Doc. ID: RO-SGS-IF-0001 EAICD Version: 4.0 ROSETTA-NAVCAM ROSETTA-NAVCAM to Planetary Science Archive Interface Control Document Prepared By: Bernhard Geiger, Maud Barthelemy, Colin Archibald Approved By: David Heather Table 1: Distribution List. Recipient | Organisation | Contact Rosetta SGS | ESA/ESAC | Table 2: Document Change Log. Date of Update | Update to Document | New Version | Name 2010 Oct 20 | Creation of document| V 1.0 |Colin Archibald 2012 Jun 26 | Corrections | V 2.0 |Maud Barthelemy 2013 Jan 08 | Corrections | V 3.0 |Bernhard Geiger 2013 Aug 30 | Corrections in | V 3.1 |Bernhard Geiger | Sections | | 2015 Feb 06 | Major revision | V 4.0 |Bernhard Geiger | description of comet| | | phase datasets | | | authorship changed | | Contents 1 Introduction 1 1.1 Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Archiving Authorities . . . . . . . . . . . . . . . . . . . . . . . . .1 1.3 Contents . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 1 1.4 Intended Readership . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.5 Applicable Documents . . . . . . . . . . . . . . . . . . . . . . . . 2 1.6 Reference Documents . . . . . . . . . . . . . . . . . . . . . . . . . .2 1.7 Contact Names and Addresses . . . . . . . . . . . . . . . . . . . . . .3 2 Overview of Instrument Design 4 2.1 Architecture and Configurations . . . . . . . . . . . . . . . . . . . .4 2.1.1 Camera Optical Head . . . . . . . . . . . . . . . . . . . . . . .5 2.1.2 Camera Electronic Unit . . . . . . . . . . . . . . . . . . . . . 6 2.1.3 Camera Baffle . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3 Data Handling Process and Product Generation 8 3.1 Telemetry Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8 3.2 Data Product levels . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2.1 Uncalibrated Data . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2.2 Geometrically Calibrated Data . . . . . . . . . . . . . . . . . . . .9 3.2.3 Radiometrically Calibrated Data . . . . . . . . . . . . . . . . . . . 9 4 Archive Conventions and Meta-Information 10 4.1 Format and Conventions . . . . . . . . . . . . . . . . . . . . . . . . 10 4.1.1 Data Set ID Formation . . . . . . . . . . . . . .. . . . . . . 10 4.1.2 File Naming Convention . . . . . . . . . . . . . . . . . . . . . 13 4.1.3 PDS Standards . . . . . . . . . . . . . . . . . . . . . . . . . 13 4.1.4 Time Standards . . . . . . . . . . . . . . . . . . . . . . . . .13 4.2 Reference Frames and Geometry . . . . . . . . . . . . . . . . . . . . 14 4.2.1 Camera Reference Frames . . . . . . . . . . . . . . . . . . . . .14 4.2.2 Image Orientation . . . . . . . . . . . . . . . . . . . . . . . .14 4.2.3 Window Size and Position . . . . . . . . . . . . . . . . . . . . 15 4.2.4 Geometric Calibration . . . . . . . . . . . . . . . . . . . . . .15 4.2.5 Geometric Information in Label Files . . . . . . . . . . . . . . 15 4.3 Data Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 4.4 Observation Type . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 5 Dataset Content 18 5.1 Volume Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.2 Data Set Naming . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 5.3 Directories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 6 Product File Content 22 6.1 Content of *.LBL Files . . . . . . . . . . . . . . . . . . . . . . . . 22 6.2 Content of *.FIT File Header . . . . . . . . . . . . . . . . . . . . . 29 7 Product File Content - Cruise Phase 31 List of Tables 1 Distribution List. . . . . . . . . . . . . . . . . . . . . . . . . . . . ii 2 Document Change Log. . . . . . . . . . . . . . . . . . . . . . . . . . .ii 3 List of contacts for the NavCam instrument archive. . . . . . . . . . . . 3 4 Overview of NavCam properties . . . . . . . . . . . . . . . . . . . . . . 4 5 Data Processing levels. . . . . . . . . . . . . . . . . . . . . . . . . .8 6 Description of Components of the DATA_SET_ID. . . . . . . . . . . . . . 11 7 List of TARGET_ID values for Rosetta. . . . . . . . . . . . . . . . . . 11 8 List of MISSION_PHASE_NAME and ABBREVIATION values. . . . . . . . . . . 12 9 File naming parameters. . . . . . . . . . . . . . . . . . . . . . . . . .13 10 Mandatory keywords and standard values for the VOLUME object. . . . . . .18 11 Data set naming parameters. . . . . . . . . . . . . . . . . . . . . . .19 12 Keywords used in the label files. . . . . . . . . . . . . . . . . . . .23 13 Rosetta mission specific dictionary entries. . . . . . . . . . . . . . .25 14 Correspondence between PDS and FITS keywords. . . . . . . . . . . . . . 29 15 Keywords used in the label files (Cruise Phase). . . . . . . . . . . . .31 16 Rosetta mission specific dictionary entries (Cruise Phase). . . . . . . 33 List of Acronyms A/D Analogue-to-Digital AIU Avionics Interface Unit AOCS Attitude and Orbit Control System APID Application Process Identi er CAM-BAF Camera Ba e CAM-EU Camera Electronic Unit CAM-OH Camera Optical Head CCD Charge Coupled Device CODMAC Committee On Data Management, Archiving, and Computation DDS Data Distribution System DMS Data Management System DNA Defocused imaging with No Attenuation EAICD Experiment to Archive Interface Control Document ESA European Space Agency ESAC European Space Astronomy Centre ESOC European Space Operations Centre EU Electronic Unit FA Focused imaging with Attenuation FITS Flexible Image Transport System FNA Focused imaging with No Attenuation FOV Field of View ftp file transfer protocol HK Housekeeping JPEG Joint Photographic Experts Group NASA National Aeronautics and Space Administration NavCam Navigation Camera OBT On-Board Time OH Optical Head PDS Planetary Data System PSA Planetary Science Archive PSA-DH Planetary Science Archive Data Handler RMOC Rosetta Mission Operations Centre RO Rosetta Orbiter S/C Spacecraft SCIOPS Science Operations Department SGS Science Ground Segment SSMM Solid State Mass Memory TC Telecommand TM Telemetry UTC Coordinated Universal Time WCS World Coordinate System (FITS) 1 Introduction 1.1 Purpose and Scope This Experiment to Archive Interface Control Document (EAICD) has two main purposes. Firstly, it gives users of the Navigation Camera (NavCam) instrument data a detailed description of the product and how it was generated, including data sources and destinations. Secondly, it acts as an interface between the NavCam data producers and the data archiving authority. One point of note is that there are two identical NavCams installed on the Rosetta spacecraft, however, for the purposes of this document the singular is generally referred to when discussing the NavCams. 1.2 Archiving Authorities The Planetary Data System (PDS) standard is used as the archiving standard by: - the National Aeronautics and Space Administration (NASA) for U.S. Planetary Missions, implemented by PDS; - the European Space Agency (ESA) for European Planetary Missions, implemented by the Science Operations Department (SCIOPS) of ESA. ESA implements an on-line science archive, the Planetary (PSA), for several reasons: - to support and ease data ingestion; - to offer additional services to the scientific user community and science operations teams, such as, e.g.: 1. search queries that allow searches across instruments, missions and scientific disciplines; 2. several data delivery options, such as: - direct download of data products, linked files and data sets; - file transfer protocol (ftp) download of data products, linked files and data sets. The PSA aims for on-line ingestion of logical archive volumes and will offer the creation of physical archive volumes on request. 1.3 Contents This document describes the data flow of the NavCam instrument on Rosetta from the Spacecraft (S/C) until the insertion into the PSA by ESA. It includes information on how data were processed, formatted, labelled and uniquely identified; along with discussing the general naming schemes for NavCam data volumes, data sets, data and label files. The standards used to generate such products are explained and the design of the data set structure and data products are also given within this document. 1.4 Intended Readership The staff of the archiving authority (PSA, PDS), members of the Rosetta Science Ground Segment and the instrument team community as well as any potential user of the NavCam data. 1.5 Applicable Documents AD1: Rosetta Archive Generation, Validation and Transfer Plan, January 10, 2006, RO-EST-PL-5011 AD2: Rosetta Archive Conventions, Issue 7, Rev. 6, March 21, 2014, RO-EST-TN-3372 1.6 Reference Documents RD1: Rosetta Navigation Camera User's Manual, January 2002, RO-GAL-MA-2008 RD2: Rosetta Navigation Camera Design Description, January 2002, RO-GAL-RP-2007 RD3: Navigation Camera TM/TC and Software ICD, November 2001, RO-MMT-IF-2007 RD4: Rosetta SPICE Frame Kernel, ROS V24.TF RD5: Rosetta Data Delivery Interface Document, Appendix H, November 2013, RO-ESC-IF-5003 1.7 Contact Names and Addresses Table 3: List of contacts for the NavCam instrument archive. SRE-OO | Bernhard Geiger | Tel.: ESAC, P.O. Box, 78, | | +34 91 81 31 169 Villanueva de la Canada | | E-Mail: 28691, Madrid, Spain. | | Bernhard.Geiger@sciops.esa.int ------------------------------------------------------------------------------ SRE-OO | Maud Barthelemy | Tel.: ESAC, P.O. Box, 78, | | +34 91 81 31 248 Villanueva de la Canada | | E-Mail: 28691, Madrid, Spain. | | Maud.Barthelemy@sciops.esa.int ---------------------------------------------------------------------------- SRE-OO | David Heather | Tel.: ESAC, P.O. Box, 78, | | +34 91 81 31 183 Villanueva de la Canada | | E-Mail: 28691, Madrid, Spain. | | David.Heather@sciops.esa.int ---------------------------------------------------------------------------- SRE-OO | Michael Kueppers | Tel.: ESAC, P.O. Box, 78, | | +34 91 81 31 149 Villanueva de la Canada | | E-Mail: 28691, Madrid, Spain. | | Michael.Kueppers@sciops.esa.int 2 Overview of Instrument Design In order to fully satisfy the requirements and objectives regarding navigation and attitude control, Galileo Avionica developed a mission-specific Navigation Camera for Rosetta by building on the heritage of existing models. Table 4 provides an overview of some of the physical and operational parameters of the NavCam. Table 4: Overview of NavCam properties. Parameter Value Comment Mass CAM-OH | 6.050 kg | Camera Optical Head Mass CAM-EU | 2.700 kg | Camera Electronic Unit Mass CAM-BAF | 1.408 kg | Camera Baffle Total Mass | 10.158 kg | Total Power | 16.8 W | Field of View | 5deg x 5deg | Sensor Type | CCD | CCD47-20 by e2v Number of Pixels | 1024 x 1024 | Focal length | 152.5 mm | Pixel Size | 13 micro m | Pixel Angular Size | 17 arcsec | Aperture | 70 mm | Non-Attenuated Modes | 30 mm | Attenuated Mode F/Number | f/2.2 | Non-Attenuated Modes | f/5.1 | Attenuated Mode Limit Magnitude | Mv = 11 | Exposure time 5 s, SNR Saturation Magnitude | Mv = 1.6 | Whole spectral range, | Mv = 0.8 | G2 Class; exposure time = 10ms Integration Time | 10 ms | Minimum, | 30 s | Maximum Bias error (1 sigma) | 0.2 pixels | Mv = 11, exposure time = 5 s, | | Defocused mode NEA (1 sigma) | 0.1 pixels | Mv = 11, exposure time = 5 s, | | Defocused mode Commanded Window Size | 20 x 20 | Minimum pixel array | 1024 x 1024 | Maximum pixel array CCD Operative Temp. | -50 C | Minimum Range | +50 C | Maximum CCD Performance Temp. | -25 C | Minimum Range | 0 C | Maximum 2.1 Architecture and Con gurations The Rosetta NavCam consists of a Camera Optical Head (CAM-OH), a Camera Electronic (CAM-EU) and a Camera Baffle (CAM-BAF). Information given in this section is mainly extracted from the User's Manual [RD1] and the Design Description Document [RD2]. In general the Rosetta NavCam camera has three major functions: 1. Track point-like targets (in Point Target Tracking Mode). 2. Track one extended object, during asteroid y-by and comet approach phases (in Asteroid Tracking Mode). 3. Acquire navigation images of asteroids and the comet nucleus (Imaging mode, also per-formed in Asteroid Tracking Mode). 2.1.1 Camera Optical Head The Camera Optical Head for the Rosetta NavCam contains the optical system, the CCD detector and the electronics required to operate the CCD. It also supports the dust cover and attenuation mechanism in front of the optics. Figure 1 depicts three possible configurations of the optical system with exchangeable first element. - DNA mode. Defocused not attenuated. The first element is a plano-parallel window. The aperture is 70mm. This mode is used for determining the position of point sources with improved centroiding. During the comet escort phase this mode is also used by default as a dust cover when the camera is not operated. ROSETTA:CAM_COVER_POSITION = DEFOC_NATT - FA mode. Focused attenuated. The first lens is a quasi-plano parallel window, i.e. a lens with a very low converging power, in order to focus the image on the CCD. One face has an atenuation coating in order to decrease the transmission. The aperture is 30mm. This mode is used for imaging and navigation close to the extended comet nucleus. ROSETTA:CAM_COVER_POSITION = FOC_ATT - FNA mode. Focused not attenuated. The first lens is a quasi-plano parallel window with an aperture of 70mm. The image is focused on the CCD and there is no attenuation coating. ROSETTA:CAM_COVER_POSITION = FOC_NATT. For each acquired image the mission specific keyword ROSETTA:CAM_COVER_POSITION records the applicable cover position in the meta-information of the data product files (see Table 13). The effects of the reduced aperture and the attenuation coating combined result in a reduction of the transmission by a factor of 580 for the attenuated mode. For the defocused mode the point spread function is broader. For a point source located in the centre of a pixel approximately 50-55% of the signal are counted in the respective pixel, whereas this fraction ranges between 65 and 70% for the focused modes. Figure 1: Optical system of the NavCam with exchangeable first element. The lenses are made of radiation resistant glasses with high transmission in the visible wavelength range (LAK9 G15 and SF6 G05 produced by Schott). [RD2] The CCD detector is a front-illuminated frame transfer device with a broad spectral sensitivity in the visible range. Two different values of the gain can be selected when commanding the camera. 1. High Gain. Increases the grey signal level resolution when faint targets are imaged. In this case the A/D Converter saturates (at 12 bits) before saturation of the CCD is reached. ROSETTA:CAM_GAIN = HIGH 2. Low Gain. The A/D Converter saturates at the same time as the CCD and so the full dynamic range can be used. ROSETTA:CAM_GAIN = LOW The chosen gain value is documented in the mission specific keyword ROSETTA:CAM_GAIN in the product files (see Table 13). 2.1.2 Camera Electronic Unit The Camera Electronic Unit contains the digital electronics and interfaces for data transfer with the Avionics Interface Unit (AIU) and the Solid State Mass Memory (SSMM). Another major function of this module is to provide the programmable constant-current driver for both the heater in the optical head and the stepper motor that actuates the attenuation cover mechanism of the NavCam. 2.1.3 Camera Baffle The Camera Baffle provides protection against stray light produced by the Sun and reflected from planetary bodies and the satellite. This level of protection allows the tracking of faint objects. The baffle is mechanically supported by the S/C structure so as to avoid mechanical stress of the optical head. This is done owing to the required high pointing stability of the camera boresight in order to achieve the desired accuracy. 2.2 Operating Modes The following series of operating modes are available in order to exploit the capabilities of the NavCam: - Off Mode. - Initialisation Mode. - Stand-by Mode. - Imaging Mode. In this mode the instrument operates as a standard camera in order to acquire images of star-fields or extended objects in the field of view such as the comet nucleus during the escort phase. INSTRUMENT MODE ID = "IMAGING" - Point Target Tracking Mode. In this mode the NavCam can track simultaneously up to five point-like objects in the field of view. - Asteroid (Extended Object) Tracking Mode. In this mode the NavCam can detect and track an extended object in the eld of view. Optionally information on the position of this object can be fed into the autonomous attitude control system of the spacecraft. (This was done during the asteroid fly-bys.) In the Asteroid Tracking Mode images can also be acquired and downlinked in the same way as in the Imaging Mode. INSTRUMENT MODE ID = "ASTEROID TRACKING" - Self Test Mode. Image data can be generated and downlinked to ground in the Imaging and Asteroid (Ex-tended Object) Tracking modes. In the archived data sets, the used mode is indicated by the INSTRUMENT MODE ID keyword of the label files as indicated above (see also Table 12). 3 Data Handling Process and Product Generation The NavCam data are primarily used by the Flight Dynamics Team of the Rosetta Mission Operations Centre (RMOC) located at ESOC in Darmstadt, Germany. The images acquired with this camera are essential for determining the spacecraft position with respect to the comet nucleus and hence for safely navigating Rosetta. In addition, the images are also processed from the raw telemetry data at the Rosetta Science Ground Segment (SGS) based at ESAC near Madrid, Spain. The data are made available to the Rosetta instrument team community shortly after acquisition in order to support analysis and interpretation of their scientific data. Later, datasets of the product files are prepared for public release via the Planetary Science Archive (PSA). 3.1 Telemetry Data For generating the product files the following telemetry data are processed: - Science Data Report: TM APID 460 (CAM1) and 476 (CAM2), Type 20, Subtype 13. This set of telemetry data contains images as well as a number of meta data parameters. The latter are included in the label files of the generated data products. - Housekeeping and Health-Check Report: TM APID 452 (CAM1) and 468 (CAM2), Type 3, Subtype 25. From the set of available housekeeping parameters only the CCD temperature and the optics temperature are extracted and included in the label files of the generated data products. 3.2 Data Product levels Table 5: Data Processing levels. PSA | CODMAC | Description 1a |1 | Raw telemetry packet data that have been separated by | | instrument. This is the level which is distributed by the | | DDS (ESOC). 1b |2 | level 1a data that have been sorted by instrument data | | types and instrument modes. Data are in scienti cally | | useful form, e.g. as images. These data are still | | uncalibrated. 2 |3 | level 1b data with calibration and corrections applied to | | yield data in scientific units. 3 |5 | Higher level data products developed for specific | | scientific investigations. Table 5 summarises the definition of data product levels according to both PSA and CODMAC (Committee On Data Management, Archiving, and Computation). 3.2.1 Uncalibrated Data Uncalibrated data, i.e. products at CODMAC level 2, were released for the entire cruise phase including images from the Earth and Mars swing-bys as well as distant (unresolved) navigation images of the visited asteroids 2878 Steins and 21 Lutetia. Presently the images acquired after hibernation exit during the comet approach and escort phases are successively being archived and made available. The uncalibrated data products consist of image files with extensive meta-information. For each image pixel the original unaltered digital number values are given as read out from the CCD. 3.2.2 Geometrically Calibrated Data Accurate geometric information is required for the operational objective of the NavCam and the respective image characteristics are therefore well established (see Section 4.2.4). However, it is not appropriate to generate geometrically calibrated data products by re-sampling the images. The correction shall better be taken into account for each specific application by directly using the existing data products. 3.2.3 Radiometrically Calibrated Data Radiometrically calibrated data, i.e. products at CODMAC level 3, are currently not yet available but are foreseen to be provided. This requires removing artefacts caused by the optical system and the CCD detector from the raw images and converting the digital number counts into physical radiance units. It is currently not planned by the Rosetta SGS to generate higher level data products such as map projections on a shape model for the comet nucleus images. 4 Archive Conventions and Meta-Information This chapter describes general rules and conventions for producing the datasets and also gives an overview of important meta-information included in the product files. 4.1 Format and Conventions The directory tree must be compatible, in terms of directory organisation and naming and file organisation, with the PDS standards and such that: - each logical archive volume shall contain one NavCam PDS data set; data sets will contain data from both NavCams; - one data set shall be created for each separate mission phase; a different data set shall be created for each processing level; - the top level directory of each logical archive volume shall match that of the NavCam data set ID; and, - the volume set name shall be as that of the data set. 4.1.1 Data Set ID Formation The data set ID formation shall be done according to the following rule: DATA SET ID = ---- - Each of the components are described, briefly, in Table 6, with a list of options for TARGET_ID and MISSION_PHASE being given in Tables 7 and 8 respectively. Examples include: RO-X-NAVCAM-2-PRL-COM-V1.0 RO-C-NAVCAM-2-PRL-MTP004-V1.0 In some instances there are several TARGET ID terms in the DATA SET ID naming formation. These terms are combined and included in a list, separated by hyphens, between the and terms in the data set name. Examples from the cruise phase include: RO-A-CAL-NAVCAM-2-AST2-V1.0 RO-E-X-NAVCAM-2-CR1-V1.0 Table 6: Description of Components of the DATA SET ID. Component | Examples | Description INST_HOST | RO | Rosetta Orbiter TARGET_ID | A, C, E, M | Asteroid, Comet, Earth, Mars INST | NAVCAM | Navigation Camera CODMAC_LEVEL | 2, 3, 5 | See Table 5 MISSION_PHASE | AST1, | Asteroid 1 Flyby, Earth Swingby 3, Cruise ABBREVIATION | EAR3, | 4-B, Mars Swingby, see Table 8 | CR4B, | | MARS | VERSION | Vx.y e.g. | x and y are numerical values indicating | V1.0, V1.1, | the version level and revision number | V2.0 | ----------------------------------------------------------------------------- Table 7: List of TARGET ID values for Rosetta. Abbreviation | TARGET_TYPE | TARGET_NAME A | ASTEROID | 21 LUTETIA | | 2867 STEINS C | COMET | C/LINEAR (2002 T7) | | 9P/TEMPEL 1 (1867 G1) | | 67P/CHURYUMOV-GERASIMENKO 1 (1969R1) E | PLANET | EARTH J | PLANET | JUPITER M | PLANET | MARS | SATELLITE | MOON | STAR | ZETA CAS CAL | CALIBRATION | CALIBRATION X | N/A | CHECKOUT ----------------------------------------------------------------------------- Table 8: List of MISSION PHASE NAME and ABBREVIATION values. Phase Name Abbreviation Start Time GROUND GRND 2000-01-01 00:00:00 LAUNCH LEOP 2004-03-03 00:00:00 COMMISSIONING 1 CVP1 2004-03-05 00:00:00 CRUISE 1 CR1 2004-06-07 00:00:00 COMMISSIONING 2 CVP2 2004-09-06 00:00:00 EARTH SWING-BY 1 EAR1 2004-10-17 00:00:00 CRUISE 2 CR2 2005-04-05 00:00:00 MARS SWING-BY MARS 2006-07-29 00:00:00 CRUISE 3 CR3 2007-05-29 00:00:00 EARTH SWING-BY 2 EAR2 2007-09-13 00:00:00 CRUISE 4-1 CR4A 2008-01-28 00:00:00 STEINS FLY-BY AST1 2008-08-04 00:00:00 CRUISE 4-2 CR4B 2008-10-06 00:00:00 EARTH SWING-BY 3 EAR3 2009-09-14 00:00:00 CRUISE 5 CR5 2009-12-14 00:00:00 LUTETIA FLY-BY AST2 2010-05-17 00:00:00 RENDEZVOUS MANOEUVRE 1 RVM1 2010-09-04 00:00:00 CRUISE 6 CR6 2011-07-14 00:00:00 PRELANDING COMMISSIONING PRL-COM 2014-01-20 10:00:00 PRELANDING MTP003 PRL-MTP003 2014-05-07 12:48:00 PRELANDING MTP004 PRL-MTP004 2014-06-04 10:50:00 PRELANDING MTP005 PRL-MTP005 2014-07-02 08:35:00 PRELANDING MTP006 PRL-MTP006 2014-08-01 10:00:00 PRELANDING MTP007 PRL-MTP007 2014-09-02 10:00:00 PRELANDING MTP008 PRL-MTP008 2014-09-23 10:00:00 PRELANDING MTP009 PRL-MTP009 2014-10-24 10:00:00 COMET ESCORT 1 MTP010 ESC1-MTP010 2014-11-21 23:25:00 COMET ESCORT 1 MTP011 ESC1-MTP011 2014-12-19 23:25:00 COMET ESCORT 1 MTP012 ESC1-MTP012 2015-01-13 23:25:00 COMET ESCORT 1 MTP013 ESC1-MTP013 2015-02-10 23:25:00 COMET ESCORT 2 MTP014 ESC2-MTP014 2015-03-10 23:25:00 COMET ESCORT 2 MTP015 ESC2-MTP015 2015-04-08 11:25:00 COMET ESCORT 2 MTP016 ESC2-MTP016 2015-05-05 23:25:00 COMET ESCORT 2 MTP017 ESC2-MTP017 2015-06-02 23:25:00 4.1.2 File Naming Convention Each image data product is generated in the form of a binary file (*.IMG) and a FITS-format file (*.FIT) with associated label files (*.LBL) of the same name that point to the image file. The label files contain meta-information about the camera operating parameters and geometric conditions. For every image a browse version file (*.JPG) with reduced resolution and an associated label file are created. The file naming convention for these files is as follows: . Table 9 summarises the definitions of each part: Table 9: File naming parameters. Variable Possible Values Description MISSION | ROS | The Rosetta mission. CAM# | CAM1, CAM2 | Denotes which NavCam pro- | | duced the data. EXT | IMG, FIT, JPG, LBL | Denotes the file type in ques- | | tion. F | F, or absent | Is present for the FIT format | | file and its label file. ------------------------------------------------------------------------- The parameter is the Coordinated Universal Time (UTC) without the fractional seconds (see Section 4.1.4) and provides the date and time at which the image was acquired on-board the spacecraft. 4.1.3 PDS Standards Each complete volume produced will be compliant with both the PDS and PSA standards. In general each individual file is created using PDS Version 3 standards. The PDS format uses the ISO 9660 level 2 standard for the file names. Hence, no complete file name shall be longer than 31 characters and the "27.3" structure shall be obeyed, that is, a maximum of 27 characters before the "." for the file name and 3 characters after for the extension type. 4.1.4 Time Standards Two time standards are used in the meta-information of the NavCam data product files: - UTC is expressed in the format where YYYYMMDD provides the calendar date (year, month and day), T is a fixed separator and hhmmss. fff indicates the time in hours, minutes, seconds and fractions of a second. UTC is used in the following keywords for time stamping the data products: - PRODUCT_CREATION_TIME - IMAGE_TIME - START_TIME - STOP_TIME Here START_TIME = IMAGE_TIME - 0.5 EXPOSURE_DURATION and STOP_TIME = IMAGE TIME + 0.5 EXPOSURE TIME. - Spacecraft Clock Time is given in the format 1/