) Mars Observer Project Archive Policy and Data Transfer Plan, 642-447. Planetary Science Data Dictionary Document, PDS Version 2.0, May 1991. Margaret Cribbs, "Comments on the MOC label", IOM# 361-92- MAC016, 2 April 1992. 1.4. Functional Description _ _ __________ ___________ 1.4.1. Data Content Summary _ _ _ ____ _______ _______ Each MOC Decompressed Standard Data Product is a single image in decompressed format. September 1998 1 The only formatting differences between Narrow and Wide Angle products are the maximum possible width of the image (2048 for the Narrow Angle and 3456 for the Wide Angle) and the presence or values of some of the keywords; the products are otherwise formatted identically. 1.4.2. Source and Transfer Method _ _ _ ______ ___ ________ ______ MOC products are produced by the `makepds' program from the format internally used at the MOC Mission Operations Facil- ity (MOF). This program reads a raw image file (see the MOC Software User's Guide), extracts some information from its headers, formats and attaches the PDS labels, and appends the image data. It is expected that there will be three ways to receive MOC products: by electronic file transfer from the MOC MOF, by electronic file transfer from the Project Database, and on some archival medium such as CD-ROM. 1.4.3. Recipients and Utilization _ _ _ __________ ___ ___________ These products will be available to MOC team members, the Mars Global Surveyor science community, the planetary sci- ence community, and other interested parties. Descriptions of data rights and proprietary periods are beyond the scope of this document, and are discussed in the Mars Global Sur- veyor Project Archive Policy and Data Transfer Plan, and in unique Operational Interface Agreements between the MOC Sci- ence Team and other parties. These products will be used for engineering support, direct science analysis, or the construction of other science pro- ducts. 1.4.4. Pertinent Relationships with Other Interfaces _ _ _ _________ _____________ ____ _____ __________ See the MOC Software User's Guide for descriptions of other interfaces. 1.5. Assumptions and Constraints _ _ ___________ ___ ___________ Note that this file contains decompressed image data. It is a raw image that is not corrected for instrument signature, effects of spacecraft motion, or the effects of imaging geometry. Although there is enough information in the header to do some processing, for more sophisticated pro- cessing ancillary files will be required. These ancillary files are not described in this document. Every effort will be made to insure that this ancillary information will be conveniently accessible to users of MOC products (for exam- ple, it may be included on the same CDROM volumes as the data products themselves.) Examples of ancillary files are September 1998 2 calibration files, viewing geometry files (e.g., SPICE ker- nels), image index tables, etc. 2. Environment _ ___________ 2.1. Hardware Characteristics and Limitations _ _ ________ _______________ ___ ___________ 2.1.1. Special Equipment and Device Interfaces _ _ _ _______ _________ ___ ______ __________ Interfaces to access either CD-ROM volumes or electronic file transfer are described elsewhere; for example, see TBD. 2.1.2. Special Setup Requirements _ _ _ _______ _____ ____________ None. 2.2. Interface Medium Characteristics _ _ _________ ______ _______________ 2.3. Failure Protection, Detection, and Recovery _ _ _______ __________ _________ ___ ________ Raw instrument telemetry will be archived in the PDB. Depacketized compressed image data will be archived at the MOC MOF. 2.4. End-of-File Conventions _ _ ___ __ ____ ___________ End-of-file labeling shall comply with SFDU standards; specifically, fixed-size records are used, the header expli- citly contains the record offset of each subelement of the dataset, and the size of each subelement can be computed from information in the header. 3. Access _ ______ 3.1. Access Tools _ _ ______ _____ Existing PDS image display programs can display these files. 3.2. Input/Output Protocols _ _ _____ ______ _________ None identified. 3.3. Timing and Sequencing Characteristics _ _ ______ ___ __________ _______________ None. 3.4. PDB Information _ _ ___ ___________ These products can be retrieved using the standard PDB key- words. (The keywords expected to be useful for retrieval are FILE_NAME and START_TIME. A higher-level catalog may be available but is beyond the scope of this document.) September 1998 3 4. Detailed Interface Specifications _ ________ _________ ______________ 4.1. Labeling and Identification _ _ ________ ___ ______________ The dataset ID is MGS-M-MOC-NA/WA-2-DSDP-L0-V1.0. Each product will have a file name of the form ".IMG", where the ID is not to exceed 8 characters, will start with an alphabetic character, and will consist only of alphanumeric characters. For pre-mapping images, the id will be of the form PPPNNNMM, where PPP is a mission phase descriptor, NNN is the orbit number, and MM is the image of that orbit. (For the mapping mission, the expected form will be PPPIIIII, where PPP will be a three-character string defining the mapping cycle, and IIIII will be an index within the mapping cycle.) The file name will be unique across all MOC data product files. Case is not significant; under the Unix operating system, the names will be con- sidered to be in all lower-case. 4.2. Structure and Organization Overview _ _ _________ ___ ____________ ________ All MOC images must be a multiple of 16 pixels in both width and height. Images are broken up into subimages (also called fragments), and each fragment is transmitted separately. Raw and predictively compressed images are reconstructed by concatenating all of their image fragments and then processing; transform compressed images are pro- cessed a fragment at a time. A MOC data product consists of one image with decompression applied. In the event of data loss caused by packets dropped in the space-to-earth link or in the ground segment of the DSN, a standard first-order correction algorithm has been applied. Selected MOC images may have had additional corrections applied; this archive represents the best avail- able reconstruction at the time of archive production. PDS_VERSION_ID PDS3 FILE_NAME "filename" RECORD_TYPE FIXED_LENGTH RECORD_BYTES nnnn FILE_RECORDS nn LABEL_RECORDS nn ^IMAGE nn SPACECRAFT_NAME MARS_GLOBAL_SURVEYOR MISSION_PHASE_NAME AEROBRAKING-1; SPO-1; SPO-2; MAPPING TARGET_NAME MARS INSTRUMENT_ID MOC-NA or MOC-WA PRODUCER_ID MGS_MOC_TEAM DATA_SET_ID MGS-M-MOC-2-DSDP-L0-V1.0 PRODUCT_RELEASE_DATE yyyy-mm-ddThh:mm:ss.fff September 1998 4 PRODUCT_CREATION_TIME yyyy-mm-ddThh:mm:ss.fff SOFTWARE_VERSION "id-string" UPLOAD_ID "version-id" PRODUCT_ID "product-id" START_TIME yyyy-mm-ddThh:mm:ss.fff IMAGE_TIME yyyy-mm-ddThh:mm:ss.fff STOP_TIME yyyy-mm-ddThh:mm:ss.fff SPACECRAFT_CLOCK_START_COUNT "sclk-string" SPACECRAFT_CLOCK_STOP_COUNT "N/A" FOCAL_PLANE_TEMPERATURE ff.fff GAIN_MODE_ID "gain-id" OFFSET_MODE_ID "offset-id" LINE_EXPOSURE_DURATION ff.fff DOWNTRACK_SUMMING nn CROSSTRACK_SUMMING nn EDIT_MODE_ID "nnnn" FILTER_NAME RED or BLUE RATIONALE_DESC string OBJECT IMAGE LINES nnn LINE_SAMPLES nnn LINE_PREFIX_BYTES nnn LINE_SUFFIX_BYTES nnn SAMPLE_TYPE UNSIGNED_INTEGER SAMPLE_BITS 8 SAMPLE_BIT_MASK 2#11111111# CHECKSUM 16#xxxx# END_OBJECT END CCSD3... 4.3. Substructure Definition and Format _ _ ____________ __________ ___ ______ PDS_VERSION_ID The PDS version number for the header format; e.g., PDS3. FILE_NAME The file name for these products; see above. RECORD_TYPE The record type; always FIXED_LENGTH for these pro- ducts. RECORD_BYTES The number of bytes per record. For these products, the same as the LINE_SAMPLES field of the IMAGE object. FILE_RECORDS The total number of records in this file. The last record will be padded with zeros if necessary. September 1998 5 LABEL_RECORDS The number of records used for header data. If needed, the last record of the header will be padded with blanks. ^IMAGE Pointer to the starting record of the image object in the file. SPACECRAFT_NAME Always MARS_GLOBAL_SURVEYOR. MISSION_PHASE_NAME Name of the mission phase; e.g., AEROBRAKING-1. TARGET_NAME The name of the target body; typically MARS. PRODUCER_ID Always MGS_MOC_TEAM. DATA_SET_ID Always MGS-M-MOC-2-DSDP-L0-V1.0. PRODUCT_RELEASE_DATE Date of this product's release to the Project Data Base. This date does not imply the end of the proprietary period. PRODUCT_CREATION_TIME Time and date of this file's creation. Note that this time is the time of this file's creation in this for- mat, and does not reflect the acquisition time or the time of any other processing that may be associated with this product. SOFTWARE_VERSION Identifier of the version of the MOC Ground Data System software that created this product. UPLOAD_ID Identifier of version of the MOC flight software used to acquire this image. PRODUCT_ID (This field replaces the earlier IMAGE_ID field.) This uniquely identifies this MOC product among all MOC pro- ducts. The MOC product ID format for pre-mapping is xxx-ooo/nnn, where xxx is a mission phase string, ooo is the orbit number and nnn is the image on that orbit; e.g., SPO1-501/01. For the mapping mission, we expect to use Mcc/nnnnn, where c is the mapping cycle number and nnnnn is an index within that mapping cycle; e.g., September 1998 6 M01/12345. START_TIME, IMAGE_TIME SCET (UTC) time at start of image acquisition. These two fields are always the same. (IMAGE_TIME is included for compatibility with earlier non-MOC pro- ducts.) STOP_TIME SCET (UTC) time at end of image acquisition. This is redundant and can be computed from the start time, the line clocking rate, and the number of lines. SPACECRAFT_CLOCK_START_COUNT Value of spacecraft clock at start of image acquisi- tion. This is redundant with the above times, unless there is an anomaly with the spacecraft clock. The format of this field is compatible with the NAIF Toolkit software (e.g., "00610499:32") There is no corresponding STOP_COUNT because the timing of a MOC image, once started, is independent of the spacecraft clock. The following information can be used, along with calibra- tion files to be included on the volume, to calibrate each image. This information is in some sense redundant with that in the E-kernel (presumably a separate file on the volume), but as of now, the E-kernel is still too ill- defined to be a reliable source of information. See the MOC I-kernel for more information on calibration. FOCAL_PLANE_TEMPERATURE Temperature of focal plane of optical system associated with this image, in degrees Kelvin. GAIN_MODE_ID The MOC gain setting in hexadecimal. OFFSET_MODE_ID The MOC offset in integer steps of 5 DN. LINE_EXPOSURE_DURATION Per-line exposure duration in units of milliseconds. The time a given line was acquired can be determined by multiplying the line exposure time by the number of previous lines and adding it to the image start time. Note that the NA implements downtrack summing by increasing the line time; for example, a 2X2 summed image has an actual line time twice that given by this field. Similarly, the gain is adjusted appropriately for summed NA images; for example, a 2X2 summed image's gain is reduced by a factor of 2. September 1998 7 DOWNTRACK_SUMMING, CROSSTRACK_SUMMING The MOC can do pixel averaging in the instrument before transmission. For the NA, this must range from 1 (no summing) to 8x summing, and downtrack and crosstrack summing must be equal. For the WA, downtrack and crosstrack summing range from 1 to 127, and can be dif- ferent. EDIT_MODE_ID The edit mode is the first pixel of the CCD sampled for the image acquisition, and thus specifies the off-nadir look angle. For WA products, the special value 3456 indicates that the leading dark reference pixels were acquired as the first eight pixels of each line; the special value 3472 indicates that the trailing dark reference pixels were acquired as the last eight pixels of each line. For WA products, if dark pixels were acquired and compression was enabled, the dark refer- ence pixels are compressed and included in the data. An EDIT_MODE_ID value of "0" refers to the first pixel in the array. FILTER_NAME Either RED for the red Wide Angle or BLUE for the blue Wide Angle. Does not appear for NA products. RATIONALE_DESC A text description of the scientific purpose for the acquisition of this image; e.g., "Monthly monitoring of aeolian features on summit of Pavonis Mons". For some specific images, this string will contain a description of the image as actually received; for routine mapping operations, it will more likely be the goal of the image as targeted (which may not be met if the image missed its target significantly.) The following describe keywords found internal to the IMAGE object. LINES Number of lines in the image. LINE_SAMPLES Number of samples per line in the image. LINE_PREFIX_BYTES Number of bytes of prefix information per line. If these bytes are present, they are the leading dark reference pixel values. LINE_SUFFIX_BYTES Number of bytes of suffix information per line. If September 1998 8 these bytes are present, they are the trailing dark reference pixel values. SAMPLE_TYPE Type of each sample; for MOC, always UNSIGNED_INTEGER. SAMPLE_BITS Number of bits for each sample; for MOC, always 8. SAMPLE_BIT_MASK Bit mask description for each sample; for MOC, always 2#11111111#. CHECKSUM This is a checksum for the entire data part of the image, to be used for data validation. 4.3.1. Header/Trailer Description Details _ _ _ ______ _______ ___________ _______ See above. No trailers are present. 4.4. Volume, Size, and Frequency Estimates _ _ ______ ____ ___ _________ _________ The total volume of MOC data to be returned is approximately 45 GBytes. Volume returned varies as a function of the available data rate; see the Archive Policy and Data Manage- ment Plan for more details. It is not known what fraction of total MOC return will be used for products of a particular type (e.g., NA or WA). It is also not known what average amounts of compression will be used, although a nominal value of 5:1 is expected. September 1998 9