INAF-IFSI MARS EXPRESS PLANETARY FOURIER SPECTROMETER MEX-PFS To Planetary Science Archive Interface Control Document MEX-PFS-PSA-ICD-25 Issue 2.5 30 January 2008 ___________________________ Prepared by: Mario D'Amore ____________________________ Approved by: Vittorio Formisano Distribution List Recipient Organisation Joe Zender RSSD/ESTEC David Heather RSSD/ESTEC Change Log Date Sections Changed Reasons for Change 30 January 2007 All General Archive Modification 30 January 2008 All General update for review TBD ITEMS Section Description Table of Contents 1 Introduction 1 1.1 Purpose and Scope 1 1.2 Archiving Authorities 1 1.2.1 ESA’s Planetary Science Archive (PSA) 1 1.3 Contents 1 1.4 Intended Readership 1 1.5 Scientific Objectives 2 1.6 Applicable Documents 2 1.7 Relationships to Other Interfaces 3 1.8 Acronyms and Abbreviations 3 1.9 Contact Names and Addresses 4 2 Overview of Instrument Design, Data Handling Process and Product Generation 5 2.1 Technical description 6 2.1.1 Module O 6 2.1.2 Optical scheme of PFS-O 7 2.1.3 Mechanical description of PFS-O 8 2.1.3.1 The optical bench 9 2.1.3.2 The pendulum system 9 2.1.3.3 The gas-tight box 9 2.1.4 Thermal description of PFS-O 9 2.1.4.1 The thermal control 10 2.1.4.2 The ASTRA system 10 2.2 Detailed Scientific Objectives 10 2.3 Data Handling Process 11 2.4 Overview of Data Products 12 2.4.1 In-Flight Data Products 12 2.4.2 Software 12 2.4.3 Documentation 16 2.4.4 Derived and other Data Products 16 2.4.5 Ancillary Data Usage 16 3 Archive Format and Content 17 3.1 Format and Conventions 17 3.1.1 Deliveries and Archive Volume Format 17 3.1.2 Data Set ID Formation 17 3.1.3 Data Directory Naming Convention 18 3.1.3.1 Cruise and Near Earth Verification Phase Data Directory Structure 18 3.1.3.2 Nominal and Extended Mission Phase Data Directory Structure 18 3.1.4 File naming Convention 19 3.2 Standards Used in Data Product Generation 20 3.2.1 PDS Standards 20 3.2.2 Time Standards 21 3.2.2.1 START_TIME and STOP_TIME Formation 21 3.2.2.2 SC_CLOCK_START_COUNT and SC_CLOCK_STOP_COUNT 21 3.2.2.3 On-Board Time (OBT) to UTC time conversion 21 3.2.3 Cartographic Standards 22 3.3 Data Validation 22 3.3.1 Internal Data Validation 22 3.3.2 PSA and External Validations (Peer Reviews) 22 3.4 Content 22 3.4.1 Volume Set 22 3.4.2 Directories 22 3.4.2.1 ROOT Directory 23 3.4.2.2 Catalog Directory 23 3.4.2.3 Data Directory 24 3.4.2.4 Document Directory 24 3.4.2.5 Extras Directory 25 3.4.2.6 Index Directory 25 3.4.2.7 Geometry Directory 26 3.4.2.8 Label Directory 26 3.4.2.9 Software Directory 27 4 Detailed Interface Specifications 27 4.1 Structure and Organization Overview 27 4.2 Data Sets, Definition and Content 28 4.3 Data Product Design 29 4.3.1 Data Product Design 29 4.3.1.1 File Characteristics Data Elements 29 4.3.1.2 Data Object Pointers Identification Data Elements 29 4.3.1.3 Identification Data Elements 29 4.3.1.4 Instrument Related Parameters 30 4.3.1.5 Data Object Definition 31 4.3.2 Data Product B Design 35 4.3.2.1 Geometry Product A Design 35 5 Appendix: Example of Directory Listing of PFS Data Set 37 6 Appendix: Complete Label file Examples 40 1 Introduction 1.1 Purpose and Scope The purpose of this EAICD (Experimenter to (Science) Archive Interface Control Document) is twofold. First, it provides users of the MEX-PFS instrument with a detailed description of the product and a description of how it was generated, including data sources and destinations. Secondly, it is the official interface between the Planetary Fourier Spectrometer (PFS) instrument and the archiving authority at the European Space Agency (ESA). 1.2 Archiving Authorities The Planetary Data System Standard is an archiving standard used by * NASA for U.S. planetary missions, implemented by the PDS * ESA, for European planetary missions, implemented by the Research and Scientific Support Department (RSSD) of ESA. 1.2.1 ESA’s Planetary Science Archive (PSA) ESA implements an online science archive called the PSA: * to support and ease data ingestion * to offer additional services to the scientific user community and science operations teams, such as: o search queries that allow searches across instruments, missions and scientific disciplines o several data delivery options, such as: * direct download of data products, linked files and data sets * ftp download of data products, linked files and data sets The PSA aims for online 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 PFS instrument on Mars Express (MEX), from the spacecraft until ingestion into the PSA for ESA. It includes information on how data were processed, formatted, labeled and uniquely identified. The document discusses general naming schemes for data volumes, data sets, data and label files. Standards used to generate the product are explained. Software that may be used to access the product is explained further on. The design of the data set structure and the data product is provided. Examples of these are given in the appendix. 1.4 Intended Readership This document will be of interest to any user who is interested to understand the format, design and content of the PFS data products and datasets. This will include any potential user of the MEX-PFS data sets and the staff of the archiving authority (Planetary Science Archive, ESA, RSSD, design team). 1.5 Scientific Objectives PFS is capable of investigating both the atmospheric and surface properties of Mars, as well as the interaction between the two. The primary scientific objectives include: - Three dimensional modelling of the current Martian climate, including physical and chemical parameters, and mapping of circulation features throughout the Mars Express mission - Mapping seasonal variations of the atmosphere and the thermal properties of the Martian surface - Constraining the mineralogical properties of the surface layer of Mars Details of the individual scientific objectives and a breakdown on the measurements PFS will take to achieve these goals can be found in Section 2.2. 1.6 Applicable Documents Rif. Reference Notes [1] Planetary Data System Standards Reference, August 1, 2003, Version 3.6, JPL, D-7669, Part 2 [2] Mars Express Archive Generation, Validation and Transfer Plan, May 10, 2003, Rev 1.1, ESA-MEX-TN-4009 [3]The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission see DOCUMENT/PFS_ON_MARS_EXPRESS.PDF [4]Calibration of the Planetary Fourier Spectrometer Short Wavelength Channel see DOCUMENT/PFS_SWC_CALIB.PDF [5]Calibration of the Planetary Fourier Spectrometer Long Wavelength Channel see DOCUMENT/PFS_LWC_CALIB.PDF [6]PFS Flight User Manual 9, Tm_Tc interface see DOCUMENT/PFS_MEX_FUM9.PDF [7]PFS Flight User Manual 1, Instrument Description see DOCUMENT/PFS_MEX_FUM9.PDF [8]Master Science Plan Overview Documentation, Part I – Introduction MEX-EST-PL-11912 [9]RMCS/MMCS/VMCS Data Delivery Interface Document MEX-ESC-IF-5003 [10] ESA Packet Telemetry Standard ESA-PSS-04-106 [11] MEX-PFS-NEV-REPORT PFS Near Earth Verification Operations Report 1.7 Relationships to Other Interfaces - Other interfaces that have an impact upon the generation, packaging, distribution and documentation involved in the PFS dataset / volume production include:PFS raw data: these are produced from telemetry and are used to produce the PDS compliant data found in the PFS datasets. Any reprocessing of these data, for any reason, will have a direct impact upon the data provided in the datasets produced by PFS. - SPICE data: The SPICE data used to to produce the GEOMETRY information (see Section 3.4.2.6) are retrieved from ESTEC / NAIF. Any changes made to these files will directly affect the GEOMETRY information provided in the dataset. - Software libraries: The PSA and NAIF software libraries used for SPICE and for the generation of the geometry index file. If these libraries are update, this could lead to the generation of new geometry files for the PFS datasets. - PFS software: software used to pipeline the PFS data to the PDS format. If this software is changed, there will be a direct impact upon the final PFS datasets. - PFS calibration procedures: the calibration procedures affect the PFS calibrated data. Details of the calibration procedures are provided in [3] and [4]. - PSA Delivery Requirements: Any changes made to the requirements for the delivery of datasets to the PSA could change the way the PFS datasets are to be packaged and distributed. - PVV software: The PSA Volume Verification (PVV) software is used to validate the PFS datasets before they are ingested into the Planetary Science Archive at ESA. Any updates to this software could require updates to the PFS dataset deliveries. - Mars Express Archive Plan [2]: Any update to the Mars Express Data Archive Plan [2] can affect the design, packaging and / or deliver of the PFS data products and data sets. 1.8 Acronyms and Abbreviations ADC Analog Digital Converter APID Application Process Identifier A/D Analog-to-digital CTE Coefficient of Thermal Expansion DDS Data Distribution System DOF Degree Of Freedom DTM Data Transmission Mode FFT Fast Fourier Transformation FOV Field Of View FUM Flying User Manual FWHM Full width at half maximum HK Housekeeping IB Internal Blackbody IDL Interactive Data Language ICD Interface Control Document IFSI Istituto di Fisica dello spazio Interplanetario INAF Istituto Nazionale di Astrofisica LW Long Wavelength MEX Mars Express MLI Multi-Layer Insulation NEB Noise Equivalent Brightness NER Noise Equivalent Radiance OB On-Board OBDM Optical Bank Digital Module OBS On Board Software PDF Portable Document Format PDS Planetary Data System PFS Planetary Fourier Spectrometer PNG Portable Network Graphics PSA Planetary Science Archive PVV PSA Volume Verifier SCET Spacecraft Elapsed Time SW Short Wavelength TRW TRW Incorporeted ZOPD Zero Optical Path Difference 1.9 Contact Names and Addresses The following persons are involved in the PFS instrument design and data archiving: Institute | Name | E-Mail | Telephone | Position --------------------------------------------------------------------------------------------------- INAF-IFSI | Formisano, Vittorio |formisano@ifsi-roma.inaf.it | +390649934362| Principal Investigator INAF-IFSI | D’Amore, Mario |damore@ifsi-roma.inaf.it | +390649934363| Data Archiving manager INAF-IFSI | Giuranna, Marco |giuranna@ifsi-roma.inaf.it | +390649934042|Calibrations responsible --------------------------------------------------------------------------------------------------- 2 Overview of Instrument Design, Data Handling Process and Product Generation PFS is a double pendulum interferometer working in two wavelength ranges ( 1.2 – 5.5 and 5.5 - 45 ?m). Mars radiation is split into 2 beams by a dichroic mirror and then filtered so that the two ranges also correspond to 2 planes, one on top of the other, in which the two interferometers are placed. In this way, the same motor can simultaneously move the 2 pendulums, and the two channels are sampled simultaneously and independently. The pendulum motion is accurately controlled by means of a laser diode reference channel making use of the same optics as for Martian radiation. The same laser diode also generates the sampling signal for the A/D converter, measuring displacements of the double pendulum mirror of 600 nm ( sampled 4 times per movement, back or forward). The measurements obtained are double sided interferograms, so that on-board FFT can be computed without caring much about the zero optical path difference location. TABLE 1 - DETAILED PFS SCIENTIFICS PARAMETERS ----------------------------------------------- PARAMETERS SW LW UNITS SPECTRAL RANGE 1.2 - 5.0 5.5 - 45 [m] SPECTRAL RANGE 2000 - 8200 230 - 1750 [cm-1] SPECTRAL RESOLUTION 1.5 1.5 [cm-1] (by triangular apodization) FOV FWHM 1.6 2.7 (deg) NEB 5 10-9 4 10-8 (1) [W cm- 2 sr -1] MEASUREMENT CYCLE DURATION 10.0 10.0 [s] DETECTOR TYPE Photoconductor Pyroelectric - MATERIAL PbSe LiTaO3 - SHAPE/SIZE Square/0.7x0.7 Round/r=1.4 [mm] NEP 1*10^-12 (2) 4*10^-10(3) [W/Hz.5] SENSITIVITY 90 (2) 30 (3) [KV/W] TEMPERATURE 220 (4) 290 [K] INTERFEROMETER TYPE Double Pendulum - REFLECTING ELEMENTS Cubic corner reflectors - BEAMSPLITTER CaF2 CsI - REFL. ELEMENTS MOTION +/- 1.5 +/- 1.5 (5) [mm] MAX OPTIC PATH DIFFER. 5 5 [mm] TIME FOR MOTIONS 5 5 [s] TIME FOR MEASUREMENTS 4.5 4.5 [s] REFERENCE SOURCE Laser diode Laser diode - REF. SOURCE WAVELENGTH 1216 1216 [nm] COLLECTOR OPTICS Parabolic mirror - DIAMETER 49 38 [mm] FOCAL LENGTH 20 20 [mm] COATING Gold Gold - SW/LW SEPARATION KRS-5 with a multilayer coating reflecting SW radiation - OPTICS TRANSMISSION 0.64 0.78 (6) - MODULATION FACTOR 0.87 0.98 (7) - INTERFEROGRAM TWO-SIDED TWO-SIDED - SAMPLINGS NUMBER 16384 4096(16384) - SAMPLING STEP 608 2432 [nm] DYNAMICAL RANGE +/- 215 +/- 215 - SPECTRA (from on-board FFT) - QUANTITY OF POINT 8192 2048 - DYNAMICAL RANGE 6000 6000 - ELECTRONICS MODULATION FREQUENCY RANGE 423-1600 50-400 [Hz] ONB FFT COMPUTATION TIME 3.35 0.83 [s] BUFFER MEMORY VOLUME 32 [MBits] Note --------------------------------------------------------------------- (1) Values are given for wavelengths 2.5 and 15 m. Results of measurements for PFS 07 in SW. (2) In peak of the spectral responsivity curve (near 4.8 m and for the modulation frequency 1000 Hz. (3) By the modulation frequency 200 Hz. NEB and sensitivity are given for the output of the preamplifier. (4) Radiative cooling. (5) Linearized deviation from the position, corresponding to zero path difference. (6) From measurements of reflection and transmission of optical elements. Values are given for wavelengths 2.5 and 15 m (7) From estimates of tolerances. Values are given for wavelengths 2.5 and 15 microns. TABLE 2 - DETAILED PFS TECHNICAL PARAMETERS PARAMETERS VALUES UNITS FULL PFS MASS (all blocks) 31.2 [Kg] MODULE O ( Optics and part of electron. ) 19.9 [Kg] MODULE E ( Main electronics ) 3.5 [Kg] MODULE P ( DC/DC converter, Power ) 2.3 [Kg] MODULE S ( Pointing/scanning system ) 4.0 [Kg] HARNESS 1.1 [Kg] PFS POWER CONSUMPTION IN FLIGTH ON MARS 5 [W] PEAK DURING OBSERVATIONS 45 [W] ON THE ORBIT IN “SLEEPING MODE” 10 [W] 2.1 Technical description The flight hardware of the experiment is divided into four parts called modules, plus the connecting cables. The four modules are: the Interferometer with its optics and proximity electronics, which is the core of the experiment, and is called Module O. The pointing device, which receives radiation from Mars or from the in-flight calibration sources, which is called Module S. The Digital electronics, including a 32 Mbit mass memory, and a real time FFT, called Module E. The Power Supply, Module P, with the DC/DC converter, the redundancies, and the galvanic separated power for the 16 bits A/D converters. Below we describe Module O (the core of the experiment) in further detail. Details of other modules can be found in FUM Manual 1 [7]. 2.1.1 Module O Module O is the core of PFS. Module O (hereafter PFS-O), stands for Optical Module and contains the interferometer with its proximity electronics. PFS-O is divided into two blocks: IB (Interferometer Block) and EB (Electronics Block). The two blocks are mechanically separated but electrically connected through a six cable interface. Furthermore IB is a gas tight box filled with dry nitrogen in order to preserve the optical parts that are hygroscopic. The IB is very compact and in practice it contains two interferometers working simultaneously, covering the full range of PFS between 1.2 ?m and 45 ?m. The two ranges are named "SW" as Short Wavelength and "LW" as Long Wavelength. The range of the SW channel is within (1.2 - 5.5) ?m while the LW is within (5.5 – 45) ?m. 2.1.2 Optical scheme of PFS-O Martian radiation The main optical design of the PFS is shown in Figure 1. The incident IR beam falls onto the entrance filter that separates the radiation of SW channel from the LW channel and directs each into the appropriate interferometer channel. The scanner in front of the interferometer allows the FOV to be pointed along and laterally to the projection of the flight path onto the Martian surface. It also directs the FOV at internal black body sources, diffusers and to open space for in-flight calibration. The optical path difference is generated by the angular movement of the retroreflectors. The controller of the torque motor uses the outputs of two reference channels, which are equipped with laser diodes. This interferometer design is very robust against slight misalignment in harsh environment compared with the classical Michelson-type interferometer. Fig.1 Optical scheme of PFS The cube corners make it possible to use a double pendulum configuration in an easy way without complex mechanics. At the same time, they can lower the sensitivity of the interferometer in terms of mirrors tilting. Furthermore, the optical alignment of the instrument becomes easier and faster. The double pendulum axis rotates by means of a brushless motor (two for redundancy) that does not experience any kind of mechanical friction. Thus the shaft of the double pendulum is sustained just by two preloaded ball bearings at very low friction. An additional mechanical friction instead is added for the purpose of a better stability of the pendulum speed. The reference channel The source of the reference beam is a laser diode (InGaAsP at 1.2 ?m) and its detector is an infrared photodiode with maximum responsivity at about 1.2 ?m. The beam of the reference channel is processed like the input signal so that the optical path of the reference is almost exactly coincident with the optical path of the signal to be studied. At the corner cubes the laser beam moves from one side to the other of the main beam, so that the part of the beam directed backward toward the source is displaced with respect to the inward part. This part terminates into an optical trap (one per each channel). The zero optical path difference signal (ZOPD) The ZOPD signal is generated using IR radiation from a TRW device, which, if a thin mirror is placed at the correct distance, will give a pulse when the mirror is in front of the device, while no signal is obtained for any other position. The linear mirror for PFS is placed on the edge of an arrow fixed to the shaft of the double pendulum. During assembly it is adjusted so that its signal is within 100 pulses from the optical zopd. During the double pendulum motion the arrow moves in front of the TRW detector so that a pulse is generated at the zopd position. The detectors : SW We use a photo-conductor type detector for the SW channel capable of working at temperatures down to 200K. The main characteristics of this detector are listed in Table 4. Main characteristics of the SW detector Size [mm] 0.7 x 0.7 square Spectral range [?m] 1.2 - 5.5 D*(? max) [cm Hz1/2 /W] 0.9 1011 at 200 K, 1.2 kHz D*(? max) [cm Hz1/2 /W] 0.3 1011 at 250 K, 1.2 kHz Table 4. SW detector characteristics The SW detector is passively cooled through a radiator and its holder is partially insulated from the rest of theIB. The minimum conductance between the holder and the fixing point acts as a thermal sink to cool down the whole IB itself. The operative temperature of the SW detector is about 220K. The detectors :LW For the LW channel we have used a pyroelectric detector whose characteristics are listed in Table 5. Main characteristics of the LW detector Size [mm] 1.4 ? round Spectral cutoff [?m] > 50 Threshold [W/ Hz1/2] About 5 10-10 at 200 Hz Responsivity [V/W] About 70k Noise [V/Hz] About 5 10-6 Table 5. LW detector characteristics The LW detector is able to work without performance degradation even at ambient temperature. In our case the ambient temperature is the temperature of the IB, which is about 13°C. 2.1.3 Mechanical description of PFS-O Module «O» contains the interferometer that consists of three main parts: the optical bench, the pendulum system, and the gas tight box. 2.1.3.1 The optical bench The optical bench is a structure made in Al7075 alloy, obtained by machining and electro-erosion from a single aluminum alloy billet. All the optical elements of the interferometer are directly mounted or have a reference to the optical bench. The beam splitters are flange mounted on the reference plane of the optical bench while the supports of the axle on which the cubic corners are mounted are machined with a strict tolerance of planarity with the reference plane. The sensors are mounted on a surface of the optical bench with a 2 DOF regulation system that allows to align the detector group axes with the instrument one. 2.1.3.2 The pendulum system The pendulum shaft is mounted on two angular contact ball bearings, axially pre-loaded with an elastic system allowing the differential thermal expansion without inducing sensible stress. The movement of the axle is a rotation of about ? 1.5° for the useful part and is up to 2.5° considering the extra- travels. The rotation is made by an electrical brushless torque motor that, for safety, is totally redundant. For the stability of the control loop a friction torque is applied to the axle. A locking device keeps the pendulum in a position outside the useful travel during the launch phase and in case of orbit correction/manoeuvring. The locking/unlocking procedures take about 10 minutes, the actuator being a paraffin one. The movement is therefore slow and no vibration or relevant electromagnetic fields are induced. The balancing mass is kinetically mounted on the pendulum axle to avoid thermal stresses induced by the different CTE of the materials. Regulation devices are mounted in place of the balancing mass during the alignment of the interferometer and afterwards removed. 2.1.3.3 The gas-tight box The optical bench is included in a gas-tight box that during ground operation has to be filled with dry nitrogen. The gas tight box is required to avoid the degradation of the CsI beam splitter for moisture absorption. A bellow valve automatically opens and stays open when the environment pressure goes below 90 kPa allowing the inner gas to leave the instrument; when the external pressure increases above that value the valve closes again. The failure position of the valve is open in order to avoid an excessive overpressure in the instrument that would damage the entrance optics. The gas tight box is also mechanically supporting the thermal interface to the radiator, where a thermal flexible strap is fixed. 2.1.4 Thermal description of PFS-O PFS-O has four main thermal requirements: the temperature of the Short Wavelength detector, the Temperature/stability of the Long Wavelength detector, the temperature/stability of the two diode lasers and the temperature/stability of the optical bench. The requirement for the SW detector is to have a working temperature lower than 220 K. This goal is achieved by means of a passive radiator, connected to the sensor by means of an aluminum cold finger. The requirement for the long wavelength sensor are less stringent for the working temperature, about 25 °C, but challenging for the stability, <0.01°C/h. The sensor is mounted on an insulating stainless steel structure and the temperature is controlled by an electrical heater placed at its back, fed by an electronic circuit. A wrong operative temperature of the diode lasers along with its fluctuations in time may cause degradation of the spectral resolution of the interferometer. For this reason the choice of the best operative temperature of the diode lasers must be planned in the calibration procedure. The temperature itself can be set in a wide range, from 2°C up to 42°C, but the maximum allowed depends on the operative temperature of the IB. In our case a gradient of 4°C between the fixing points and the laser diode case is achieved as a maximum. In the interferometer unit there is, during operation, a dissipation of about 5 W of electrical power, mainly in the motor of the pendulum and the sensors proximity electronics. The thermal requirement is mainly in uniformity of the temperature; differences of the order of 2 °C between the average temperatures of the brackets of the pendulum leads to a reduction of the SNR of 1%. The whole module "O" is thermally insulated from the spacecraft because of the low thermal conductance of the dampers and of the MLI covering all the external surfaces. 2.1.4.1 The thermal control Thermal control is also very important for an infrared interferometer and for PFS this is achieved using eight points to read the temperatures across the instrument and to heat the structure. The controlling is passive so that only heating is permitted. Every point is read and set again through OBDM. Additionally, the two detectors (SW and LW) are thermally controlled. This is important to accurately maintain the radiometric calibration without greatly increasing the in-flight calibration cycles. In this way, the temperature of the IB is kept at a constant temperature of 13°C. 2.1.4.2 The ASTRA system An additional thermal control with no electrical connections to the rest of PFS, is the block named "ASTRA". This stand-alone electronics box provides thermal control for the IB during the cruise phase, while the instrument is off. In this way, the temperature inside the IB is kept around the operative temperature and the thermal cycles are reduced ta a minimum even while PFS is in operation during the cruise phase. The total power dissipated by ASTRA is 6 W. 2.2 Detailed Scientific Objectives The Planetary Fourier Spectrometer (PFS) is an infrared spectrometer optimised for atmospheric studies. The instrument is able to cover wavelengths from 1.2 to 45 ?m, divided into two channels with a boundary at 5.5 ?m. The spectral resolution is 2 cm-1. The instrument field of view (FOV) is about 1.6° for the Short Wavelength (SW) channel and 2.8 ° for the Long Wavelength (LW) channel, which corresponds to a spatial resolution of 7 and 12 km respectively, when Mars is observed from an height of 250 km (nominal height of the pericentre ). PFS can give unique data necessary to improve our knowledge not only of the atmospheric properties of Mars, but also about the mineralogical composition of the surface and the surface-atmosphere interaction. The scientific objectives of the PFS experiment can be summarised as follows: 1) Atmospheric studies: a) global long duration monitoring of the three-dimensional temperature field in the lower atmosphere (from the surface up to 40-60 km); b) measurements of the minor constituents variations (water vapour and carbon monoxide); c) search for other possible small components of the atmosphere; d) new determination of the D/H ratio; e) study of the optical properties of the atmospheric aerosols: dust clouds, ice clouds, hazes; determination of the size distribution and chemical composition; f) investigation of radiance balance of the atmosphere and the influence of aerosols on energetics of the atmosphere. g) study of global circulation, mesoscale dynamics and wave phenomena. 2) Surface studies: a) monitoring of the surface temperature; b) determination of the thermal inertia obtained from the daily surface temperature variations; c) determination of constraints on the mineralogical composition of the surface layer; d) determination of the nature of the surface condensate and seasonal variations of its composition; e) measurements of the scattering phase function for selected regions of interest on the planet’s surface; f) local pressure and height determination (CO2 altimetry) for selected regions; g) surface-atmosphere exchange processes. The experiment will have real-time FFT on-board to be able to select the spectral range of interest for data transmission to ground. Measurement of the 15 micron CO2 band is very important. Its profile gives, by means of a complex temperature profile retrieval technique, the vertical pressure temperature relation, which forms the basis of the global atmospheric study. Since the repetition time of the measurements is 8.5 to 10 sec and the working time is ± 40 minutes around pericentre, a total of more than 564 measurements per orbit will be acquired, corresponding to 1790 measurements per day for a 7.6 hours orbit. In the 80 minutes of data collection, the atmospheric measurements will be made at high altitude, because high space resolution is not needed, while surface oriented measurements will be taken closer to pericenter, where higher spatial resolution can be achieved. An important requirement of PFS is that we need to measure at all local times in order to have the atmospheric vertical temperature profiles also from the night side. 2.3 Data Handling Process On the spacecraft, data from each sensor are either downloaded as raw or are downloaded after running through an onboard FFT. Both types of data are retrieved from ESA’s Data Distribution System (DDS) at INAF-IFSI. These are splitted into the two sensors channel and calibrated using the procedure fully described in [4] and [5] and then distributed to Co-Is as working data for internal purposes. The calibration to this level involves Marco Giuranna. The PDS archive data are produced for each Mission Phase, i.e. Nominal Mission and Extended Mission. These data are Experimental Data Records – CODMAC level 2, and are then pipelined through to a complete PDS formatted data set via a piece of software developed at INAF-IFSI by Mario D’Amore. The rough data flow is illustrated in the figure below. Fig.2 PFS data acquisition and processing scheme. 1. ACQUISITION The OBS acquires 18000 points from the ADC converters of each channel in 4.5 seconds. These are sampled by a laser diode reference signal (for more information see [3]) 2. ON-BOARD CORRECTION The OBS finds the central part of the interferograms using the Hardware (HW) zero signal read from the sensor, and adds the ZOPD offset (this value is the difference between the interferogram central part and the and the position of HW zero) taking 8192 points from the left side and 8192 points from the right side. The final SW and LW size is 16384 points and both interferograms are centered to the Zero Optical. 3. ON-BOARD AVERAGE In this stage LW interferogram is smoothed by averaging every four points, resulting in a reduction from 16384 to 4096 poins. 2.4 Overview of Data Products 2.4.1 In-Flight Data Products Raw data (at ESOC, PSA and IFSI-INAF) ESOC and PSA will archive all data downlinked by MEX, sorted by APID IAS will archive the packets relevant to PFS in DDS format (definied in [9] and [10]) Experiment Data Records (at IFSI-INAF and PSA) Level-1A Science data product filename convention : PFS____.DAT1 During cruise and Mars orbital phases, PFS produces eight files in PDS format for each orbit (or cruise sub-phase), including decompressed science data (level-1A), and all PFS acquired instrumental housekeeping information. The product name (PRODUCT_ID) contains the following information (see Section 3.1.4 for details): - PFS__ YYYY _ ZZ _KK.DAT : for a fixed value represent all the data from a single orbit or cruise sub-phase - PFS_XXXX__ ZZ _ KK.DAT : for a fixed < inst_mode> value represent all the data from an instrument mode (i.e. calibration measurements or science data). - PFS_ XXXX _ YYYY __ KK.DAT : for a fixed < datatype> value represent all the data for a single datatype (i.e. the housekeeping or PFS measurements) - PFS_ XXXX _ YYYY_ ZZ _ .DAT : for a fixed value represent all the data from a single detector ( i.e. SW or LW) Letters blocks represent all the possible accepted value for each position in filename, or: - XXXX = mission orbit - YYYY = inst mode - ZZ = datatype - KK = detector 2.4.2 Software Provided software in the SOFTWARE directory are functions in IDL language, suited to read data and labels (in FUNCTIONS subdirectory in SOFTWARE directory) both for DATA or GEOMETRY geometry products. These routines are intended as lower level interface between user program and the PFS data. Some example programs, showing how to read data products, are provided in DATA and in GEOMETRY subdirectories as IDL program files, based on routines mentioned. When downloading the SOFT.ZIP file, the user should put it in a working directory dedicated to PFS software, then unzip it. This will create two subdirectories: /SOFTWARE/ | |- /DATA/ | |- /GEOMETRY/ The essential functions to open and read the data are in the FUNCTIONS subdirectory. To run example code do the following steps: 1. open a .PRJ file (for DATA or for GEOMETRY) 2. change the PATH variable to your PFS Data directory 3. Menu Project > Compile > All Files 4. Menu Project > Run Follow a list of provided functions to open and read the data and their output. Function read_pfs_data(FILE,NUM,RECORDS) return a structured variable array with the data. Array length is NUM. Each array element is defined as : OBT_OBSERVATION_TIME: OUBLE PRECISION FLOAT SCET_OBSERVATION_TIME: UNSIGNED LONG INTEGER INTERFEROGRAM: INTEGER ARRAY WHITH LENGHT = RECORDS INPUT: FILE : path of the data file to NUM : total number of the field (= observation) stored in the file RECORDS : length of a single interferogram Function read_pfs_hk(FILE,NUM): return a structured variable array with the housekeeping data. Array length is NUM. Each array element is defined as : OBT_OBSERVATION_TIME : DOUBLE PRECISION FLOAT SCET_OBSERVATION_TIME : UNSIGNED LONG INTEGER TypeOfMes : UNSIGNED LONG INTEGER SD_Version : UNSIGNED LONG INTEGER ZOPD_SW_FWD : UNSIGNED LONG INTEGER ZOPD_SW_REV : UNSIGNED LONG INTEGER ZOPD_LW_FWD : UNSIGNED LONG INTEGER ZOPD_LW_REV : UNSIGNED LONG INTEGER SCANPOS : UNSIGNED LONG INTEGER SW_ZeroX_Cutoff_Status : DOUBLE PRECISION FLOAT LW_ZeroX_Cutoff_Status : DOUBLE PRECISION FLOAT SPEEDCLOCK_Status : DOUBLE PRECISION FLOAT ADCCLOCK_Status : DOUBLE PRECISION FLOAT SW_Detector_Cutoff_Status : DOUBLE PRECISION FLOAT LW_Detector_Cutoff_Status : DOUBLE PRECISION FLOAT SWGAIN_Status : UNSIGNED LONG INTEGER LWGAIN_Status : UNSIGNED LONG INTEGER First_ADC_1_Status : UNSIGNED LONG INTEGER Second_ADC_1_Status : UNSIGNED LONG INTEGER First_ADC_2_Status : UNSIGNED LONG INTEGER Second_ADC_2_Status : UNSIGNED LONG INTEGER Select_Motor_Coil_Status : UNSIGNED LONG INTEGER DPDIR_Status : UNSIGNED LONG INTEGER SW_ZOPD_Position : UNSIGNED LONG INTEGER LW_ZOPD_Position : UNSIGNED LONG INTEGER Right_Collisions : UNSIGNED LONG INTEGER Left_Collisions : UNSIGNED LONG INTEGER SWLASERPWR_10V : DOUBLE PRECISION FLOAT LWLASERPWR_10V : DOUBLE PRECISION FLOAT SWPHOTODIODEPWR_10V : DOUBLE PRECISION FLOAT LWPHOTODIODEPWR_10V : DOUBLE PRECISION FLOAT T1_10V : DOUBLE PRECISION FLOAT T2_10V : DOUBLE PRECISION FLOAT T3_10V : DOUBLE PRECISION FLOAT T4_10V : DOUBLE PRECISION FLOAT T5_10V : DOUBLE PRECISION FLOAT T6_10V : DOUBLE PRECISION FLOAT T7_10V : DOUBLE PRECISION FLOAT T8_10V : DOUBLE PRECISION FLOAT LDTEMPSW_10V : DOUBLE PRECISION FLOAT LDTEMPLW_10V : DOUBLE PRECISION FLOAT SWTEMP_10V : DOUBLE PRECISION FLOAT LWTEMP_10V : DOUBLE PRECISION FLOAT TEMPA1_10V : DOUBLE PRECISION FLOAT TEMPA2_10V : DOUBLE PRECISION FLOAT SWTRW_10V : DOUBLE PRECISION FLOAT LWTRW_10V : DOUBLE PRECISION FLOAT CLVOLTAGE_10V : DOUBLE PRECISION FLOAT INPUT: FILE : path of the data file to open NUM: total number of the field (= observation) stored in the file Function read_pfs_label(FILE,NAME) return value stored in a PDS label file in the NAME field of provided LABEL file. INPUT: FILE : path of the label file to open NAME: name if the fiel to search for (i.e. ROWS or FIELDS) Function reader_geometry(FILE,NUM) return a structured variable array with all the geometrical information. Array length is NUM. Each array element is defined as : SCET : DOUBLE PRECISION FLOAT LONGITUDE : DOUBLE PRECISION FLOAT LATITUDE : DOUBLE PRECISION FLOAT SPACECRAFT_ALTITUDE : DOUBLE PRECISION FLOAT Local_Time : SINGLE PRECISION FLOAT Solar_Longitude : DOUBLE PRECISION FLOAT INCIDENC_EANGLE : SINGLE PRECISION FLOAT EMISSION_ANGLE : SINGLE PRECISION FLOAT PHASE_ANGLE : SINGLE PRECISION FLOAT MOLA_ALTIMETRY : SINGLE PRECISION FLOAT LW_TANGENT_ALTITUDE : SINGLE PRECISION FLOAT LW_TARGET_DISTANCE : SINGLE PRECISION FLOAT SOLAR_DISTANCE : SINGLE PRECISION FLOAT SUBSOLAR_LONGITUDE : DOUBLE PRECISION FLOAT SUBSOLAR_LATITUDE : DOUBLE PRECISION FLOAT PLANETARY_PHASE_ANGLE : SINGLE PRECISION FLOAT SUB_SPACECRAFT_LONGITUDE : DOUBLE PRECISION FLOAT SUB_SPACECRAFT_LATITUDE : DOUBLE PRECISION FLOAT JULIAN_DATE : DOUBLE PRECISION FLOAT AIR_MASS : SINGLE PRECISION FLOAT INPUT: FILE : path of the geometry file to open NUM : total number of the field (= observation) stored in the file The data are in standard PDS format and should be open with any standard PDS viewer also. These packages are all available for download from the PDS website (http://pds.jpl.nasa.gov). 2.4.3 Documentation Several documents are provided in the document directory of the PFS data set. The following documents are useful to the understanding of the data set / archive, and the PFS instrument itself: 1. The PFS Experimenter to Archive Interface Control Document (this document). This document describes the details of the PFS data products and data sets and provides all of the information necessary for a user to understand how to use the data products. 2. PFS Flight User Manual, in which details of the PFS instrument are described, includes the instrument itself, the structure of the HK products, the structure of the science products, and many other aspects of the instrument operations and functionality. 3. “The Planetary Fourier Spectrometer (PFS) onboard the European Mars Express mission” document that describe the PFS instrument. 4. “Calibration of the Planetary Fourier Spectrometer Short Wavelength Channel” document that describe the procedure for the SW channel calibration. 5. “Calibration of the Planetary Fourier Spectrometer Long Wavelength Channel” document that describe the procedure for the LW channel calibration. All documentation that is critical to the understanding and use of this data set is provided in plain ASCII format as well as other non-proprietary formats (e.g. PDF for documents and PNG for figures). Non-critical documentation is only delivered in PDF format and no ASCII version is provided. 2.4.4 Derived and other Data Products No derived Data products are provided with the PFS archive. There are currently no plans for these data to be distributed beyond the team, and micro-vibrations on Mars Express have complicated calibrations so that no schedule is currently available for their production (for calibration details and discussion see documents [4] and [5] ) 2.4.5 Ancillary Data Usage Orbit, attitude and event data provided from ESOC and translated into SPK, PcK, CK, SCLK, Orbnum Spice Kernels files are used to compute the geometry files provided in the PFS data set. For each measurement, the SCET (Spacecraft Event Time) is transformed into UTC and used to compute all of the geometric and illumination parameters that describe the measurements. Information about the footprint on the planet and the relative positions of MEX, Mars, Sun and Earth are also provided. These data are distributed to the CoIs and archived in the Geometry Directory. In the Geometry file (one for each orbit), the list of the actual Spice Kernels used to compute these parameters for each measurement is provided (see par.3.4.2.7 ). 3 Archive Format and Content This chapter contains general rules and constraints for the PFS data sets.The schemes or conventions used for naming the directories and files is specified below. Specific and detailed information are provided in subchapters of chapter 4.3. 3.1 Format and Conventions 3.1.1 Deliveries and Archive Volume Format PFS team will deliver a complete dataset for each Mission Phase (NOMINAL, EXTENDED 1 etc.),conforming to the schedule outlined in the Mars Express Archive Plan [2]. Because the PSA is an online archive, we do not deal directly with volumes in the same sense as the PDS. For the purposes of the PSA, a volume is equivalent to a dataset, so volume identifiers are typically not applicable. The VOLUME_SET_ID follows a strict formation rule defined in [1][1], section 19.5.1, with the Country (IT for Italy), Government Branch (CNR), Discipline within government branch (IFSI), mission and instrument ID (MEXPFS), and a 4-digit sequence number (1001). For the number, the first digit represents the VOLUME_SET and the last number the VOLUME within the VOLUME_SET. The keyword used thorugh the datase are then: VOLUME_SERIES_NAME = "MISSION TO MARS" VOLUME_SET_ID = IT_CNR_IFSI_MEXPFS_1000 VOLUME_SET_NAME = "MARS EXPRESS PFS DATA" VOLUME_ID = MEXPFS_1001 VOLUME_NAME = "VOLUME 1: MARS EXPRESS PFS 3.1.2 Data Set ID Formation The PFS data set ID is generated using the follow syntax: ----- -V Where: : MEX this is fixed, and is the mission ID for Mars Express. : M this is fixed, and refers to the target of Mars. : PFS this is fixed and identifies the instrument as PFS (Planetary Fourier Spectrometer). : 2 this number indicates the level of processing the data has undergone on the CODMAC scale. A full description of the CODMAC levels is provided in [1]. : EDR this represents the type of data in the data set. For the standard PFS deliveries, this will always be set to ‘EDR’ meaning ‘Experimental Data Record’. A description of the different data set types can be found in [1]. : this is a descriptive secion of the ID and will typically refer to the mission phase ID or an orbital range for the nominal mission. NOMINAL nominal mission phase. EXT1 first extended mission phase. EXT2 second extended mission phase. EXT3 third extended mission phase. : <1.0> this is the version of the data set, starting at 1.0 and increasing incrementally if changes are made to the products or the dataset itself. When all of this is put together, it provides a data set ID of the form: MEX-M-PFS-2-EDR-NOMINAL-V1.0 or MEX-M-PFS-2-EDR-EXT1-V1.0 3.1.3 Data Directory Naming Convention Inside the DATA directory, the data products are organized into several subdirectories. The structure of the directories will depend upon the phase of the mission in the dataset. 3.1.3.1 Cruise and Near Earth Verification Phase Data Directory Structure During the Near Earth Verification (NEV) and Interplanetary Cruise (IC) phases of the mission, PFS only took measurements of the internal calibration source (Internal Black Body and Lamp) and of deep space. The limited number of observations are simply divided by sensor into the following directory structure: DATA | |-NEV | |- LWC [Long Wave detector] | |- SWC [Short Wave detector] 3.1.3.2 Nominal and Extended Mission Phase Data Directory Structure For the nominal and extended mission phases at Mars, data will be split into groups of 10 orbits, whith the following syntax: The base directory will be MARS as all products from these phases will be from the planet. Beneath this, data will be separated into observations from the long-wave (LWC) and short-wave (SWC) sensors. Finally, data will be divided into blocks of 10 orbits using the following taxonomy: ORBX ORB This is fixed and means ORBIT This will be the first 3 digits of all orbits contained in this directory X This is fixed and means that inside this directory are data from orbits YYY0 to YYY9. For example, the directory ORB000X will contain all products from orbits 0001 to 0009. The DATA subdirectory structure for the nominal mission data will therefore follow the scheme: DATA | |-NEV | | | |-LWC | |-SWC | |- IC | |-LWC | |-SWC | |-MARS | | | |-LWC | | |-ORB001X | | |-ORB002X | | | |-SWC | | |-ORB001X | | |-ORB002X 3.1.4 File naming Convention the data products are identified principally by orbit numer and detector type, following the scheme: PFS____. Orbit number. For the Near Earth Verification and Interplanetary Cruise Phase the Orbit field is substitute with the name of the Phase and Sub-phase (for a Phase and Sub-phase definition see [8], table.1, pag.9) . : IC for Interplanetary Cruise Phase NEV for Near Earth Verification Phase : C Check Out Sub-phase D Dry Earth Sub-phase E Earth Moon Sub-phase (Observation to Earth and Moon) 1 PS001 Sub-phase (First Switch ON) 2 PS002 Sub-phase (Calibration) 3 PS003 Sub-phase (DTM, Pericenter Pass Simulation, Calibration) 4 PS004 Sub-phase (FOV, Calibration) 5 PS005 Sub-phase (Calibration, heating of SW detector) S Star Calibration Sub-phase M Mars Crossing Sub-phase all the sub-phases refer to specific PFS test operations performed during the NEV phase and described in [11]. Defines if the instrument is in calibration mode or in measurement mode: CAL Calibration MEAS Measurement For the HK file field is referred to the corrisponding RAW file field. indicates the type of data provided: RAW – HK - RAD. RAW contains interferogram HK contains the HK information about PFS during the acquisition RAD contains radiance spectra (calibrated data only). GEO contains geometrical data and are located in the GEOMETRY directory (see Section 3.4.2.7). defines the type of the detector used for the interferogram acquisition: Short wavelength (SW) or Long wavelength (LW). the extension depends on the type of file (LBL for a label file, DAT for the data product associated with the label). E.G. : For Mars: PFS_0010_ MEAS_HK_SW.LBL PFS_0010_ MEAS_HK_SW.DAT would be a PFS product from Mars orbit 0010. It would be a raw calibration data product from the short wavelength sensor with its associated label. ‘For the Near Earth Verification and Interplanetary Cruise Phase: PFS_NEV1_MEAS_HK_SW.DAT PFS_NEV1_MEAS_HK_SW.LBL would be a PFS product from the PS001 Sub-phase of the Near Earth Verification phase. It would be a raw calibration product from the short wavelength sensor with its associated label. PFS_IC_CAL_HK_SW.DAT PFS_IC_CAL_HK_SW.LBL would a PFS product from the Check Out sub-phase of the Interplanetary Cruise. It would be a raw calibration product from the long wavelength sensor with its associated label. 3.2 Standards Used in Data Product Generation 3.2.1 PDS Standards The PFS archive follows the Planetary Data System (PDS) standards as detailed by the PDS Standards Reference document [1]. For this archive, we use Version 3.6 of the Standards Reference, dated August 1, 2003. 3.2.2 Time Standards Within the data products themselves, the time standard used is SCET (Spacecraft Elapsed Time), which is an integer with seconds and fractions of seconds. This value does not have fixed calibration, and is dependent upon the spacecraft. To address this issue, the time is also provided in Julian Date, starting from 1970-01-01t12:00:00. Outside of the products themselves, there are several instances in the PFS data sets where time flags are provided. The main time values are provided in the data product labels, which provide a start and stop time for the measurement, and a corresponding clock count from the spacecraft. Below, the standards used to define these values are described, and the method by which the on-board time is converted to universal time. 3.2.2.1 START_TIME and STOP_TIME Formation The PDS formation rule for dates and time in UTC is: YYYY-MM-DDThh:mm:ss.fff or YYYY-DDDThh:mm:ss.fff YYYY year (0000-9999) MM month (01-12) DD day of month (01-31) DDD day of year (001-366) T date/time separator hh hour (00-23) mm minute (00-59) ss second (00-59) fff fractions of second (000-999) (restricted to 3 digits) This standard is followed for all START_TIME and STOP_TIME values in the products included in the PFS data sets. The first formation rule is applied for PFS (YYYY-MM-DDThh:mm:ss:fff). 3.2.2.2 SC_CLOCK_START_COUNT and SC_CLOCK_STOP_COUNT The SC_CLOCK_START_COUNT and SC_CLOCK_STOP_COUNT values represent the on-board time counters (OBT) of the spacecraft and instrument computers. This OBT counter is given in the headers of the experiment telemetry source packets. It contains the data acquisition start time as 32-bit of unit seconds followed by 16-bit of fractional seconds. The time resolution of the fractional part is 2^-16 = 1.52×10^-5 seconds. Thus, the OBT is represented as a decimal real number in floating-point notation with 5 digits after the decimal point. A reset of the spacecraft clock is represented by an integer number followed by a slash, e.g. “1/” or “2/”. Example 1: SPACECRAFT_CLOCK_START_COUNT = "1/21983325.39258" Example 2: SPACECRAFT_CLOCK_START_COUNT = "21983325.39258" Example 3: SPACECRAFT_CLOCK_START_COUNT = "2/0000325.39008" Example 1 and Example 2 represents the same time instance. 3.2.2.3 On-Board Time (OBT) to UTC time conversion UTC time is a function of the time correlation packages and the on-board time. The time correlation packages are archived and distributed in the SPICE auxiliary data set and contain linear segments that map the on-board time to UTC time. The linear segment is represented by a time offset and a time gradient. The conversion function is: Time in utc = offset + (obt(seconds) + (obt(fractional part)*2^-16)) *gradient 3.2.3 Cartographic Standards Inertial Reference frame – The Earth Mean Equator and Equinox of Julian Date 2451545.0 (referred to as the J2000 system) is standard inertial frame. Mars Body-Fixed Frame – Body fixed frames are reference frames that do not move with respect to surface features of an object. The Mars Body-Fixed frame center is the center of mass of Mars. The spin axis of Mars defines the z- axis, whereas the prime meridian provides the direction of the x-axis that lies on the equatorial plane. The y-axis completes the right-handed frame. Values used to model the orientation of the North Pole (including precession), and the prime meridian as a function of time, are those recommended by the International Astronomical Union and adopted by the Mars Express project. Coordinates System – We use the planetocentric coordinates system that consists of longitude measured positive eastward and planetocentric latitude, defined as the angle between the equatorial plane and a line from the center of mass of Mars to given point. This system is right-handed and identical to spherical polar coordinates as commonly defined. Longitudes range from 0 to 360 degrees, and latitudes range from –90 to 90 degrees. Reference Surface – The standards used to model the surface of Mars is a triaxial ellipsoid centered on the planetocentric system origin, as in SPICE. 3.3 Data Validation 3.3.1 Internal Data Validation Before delivery to the PSA for archiving, the PFS data are processed to CODMAC level 2 and are validated both in terms of PDS compliance and for quality of data. Data are checked for syntax, PDS Standards compliance and volume / data set integrity using the PVV software provided by the PSA. 3.3.2 PSA and External Validations (Peer Reviews) Before the PFS data are archived and released to the scientific community, the data sets and documentation undergo a thorough peer review. This is completed in several stages by independent external reviewers who validate the usefulness of the archive and provide constructive input to improve the data sets in the same way as a professional paper may be reviewed. In addition, prior to the data being ingested into the online Planetary Science Archive (http://www.rssd.esa.int/PSA), the data sets are fully tested for compliancy using the ‘PVV’ tool (PSA Volume Verifier Tool). This software checks the syntax of all keywords and labels within the data sets, and crosschecks values for keywords that should be identical. If the PVV tool successfully verifies a data set then the data set is PSA compliant and will be ingested into the online PSA. 3.4 Content In this Section , we outline the non-data directory contents and information that will remain effectively static for all PFS data sets. This includes details of documentation, catalog information and calibration or geometry information, as well as details of the volume conventions used for PFS data sets. 3.4.1 Volume Set For the Mars Express PFS data deliveries to the PSA, a data set is equivalent to a volume, since no physical media are to be generated. Therefore, the volume as defined by the PDS does not apply to the PFS data sets and all volume identifiers are delivered with a specific PSA defined value (see 3.1.1). 3.4.2 Directories The structure of our volume-set/data-set is illustrated below: 3.4.2.1 ROOT Directory The following files are contained in the data set root directory, prepared by the PFS team. These files are required by the PDS Standards [1]: - AAREADME.TXT: This file is the entry point to the PFS data sets, and provides a complete description of the organisation and contents of the PFS data sets. - VOLDESC.CAT: This is a description of the volume (data set) in PDS format, describing the catalog documentation provided in the archive and all volume identifiers. - ERRATA.TXT: This file describes known errors and anomalies of PFS on this volume. The CATALOG directory contains all standard PDS catalog files, see [1]. 3.4.2.2 Catalog Directory The CATALOG directory contains a series of plain text files describing the various elements of the PFS data set / instrument and the Mars Express spacecraft / mission. These files are a basic reference resource that should be used to provide a fundamental understanding of the PFS data, its acquisition and use, and any issues that may be present in its scientific application. The CATALOG directory contains the following files: * CATINFO.TXT: This file identifies and describes the function of each file in the CATALOG subdirectory * DATASET.CAT: Data set information for the PDS catalog, as know problems in the dataset at the moment of archive creation and team citation. * INST.CAT: Instrument information for the PDS catalog * INSTHOST.CAT: Instrument host (spacecraft) information for the PDS catalog * MISSION.CAT: Mission information for the PDS catalog * REFERENCE.CAT: Bibliographic reference used in the Dataset and the documentation * RELEASE.CAT: For each data set, there is one release catalog file which defines, through release objects, a data products delivery to the PSA * SOFT.CAT: Software information for the PDS catalog * TARGET.CAT: Primary target (Mars) description 3.4.2.3 Data Directory The DATA directory contains all data products for PFS. Each data set contains several orbits of data, organized into subdirectories containing blocks of 10 orbits. The scheme used for this is described in detail in Section 3.1.3 and is presented in the figure below. Details of the products to be provided in the DATA directory and their structure and labelling can be found in Section 4.3 and its sub-sections. 3.4.2.4 Document Directory This directory contains all of the Flight user manual documents, which have been divided into 9 chapters, describing in detail all of the features of the experiment. In addition, the ICD (this document) is provided also in ASCII format, and papers describing the calibration procedures for PFS are provided. A complete list and a short description: - DOCINFO.TXT DOCUMENTS directory content list - MEX-PFS-PSA-ICD-24.ASC Interface Control Document in ASCII Format - MEX-PFS-PSA-ICD-24.LBL Label file for Interface Control Document - MEX-PFS-PSA-ICD-24.PDF Interface Control Document in Portable Document Format - MEX-PFS-PSA-ICD_FIG_1.PNG ICD figure 1 – Pfs optical scheme - MEX-PFS-PSA-ICD_FIG_2.PNG ICD figure 2 – Data acquisition and processing scheme - MEX-PFS-PSA-ICD_FIG_3.PNG ICD figure 3 – High level directory structure - MEX-PFS-PSA-ICD_FIG_4.PNG ICD figure 4 –DATA directory structure - MEX_ORIENTATION_DESC.LBL Label file for Mars express spacecraft orientation - MEX_ORIENTATION_DESC.TXT Mars express spacecraft orientation - PFS_CAL_LAB_1.LBL Label file for Internal Note on Pfs Calibration – Volume I - PFS_CAL_LAB_1.PDF Internal Note on Pfs Calibration – Volume I - PFS_CAL_LAB_2.LBL Label file for Internal Note on Pfs Calibration – Volume I - PFS_CAL_LAB_2.PDF Internal Note on Pfs Calibration – Volume II - PFS_CAL_NEAREARTH.LBL Label file for Internal Note on Pfs Calibration in Space - PFS_CAL_NEAREARTH.PDF Internal Note on Pfs Calibration in Space - PFS_LWC_CALIB.LBL Label file for LWC channel Calibration article - PFS_LWC_CALIB.PDF LWC channel Calibration article - PFS_MEX_FUM.LBL Label file for FUMs Index - PFS_MEX_FUM.PDF FUMs Index - PFS_MEX_FUM1.LBL Label file for FUM 1 - Instrument description - PFS_MEX_FUM1.PDF FUM 1 - Instrument description - PFS_MEX_FUM2.LBL Label file for FUM 2 - Instrument performance budgets - PFS_MEX_FUM2.PDF FUM 2 - Instrument performance budgets - PFS_MEX_FUM3.LBL Label file for FUM 3 - Instrument software and memory map - PFS_MEX_FUM3.PDF FUM 3 - Instrument software and memory map - PFS_MEX_FUM4.LBL Label file for FUM 4 - Housekeeping information - PFS_MEX_FUM4.PDF FUM 4 - Housekeeping information - PFS_MEX_FUM5.LBL Label file for FUM 5 - Operating, non-operating conditions and interfaces - PFS_MEX_FUM5.PDF FUM 5 - Operating, non-operating conditions and interfaces - PFS_MEX_FUM7.LBL Label file for FUM 7 - Instrument operation manual - PFS_MEX_FUM7.PDF FUM 7 - Instrument operation manual - PFS_MEX_FUM8.LBL Label file for FUM 8 - Science operations - PFS_MEX_FUM8.PDF FUM 8 - Science operations - PFS_MEX_FUM9.LBL Label file for FUM 9 - Tm_tc interface data base - PFS_MEX_FUM9.PDF FUM 9 - Tm_tc interface data base - PFS_ON_MARS_EXPRESS.LBL Label file for Instruments description article - PFS_ON_MARS_EXPRESS.PDF Instruments description article - PFS_SWC_CALIB.LBL Label file for SWC channel Calibration article - PFS_SWC_CALIB.PDF SWC channel Calibration article 3.4.2.5 Extras Directory The EXTRAS directory contains items that may be useful to a user, but are non- essential for the use of the data in the PFS data sets and are not essential for the PSA or compliance to the PDS Standards. The contents of the EXTRAS directory do not need to conform to PDS standards, and all files within this directory are produced and presented by the PFS team. In the PFS EXTRAS directory is a file that describes any special features of a given orbit. For example, any specific scientific objectives targeted, special events that occurred or tests that were completed for a given orbit are listed in this file. The file is presented in ASCII format. 3.4.2.6 Index Directory In this directory, there will be the following files produced by the PFS team. The PVV tool provided by the PSA generates the standard PDS index files automatically. The geometry index files are generated using the library provided by the PSA team. * INDXINFO.TXT: This ASCII file describes the contents of the INDEX directory * INDEX.TAB: This table lists the PFS data products in the data set * INDEX.LBL: This PDS detached label describes the INDEX.TAB file * GEO_MARS.TAB: A table of geometry and position information for the data products with a target reference body of Mars. * GEO_MARS.LBL: A PDS detached label describing the GEO_MARS.TAB file. 3.4.2.7 Geometry Directory The GEOMETRY directory contains the geometry file for PFS observation. The sub-directory structure is the same as the DATA directory, i.e. separated for LW and SW sensor and split in groups of 10 orbits. GEOMETRY data are only provided for Mars Commissioning Phase and only during science data acquisition: for these data there is a one-to-one link between data files and geometry files. The reason is that geometry information are used to localize each single observation in the local coordinate system of Mars, thus observations not relative to Mars have not meaningful geometry data. (except for Phobos) Geometry data structure are explained in detail in Par.4.3.2.1:Geometry Product A Design . These products are essential for data calibration and data analysis. GEOMETRY directory structure outline: GEOMETRY | | -LWC | |- ORB001X | |- ORB002X | |- SWC | - ORB001X | - ORB002X GEOMETRY files naming convection: PFS__MEAS_GEO_.DAT Orbit number. defines the type of the detector used for the interferogram acquisition: Short wavelength (SW) or Long wavelength (LW). extension depends on the type of file (LBL for a label file, DAT for the data product associated with the label). E.G. : PFS_0030_MEAS_GEO_LW.DAT PFS_0030_MEAS_GEO_LW.LBL The ‘.DAT’ product and ‘.LBL’ label above are product associated to data file aquired during science data acquisition in the orbit 30, namely the files PFS_0030_MEAS_HK_LW.DAT > housekeeping information collected during science data acquisition in orbit 30 PFS_0030_MEAS_RAW_LW.DAT> RAW data collected during science data acquisition in orbit 30 3.4.2.8 Label Directory The LABEL directory includes files that describe specific aspects of the data format and organization, like the common format for housekeeping and geometric data: * LABINFO.TXT: This file identifies and describes the function of each file in the LABEL subdirectory * PFS_HK.FMT: PFS Housekeeping file common structure definition 3.4.2.9 Software Directory The SOFTWARE directory contains software designed only to extract the data. It is written in IDL language. For analyses, the PFS team use internal software specifically developed. The products are in standard PDS format, so it is possible to use PDS reader software to read all products. Subdirectory contains: * SOFTINFO.TXT: This file identifies and describes the function of each file in the SOFTWARE subdirectory * ZIPINFO.ZIP: This file provides an overview of the ZIP file format * SOFT.ZIP: This file contains all provided software in ZIP format. For extended description see SOFT_README.TXT inside 4 Detailed Interface Specifications This section describes in detail the contents of the PFS data sets, describing the structure of the data sets themselves and the design of the individual data products provided. The Appendices provide examples of the PDS labels and the complete directory structure of an example data set. 4.1 Structure and Organization Overview The PFS data sets are structured as illustrated in Section 3.4.2. During the nominal mission, essentially 20 products will be provided for every observational orbit. These will be organized into DATA subdirectories as described in chapter 3.4.2.3, separating observations into groups of 10 orbits. For each orbit, 8 files will be present, 4 for each sensor. In the long-term when calibrated data are available, a further 2 products will be available, one for each sensor, as listed below: PFS__CAL_RAW_SW.DAT PFS__CAL_RAW_SW.LBL Current Delivery PFS__CAL_HK_SW.DAT PFS__CAL_HK_SW.LBL PFS__MEAS_RAW_SW.DAT PFS__MEAS_RAW_SW.LBL PFS__MEAS_HK_SW.DAT PFS__MEAS_HK_SW.LBL PFS__CAL_RAW_LW.DAT PFS__CAL_RAW_LW.LBL PFS__CAL_HK_LW.DAT PFS__CAL_HK_LW.LBL PFS__MEAS_RAW_LW.DAT PFS__MEAS_RAW_LW.LBL PFS__MEAS_HK_LW.DAT PFS__MEAS_HK_LW.LBL PFS__MEAS_RAD_SW.DAT PFS__MEAS_RAD_SW.LBL Long term PFS__MEAS_RAD_LW.DAT PFS__MEAS_RAD_LW.LBL PFS__MEAS_GEO_SW.DAT PFS__MEAS_GEO_SW.LBL Current Delivery PFS__MEAS_GEO_LW.DAT PFS__MEAS_GEO_LW.LBL Files are named according to the scheme described in Section 3.1.4: PFS____. As can be seen, there will be a data product, and associated geometry and housekeeping files for each orbit, along with their corresponding detached PDS label files. The data provided contain the raw data from the SW and LW sensors. These are interferograms acquired directly from PFS with no modification or validation. Currently, there are no plans to deliver higher- level products to the PSA for archiving, as the calibration is extremely unstable (see [4] and [5]) 4.2 Data Sets, Definition and Content PFS data sets will be generated and delivered to the PSA for every mission phase. The data sets will follow the identifier conventions outlined in Section 3.1.2, whereby a DATA_SET_ID will be of the form: ----- -V Where: = MEX for Mars Express = M for Mars. = PFS for the Planetary Fourier Spectrometer = 2 the CODMAC processing level [1] : = EDR the type of data in the data set (Experimental Data Record) [1]. : = NOMINAL this will refer to the mission phase. = <1.0> the version of the data set This gives a data set ID of the form: MEX-M-PFS-2-EDR-NOMINAL-V1.0 > data set for the nominal mission phase data. MEX-M-PFS-2-EDR-EXT1-V1.0 > data set containing data from the first extended MISSION phase. MEX-M-PFS-2-EDR-EXT2-V1.0 > data set containing data from the second extended MISSION phase. MEX-M-PFS-2-EDR-EXT3-V1.0 > data set containing data from the third extended MISSION phase. During the nominal Mars phase, the Mars Express spacecraft completes approximately 100 orbits every 4 weeks, of which around 80 will be science orbits. 4.3 Data Product Design In this section, we break down the structure of the individual product labels and describe the PDS keywords used for each data product type. 4.3.1 Data Product Design The following is a breakdown of an example label for the data product. A complete label example is provided in Appendix 7. 4.3.1.1 File Characteristics Data Elements These elements are present in the labels for every data product, and they describe the basic characteristics of the data product in terms of structure and naming: RECORD_TYPE = FIXED_LENGTH This describes the type of records used in the file. A ‘record’ is a single line in a data product, and records can therefore be fixed in length throughout the product, variable in length within a product, or can be a stream. For PFS products, every record inside the file has a fixed length. RECORD_BYTES = 32780 This element defines the length for every record. The value used is different for the SW and LW channel data and depend on the transmission mode used. The example above is for data from the SW channel using DTM 17 (for details on data packet structure see [6]). FILE_RECORDS = 240 This element defines the number of records inside the file. The value depends of the acquisition session duration inside the orbit. FILE_NAME = “PFS_0010_MEAS_RAW_SW.LBL" This element defines the Product File Name. 4.3.1.2 Data Object Pointers Identification Data Elements These elements are the same for every data product, and point to the data product that corresponds to the label being read: ^TABLE =” PFS_0010_MEAS_RAW_SW.DAT” For PFS, only one pointer is present, identifying the binary table within which the data are stored. 4.3.1.3 Identification Data Elements These elements are present in every product label, and are used to describe and identify the data set, the target, and the mission. DATA_SET_ID = MEX-M-PFS-2-EDR-NOMINAL-V1.0 Data set ID that uniquely identifies the PFS dataset. DATA_SET_NAME = “Mars Express Mars PFS EDR Nominal Mission Data V1.0” Dataset Name describing in long hand the identification elements of the DATA_SET_ID. PRODUCT_ID = PFS_0010_MEAS_RAW_SW This element uniquely identifies the product within the data set. PRODUCT_CREATION_TIME = 2007-02-01T10:08:39 MISSION_NAME = “MARS EXPRESS” INSTRUMENT_HOST_NAME = “MARS EXPRESS” INSTRUMENT_HOST_ID = MEX PRODUCT_TYPE = EDR The product type keyword describes the type of data present. For the default PFS datasets, this will always be EDR, meaning Experiment Data Record. This corresponds to CODMAC level 2 data [1]. TARGET_NAME = "MARS" Target Name for the observation: “MARS” , ”PHOBOS” or “INTERNAL SOURCE” TARGET_TYPE = “CALIBRATION" Type of target observed: “CALIBRATION”, “PLANET” or “SATELLITE” MISSION_PHASE_NAME =” MC Phase 0” This identifies the phase of the mission in which the data were produced. START_TIME = 2004-01-10T12:55:37.796 STOP_TIME = 2004-01-10T12:59:37.845 Start and stop time of the observation. SPACECRAFT_CLOCK_START_COUNT = 1\ 21819852.1234 SPACECRAFT_CLOCK_STOP_COUNT = 1\ 21819856.1234 For details of the spacecraft, clock formation, please see Section 3.2.2 on Time Standards. PRODUCER_ID = "PFS_TEAM" PRODUCER_FULL_NAME = “PFS SCIENCE TEAM" PRODUCER_INSTITUTION_NAME = "INAF-CNR" 4.3.1.4 Instrument Related Parameters These elements are present in the labels of every data product INSTRUMENT_ID = "INFRARED INTERFEROMETER" INSTRUMENT_NAME = "PLANETARY FOURIER SPECTROMETER" INSTRUMENT_TYPE = "SPECTROMETER" INSTRUMENT_MODE_ID = CAL_17 Instrument mode used for this observation. For details of the various instrument modes, please see [6], chapter 4.5. Each mode contains data packets of different length and different kind: for example the most used, themode 17, contains a 256 byte header, the full interferogram from SW channel (32768 byte) and the full interferogram from LW channel (8192 byte). On the other hand the mode 0, used to test instrument perfomances, contains a 512 byte header, a data section of 32768 bytes filled with the zero crossing of the reference channel , a 8100 byte length section containing sinewave from reference channel with different sampling and a 72 byte empty byte. DETECTOR_ID = "SW" Inside PFS, there is a Short Wavelength detector and Long Wavelength detector. This object indicates which detector is used to acquire the data: SW for Short Wavelength detector and LW for Long Wavelength detector. DETECTOR_DESC = "SW IS A SHORT WAVELENGTH DETECTOR; LW IS A LONG WAVELENGTH DETECTOR” SPACECRAFT_POINTING_MODE = NADIR For Mars Express the following pointing modes are possible: NADIR, ALONGTRACK, ACROSSTRACK, TRACKING, INERT, LIMB. SPACECRAFT_POINTING_MODE_DESC = "NADIR - This pointing mode is used to define a pointing to center the target body” SPACECRAFT_ORIENTATION = (0,1,0) ^MEX_ORIENTATION_DESC = "MEX_ORIENTATION_DESC.TXT" INSTRUMENT_CALIBRATION_DESC = “N/A" The INSTRUMENT_CALIBRATION_DESC element explains the calibration method adopted and identifies reference documents, which explain in detail the calibration of the instrument. For example, this element might explain whether the calibration was time-independent (i.e. a single algorithm was used) or time-dependent, and whether the calibration was performed in-flight or in a laboratory. This keyword will only be used for the calibrated data set and will remain “N/A:” for all other data sets. 4.3.1.5 Data Object Definition This section of the label defines the structure and content of the data product. For PFS, these are different for the LW and SW detectors. The data objects for PFS are binary tables. The columns within each table are described in the sections below. 4.3.1.5.1 SW channel RAW data file content for mesurement and calibration C = column TABLE = SW_PERICENTER_UNPROCESSED_TABLE SIZE = 32780 byte C OBT OBSERVATION TIME 10 byte REAL enumerated C Start Time of observation given in SCET, the SCET is a time format given in sun modified Julian date starting from 1970-01-01T12:00:00 (TBC). C SCET OBSERVATION TIME 4 byte PC_INTEGER enumerated C Start Time of observation given in on-board time that is seconds and fraction of seconds since 2003-05-04 (TBC). C SW RAW POINT 2 byte PC_INTEGER enumerated C SW interferogram quantization element. This is the RAW value acquired directly from the AD converter connected to SWC detector. Every point is a 16 bit signed integer. TABLE = SW_PERICENTER_UNPROCESSED_TABLE 4.3.1.5.2 LW channel RAW data file content for mesurement and calibration C = column TABLE = LW_PERICENTER_UNPROCESSED_TABLE SIZE = 8204 byte C OBT OBSERVATION TIME 10 byte PC_REAL enumerated C Start Time of observation given in SCET, the SCET is a time format given in sun modified Julian date starting from 1970-01-01T12:00:00 (TBC). C SCET OBSERVATION TIME 4 byte PC_INTEGER enumerated C Start Time of observation given in on-board time that is seconds and fraction of seconds since 2003-05-04 (TBC). C LW RAW POINT 2 byte PC_INTEGER enumerated C SW interferogram quantization element. This is the RAW value acquire directly from the AD converter connected to LWC detector. Every point is a 16 bit signed integer. END TABLE = LW_PERICENTER_UNPROCESSED_TABLE 4.3.1.5.3 LW and SW channel HK data file content C = column C OBT OBSERVATION TIME 10 byte PC_INTEGER enumerated C Start Time of observation given in SCET, the SCET is a time format given in sun modified Julian date starting from 1970-01-01T12:00:00 (TBC). C SCET OBSERVATION TIME 4 byte PC_INTEGER enumerated C Start Time of observation given in on-board time that is seconds and fraction of seconds since 2003-05-04 (TBC). C TYPE OF MEASUREMENTS 2 byte PC _UNS_INT enumerated C Type of measurement: (0: Calibration, 1: Real Measurement, 2: Reference Channel). C SOFTWARE VERSION 2 byte PC_ UNS_INT enumerated C Number of software version. C ZOPD SW FW 2 byte PC_ UNS_INT enumerated C Number of point offset for SW channel zero optical path difference in forward. C ZOPD SW RV 2 byte PC_ UNS_INT enumerated C Number of point offset for SW channels zero optical path difference in reverse. C ZOPD LW FW 2 byte PC_ UNS_INT enumerated C Number of point offset for LW channel zero optical path difference in forward. C ZOPD LW RV 2 byte PC_ UNS_INT enumerated C Number of point offset for LW channel zero optical path difference in reverse. C SCANNER POSITION 2 byte PC_ UNS_INT enumerated C Scanner orientation: (0 – Internal Black Body; 2 - Deep Space; 1 - Angle +25; 3 - Angle +12.5; 7 - Nadir; 6 - Angle -12.5; 4 - Angle -25; 5 – Internal Calibration lamp) C HIGHEST CUTOFF FREQ. SW ZEROX 4 byte PC_REAL Hz C This parameter defines the period of the highest cutoff frequency for the SW Zero Crossing Preamplifier Filter (8th order). The lowest cutoff frequency is fixed (500 Hz, 2nd order) and unalterable. This value should be at least twice the reference frequency in order to maintain the speed control loop within the settling time value. This is of course true only for the reference signal used for such a purpose. C HIGHEST CUTOFF FREQ. LW ZEROX 4 byte PC_REAL Hz C The same as “HIGHEST CUTOFF FREQ. SW ZEROX” but for the LW Zero Crossing Preamplifier Filter. C SPEED CLOCK 4 byte PC_REAL Hz C This parameter sets the reference frequency for the speed control loop (normally 2000 Hz). Thus this value sets the speed of the double pendulum and consequently also the medium sampling frequency of the reference channel used for controlling the speed. C ADCs SERIAL CONVERTERS CLOCK 4 byte PC_REAL Hz C This parameter defines the frequency used for the serial to parallel converter for the ADCs. In normal conditions it should not be touched. C HIGHEST CUTOFF FREQ. SW DET 4 byte PC_REAL Hz C This parameter defines the period of the highest cutoff frequency for the SW Detector Preamplifier Filter (8th order). The lowest one is fixed (500 Hz, 2nd order). It should be set at 4 kHz but for the quantization error, it is set at 4.4 kHz. This filter is an anti-aliasing filter for the SW ADCs, so it should be changed according to the speed of the double pendulum. Along the lowest cutoff frequency, it also limits the band pass of signal and noise and consequently the spectral range, too. C HIGHEST CUTOFF FREQ. LW DET 4 byte PC_REAL Hz C This parameter defines the period of the highest cutoff frequency for the LW Detector Preamplifier Filter (8th order). The lowest one is fixed (50 Hz, 2nd order). It should be set at 500 Hz but for the quantization error, it is set at 513 Hz. This filter is an anti-aliasing filter for the LW ADCs, so it should be changed according to the speed of the double pendulum. Along the lowest cutoff frequency, it also limits the band pass of signal and noise and consequently the spectral range, too. C SW DETECTOR GAIN 2 byte PC _UNS_INT enumerated C SW detector gain (1 to 128) C LW DETECTOR GAIN 2 byte PC _UNS_INT enumerated C LW detector gain (1 to 8) C SW ADC 2 byte PC _UNS_INT enumerated C SW channel A/D converter (1: Wake up ADC 1a SW signal sampled every SW zero crossing pulse (Default); 2: Wake up ADC 2b SW signal sampled every LW zero crossing pulse (Recovery))" C SW ADC SECOND 2 byte PC _UNS_INT enumerated C Redundant SW channel A/D converter (1: Wake up ADC 1a SW signal sampled every SW zero crossing pulse (Default); 2: Wake up ADC 2b SW signal sampled every LW zero crossing pulse (Recovery))" C LW ADC 2 byte PC _UNS_INT enumerated C LW channel A/D converter (1: Wake up ADC 2a LW signal sampled every LW zero crossing pulse (Default); 2: Wake up ADC 1b LW signal sampled every SW zero crossing pulse (Recovery))" C LW ADC SECOND 2 byte PC _UNS_INT enumerated C Redundant LW channel A/D converter (1: Wake up ADC 2a LW signal sampled every LW zero crossing pulse (Default); 2: Wake up ADC 1b LW signal sampled every SW zero crossing pulse (Recovery))" C PENDULUM MOTOR 2 byte PC _UNS_INT enumerated C This value shows the double pendulum motor being used : Secondary or Primary. In case of motor or driver failure one can select the working one, if any! By default is set to the primary one ( 0:Secondary ;1:Primary). C PENDULUM DIRECTION 2 byte PC _UNS_INT enumerated C Double Pendulum direction 0:Forward; 1:Reverse). C ZOPD SW 2 byte PC _UNS_INT enumerated C This represents the Zero Optical Path Difference Position revealed by the TRW 1 detector (ZOPDD). This information gives to OBDM the reference in order to centre the SW interferogram. The correct value should be around 18000 (number of bytes from the beginning up to the centre of SW interferogram) but it can change a little (overall when Module-O is not horizontal) maintaining the interferogram centered. C ZOPD LW 2 byte PC _UNS_INT enumerated C This represents the Zero Optical Path Difference Position revealed by TRW 2 detector (ZOPDD). This information gives to OBDM the reference in order to centre the LW interferogram. The correct value should be around 4500 (number of bytes from the beginning up to the centre of LW interferogram) but it can change a little (overall when Module-O is not horizontal) maintaining the interferogram centered. C PENDULUM END RIGHT 2 byte PC _UNS_INT enumerated C That reveals if during the measure the double pendulum has touched the Right micro switch and, if so, how many times it did. If different from 0 this can highlight a malfunction of the motion. C PENDULUM END LEFT 2 byte PC _UNS_INT enumerated C That reveals if during the measure the double pendulum has touched the Left micro switch and, if so, how many times it did. If different from 0 this can highlight a malfunction of the motion. C LASER 1 POWER 8 byte PC _REAL mW C This parameter defines the power set point for the Short Wavelength Laser Diode. Even though the power can be changed from 0 up to 4.97 mW, normally there is an ideal value (depending on the working Temperature and on the single device), which reduces at the minimum level the low frequency modulation due to the side lobs. The narrower the emission line the better reference signal. C LASER 2 POWER 8 byte PC _REAL mW C The same as Laser 1 Power but for Long Wavelength. C DETECTOR 1 POWER 8 byte PC _REAL mW C This parameter defines the power set point for the Short Wavelength Detector. C DETECTOR 2 POWER 8 byte PC _REAL mW C The same as Detector 1 Power but for Long Wavelength. C IB1 TEMP 8 byte PC _REAL K C High thermal gradients on the mono block (the holder for the beam splitters) can be in principle not a good start point to begin a measurement, so we should reduce them. IB1, IB8 defines the set points of the 8 individual temperature controllers. Normally, in the real conditions, they should be kept at 13? C. In the FUM document you can find where the temperature readings and controlling are placed inside IB (Interferometer Block)". C IB2 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB3 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB4 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB5 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB6 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB7 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C IB8 TEMP 8 byte PC _REAL K C The same as the IB 1 temp. C LASER DIODE 1 TEMP 8 byte PC _REAL K C This defines the Temperature set point for the Short Wavelength Temperature controller. This should be set at least 1.5? C over the average Temperature of IB for having a good stability. In our case, it is set at 15? C. This parameter is crucial for the good working of Module-O. The Temperature of Laser, more than the power, determines the presence of the side lobs and it can make them become so strong that the speed controller could fail (in this extreme case Module-O is not capable of taking any measurements at all!). In case of this very bad condition, we can of course use the other reference channel, the one not used at the moment. The temperature of the Laser is also important for the spectral calibration, because the emission line wavelength changes versus Temperature for approximately 0.4 nm per 1K. C LASER DIODE 2 TEMP 8 byte PC _REAL K C The same as Laser 1 (SW) Temperature but for Long Wavelength. C SW DETECTOR TEMP 8 byte PC _REAL K C This parameter defines the set point temperature for the Short Wavelength detector controller and should be set between 200 K and 250 K depending on the condition. This one is important for the calibration as the detector changes its responsivity along with its temperature. Keep in mind that clearly the temperature controlling is done by set-points level. C LW DETECTOR TEMP 8 byte PC _REAL K C This parameter defines the set point temperature for the Long Wavelength detector controller. Also in this case the temperature controlling is done by set-points level. C INTERNAL BLACKBODY TEMP. 1 8 byte PC _REAL K C This parameter defines the set point Temperature for the internal Blackbody source. C INTERNAL BLACKBODY TEMP. 2 8 byte PC _REAL K C This parameter defines the redundant set point Temperature for the internal Blackbody source. C TRW 1 TEMP 8 byte PC _REAL K C Temperature of SW TRW. C TRW 2 TEMP 8 byte PC _REAL K C Temperature of LW TRW. C CALIBATION LAMP VOLTAGE 8 byte PC _REAL V C Voltage of internal calibration lamp. 4.3.2 Data Product B Design 4.3.2.1 Geometry Product A Design C = column C SCET 8 byte PC_REAL sec   C Spacecraft event time C LONGITUDE 8 byte PC_REAL deg   C FOV center Longitude C LATITUDE 8 byte PC_REAL deg   C FOV center Latitude C SPACECRAFT_ALTITUDE 8 byte PC_REAL Km   C Spacecraft altitude C Local_Time 4 byte PC_REAL Hours   C FOV center local time C Solar_Longitude 8 byte PC_REAL deg   C Solar Longitude C INCIDENC_EANGLE 4 byte PC_REAL deg   C Incidence angle C EMISSION_ANGLE 4 byte PC_REAL deg   C Emission angle C PHASE_ANGLE 4 byte PC_REAL deg   C Phase angle C MOLA_ALTIMETRY 4 byte PC_REAL m   C FOV center Mola Altimetry C LW_TANGENT_ALTITUDE 4 byte PC_REAL Km   C Limb altitude C LW_TARGET_DISTANCE 4 byte PC_REAL Km   C Distance from the spacecraft to the target point C SOLAR_DISTANCE 4 byte PC_REAL AU   C Mars-Solar distance C SUBSOLAR_LONGITUDE 8 byte PC_REAL deg   C Longitude of the sub-solar point C   SUBSOLAR_LATITUDE 8 byte PC_REAL deg   C Latitude of the sub-solar point C PLANETARY_PHASE_ANGLE 4 byte PC_REAL deg C Planetary phase angle C SUB_SPACECRAFT_LONGITUDE 8 byte PC_REAL deg   C Longitude of the sub-spacecraft point C SUB_SPACECRAFT_LATITUDE 8 byte PC_REAL deg   C Latitude of the sub-spacecraft point C JULIAN_DATE 8 byte PC_REAL     C Julian Date C AIR_MASS 4 byte PC_REAL     C Secant of the emission angle TABLE = SW_PERICENTER_UNPROCESSED_TABLE SIZE = 32780 byte C OBT OBSERVATION TIME 10 byte REAL enumerated C Start Time of observation given in SCET, the SCET is a time format given in sun modified Julian date starting from 1970-01-01T12:00:00 (TBC). C SCET OBSERVATION TIME 4 byte PC_INTEGER enumerated C Start Time of observation given in on-board time that is seconds and fraction of seconds since 2003-05-04 (TBC). C SW RAW POINT 2 byte PC_INTEGER enumerated C SW interferogram quantization element. This is the RAW value acquired directly from the AD converter connected to SWC detector. Every point is a 16 bit signed integer. TABLE = SW_PERICENTER_UNPROCESSED_TABLE 5 Appendix: Example of Directory Listing of PFS Data Set A full example of PFS Dataset structure is listed here. Some obvious repetition are not shown here, but replaced with […] : e.g., for DATA subdirectory, from LW/ to SW/ subdirectories the only changes is “LW” to “SW” in filename. ROOT/ |-AAREADME.TXT | |-CATALOG/ | |-CATINFO.TXT | |-DATASET.CAT | |-INST.CAT | |-INSTHOST.CAT | |-MISSION.CAT | |-REFERENCE.CAT | |-RELEASE.CAT | |-SOFT.CAT | |-TARGET.CAT | |-DATA/ | |-IC/ | | |-LWC/ | | | |-PFS_ICM_CAL_HK_LW.DAT | | | |-PFS_ICM_CAL_HK_LW.LBL | | | |-PFS_ICM_CAL_RAW_LW.DAT | | | |-PFS_ICM_CAL_RAW_LW.LBL | | | |-PFS_ICM_MEAS_HK_LW.DAT | | | |-PFS_ICM_MEAS_HK_LW.LBL | | | |-PFS_ICM_MEAS_RAW_LW.DAT | | | |-PFS_ICM_MEAS_RAW_LW.LBL | | |-SWC/ | | |-[...] | | | |-MARS/ | | |LWC/ | | | |-ORB001X/ | | | | |-PFS_0010_CAL_HK_LW.DAT | | | | |-PFS_0010_CAL_HK_LW.LBL | | | | |-PFS_0010_CAL_RAW_LW.DAT | | | | |-PFS_0010_CAL_RAW_LW.LBL | | | | |-PFS_0010_MEAS_HK_LW.DAT | | | | |-PFS_0010_MEAS_HK_LW.LBL | | | | |-PFS_0010_MEAS_RAW_LW.DAT | | | | |-PFS_0010_MEAS_RAW_LW.LBL | | | |-ORB002X/ | | | [...] | | |-SWC/ | | |-[...] | |-NEV/ | |-LWC/ | | |-PFS_NEV2_CAL_HK_LW.DAT | | |-PFS_NEV2_CAL_HK_LW.LBL | | |-PFS_NEV2_CAL_RAW_LW.DAT | | |-PFS_NEV2_CAL_RAW_LW.LBL | | |-PFS_NEV2_MEAS_HK_LW.DAT | | |-PFS_NEV2_MEAS_HK_LW.LBL | | |-PFS_NEV2_MEAS_RAW_LW.DAT | | |-PFS_NEV2_MEAS_RAW_LW.LBL | |-SWC/ | |-[...] | |-DOCUMENT/ | |-DOCINFO.TXT | |-MEX-PFS-PSA-ICD-24.ASC | |-MEX-PFS-PSA-ICD-24.LBL | |-MEX-PFS-PSA-ICD-24.PDF | |-MEX-PFS-PSA-ICD_FIG_1.PNG | |-MEX-PFS-PSA-ICD_FIG_2.PNG | |-MEX-PFS-PSA-ICD_FIG_3.PNG | |-MEX-PFS-PSA-ICD_FIG_4.PNG | |-MEX_ORIENTATION_DESC.LBL | |-MEX_ORIENTATION_DESC.TXT | |-PFS_CAL_LAB_1.LBL | |-PFS_CAL_LAB_1.PDF | |-PFS_CAL_LAB_2.LBL | |-PFS_CAL_LAB_2.PDF | |-PFS_CAL_NEAREARTH.LBL | |-PFS_CAL_NEAREARTH.PDF | |-PFS_LWC_CALIB.LBL | |-PFS_LWC_CALIB.PDF | |-PFS_MEX_FUM.LBL | |-PFS_MEX_FUM.PDF | |-PFS_MEX_FUM1.LBL | |-PFS_MEX_FUM1.PDF | |-PFS_MEX_FUM2.LBL | |-PFS_MEX_FUM2.PDF | |-PFS_MEX_FUM3.LBL | |-PFS_MEX_FUM3.PDF | |-PFS_MEX_FUM4.LBL | |-PFS_MEX_FUM4.PDF | |-PFS_MEX_FUM5.LBL | |-PFS_MEX_FUM5.PDF | |-PFS_MEX_FUM7.LBL | |-PFS_MEX_FUM7.PDF | |-PFS_MEX_FUM8.LBL | |-PFS_MEX_FUM8.PDF | |-PFS_MEX_FUM9.LBL | |-PFS_MEX_FUM9.PDF | |-PFS_ON_MARS_EXPRESS.LBL | |-PFS_ON_MARS_EXPRESS.PDF | |-PFS_SWC_CALIB.LBL | |-PFS_SWC_CALIB.PDF | |-ERRATA.TXT | |-EXTRAS/ | |-EXTRINFO.TXT | |-PFS_REPORT.LBL | |-PFS_REPORT.TXT | |-GEOMETRY/ | |-GEOMINFO.TXT | |-LWC/ | | |-ORB001X/ | | | |-PFS_0010_MEAS_GEO_LW.DAT | | | |-PFS_0010_MEAS_GEO_LW.LBL | | |-ORB002X/ | | |-[...] | |-SWC/ | |-[...] | |-INDEX/ | |-LABEL/ | |-LABINFO.TXT | |-PFS_HK.FMT | |-SOFTWARE/ | |-SOFT.LBL | |-SOFT.zip | |-SOFTINFO.TXT | |-ZIPINFO.TXT | |-VOLDESC.CAT 6 Appendix: Complete Label file Examples PDS_VERSION_ID = PDS3 LABEL_REVISION_NOTE = "PFS PRODCUTION SOFTWARE 2.10" /* File Characteristics */ RECORD_TYPE = FIXED_LENGTH RECORD_BYTES = 8204 FILE_RECORDS = 240 FILE_NAME = "PFS_0010_MEAS_RAW_LW.LBL" RELEASE_ID = 1 REVISION_ID = 0 /* Data Pointers */ ^TABLE = "PFS_0010_MEAS_RAW_LW.DAT" /* Identification Elements */ DATA_SET_ID = "MEX-M-PFS-2-EDR-NOMINAL-V1.0" DATA_SET_NAME = "Mars Express Mars PFS EDR Nominal Mission Data V1.0" PRODUCT_ID = PFS_0010_MEAS_RAW_LW PRODUCT_CREATION_TIME = 2007-02-06T15:10:25.980 MISSION_NAME = "MARS EXPRESS" INSTRUMENT_HOST_NAME = "MARS EXPRESS" INSTRUMENT_HOST_ID = MEX PRODUCT_TYPE = EDR TARGET_TYPE = "PLANET" TARGET_NAME = "MARS" MISSION_PHASE_NAME = "MC Phase 0" ORBIT_NUMBER = 10 START_TIME = 2004-01-10T11:04:12.189 STOP_TIME = 2004-01-10T12:55:38.719 SPACECRAFT_CLOCK_START_COUNT = 21819852.18989 SPACECRAFT_CLOCK_STOP_COUNT = 21826538.71960 PRODUCER_ID = PFS_TEAM PRODUCER_FULL_NAME = "PFS SCIENCE TEAM" PRODUCER_INSTITUTION_NAME = "INAF-CNR" INSTRUMENT_ID = PFS INSTRUMENT_NAME = "PLANETARY FOURIER SPECTROMETER" INSTRUMENT_TYPE = "INFRARED INTERFEROMETER" INSTRUMENT_MODE_ID = MEAS_17 DETECTOR_ID = LW DETECTOR_DESC = "SW IS A SHORT WAVELENGTH DETECTOR; LW IS A LONG WAVELENGTH DETECTOR" SPACECRAFT_POINTING_MODE = NADIR SPACECRAFT_POINTING_MODE_DESC = "NADIR - This pointing mode is used to define a pointing to centre the target body" SPACECRAFT_ORIENTATION = (0,1,0) ^MEX_ORIENTATION_DESC = "MEX_ORIENTATION_DESC.TXT" INSTRUMENT_CALIBRATION_DESC = "N/A" /* Object Definitions */ OBJECT = TABLE NAME = PFS_LW_RAW_DATA INTERCHANGE_FORMAT = BINARY ROWS = 240 ROW_BYTES = 8204 COLUMNS = 3 DESCRIPTION = RAW DATA OBJECT = COLUMN BYTES = 8 DATA_TYPE = REAL NAME = "OBT OBSERVATION TIME" START_BYTE = 1 UNIT = "second" DESCRIPTION = "START TIME OF OBSERVATION GIVEN IN SCET, THE SCET IS A TIME FORMAT GIVEN IN SUN MODIFIED JULIAN DATE " END_OBJECT = COLUMN OBJECT = COLUMN BYTES = 4 DATA_TYPE = LSB_FLOAT NAME = "SCET OBSERVATION TIME" START_BYTE = 9 UNIT = "UT" DESCRIPTION = "START TIME OF OBSERVATION GIVEN IN ON-BOARD TIME THAT IS SECONDS SINCE 2003- 05-03 " END_OBJECT = COLUMN OBJECT = COLUMN BYTES = 8192 DATA_TYPE = LSB_INTEGER NAME = "INTERFEROGRAM RAW DATA" ITEMS = 4096 ITEM_BYTES = 2 DESCRIPTION = "RAW INTERFEROGRAM ACQUIRED DIRECTLY FROM LW CHANNEL" START_BYTE = 13 UNIT = "N/A" END_OBJECT = COLUMN END_OBJECT = TABLE END 1 see Section 3.1.4 for details --------------- ------------------------------------------------------------ 8 PFS EAICD Document No. Issue/Rev. No. Date Page : MEX-PFS-DARC-EAICD-22 : 2.3 : 12 November 2004 : ii PFS EAICD Document No. Issue/Rev. No. Date Page : MEX-PFS-DARC-EAICD-25 : 2.5 : 30 January 2008 : i 8 PFS EAICD Document No. Issue/Rev. No. Date Page : MEX-PFS-DARC-EAICD-25 : 2.5 : 30 January 2008 : iii ESOC European Space Operations Centre PFS EAICD Document No. Issue/Rev. No. Date Page : MEX-PFS-DARC-EAICD-25 : 2.5 : 30 January 2008 : 30