Phoenix Project

Software Interface Specification (SIS)

MECA Non-imaging

Reduced Data Record (RDR)

Authors:

M. Hecht (JPL), S. Slavney (Washington U.), M.K. Crombie (Indigo Information Services, LLC) A. Stanboli (JPL), P. Zamani (JPL)

Custodian:

M. Hecht

Paper copies of this document may not be current and should not be relied on for official purposes.  The current version is in the Community Server at: Team Work Area/Mission System/MOS/GDS/OPGS-MIPL

JPL D-33232

19-DEC-2008

Jet Propulsion Laboratory

California Institute of Technology

DOCUMENT CHANGE LOG

TBD ITEMS

CONTENTS

1.       Purpose and Scope of Document................................................................................................... 6

2.       Applicable Documents......................................................................................................................... 6

3.       Relationships with Other Interfaces.................................................................................... 6

4.       Data Product Characteristics and Environment......................................................... 7

4.1     Instrument Overview........................................................................................................................ 7

4.1.1       Atomic Force Microscope (AFM)...................................................................................................... 7

4.1.2       Thermal and Electrical Conductivity Probe (TECP).................................................................. 13

4.1.3       Wet Chemistry Laboratory (WCL)................................................................................................... 15

4.1.4       Software and Electronics................................................................................................................. 17

4.2     Data Product Overview................................................................................................................. 17

4.3     Data Processing Overview........................................................................................................... 18

4.3.1 Data Processing Level............................................................................................................................. 19

4.1.2       Data Product Generation................................................................................................................. 19

4.3.1.1     AFM.................................................................................................................................................. 19

4.3.1.2     TECP................................................................................................................................................. 23

4.3.1.3     WCL.................................................................................................................................................. 25

4.3.1.3.1       ISE.......................................................................................................................................... 25

4.3.1.3.2       Conductivity............................................................................................................................ 28

4.3.1.3.3       CV.......................................................................................................................................... 30

4.3.1.3.4       CP........................................................................................................................................... 33

4.3.1.3.5       PT........................................................................................................................................... 36

4.3.2       Data Flow............................................................................................................................................ 39

4.3.3       Labeling and Identification standards.......................................................................................... 39

4.3.4       PDS Standards.................................................................................................................................... 39

4.3.5       Time Standards................................................................................................................................... 39

4.3.6       Data Storage Conventions............................................................................................................... 40

4.4     Data Validation and Peer Review........................................................................................... 40

5.       Detailed Data Product Specifications................................................................................ 41

5.1     Data Product Structure and Organization................................................................... 41

5.1.1       AFM...................................................................................................................................................... 41

5.1.1       TECP..................................................................................................................................................... 41

5.1.2       WCL...................................................................................................................................................... 41

5.2     Label and Header............................................................................................................................... 42

6.       Applicable Software.......................................................................................................................... 42

APPENDIX A - PRODUCT LEVELS..................................................................................................................... 44

APPENDIX B - PDS LABEL KEYWORDS.......................................................................................................... 45

APPENDIX C - RDR File naming convention....................................................................................... 52

Standards........................................................................................................................................................... 52

File Naming Rules.......................................................................................................................................... 52

APPENDIX D - Example RDR PDS LABELS................................................................................................. 56

AFM........................................................................................................................................................................... 56

AFM_SDR............................................................................................................................................................ 56

AFM_HEADER.FMT................................................................................................................................. 60

AFM_SDD............................................................................................................................................................ 64

AFM_D_HEADER.FMT............................................................................................................................ 69

AFM REPORT..................................................................................................................................................... 72

TECP.......................................................................................................................................................................... 73

TECP_EC............................................................................................................................................................. 73

TECP_HUM......................................................................................................................................................... 80

TECP_PRM......................................................................................................................................................... 85

TECP_TC............................................................................................................................................................. 90

WCL........................................................................................................................................................................... 96

ISE......................................................................................................................................................................... 96

CND.................................................................................................................................................................... 103

CV....................................................................................................................................................................... 107

CP....................................................................................................................................................................... 111

PT........................................................................................................................................................................ 115

APPENDIX E - Acronyms................................................................................................................................. 123

TABLES

Table 4‑1AFM RDR Data Types.............................................................................................................................. 17

Table 4‑2 TECP Data Types..................................................................................................................................... 18

Table 4‑3 WCL Data Types...................................................................................................................................... 18

Table 4‑4 AFM Header Table Column Names and Descriptions.................................................................... 19

Table 4‑5 TECP DN to Physical Unit Conversions............................................................................................. 23

Table 4‑6 Phoenix Coordinate Systems................................................................................................................. 25

Table 4‑7 ISE Header Fields..................................................................................................................................... 26

Table 4‑8 ISE Data Table Fields.............................................................................................................................. 27

Table 4‑9 Conductivity Header Fields................................................................................................................... 29

Table 4‑10. CV Header Table Fields...................................................................................................................... 31

Table 4‑11 CV Conversion from DN to physical units*..................................................................................... 31

Table 4‑12 CV Scan Header Fields......................................................................................................................... 32

Table 4‑13 CP Header Table Fields........................................................................................................................ 34

Table 4‑14 CP Conversions from DN to Physical Units..................................................................................... 34

Table 4‑15 CP Scan Header Fields.......................................................................................................................... 35

Table 4‑16 PT Header Table Fields........................................................................................................................ 37

Table 4‑17 PT DN to Physical Unit Conversion Factors................................................................................... 37

Table 4‑18 PT Data Fields and Descriptions........................................................................................................ 38

Table C‑19 MECA AFM Naming Conventions.................................................................................................... 52

Table C‑20 MECA TECP File Naming Conventions.......................................................................................... 53

Table C‑21 MECA WCL File Naming Conventions........................................................................................... 54

1.      Purpose and Scope of Document

The purpose of this document is to provide users of MECA Reduced Data Records (RDR) with a detailed description of the products and how they are generated, including data sources and destinations.

The document is intended to provide enough information to enable users to read and understand the data products. Intended users of this document are the scientists who will analyze the mission and supporting data, both those associated with the Phoenix Project and members of the general planetary science community.

2.     Applicable Documents

1.      Planetary Data System Standards Reference, JPL D-7669 part 2, version 3.7, March 20, 2006.

2.      Phoenix Project Archive Generation, Validation and Transfer Plan, JPL D-29392, Rev. 1.0, December 20, 2004.

3.      Planetary Data System Archive Preparation Guide, version 1.1, August 29, 2006.

4.      Mars Exploration Program Data Management Plan, Arvidson et al., Rev. 3.0, March 20, 2002.

5.      Data Management and Computation, Volume 1: Issues and Recommendations, Committee on Data Management and Computation, Space Science Board, Assembly of Mathematical and Physical Sciences, National Research Council, National Academy Press, Washington D.C., 1982

6.      Issues and Recommendations Associated with Distributed Computation and Data Management Systems for Space Sciences, Space Science Board, Assembly of Mathematical and Physical Sciences, National Research Council, National Academy Press, Washington D.C., 1986

7.      MECA Non-Imaging Experiment Data Record (EDR) Software Interface Specification, JPL-33232, January 25, 2007.

8.      MECA Non-Imaging EDR and RDR Archive Volume Software Interface Specification, Version 1.0, February 18, 2008.

3.     Relationships with Other Interfaces

This SIS document, and the products that it describes, could be affected by changes to the MECA or Phoenix flight software, the MECA EDR SIS [Applicable Document #7], or PDS standards. Such changes may require updates to this document as applicable. Major changes would require re-approval of all listed individuals and teams per the signature page.

4.     Data Product Characteristics and Environment

The Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) is a suite of soil analysis instruments that combines a wet chemistry laboratory (WCL), an optical microscope (OM), an atomic-force microscope (AFM), and a thermal and electrical-conductivity probe (TECP), with common supporting structure, electronics, and software.

Data in this product has been transformed from the digital numbers (DNs) in the lower level packets to physical units. Data from the OM, which are described in the Phoenix Camera EDR/RDR SIS, are archived on the Imaging node of the Planetary Data System. However, status information pertaining to those images and various tabular data that determine how they are acquired are part of this Non-Imaging product.

4.1      Instrument Overview

The MECA instrument suite is a component of the Mars ’07 Phoenix investigation, which will also return data from a Thermal and Evolved Gas Analyzer (TEGA), three cameras, and a meteorology suite (MET). Phoenix is motivated by the goals of (1) studying the history of water in all its phases, and (2) searching for habitable zones. Samples of surface and subsurface soil and ice will be delivered to MECA and TEGA from a trench excavated by a Robot Arm (RA), while MECA’s Thermal and Electrical Conductivity Probe (TECP) will be deployed in soil and air by the Robot Arm. The Robot Arm Camera (RAC) will document the morphology of the trench walls, while the Surface Stereo Imager (SSI) and the Mars Descent Imager (MARDI) establish a geological context. Throughout the mission, MET will monitor polar weather and local water transport.

4.1.1     Atomic Force Microscope (AFM)

The Atomic Force Microscope (AFM) is part of the MECA Microscopy Station, which comprises a Sample Wheel and Translation Stage (SWTS), an optical microscope (OM), and the AFM. As shown in Figure 4-1, the MECA AFM is located between the OM and the SWTS inside the darkened MECA enclosure on the spacecraft deck. It scans a small region (from 1-65 µm square) on any of 69 substrates, each 3-mm in diameter, positioned along the rim of the SWTS. The chief scientific objectives of the AFM are to analyze small dust and soil particles in terms of their size, size distribution, shape, and texture. The AFM is particularly well suited to analyze particles carried by the wind, which are believed to be in the size range 1-3 µm.

Prior to AFM scanning, OM images are acquired to document the substrates and provide context for the AFM scans. OM data is described in the Phoenix camera SIS, along with the RAC and SSI, and is outside the scope of this document. The reader is also referred to that document for more detailed description of the SWTS and its substrates.

The AFM is contributed by a Swiss-led consortium spearheaded by the University of Neuchatel. Run by a dedicated microcontroller, the AFM uses one of an array of eight micromachined cantilevers with sharp tips to obtain topographs (sometimes called “scans” or “images”) of up to a 65×65-µm area of the sample. Within this constraint the scan can be of any size, but the AFM can only address a narrow horizontal stripe of each substrate. Since the sample wheel can be rotated (but not elevated) prior to initiation of scanning, the AFM can access a thin band approximately 1/3 of the way up from the bottom of the corresponding OM image. Note that the x and y axes of the MECA AFM image are rotated by +45 degrees relative to the OM images (Figure 4-2).

The 69 substrates on the SWTS are divided into ten sets of six (a weak and a strong magnet, two “microbuckets”, a textured substrate, and a sticky silicone pad) and nine utility or calibration targets. Using the SWTS, these can be coated with a thin layer of dust or soil, and then rotated to the vertical scanning position where they can be imaged by the optical microscope. Of the six substrates in each set, two are specifically designed for AFM use in that they resist the tendency for particles to become dislodged and to adhere to the AFM tip. Such particle adhesion can degrade the scans in question and the quality of the tip in general. One of these substrates is a uniform piece of silicone that remains pliant under martian conditions. The second is a custom micro-machined silicon substrate with pits and posts that hold particles of an appropriate scale for AFM scanning. Two of the remaining four substrates are magnets that may, under certain circumstances, be appropriate for AFM scanning. The final two substrates are deep “buckets” that would not normally be accessible to the AFM.

There are three types of AFM calibration targets. The tip standard target is used to check the profile of the AFM tip and for 'reverse imaging'. The target is made up of an array of very sharp silicon tips (radius < 10nm), with a period of 3±0.05 microns, a diagonal period of 2.12 microns and a height of 0.3-0.5 microns. The tip opening angle is about 50 degrees. For more information on the target, see: http://www.ntmdt-tips.com/catalog/gratings/afm_cal/products/TGT1.html

The linear calibration target is used to check and correct the orthogonality of the AFM scan plane. It is an etched silicon target with a checkerboard pattern of square pillars with sharp undercut edges. The period is 3±0.05 microns and height is 0.3-0.6 microns. The curvature radius is less than 10 nm. For more information on the target, see: http://www.ntmdt-tips.com/catalog/gratings/afm_cal/products/TGX1.html

The tip finder target is used to accurately locate the AFM tip relative to the OM frame. The central part of the target is a 2x2 mm piece of quartz glass with an aluminium pattern on top. The quartz glass is painted with a white epoxy on the back before bonding to a cylindrical 3 mm aluminium disk that is inserted into the SWTS. 

Figure 4-2 shows an optical micrograph of the aluminum pattern.

There are 9 areas each of which are 320 microns wide by 256 microns tall. The “outer” 8 areas consist of vertical lines with a specific pitch. The pitch ranges from 6 microns to 20 microns between the white lines. All lines have a width of 4 microns.

The central region (Area 5) has a detailed pattern which includes a coding scheme to identify the position of the features (both laterally and vertically) within that region. Figure 4-3 shows a schematic of how the 8-bit binary coding is implemented for the vertical direction.

The top right hand corner of the detailed pattern is shown in Figure 4-4. The features are vertical lines and dots with 16 repeating patterns in the horizontal direction, each with a period of 20 microns. The periods are numbered 0-15 from left to right with a least significant bits 4-bit binary code.

The nanobucket substrates provide the possibility of in-situ scanner calibration and scan region location as they include patterns of micro-fabricated etched features. Figure 4-5 shows an optical image of one of the nanobucket substrates.

Five different features are included in these substrates:

            a) tear-shape beakers, ~ 5µm deep, on both sides of the substrate

            b) 5µm diameter round beakers with a pitch of 7µm and a depth of ~ 5µm,

            c) 20µm diameter round beakers with a pitch of 24µm and a depth of ~ 5µm,

            d) round posts of 3µm diameter and about 5µm height, having a pitch of 8µm,

            e) round posts of 3µm diameter and about 5µm height, having a pitch of 23µm.

To operate the microscopy station, soil samples are deposited by the RA (or dust from the air) onto a segment of the SWTS ring that has been extended such that exactly one set of 6 substrates protrudes from a horizontal slot in the MECA enclosure. Excess material is removed by passing the substrates under a blade positioned 0.2 mm above the surface, after which the samples are rotated from their horizontal load positions into their vertical imaging positions for imaging by the OM and AFM. The SWTS is also used for focusing and AFM coarse positioning.  

Attempting to scan excessively steep or ragged surfaces with the AFM will result in scans that are largely out of range, and could conceivably damage the tip. Further, bandwidth and time constraints severely limit the number of scans that can be acquired and returned to Earth. These considerations dictate a two-day imaging strategy for each set of microscopy samples. On the first day a sample is delivered, then characterized by the optical microscope. AFM calibration scans are also acquired. These images are evaluated on the ground and targets for AFM scanning are selected. On the second day the targeted areas are imaged again with the optical microscope, and then scanned with the AFM.

MECA’s AFM comprises three major components, a microfabricated probe-chip, an electro-magnetic scanner-actuator and single board control electronics. The probe-chip features 8 cantilevers, numbered 0-7. The chip is mounted with two orthogonal tilt angles of 10 degrees relative to the sample to ensure that only one tip contacts the sample at a time. In case of contamination or malfunction of this front-most tip, the defective cantilever and its support beam can be cleaved off by a special tool on the sample wheel, after which the next one in the array becomes active. The force constant of the levers varies between 9 and 13 N/m.

Each of the 8 MECA cantilevers features an integrated piezo-electric stress sensor, which is used to measure its pure deflection (static mode) or its vibration amplitude, frequency and phase (dynamic mode). In static mode the deflection signal is proportional to the force, while in dynamic mode the shift of the resonance frequency is a measure of the force gradient. Dynamic mode minimizes the interactions between tip and surface and is less likely to result in particles being moved around or dislodged during the scan. In either mode, these signals are used to regulate the distance between the tip and the sample in the z-direction by means of a proportional-integral feedback loop.

The z-axis servo signal (referred to has height) represents the sample topography as the tip is rastered across the surface in the x (fast) and y (slow) directions. (Though the resulting topograph is sometimes referred to as an image, it bears little resemblance to an optical image until it is transformed and processed.) Imperfect feedback or an out-of-range condition can result in residual bending of the cantilever in static mode, or a phase shift of the oscillation in dynamic mode. This error signal may optionally be recorded in a second data channel. Since each line in the raster scan begins at the same point on the x-axis, both primary and error signals may be recorded either on the forward or the backward legs of the scan (or, typically, both). Thus a single raster scan can produce up to four arrays of data: Forward (height), forward (error), backward (height), and backward (error), each of which can be displayed in image format.

Several of the status values returned in MECA telemetry refer to the configuration and status of the AFM digital feedback loop. The piezoresistors on the cantilevers are addressed by a multiplexer, which links them to a temperature-compensated Wheatsone bridge. For static mode imaging the value of the bridge is directly compared to a setpoint. For dynamic mode imaging a frequency modulation technique is applied that maintains the resonant frequency of the cantilever at a setpoint while stabilizing the amplitude. The measured parameters are the phase-shift between the excitation of the cantilever and the measured signal from the Wheatstone bridge, maintained by a phase locked loop. The array geometry is designed to spread the resonant frequencies of the levers between 30 and 40 kHz in order to avoid cross-talk during dynamic operation (these shift slightly with temperature).

It must be emphasized that an AFM scan is acquired by rastering a physical tool across a surface. As a result, line-to-line noise and artifacts may be significantly different than point-to-point artifacts along the scan direction. Moreover, outside the range of authority of the cantilever (approximately 65 x 65 micrometers laterally and 13 micrometers in height) the topograph does not go “out of focus” but simply saturates, while anywhere within its range of authority it is equally “in focus.” The topograph itself reflects the interaction between a tip of finite size and a non-uniform surface, and therefore convolves physical characteristics of both the probe and the target. Thus, while an AFM topograph may look like an image product, the processing required bears little in common with the processing of an actual optical image. The AFM data processing algorithms will be discussed in Section 4.3.1.1.

A full description of the MECA AFM instrument can be found in Hecht et al 2008. To jump to the next AFM section of the document see paragraph 4.3.1.1.

4.1.2     Thermal and Electrical Conductivity Probe (TECP)

An end-effector on the Phoenix Robotic Arm (figure 4-7), the TECP is a probe of soil physical properties including temperature, thermal conductivity and diffusivity, electrical conductivity and permittivity, as well as atmospheric temperature, humidity, and wind speed. These measurements are made with four conical needles, three of which contain electrical heaters and thermometers, and a hygrometer sensor mounted separately in the body of the TECP.

Three of the four parallel needles contain a thermocouple and a heater. The two needle pairs are used as electrodes for regolith electrical properties measurements (see figure 4-8). The same needles also serve as heating elements and thermometers for regolith thermal properties and wind speed measurements. The needles can be inserted into the soil for thermal and electrical measurements or positioned above the surface for atmospheric temperature, and wind speed measurements. Regolith thermal properties (including temperature, thermal conductivity, thermal diffusivity, volumetric heat capacity, and thermal inertia) as well as wind speed are derived from the heating and cooling behavior of the needles before and after a known amount of heat is added. Regolith electrical properties, including electrical conductivity and dielectric permittivity, are measured with capacitance and resistance sensors coupled to the regolith through the sensing needles. Atmospheric water vapor concentration is measured with a calibrated capacitance hygrometer mounted near a temperature sensor on the TECP printed circuit board, but exposed to the atmosphere through a particulate filter.

The humidity sensor determines the capacitance of the thin film hygrometer, which is a calibrated function of the relative humidity at the film surface. By measuring the film temperature with the adjacent temperature sensor, the result can be converted to absolute humidity. Under the assumption that gradients in vapor pressure are small, external relative humidity can be determined by comparison of the TECP result with the MET temperature sensors.

The scientific objectives of the TECP are:

• To provide ground-truth for orbital surface thermal measurements and input parameters for thermal models by directly measuring the thermal properties of Martian regolith.
• To measure the concentration and nature of water in martian regolith in solid, “non-frozen,” liquid, and vapor states.
• To determine changes in the reservoirs of water when soil is freshly exposed.
• To characterize the movement of water in and out of the soil by measuring atmospheric humidity, temperature, and wind speed above the surface.

Figure 4-7: TECP (right) mounted on the robotic arm. The small white circle on the lower left is the humidity sensor. The four needles at right perform the other sensor measurements.

Figure 4-8 Photograph of the TECP instrument (top) and with the external cover removed to allow access to the electronics board (bottom). For each needle, the numerical designation and functionality is identified at right.

TECP thermal and electrical properties measurement quality depends on proper needle placement by the RA. Non-linear insertion, partial insertion, and lateral movement all affect data quality negatively. Thermal properties measurements can also be negatively impacted by non steady state thermal conditions, and the TECP should therefore be allowed to equilibrate to its thermal environment before making thermal properties measurements.

Measurement electronics are contained in the body of the TECP, and include a 12 bit A/D converter, two phase detectors, three resistance bridges, and a digital shift register. The A/D converter and shift register communicate through a serial interface to an FPGA on the primary MECA control and measurement electronics (CME) board.

A full description of the TECP portion of the MECA instrument can be found in Zent et al., 2008. To skip to the next TECP specific section of this document see paragraph 4.3.1.2.

4.1.3     Wet Chemistry Laboratory (WCL)

MECA’s wet chemistry laboratory (WCL) comprises four single-use modules, each consisting of a beaker assembly and an actuator assembly (figure 4.9). The modules mix soil samples with a leaching solution in a pressure vessel for electrochemical analysis. The scientific objective of the WCL is to determine the total pH, redox properties, and concentration of the principal aqueously solvated components of the acquired soil samples.

Chemical data is returned by 26 distinct sensors, some redundant, lining the walls of each beaker. These measure: Temperature; pH (3); conductivity; oxidation-reduction potential; the anions chloride (2), bromide, and iodide; cations sodium, potassium, calcium, magnesium; and barium, used in a sulfate titration. Also included are electrodes for cyclic voltammetry, anodic stripping voltammetry, and chronopotentiometry (3). Lithium electrodes (2) are used as a reference relative to the known concentration of lithium salts in the solution. Sensors for nitrate, ammonium, dissolved oxygen and carbon dioxide, which for various reasons do not provide a quantitative measure of soil composition, are used only for context. A heater is imbedded in the base of the beaker to maintain water temperature during operation.

Each WCL actuator assembly (AA) includes a tank containing 26 ml of a calibration and leaching solution, a sample loading drawer with a capacity of ~1.0 cm³, temperature and pressure sensors, heaters, a stirring mechanism, and a device to dispense up to five small crucibles into the solution. The AA is responsible for soil, water, and solid reagent addition as well as stirring and two-zone internal heating (tank and drawer). Telemetry returned by the AA includes internal cell pressure, water storage tank and sampling drawer temperatures, and certain limit switch positions.

Each WCL experiment lasts two days (Sol A and Sol B), not necessarily sequential. After an initial post-landing checkout, preparation for a chemical experiment starts with melting the frozen leaching/calibration solution in the storage tank and delivering it to the beaker by actuating a puncture mechanism. Sensors are calibrated in that solution, and then calibrated again after addition of a crucible containing small quantities of specific salts. The combined ion concentration from the initial solution and from the crucible, less than 10-4 molar for most ions, establishes the detection floor. The final step is to open the sampling drawer and receive a sample from the robotic arm. The total sample volume is estimated with an accuracy of 0.25 cc (maximum 1 cc) from images acquired by the robot arm camera. For the remainder of the day, the concentration of major anions and cations are monitored as well as key indicators such as pH, redox potential, conductivity, and cyclic voltammetry, stirring when appropriate and maintaining a constant temperature of 5C. At the end of the day the solution is allowed to freeze in the beaker.

A second day (Sol B) of measurement begins with thawing of the solution in the beaker, determining the sensor baseline, and adding an acid-containing crucible to lower the pH. Monitoring continues as on the first day. The final activity is the sequential addition of three crucibles of barium chloride. A sulfate titration is performed by monitoring the barium and chloride levels as the crucible contents slowly dissolve.

Most sensors will have three separate calibration steps prior to their use on Mars. Each individual electrochemical sensor was first calibrated prior to integration into the beaker by laboratory measurement in several standard solutions using commercial electronics. The second calibration was performed with the same solutions after beaker integration, using flight-like analog electronics and a laboratory digital controller. The exceptions were the bromide and iodide sensors, which could not be tested after integration without contaminating the chloride sensor. The final two-point calibration will occur on Mars. In general, the ion selective electrodes exhibit classic logarithmic Nernstian behavior over the specified measurement range. Error analysis indicated that the best results for calculating unknown sample concentrations are obtained by using the average slope obtained from all the preflight calibrations anchored at the TS21 point.

Pre-amplifier circuitry for the electrochemical sensors is embedded in the beaker walls. Analog to digital conversion (12-bit) is performed on a heavily-multiplexed “Analog Board” which interfaces to an FPGA on the primary MECA control and measurement electronics (CME) board. The FPGA also generates waveforms for the voltammetric and potentiometric sensors, performs temperature control, and operates actuators. Also returned in telemetry is a reading from an external temperature sensor located on the base of the microscopy sample stage.

A complete description of the WCL portion of the MECA instrument can be found in Kounaves et al., 2008. To skip to the next WCL specific section of this document see paragraph 4.3.1.3.

4.1.4     Software and Electronics

MECA flight software (FSW) runs on the primary spacecraft computer and communicates to MECA hardware at 9600 baud via a serial Payload and Attitude Control Interface (PACI) interface. On the other side of that interface is an FPGA, located on the Command and Measurement Electronics (CME) board inside the MECA enclosure. The FPGA controls all hardware functions in the MECA suite with the exception of the Atomic Force Microscope (AFM), which has an embedded processor, and discreet switches, controlled directly by the spacecraft computer, for powering MECA and for switching between AFM processor and FPGA. Data return described here is generated by the FPGA.

The common MECA electronics return telemetry packets indicative of the overall instrument configuration, including parameter tables, the status of the command and measurement electronics, and the products of a low-level command parser that can be used to address any of the four instruments.

4.2      Data Product Overview

MECA non-imaging RDR data are broken into 12 different data types according to instrument sub-system.

The AFM sub-system has 3 ASCII data types associated with it, two data files and one text description file. The AFM Scan Data Records (SDR) are AFM scan data that has been converted from DN to physical units. AFM Scan derivative records (SDD) are line-by-line first order spatial derivatives of the SDRs, processed using the Savitzky-Golay filter method. AFM data are grouped by measurement day.

Table 4‑1AFM RDR Data Types

The TECP sub-system yields four data types. The data are the electrical conductivity, relative humidity, relative permittivity, and the thermal conductivity measurements converted from DN to physical units. TECP data are in a time-series, with a single data file for each data type per observation, where an observation is a related set of measurements spanning no more than a day (sol). Date types and description are listed in Table 4-2 TECP Data Types.

Table 4‑2 TECP Data Types

The WCL sub-system has five data types, one for each sensor type or measurement method. The data are generally EDR data that has been converted to physical units and grouped in a time-series corresponding to a single observation, which typically refers to a segment of a two-day chemistry experiment (during calibration, for example, or after acid addition). Data types and descriptions are listed in Table 4-3.

Table 4‑3 WCL Data Types

4.3      Data Processing Overview

Reduced Data Records (RDR), the Level 1 products, are generated from the MECA non-imaging EDR data, ancillary data gleaned from command logs and channelized telemetry, and calibration, characterization, and cataloguing (CCC) data generated by a variety of laboratory instruments. The intent of the RDR data product is to be an easily accessible, scientifically useful dataset that will facilitate interpretation of the MECA data. Each MECA non-imaging RDR consists of time-series data of a single type, grouped together by virtue of being acquired on the same sol with the same assigned token, which delineates a discrete observation. Tokens are embedded in the file labels and are assigned at the time of sequence generation specifically for the purpose of dividing data products into logical segments and helping to associate them with the original command sequence. The token can be used to cross-correlate data products that are related.

4.3.1 Data Processing Level

MECA non-imaging RDRs are equivalent to NASA Level 1A and 1B (CODMAC Level 3 and 4) data products as defined in Appendix-A. Higher level special products may be available at mission end for each of the MECA sub-systems.

4.1.2     Data Product Generation

The following sections describe how and by whom the MECA non-imaging RDRs are created.

4.3.1.1       AFM

AFM RDR data products will be generated by the MECA Science Team using software at the Science Operations Center (SOC), the Jet Propulsion Laboratory (JPL) or their home institutions. The RDRs produced will be “processed” data (NASA Level 1). The input will be one or more MECA non-imaging EDR or RDR data products and the output will be formatted according to this SIS and consists of a data file with a .TAB file extension, a PDS label file that has the same name as the data file with a .LBL file extension and a text (.TXT) file that contains information about how the data was collected. Additional meta-data may be added by the software to the PDS label or the data product header table.

The two scan data AFM RDR data products are formatted to have a detached ASCII PDS label (see http://pds.jpl.nasa.gov/documents/qs/labels.html for more information about PDS labels). The SDR and SDD data products consist of five attached data tables. The first table is the header table that describes the AFM scan parameters (Table 4-4) and other important information pertaining to that scan, followed by the calibrated scan data in four sequential ASCII TABLE objects. See paragraph 4.3.3, 4.3.4, 4.3.5, and 4.3.6 for conventions used in this data product.

Table 4‑4 AFM Header Table Column Names and Descriptions.

The scan data follows the header as four sequential ASCII table objects, forward scan error, forward scan height data, backward scan error and backward scan height data. Within each table, three columns (X,Y,Z) are repeated 512 times to specify the X and Y position and the Z value (height in microns or error in volts) of each point in a 512 x 512 matrix. Typically, scans will be square with 256 x 256 rows and columns but can be as little as 8 x 8 or up to 512 x 512. The data will always be presented in the 512 x 512 configuration, padded out with zeros where necessary. All four sets of data, representing one AFM scan, and the header information will be stored in the same RDR file with a unique filename in the format described in . All scans run on the same day will be grouped together in folders labeled by sol number.

The AFM scan plane is a square that is rotated clockwise by 45 degrees and flipped vertically relative to an OM image (see  The axis that defines a scan line (the one along which scan samples are taken) is called the fast-axis (i.e. it increments/decrements more rapidly). The other axis determines scan line rows and is only incremented/decremented at the end of each scan line. Thus it is referred to as the slow-axis. The default fast-axis for the AFM is the x-axis, the default slow axis is the y-axis. Note that the scan point (0,0) is in the middle of the scan plane, i.e. for a 256 x 256 scan, the scan field goes from -128 to +127 in x and -128 and +127 in y. The starting point of a scan is not the origin of the scan field however, but the most negative x and y positions, i.e for a 256 x 256 scan, the scan starts at the point (x=-128,y=-128) and proceeds to more positive values in both directions.

The scan data is ordered such that the first line of data in the file represents the first line of data acquired by the AFM. The AFM acquires the scan data in an 'upward' (or positive 'y') direction in the AFM scan coordinate system (Figure 4-10). Thus, to plot the AFM scan the right way up in the OM frame of reference, the origin (0,0) for the x and y coordinates in the AFM RDR data should be in the top left corner, with positive 'y' downwards and positive 'x' to the right. An additional 45 degree clockwise rotation is also required to allow the AFM image to be overlaid on an OM image.

The AFM_SDR data type is calibrated scan data with x-y scan ranges. Due to distortians in the scan plane, the header includes separate values for the X and Y scan ranges. As such, the images may not be square. The height and scan range data will be calibrated based on data from calibration scans of the AFM pincushion substrate that will be performed just prior to the AFM scans on Mars. It should be noted that the calibrated scans start at 0,0 in contrast to the un-calibrated scans that start in the center of the image. The scaling factor used for the conversion from DNs to micrometers (height) is included in the header of the RDR. Data are presented in units of micrometers and represented by real numbers to three decimal places. The error channel data in this data type are given in units of Volts with no in-situ calibration applied and represented by real numbers to six decimal places.

The AFM_SDD data type is a line by line derivative of the calibrated scan data. By converting slope (Z) to grayscale, derivatives are a simple way to simulate what the eye would see if the topographs represented macroscopic surfaces illuminated from overhead. In MECA team renderings, 0-slope corresponds to the middle of the grayscale, thus simulating diffuse side lighting. The derivative will be performed using the Savitsky-Golav[1] method, following the raster-scanning direction because the discontinuities that are often present between lines would produce unacceptable noise in a true 2-dimensional derivative.

Savitzky-Golay is a simple running filter that smoothes data while optionally performing various orders of derivatives, depending on the selection of filter parameters. It is a numerical algorithm for performing a local polynomial regression of degree k on at least k+1 equally-spaced points. For the AFM derivatives, selection of the number of points will be done manually depending on the noisiness of the data. The number of points used is recorded in the derivative header table in the smoothing_factor field. The derivative values are unitless.

The final AFM data type is the AFM Report file. This is an ASCII text file with an attached PDS label that contains a narrative of events during an operational day. There will be one file per sol that is manually generated by an AFM team member. This file may contain items such as rationale for picking a particular target, difficulties in making a particular measurement, or other general information that is not easily captured elsewhere.

The header includes values representing the X and Y coordinates of the estimated center

position of the AFM scan location in the context OM image. For the cases where context images were taken before and after the scan, the scan location coordinates are only given for the 'before' image. The origin of the coordinate system in the OM frame of reference is taken to be the top left of the OM image as shown in FigX.

4.3.1.2       TECP

TECP RDR data products will be generated by the MECA Science Team using software at the SOC, JPL or their home institutions. The RDRs produced will be “processed” data (NASA Level 1). The input will be one or more MECA non-imaging EDR or RDR data products and the output will be formatted according to this SIS. Additional meta-data may be added by the software to the PDS label or the data product header table.

There are four types of TECP data, electrical conductivity (designated EC), humidity (designated HUM), relative permittivity or dielectric constant (designated PRM) and temperature (TC). The EC data is formatted as six ASCII tables, a general comments table, an EC comments table, a conversions table, two tables with conversion constants, and a data table that contains a time-series of measurements. The HUM, PRM and TC data are all formatted as a general comments table, a data type specific comments table, a conversions table and a data table that contains a time-series of measurements. The conversions table contains the DN to physical unit equations for the particular data type. Table 4-5 lists all the DN to physical unit conversions used to convert TECP EDR data into TECP RDR data. In some equations the abbreviation ADC is used for Analog to Digital Converter and is equivalent to DN.

Table 4‑5 TECP DN to Physical Unit Conversions

*EC is not defined for DNs outside these ranges in the specified gain.

TECP orientation information is given in all four TECP data types. The orientation information is obtained from the Robotic Arm (RA) and was acquired at the time of the most recent RA move. The orientation information is given in both the payload frame and in the local level frame for ease of use. The definitions of the PHOENIX coordinate systems are documented in Table 4-6

Table 4‑6 Phoenix Coordinate Systems

4.3.1.3       WCL

WCL RDR data products will be generated by the MECA Science Team using software at the SOC, JPL or their home institutions. The RDRs produced will be “processed” data (NASA Level 1). The input will be one or more MECA non-imaging EDR or RDR data products and the output will be formatted according to this SIS. Additional meta-data may be added by the software to the PDS label or the data product header table.

4.3.1.3.1      ISE

The MECA WCL Ion-Selective Electrode (ISE) RDR is formatted as a header table followed by an events table followed by the ISE data header table and finally the ISE data table. The header table contains information about the instrument and how the data was collected. A complete list of fields contained in the header table can be found in Table 4-7 ISE Header Fields. The events table gives the time at which important events in the experiment were carried out. The ISE data table contains a time-series of mV data for fifteen of the ion-selective electrodes mounted in the WCL beaker walls. These sensors include 9 ISEs for directly measuring inorganic ionic species (Na⁺, K⁺, Ca²⁺, Mg²⁺, NO₃^-, NH₄⁺, Br^-, I^-, Cl^-), a single Ba²⁺ ISE for the indirect measurement of sulfate, 2 polymer pH sensors, one iridium oxide pH sensor, and two Li⁺ sensors to serve as reference electrodes. See Table 4-8 ISE Data Table Fields for a list of the data fields and their converted physical unit.

The header table is used to record information that is useful for tracking the origin of the ISE data as well as providing ancillary data useful for data interpretation. It is especially important to note the WCL_CELL_NUMBER as each of the four cells may have slightly different measurement characteristics. Also of note is the PARENT_EDR_N field(s). This field(s) contains the names of the EDR data products that were used in the generation of the RDR. Lastly, the CALIBRATION_EQUATION field contains the equation (see eq. 4-1) used to convert the EDR DN value to mV recorded in the RDR. It is possible that this equation could change over the course of the mission.  

Table 4‑7 ISE Header Fields

The events table, a three-column table with events, time and notes fields, keeps track of the significant events during the course of an experiment. For the ISE experiment the critical events are solution dispense, drawer open, drawer_close, and reagent release. The critical events are described in the following paragraphs.

Solution Dispense: The melted solution in the WCL tank is transferred from the water tank to the WCL beaker via an actuator that punctures the bottom the water tank. Nominally there is no entry in the notes field for the solution dispense event.

Drawer Open and Drawer Close: The WCL sample drawer is commanded to open and then commanded to close in three cases - for a “burp”, sample delivery, or sample verification, as specified in the notes field:

“Burp”: The WCL sample drawer is “burped” (opened and closed) to equilibrate the pressure inside the beaker.

Sample Delivery: The WCL sample drawer is opened while the Robotic Arm delivers a sample to the open drawer and documents the delivery with the Robotic Arm Camera (RAC).  The drawer is then closed, and the sample falls into the beaker solution.

Sample Verification: After sample delivery, the WCL sample drawer is open a second time for the RAC to document whether the sample was delivered successfully.

Reagent Release: One of the five WCL crucibles (calibrant, acid, 3 x BaCl₂) is commanded to be released into the beaker solution. Prior to the release of each crucible the drawer is “burped” at least once. The type of crucible released is specified in the notes field:

Calibrant Crucible: The calibrant crucible contains a pre-determined amount of specific salts that serve as a calibration reagent for the ISE sensors.

Acid Crucible: The acid crucible nominally contains 0.004g of 2-Nitrobenzoic Acid.

BaCl₂ Crucible: The BaCl₂ crucible contains 0.11g-0.12g. of barium chloride.

Note that the CMD_TIME of the reagent release events indicates the time at which the command to begin heating the actuator that delivers the crucible was issued to MECA. The time at which the crucible actually drops into the solution is a function of the thermal conditions and the voltage applied to the actuator, and it can be best estimated by referring to the studies documented in the MECA Wet Chemistry Laboratory Calibration Report (located in the archive calibrations folder). Overall, the time at which the crucible physically drops is expected to be no more than 5 minutes after the actuator begins heating.

The ISE data header table contains one row of information. The information is the label of each of the columns in the ISE data table. This table will be useful to those reading the RDR data product in either a text editor or spreadsheet program.

The ISE data header table contains one row of information. The information is the label of each of the columns in the ISE data table. This table will be useful to those reading the RDR data product in either a text editor or spreadsheet program.

The ISE data table, the fields of which are described in Table 4-8 ISE Data Table Fields, contains the mV value for each ISE sensor reading in the RDR. The readings are a result of a potential across the sensor’s membrane/solution interface, the value of which is dependent on the activity of the selected ionic species in the beaker solution. Note that oxidation-reduction potential (ORP) is not specifically listed as a sensor because it serves as the ground for all other sensors, and V_ORP = -V_Li. This grounding scheme also has an implication in determining the absolute potential of the ISEs. In order to determine the absolute potential of the ISEs, the potential of one of the lithium reference electrodes must be subtracted from the potential values of the rest of the ISEs.

Table 4‑8 ISE Data Table Fields

Note:    ORP will not be a separate sensor on this list since it is the negative of the Li ISEs.

                CO2, Cl_ref, DO_ref, and V_mon have been omitted from the RDRs

The conversion from data numbers (DN) in the corresponding ISE EDR to mV in the ISE RDR comes from the characteristics of the analog-to-digital converter circuit common to most the ISEs. Nominal values for the half-cell are:

                                     V(mV) = -0.80579∙DN + 2057.8                                   (eq. 4-1)

The equation given above is explained fully in the Calibration Report, which is the definitive reference for calibration equations.

The conversion from raw mV to molar concentration of ions in the beaker solution is a detailed process that begins with determining referenced ISE potentials by subtracting the potential measured on either of the lithium reference sensors from the raw ISE potentials.  Following the subtraction, the conversion to ionic concentrations requires beaker-specific calibration constants, conductivity data, and experimentally-determined selectivity data. The conversion to concentrations will be documented in the MECA WCL special data products that will be generated by the Phoenix science team during surface operations.

4.3.1.3.2      Conductivity

The MECA WCL electrical conductivity RDR omits the conversion from conductance to conductivity via the cell constant. Appropriate cell constant values can be determined from the Calibration Report.

The conductivity RDR is formatted as a header table followed by an events table followed by the conductivity data header table and finally the conductivity data table. The header table contains information about the instrument and how the data was collected. A complete list of fields contained in the header table can be found in Table 4‑9 Conductivity Header Fields. The events table gives the time at which important events in the experiment were carried out. The conductivity data header table gives the column names for the conductivity data table and the conductivity data table contains a time-series of two ranges of electrical conductivity microsiemen (μS) data.

The header table (Table 4‑9 Conductivity Header Fields) is used to record information that is useful for tracking the origin of the conductivity data as well as providing ancillary data useful for data interpretation. Mission and instrument parameters are recorded. It is especially important to note the WCL_CELL_NUMBER as each of the four cells may have slightly different measurement characteristics. Also of note is the PARENT_EDR_N field(s). This field(s) contains the names of the EDR data products that were used in the generation of the RDR. For the electrical conductivity data, five fields have been added to the header table. These fields contain the information necessary to use the DN to physical units equations presented below. Please note that the values for the equation constants given in the RDR data records are the definitive source for the values. It is possible that these values could change over the course of the mission.

Table 4‑9 Conductivity Header Fields

The events table, a three-column table with events, time and notes fields, keeps track of the significant events during the course of an experiment. The critical events are the same as those for the ISE data.

The data header table contains one row of data, the column labels for the conductivity data table. This table will be useful to those reading the RDR data product in either a text editor or spreadsheet program.

The MECA electrical conductance data table holds the conductance measurements in a time-series of two ranges of microsiemen (μS). The conductance of a solution is a measure of its ability to carry a current and is thus directly proportional to the total concentration of dissolved ionic species in the water. In raw EDR form, MECA WCL conductivity data consists of a time-series of data numbers (DN) that specify the current in each of two ranges and a voltage which is read twice (once for each range). Conversion to physical units begins with conversion of data numbers (DN) to resistance, with the nominal gain given by.

R_low(Ω) = 5715.3∙(V/I_low)                                                               (eq. 4-2)

R_high(Ω) = 5810.4∙(V/I_high)                                                            (eq. 4-3)

where V = 2517.95-DN and I = 2570-DN.

Conductance is the reciprocal of the resistance. Conductance is converted to conductivity by multiplying by the cell constant, which varies from beaker to beaker. Cell constants are 1.45 +0.15 or – 0.05 (depending on the conductance value) and are fully described in the WCL Calibration Report. The cell constant will be updated after in situ calibration and will be reported in this document, in the header table and in the WCL Calibration Report. Conductance is calculated as:

COND_low= 1000000∙ (2570-I_{DN_LOW})/[5715.3∙ (2517-V_{DN_LOW})]           (eq. 4-4)

COND_high= 1000000∙ (2570-I_{DN_HIGH})/[5810.4∙ (2517-V_{DN_HIGH})]         (eq. 4-5)

Where I_{DN_LOW}, V_{DN_LOW}, I_{DN_HIGH}, and V_{DN_HIGH} are the DN fields from the corresponding EDR, and K is the cell conductivity constant.

The electrical conductivity (EC) of a solution is a measure of its ability to carry a current and is thus directly proportional to the total concentration of dissolved ionic species (e.g.,

Na+, K+, Ca2+, Cl-, SO4=) in the water. The unit for EC is the siemen (S) and is measured in microsiemens per centimeter (μS/cm). Electrical conductivity is mainly affected by temperature and the nature of the ionic species. The conductance measurements reported in the RDRs will not be adjusted for temperature, but as a general rule for the salts most likely to be found on Mars, the temperature is expected to produce a 2% increase per 1°C.

4.3.1.3.3      CV

The MECA WCL Cyclic Voltammetry (CV) RDR type encompasses three types of measurements: Conventional cyclic voltammetry using either a macro-electrode or an array of micro-electrodes; Anodic Stripping Voltammetry using the micro-electrode; and a Dissolved Oxygen measurement acquired with an ion selective electrode with CV-style detection. Each CV RDR contains the scan results from only one of the three electrodes. The RDR is formatted as a header table, a conversions table, an events table, a scan header table and the CV data table. The header table (Table 4‑10) contains information about the collection parameters. The conversions table (Table 4‑11) contains the necessary information to convert DNs to physical units, i.e. mV and nA. The events table gives the time at which important events in the experiment were carried out. The scan header table contains information about how the scan data was collected. A complete list of fields contained in the scan header table can be found in Table 4‑12. The CV scan table contains a time series of electrode potential (mV) and current (nA) data for measurements made with one of the three CV electrodes. The following paragraphs describe the tables in more detail.

The CV header table is used to record information that is useful for tracking the origin of the CV data as well as providing ancillary data useful for data interpretation. Mission and instrument parameters are recorded. It is especially important to note the WCL_CELL_NUMBER as each of the four cells may have slightly different measurement characteristics. Also of note is the PARENT_EDR_N field(s). This field(s) contains the names of the EDR data products that were used in the generation of the RDR.

Table 4‑10. CV Header Table Fields

The CV conversions table (Table 4‑11) lists the nominal parameters used to convert EDR DN values to the RDR physical unit values. The definitive reference for this conversion will be the WCL calibration report, available elsewhere in this archive. Conversions are given for the specified electrode at all gain settings. The physical units are either mV or nA.

Table 4‑11 CV Conversion from DN to physical units*

^* Calibration values for review purposes only.

These are not the flight electronics calibration constants. For flight electronics values refer to the WCL Calibration Report.

The events table, a three-column table with events, time and notes fields, keeps track of the significant events during the course of an experiment. See the ISE events table section for a full description of possible events.

The CV scan header table records (Table 4‑12) important instrument parameter information for each of the measurement sets. Note that the mVmin, mVmax and the CV_scan_rate fields can be used to generate the CV waveform.

Table 4‑12 CV Scan Header Fields

The CV data table contains a time-series of electrode potential (mV) and current (nA) data for measurements made with one of the three electrodes described above. The macro-electrode (CV) is a 250 mm diameter gold disk electrode, the dissolved oxygen electrode (DO) is covered with a oxygen permeable polymer membrane, and the micro-electrode array (AS) is a 3.1mm x 3.4 mm array of 564 interconnected 12 μm gold disk microelectrodes with 66μm center-to-center spacing.

In a WCL CV experiment, a three-electrode configuration is employed, with one of the three CV electrodes as the working electrode, the WCL platinum ORP electrode as the counter electrode, and one of the chloride ISEs as the reference electrode. Current flow is measured as the potential of the working and reference electrodes is swept between two preset voltages, with a reversal in scan direction occurring at a preset switching potential. This triangular waveform is used with a constant forward and reverse scan rate.

A detailed review of the cyclic voltammetry is beyond the scope of this document and the reader is referred to the many texts that describe the theory and experimental practice of CV [e.g. Bard and Faulkner, 2000].  

In a CV measurement, the level of current that flows between the working and counter electrodes depends on a number of factors including the concentrations of soluble redox active species. The WCL voltammetry circuit has six different gain settings to allow measurement over a broad range of current levels. Since the measurement circuit does not have autoscaling capability, each CV scan will be repeated at up to 6 gain settings. The calibration constants for conversion from data numbers (DN) in the corresponding CV EDR to physical units (mV and nA) in the CV RDR are included in the Calibration Report.

The use of a WCL chloride ISE as the reference represents deviation from standard laboratory practice where a reference electrode with a constant and known potential is used. In the WCL, the potential of the reference electrode in each of four WCL cells will be a function of both electrode performance characteristics and the quantity of soluble chloride in the soil samples. Calculation of the electrode potential for each of the chloride reference ISEs will depend on their pre-flight ISE calibrations and results of the ISE measurements made on Mars. Since the chloride concentration of the Mars soil samples is unknown, the potential window over which the CV electrode is scanned relative to a standard reference will not be known until after data from the WCL Sol A operations are returned to Earth. The conversion WCL CV electrode potentials to standard reference electrode potentials will be documented in the MECA WCL special data products that will be generated by the Phoenix science team during surface operations.

4.3.1.3.4      CP

The MECA WCL Chronopotentiometry (CP) RDR is formatted as a header table, a conversions table, an events table and a scan header table followed by the CP data table. The header table (Table 4‑13) contains information about the collection parameters. The conversions table (Table 4‑14) contains the necessary information to convert DNs to physical units, i.e. mV and nA. The events table contains information about experiment. The scan header table contains information about how the scan data was collected. A complete list of fields contained in the scan header table can be found in Table 4‑15. The CP RDR data table contains a time series of electrode potential (mV) and current (nA) data for measurements made with one of the three CP electrodes mounted in the WCL beaker walls. The following paragraphs describe the tables in more detail.

The CP header table (Table 4‑13) is used to record information that is useful for tracking the origin of the CP data as well as providing ancillary data useful for data interpretation. Mission and instrument parameters are recorded. It is especially important to note the WCL_CELL_NUMBER as each of the four cells may have slightly different measurement characteristics. Also of note is the PARENT_EDR_N field(s). This field(s) contains the names of the EDR data products that were used in the generation of the RDR. For the CP data, two fields have been added to the header table. These fields contain the number of scans in the RDR and the DN to physical units conversion equation.

Table 4‑13 CP Header Table Fields

The CP conversions table (Table 4-14) lists the conversions from EDR DN values to the RDR physical unit values. The spacecraft command interface limits the maximum duration of a CP scan to ~11 seconds (Kounaves et al in press). Due to this limitation, multiple CP scans at different current levels (gain settings) will be needed to measure concentration ranges of ~1.5x10^-4 to ~1.0x10^-1M. The definitive reference for this conversion will be the WCL calibration report, available elsewhere in this archive. The calibration constants for conversion from DN in the corresponding CP EDR to physical units (mV and nA) in the CP RDR are given in Table 4-14.

Table 4‑14 CP Conversions from DN to Physical Units

^* Calibration values for review purposes only.

These are not the flight electronics calibration constants. For flight electronics values refer to the WCL Calibration Report.

The events table, a three-column table with events, time and notes fields, keeps track of the significant events during the course of an experiment. The critical events are the same as those for the ISE data.

The CP scan header table (Table 4-15) records important instrument parameter information for each of the measurement sets. Note that the nAmin, nAmax and the CV_scan_time fields can be used to generate the CV waveform.

Table 4‑15 CP Scan Header Fields

The MECA WCL Chronopotentiometry (CP) data table contains a time series of electrode potential (mV) and current (nA) data for measurements made with one of the three CP electrodes mounted in the WCL beaker walls. The CP electrodes include: two 1 mm diameter Ag electrodes (CPS1 and CPS2) and one 1 mm diameter Pt (CPP) electrode. In a WCL CP measurement, which is sometime referred to a coulombic titration, the electrochemical cell potential is measured as the current is stepped (or ramped) from zero to a set current. A three-electrode configuration is employed, with either one of the Ag electrodes or the Pt electrode as the working electrode, the platinum ORP electrode as the counter electrode, and one of the chloride ISEs serving as the reference electrode. In nominal Mars surface operations, anodic (oxidizing) polarity is used for measurements made with the Ag electrodes and cathodic (reducing) polarity is use with the Pt electrode.

In general, the concentration of a single analyte in the bulk solution C* can be calculated using the Sand equation, which for the CP current step technique can be expressed as:

C* = (2iτ^1/2)/(nFAD^1/2π^1/2)                                            (eq. 4-6)

where i is the applied current, τ the transition time, F Faraday’s constant, A the electrode

area, D the diffusion coefficient. Correction estimates for double-layer effects and other source of error will be made using the method described by Bard [Bard A. J., 1963]. In this approach:

iτ/ Co* = a + b/Co*τ^1/2                                                                                    (eq.4-7)

where a equals nFADo ^1/2π^1/2/2 and b represents a correction factor. By measuring τ in the calibration solution, prior to soil addition, at multiple known current values, both a and b can be determined from plots of τ^1/2 vs. iτ.

A detailed review of CP is beyond the scope of this document and the reader is referred to the many texts that describe the theory and experimental practice of CP [Bard and Faulkner, 2000].

The potential at which a reaction proceeds at the working electrode in a CP measurement depends, in part, upon the redox potential of the process. Additionally, as is the case with CV, the potential of the reference electrode in each of four WCL cells will be a function of both electrode performance characteristics and the quantity of soluble chloride in the soil samples. Calculation of the electrode potential for each of the chloride reference ISEs will depend on their preflight ISE calibrations and results of the ISE measurements made on Mars. The conversion of measured WCL CP electrode potentials to standard reference electrode potentials and the correlation of measured potentials to specific analytes (e.g. chloride, bromide), as well as derived concentrations, will be documented in the MECA WCL special data products that will be generated by the Phoenix science team during surface operations.

4.3.1.3.5      PT

The MECA WCL pressure and temperature (PT) RDR is formatted as a header table, a DN to physical unit conversions table, an events table, a data header table and finally the PT data table. The header table contains information about the instrument and how the data was collected. A complete list of fields contained in the header table can be found in Table 4‑16. The conversions table (Table 4‑17) provides the EDR DN to RDR physical unit equation parameters. The events table gives the time at which important events in the experiment were carried out. The data header table contains the column labels for the PT data table. The PT data table contains time-series data of pressure measurements of the internal pressure sensor, temperature data from each of four sensors mounted on the beaker wall, the water tank, the sample drawer, and the optical microscope stage, and heater states for the beaker, tank, and drawer heaters.

The header table (Table 4‑16) is used to record information that is useful for tracking the origin of the PT data as well as providing ancillary data useful for data interpretation. Mission and instrument parameters are recorded. It is especially important to note the WCL_CELL_NUMBER as each of the four cells may have slightly different measurement characteristics. Also of note is the PARENT_EDR_N field(s). The CALIBRATION_EQUATION field contains the DN to physical unit equation for the PT measurements. This field(s) contains the names of the EDR data products that were used in the generation of the RDR. 

Table 4‑16 PT Header Table Fields

The conversions table contains the DN to physical unit conversions for the PT data. Except for the stage sensor, the conversion to physical units is specific to the selected chemistry cell. The conversion follows the appropriate formula below:

                        P(mbar) = a∙DN + b                                                     (eq.4-8)

                        T(°C) = a∙DN + b                                                         (eq.4-9)

Nominal values of a and b are specified in Table 4-17. .The definitive reference for the conversion equations is the WCL calibration report found elsewhere in this archive. The definitive reference for the conversions factors are the values found in the RDRs.

Table 4‑17 PT DN to Physical Unit Conversion Factors

The events table, a three-column table with events, time and notes fields, keeps track of the significant events during the course of an experiment. The critical events are the same as those for the ISE data.

The PT data header table contains the labels for the data columns in the PT data table. This table will be useful to those reading the RDR data product in either a text editor or spreadsheet program.

The MECA WCL PT data table contains time-series data of pressure measurements of the internal pressure sensor as well as temperature data from each of three sensors mounted on the water tank, the sample drawer, and in the beaker wall (Table 4‑18). The pressure and temperature readings apply to the active WCL cell (known from the command history), and the units of the RDR data are mbar for pressure and Celsius for temperature. The tank sensor is used to monitor and verify thawing of the stored leaching solution, while the drawer sensor monitors the operation of sample introduction and reagent addition actuators. The beaker sensor is critical for analysis of chemical data. Regardless of which cell is active, each telemetry record includes a reading of the microscopy sample stage temperature. Thus many of the WCL PT RDRs may be for the purpose of supporting microscopy experiments.

Table 4‑18 PT Data Fields and Descriptions

4.3.2     Data Flow

After generation, each RDR is saved locally and delivered to the Science Operation Center (SOC) at the University of Arizona. Upon arrival at the SOC, these files/products will be published into the product catalog (ROMe) via another automated process. It will subsequently be organized in time order and delivered to the PDS in the form of an Archive Volume by the MECA team.

After the validation period has passed, all applicable products such as EDRs, RDRs, etc. will be put into a PDS archive volume and submitted to the PDS geosciences node by the MECA team.

4.3.3     Labeling and Identification standards

The RDR labeling format described in this document will follow the Phoenix product file naming conventions as described in Appendix-D. All filenames will be PDS compliant and will follow the Phoenix file naming convention described in Appendix D. Additional identification information will be contained in the PDS label as described in Appendix-C.

4.3.4     PDS Standards

MECA non-imaging RDR products will comply with the Planetary Data System’s standards as specified in the PDS Standards Reference (see Applicable Document #1). All label keywords are PDS compliant and registered in the PDS dictionary.

4.3.5     Time Standards

The following time standards and conventions are used throughout this document, as well as the Phoenix project for planning activities and identification of events.

4.3.6     Data Storage Conventions

MECA non-imaging RDR products will be stored as ASCII files with detached PDS labels, with the exception of the AFM REPORT product that has an attached label. The PDS labels conform to PDS standards using an ASCII format, with each keyword definition terminated by ASCII carriage-return and line-feed characters. The RDR products are defined as PDS table objects (Applicable Document 2). All MECA non-imaging RDRs will contain fixed length records with the exception of the MECA_WCL_CV and MECA_WCL_CP data types. The WCL_CV and MECA_WCL_CP data types are stream records. In all data types the number of rows will vary.

4.4      Data Validation and Peer Review

The MECA non-imaging RDR product design, as described in this SIS, is subject to PDS peer review. The peer review will be completed well in advance of actual production, to allow time for changes in the design as needed. This SIS document will be updated to show any such changes.

Validation of MECA non-imaging RDR products during production will be performed according to specifications in the Phoenix Archive Plan and the MECA Team – Geosciences Node ICD (Applicable Documents 2 and 10). The MECA Team will validate the science content of the data products, and the Geosciences Node will validate the products for compliance with PDS standards and for conformance with the design specified in this SIS.

5.     Detailed Data Product Specifications

5.1      Data Product Structure and Organization

5.1.1     AFM

There are three AFM data types, the AFM_SDR, the AFM_SDD and the AFM REPORT. The AFM_SDR is the converted scan data record and the AFM_SDD is the scan data derivative. The first two data types are structured as five table units (files) that contain a 22-column 4-row header table, a 1536-column forward scan error table, a 1536-column forward scan height data table, a 1536-column backward scan error table, and a 1536-column backward scan height table. The AFM REPORT is a text file that describes the activities of a measurement day. See  for label examples and table structures.

The AFM_SDR and AFM_SDD are organized as ASCII data files containing data from a single scan of the AFM, with a detached ASCII text PDS label file for each data file. The AFM REPORT is an ASCII text file with an attached ASCII PDS label. Data will be grouped by instrument (AFM) and then by sol.

5.1.1     TECP

There are four types of TECP data, TECP_EC, TECP_HUM, TECP_PRM and TECP_TC. The TECP_EC data is a time-series of electrical conductivity measurements. The TECP_HUM data is a time-series of relative humidity measurements. The TECP_PRM data is a time-series of relative permittivity data, and the TECP_TC data is a time-series of temperature measurements. The TECP data are organized as ASCII data files. The TECP_EC data files are structured as a 1-column general comments table, a 1-column EC comments table, and 2-column conversions table that holds the DN to physical unit conversion equations. The conversions table is followed by a 4-column table that holds the gain specific probe constant conversion coefficients. Next is a 7-column table that contains the gain specific resistance conversion coefficients and last the 13-column data table. The TECP_HUM, TECP_PRM, and TECP_TC data files are all structured in the same way. The file begins with a 1-column general comments table, a –column data type specific comments table, and a 2-column conversions table that holds the DN to physical unit conversions used to make the RDRs. The conversions table is followed by the data table. The EC and HUM data are 13-column data tables. The PRM data table is a 12-column data table and the TC data table is a 16-column table. See  for label examples and table structures.

Each of the four TECP data types are organized as ASCII data files containing data from a single Martian sol, with a detached ASCII text PDS label file for each data file. Data will be grouped by instrument (TECP) then by sol.

5.1.2     WCL

There are five types of WCL data, WCL_ISE, WCL_CND, WCL_CV, WCL_CP, and WCL_PT. The WCL_ISE data are a time-series of ion selective electrode data. The WCL_COND data are a time-series of electrical conductivity measurements. The WCL_CV data are a time-series of electrode potential and current cyclic voltammetry measurements. The WCL_CP data are a time-series of electrode potential and current chronopotentiometry measurements. The WCL_PT data are a time-series of pressure and temperature measurements. The ISE and CND data are formatted similarly, as are the CV and CP data. PT data is like the ISE and CND, except that is contains an additional table. The ISE and CND data are formatted with a 2-column header table, a 3-column events table, a data header table and a data table. The CV and CP data are formatted with a 2-column header table, a 6-column conversions table, a 3-column events table followed by a 2-column scan header table and a 2-column data table. The PT data is formatted as a 2-column header table, a 5-column conversions table, a 3-column events table, a 6-column data header table and a 6-column data table. See  for label examples and table structures for each of the WCL data types.

Each of the five WCL data types are organized as ASCII data files containing data from a single Martian sol, with a detached ASCII text PDS label file for each data file. Files for all the WCL data types are grouped by instrument (WCL) and then by sol.

5.2      Label and Header

Each MECA non-imaging RDR data product has a detached PDS labels stored as ASCII text in a file with the extension .lbl and the same name as the RDR data product. A PDS label is object-oriented and describes the objects in the data file. The PDS label contains the keywords for product identification and for data object definitions. The label also contains descriptive information needed to interpret or process the data objects in the file.

PDS labels are written in Object Description Language (ODL) [3]. PDS label statements have the form of “keyword = value”. Each label statement is terminated with a carriage return character (ASCII 13) and a line feed character (ASCII 10) sequence to allow the label to be read by many operating systems. Pointer statements with the following format are used to indicate the location of data objects:

^object = location

where the carat character (^, also called a pointer) is followed by the name of the specific data object. The location is the name of the file that contains the data object. Examples of the MECA non-imaging PDS labels are provided in , and definitions of the keywords used in the labels are given in .

Most of the MECA non-imaging data products also contain header information. The header information is used to record the instrument setting for a particular analysis set. AFM headers are located in the AFM_HEADER table portion of the data records. The first row in the table records the collection parameters for the first data table, the second row corresponds to the second data table etc. The TECP data type does not contain any header information. The WCL header information is captured in the WCL_HEADER table object in the WCL data types. The header information describes the collection parameters used during an analysis set. Examples of the header table labels can be found in .

6.     Applicable Software

MECA non-imaging RDRs are all provided as ASCII data. Software specifically designed for use with the MECA non-imaging RDRs will not be provided.

APPENDIX A - PRODUCT LEVELS

Definitions of Data Processing Levels

This table shows definitions of processing levels as defined by NASA and by CODMAC, the Committee on Data Management and Computation (Applicable Documents 8 and 9)

Table A.1 Data Processing Levels

APPENDIX B - PDS LABEL KEYWORDS

APPENDIX C - RDR File naming convention

Standards

The file naming convention defined for the MECA non-imaging RDRs complies with the conventions for Phoenix EDRs and RDRs, which in turn complies with the PDS Level II 27.3 file naming standards.

Each product name is uniquely identifiable throughout the mission.

File Naming Rules

A template for general filename is shown below. Character positions 9 through 25 are reserved for instrument specific information.

Detailed definitions of product filenames are defined in the tables below. The tables document the naming conventions for each of the MECA sub-systems. Both the generic and MECA-specific fields are described.

Table C‑19 MECA AFM Naming Conventions

Table C‑20 MECA TECP File Naming Conventions

Table C‑21 MECA WCL File Naming Conventions

APPENDIX D - Example RDR PDS LABELS

AFM

AFM_SDR

PDS_VERSION_ID                      = "PDS3" 

LABEL_REVISION_NOTE                 = "2008-02-02, Initial"

/* File characteristics */

RECORD_TYPE                         = FIXED_LENGTH               

RECORD_BYTES                        = 23041

FILE_RECORDS                        = 2052

/* Pointers to object in file */

^AFM_HEADER_TABLE                   = ("FT000SDR_000_2E0100000000A0.TAB",1)

^AFM_F_ERROR_TABLE                  = ("FT000SDR_000_2E0100000000A0.TAB",5)

^AFM_F_HEIGHT_TABLE                 = ("FT000SDR_000_2E0100000000A0.TAB",517)

^AFM_B_ERROR_TABLE                  = ("FT000SDR_000_2E0100000000A0.TAB",1029)

^AFM_B_HEIGHT_TABLE                 = ("FT000SDR_000_2E0100000000A0.TAB",1541)

/* Identification */

DATA_SET_ID                         = "PHX-M-MECA-4-NIRDR-V1.0"

DESCRIPTION                         = "UNK"

PRODUCT_ID                          = "FT000SDR_000_2E0100000000A0_TAB"

PRODUCT_VERSION_ID                  = "V1.0"

PRODUCT_TYPE                        = "MECA_AFM_SDR"

RELEASE_ID                          = 0001

INSTRUMENT_HOST_NAME                = "PHOENIX"

INSTRUMENT_HOST_ID                  = PHX

INSTRUMENT_NAME                     = "MECA ATOMIC FORCE MICROSCOPE"

INSTRUMENT_ID                       = "MECA_AFM"

INSTRUMENT_MODE_ID                  = "SCAN"

MISSION_NAME                        = "PHOENIX"

OPS_TOKEN                           = "NULL"

OPS_TOKEN_ACTIVITY                  = "NULL"

OPS_TOKEN_PAYLOAD                   = "NULL"

OPS_TOKEN_SEQUENCE                  = "NULL"

TARGET_NAME                         = MARS

/* Time information */

MISSION_PHASE_NAME                  = "PRE-LAUNCH"

SPACECRAFT_CLOCK_START_COUNT        = "TEST STRING"

SPACECRAFT_CLOCK_STOP_COUNT         = "TEST STRING"

START_TIME                          = 2008-03-13T10:40:36

STOP_TIME                           = 2008-03-13T10:40:36

PLANET_DAY_NUMBER                   = 356

EARTH_RECEIVED_START_TIME           = 2008-03-13T10:40:36

EARTH_RECEIVED_STOP_TIME            = 2008-03-13T10:40:36

LOCAL_TRUE_SOLAR_TIME               = "00:00:00"

PRODUCT_CREATION_TIME               = 2008-03-13T10:40:36

/* Data object definition */

OBJECT                              = AFM_HEADER_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 21

  ROWS                              = 4                     

  ROW_BYTES                         = 190

  ROW_SUFFIX_BYTES                  = 22851

  ^STRUCTURE                        = "AFM_HEADER.FMT"

  DESCRIPTION                       = "This table contains the AFM scan

                                    parameter information. The table contains

                                    190 bytes of table data followed by 22851

                                    bytes of spare data, of which the last 2

                                    bytes contain the <CR><LF> pair. "

END_OBJECT                          = AFM_HEADER_TABLE

OBJECT                              = AFM_F_ERROR_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 23041

  START_BYTE                        = 92165

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      forward error information in Volts."

  OBJECT                            = CONTAINER

    BYTES                           = 45

    DESCRIPTION                     = "This table contains the AFM scan

                                      forward error information in Volts.

                                      Each row represents a scan line along

                                      the fast scan axis."

    NAME                            = "FORWARD ERROR"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR Y COORDINATE"

      START_BYTE                    = 16

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR VALUE"

      START_BYTE                    = 31

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_F_ERROR_TABLE

OBJECT                              = AFM_F_HEIGHT_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 23041

  START_BYTE                        = 11889157

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      forward Z-height information in microns

                                      Each row represents a scan line along

                                      the fast scan axis.

                                      The table contains 23041 bytes of table

                                      data of which the last 2 bytes contain

                                      the <CR><LF> pair. "

  OBJECT                            = CONTAINER

    BYTES                           = 45

    DESCRIPTION                     = "The container holds the X-Y-Z

                                       information for each AFM forward

                                       scan data point."

    NAME                            = "FORWARD HEIGHT"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT Y COORDINATE"

      START_BYTE                    = 16

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT VALUE"

      START_BYTE                    = 31

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_F_HEIGHT_TABLE

OBJECT                              = AFM_B_ERROR_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 23041

  START_BYTE                        = 23686149

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      backward error information in Volts.

                                      Each row represents a scan line along

                                      the fast scan axis."

  OBJECT                            = CONTAINER

    BYTES                           = 45

    DESCRIPTION                     = "The container holds the X-Y-Z

                                      information for each AFM scan

                                      error data point."

    NAME                            = "BACKWARD ERROR"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR Y COORDINATE"

      START_BYTE                    = 16

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR VALUE"

      START_BYTE                    = 31

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_B_ERROR_TABLE

OBJECT                              = AFM_B_HEIGHT_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 23041

  START_BYTE                        = 35483141

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      backward Z-height information in

                                      microns. Each row represents a scan

                                      line along the fast scan axis. The

                                      table contains 23041 bytes of table

                                      data of which the last 2 bytes contain

                                      the <CR><LF> pair. "

  OBJECT                            = CONTAINER

    BYTES                           = 45

    DESCRIPTION                     = "The container holds the X-Y-Z

                                      information for each AFM backward

                                      scan data point."

    NAME                            = "BACKWARD HEIGHT"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT Y COORDINATE"

      START_BYTE                    = 16

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 14

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT VALUE"

      START_BYTE                    = 31

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_B_HEIGHT_TABLE

END

AFM_HEADER.FMT

OBJECT = COLUMN

   COLUMN_NUMBER = 1

   NAME = cmdTimewhole

   DATA_TYPE = ASCII_INTEGER

   BYTES = 9

   START_BYTE = 1

   UNIT = SECONDS

   DESCRIPTION = "This is the time that the command was issued from

   the spacecraft computer to the MECA subsystem across the serial

   interface. Units are seconds of Spacecraft Clock (SCLK)."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 2

   NAME = cmdTimeremainder

   DATA_TYPE = ASCII_INTEGER

   BYTES = 10

   START_BYTE = 11

   UNIT = “SECONDS/2**32”

   DESCRIPTION = "The remainder, where 2^32 is a full second."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 3

   NAME = readTimewhole

   DATA_TYPE = ASCII_INTEGER

   BYTES = 9

   START_BYTE = 22

   UNIT = SECONDS

   DESCRIPTION = "This is the time that the data was returned to the

   spacecraft computer across the serial interface from the MECA

   subsystem (not used for some telemetry types). Units are seconds

   of Spacecraft Clock (SCLK)."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 4

   NAME = readTimeremainder

   DATA_TYPE = ASCII_INTEGER

   BYTES = 10

   START_BYTE = 32

   UNIT = SECONDS/2**32

   DESCRIPTION = "The remainder, where 2^32 is a full second."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 5

   NAME = dataLength

   DATA_TYPE = ASCII_INTEGER

   BYTES = 6

   START_BYTE = 43

   UNIT = BYTES

   DESCRIPTION = "The length of the following record (and all records in

   this product), not including this header."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 6

   NAME = cols

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 50

   UNIT = POINTS

   DESCRIPTION = "The width (number of points per line) of the AFM image."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 7

   NAME = lines

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 54

   UNIT = LINES

   DESCRIPTION = "The height (number of lines) of the AFM image."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 8

   NAME = direction

   DATA_TYPE = ASCII_INTEGER

   BYTES = 1

   START_BYTE = 58

   DESCRIPTION = "The scan direction, 1 = forward, 2 = backward."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 9

   NAME = channel

   DATA_TYPE = ASCII_INTEGER

   BYTES = 1

   START_BYTE = 60

   DESCRIPTION = "The RDR data channel, 1= error, 2= z-height."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 10

   NAME = channelGain

   DATA_TYPE = ASCII_INTEGER

   BYTES = 1

   START_BYTE = 62

   DESCRIPTION = "Ranges form 0 to 8, with 0=full (13.8 microns), and

   reducing by factors of 2 each time, e.g. gain of 2 = 3.45 microns."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 11

   NAME = refOMimage

   DATA_TYPE = CHARACTER

   BYTES = 33

   START_BYTE = 64

   DESCRIPTION = "File name of the Optical Microscope image taken

   before the scan for sample context."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 12

   NAME = refOMimage2

   DATA_TYPE = CHARACTER

   BYTES = 33

   START_BYTE = 98

   DESCRIPTION = "Filename of the OM image taken after the scan"

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 13

   NAME = opsToken

   DATA_TYPE = ASCII_INTEGER

   BYTES = 8

   START_BYTE = 132

   DESCRIPTION = "Ops Token for this scan."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 14

   NAME = SwtsTemperature

   DATA_TYPE = ASCII_INTEGER

   BYTES = 5

   START_BYTE = 141

   UNIT = KELVIN

   DESCRIPTION = "Temperature of the SWTS just prior to the scan."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 15

   NAME = scanrange

   DATA_TYPE = ASCII_REAL

   BYTES = 6

   START_BYTE = 147

   DESCRIPTION = "AFM scan range."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 16

   NAME = scaling_factor

   DATA_TYPE = ASCII_REAL

   BYTES = 10

   START_BYTE = 154

   DESCRIPTION = "The scaling factor used to calibrate the data

   (converts DNs to micrometers for height data and volts for error

   data)"

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 17

   NAME = AFM_OM_ref_X

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 165

   DESCRIPTION = "The approximate location of the center of the AFM

   scan field relative to the OM image. X-coordinate in pixels."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 18

   NAME = AFM_OM_ref_Y

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 169

   DESCRIPTION = "The approximate location of the center of the AFM

   scan field relative to the OM image. Y-coordinate in pixels."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 19

   NAME = X_slope

   DATA_TYPE = ASCII_REAL

   BYTES = 6

   START_BYTE = 173

   DESCRIPTION = "Slope correction in the x-direction of the AFM

   scan plane."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 20

   NAME = Y_slope

   DATA_TYPE = ASCII_REAL

   BYTES = 6

   START_BYTE = 180

   DESCRIPTION = "Slope correction in the y-direction of the AFM

   scan plane."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 21

   NAME = ScanSpeed

   DATA_TYPE = ASCII_REAL

   BYTES = 4

   START_BYTE = 187

   DESCRIPTION = "Scan speed of the AFM in micrometers/second"

END_OBJECT = COLUMN

AFM_SDD

PDS_VERSION_ID                      = "PDS3" 

LABEL_REVISION_NOTE                 = "2008-02-02, Initial"

/* File characteristics */

RECORD_TYPE                         = FIXED_LENGTH

RECORD_BYTES                        = 19969

FILE_RECORDS                        = 2052                     

/* Pointers to object in file */

^AFM_D_HEADER_TABLE                 = ("FT000SDD_000_2E0100000000A0.TAB",1)

^AFM_F_ERROR_TABLE                  = ("FT000SDD_000_2E0100000000A0.TAB",5)

^AFM_F_HEIGHT_TABLE                 = ("FT000SDD_000_2E0100000000A0.TAB",517)

^AFM_B_ERROR_TABLE                  = ("FT000SDD_000_2E0100000000A0.TAB",1029)

^AFM_B_HEIGHT_TABLE                 = ("FT000SDD_000_2E0100000000A0.TAB",1541)

/* Identification */

DATA_SET_ID                         = "PHX-M-MECA-4-NIRDR-V1.0"

DESCRIPTION                         = "UNK"

PRODUCT_ID                          = "FT000SDD_000_2E0100000000A0_TAB"

PRODUCT_VERSION_ID                  = "V1.0"

PRODUCT_TYPE                        = "MECA_AFM_SDD"

RELEASE_ID                          = 0001

INSTRUMENT_HOST_NAME                = "PHOENIX"

INSTRUMENT_HOST_ID                  = PHX

INSTRUMENT_NAME                     = "MECA ATOMIC FORCE MICROSCOPE"

INSTRUMENT_ID                       = "MECA_AFM"

INSTRUMENT_MODE_ID                  = "SCAN"

MISSION_NAME                        = "PHOENIX"

OPS_TOKEN                           = "NULL"

OPS_TOKEN_ACTIVITY                  = "NULL"

OPS_TOKEN_PAYLOAD                   = "NULL"

OPS_TOKEN_SEQUENCE                  = "NULL"

TARGET_NAME                         = MARS

/* Time information */

MISSION_PHASE_NAME                  = "PRE-LAUNCH"

SPACECRAFT_CLOCK_START_COUNT        = "TEST STRING"

SPACECRAFT_CLOCK_STOP_COUNT         = "TEST STRING"

START_TIME                          = 2008-03-11T11:31:57

STOP_TIME                           = 2008-03-11T11:31:57

PLANET_DAY_NUMBER                   = 356

EARTH_RECEIVED_START_TIME           = 2008-03-11T11:31:57

EARTH_RECEIVED_STOP_TIME            = 2008-03-11T11:31:57

LOCAL_TRUE_SOLAR_TIME               = "00:00:00"

PRODUCT_CREATION_TIME               = 2008-03-11T11:31:57

/* Data object definition */

OBJECT                              = AFM_D_HEADER_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 22

  ROWS                              = 4

  ROW_BYTES                         = 193

  ROW_SUFFIX_BYTES                  = 19776

  ^STRUCTURE                        = "AFM_D_HEADER.FMT"

  DESCRIPTION                       = "This table contains the AFM scan

                                    parameter information. The table contains

                                    193 bytes of table data followed by 19776

                                    bytes of spare data, of which the last 2

                                    bytes contain the <CR><LF> pair. "

END_OBJECT                          = AFM_D_HEADER_TABLE

OBJECT                              = AFM_F_ERROR_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512                    

  ROW_BYTES                         = 19969

  START_BYTE                        = 79877

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan 

                                       forward error derivative information.

                                       Each row represents a scan

                                       line along the fast scan axis"

  OBJECT                            = CONTAINER

    BYTES                           = 39

    DESCRIPTION                     = "The container holds the X-Y-Z

                                       information for each AFM scan error

                                       derivative data point. The table

                                       contains 19969 bytes of table data of

                                       which the last 2 bytes contain the

                                       <CR><LF> pair. "

    NAME                            = "FORWARD ERROR DERIVATIVE"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR DERIVATIVE X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR DERIVATIVE Y COORDINATE"

      START_BYTE                    = 14

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD ERROR DERIVATIVE VALUE"

      START_BYTE                    = 27

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_F_ERROR_TABLE

OBJECT                              = AFM_F_HEIGHT_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 19969

  START_BYTE                        = 10304005

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      forward Z-height derivative.

                                      Each row represents a scan line along

                                      the fast scan axis"

  OBJECT                            = CONTAINER

    BYTES                           = 39

    DESCRIPTION                     = "The container holds the X-Y-Z

                                      information for each AFM forward

                                      derivative scan data point."

    NAME                            = "FORWARD HEIGHT DERIVATIVE"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT DERIVATIVE X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT DERIVATIVE Y COORDINATE"

      START_BYTE                    = 14

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "FORWARD HEIGHT DERIVATIVE VALUE"

      START_BYTE                    = 27

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_F_HEIGHT_TABLE

OBJECT                              = AFM_B_ERROR_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 19969

  START_BYTE                        = 20528133

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                       backward error derivative information

                                       Each row represents a scan line along

                                       the fast scan axis."

  OBJECT                            = CONTAINER

    BYTES                           = 39

    DESCRIPTION                     = "The container holds the X-Y-Z

                                      information for each AFM scan error

                                      derivative data point. The table

                                      contains 19969 bytes of table data

                                      of which the last 2 bytes contain

                                      the <CR><LF> pair."

    NAME                            = "BACKWARD ERROR DERIVATIVE"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR DERIVATIVE X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR DERIVATIVE Y COORDINATE"

      START_BYTE                    = 14

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD ERROR DERIVATIVE VALUE"

      START_BYTE                    = 27

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_B_ERROR_TABLE

OBJECT                              = AFM_B_HEIGHT_TABLE

  INTERCHANGE_FORMAT                = ASCII

  COLUMNS                           = 1536

  ROWS                              = 512

  ROW_BYTES                         = 19969

  START_BYTE                        = 30752261

  MISSING_CONSTANT                  = 0.00

  DESCRIPTION                       = "This table contains the AFM scan

                                      backward Z-height derivative information.

                                      Each row represents a scan

                                      line along the fast scan axis"

  OBJECT                            = CONTAINER

    BYTES                           = 39

    DESCRIPTION                     = "The container holds the X-Y-Z

                                      information for each AFM backward

                                      scan Z-height derivative

                                      data point."

    NAME                            = "BACKWARD HEIGHT DERIVATIVE"

    REPETITIONS                     = 512

    START_BYTE                      = 1

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 1

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT DERIVATIVE X COORDINATE"

      START_BYTE                    = 1

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 2

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT DERIVATIVE Y COORDINATE"

      START_BYTE                    = 14

    END_OBJECT                      = COLUMN

    OBJECT                          = COLUMN

      COLUMN_NUMBER                 = 3

      BYTES                         = 12

      DATA_TYPE                     = ASCII_REAL

      NAME                          = "BACKWARD HEIGHT DERIVATIVE VALUE"

      START_BYTE                    = 27

    END_OBJECT                      = COLUMN

  END_OBJECT                        = CONTAINER

END_OBJECT                          = AFM_B_HEIGHT_TABLE

END

AFM_D_HEADER.FMT

OBJECT = COLUMN

   COLUMN_NUMBER = 1

   NAME = cmdTimewhole

   DATA_TYPE = ASCII_INTEGER

   BYTES = 9

   START_BYTE = 1

   UNIT = SECONDS

   DESCRIPTION = "This is the time that the command was issued from

   the spacecraft computer to the MECA subsystem across the serial

   interface. Units are seconds of Spacecraft Clock (SCLK)."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 2

   NAME = cmdTimeremainder

   DATA_TYPE = ASCII_INTEGER

   BYTES = 10

   START_BYTE = 11

   UNIT = "SECONDS/2**32"

   DESCRIPTION = "The remainder, where 2^32 is a full second."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 3

   NAME = readTimewhole

   DATA_TYPE = ASCII_INTEGER

   BYTES = 9

   START_BYTE = 22

   UNIT = SECONDS

   DESCRIPTION = "This is the time that the data was returned to

   the spacecraft computer across the serial interface from the MECA

   subsystem (not used for some telemetry types). Units are seconds

   of Spacecraft Clock (SCLK)."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 4

   NAME = readTimeremainder

   DATA_TYPE = ASCII_INTEGER

   BYTES = 10

   START_BYTE = 32

   UNIT = "SECONDS/2**32"

   DESCRIPTION = "The remainder, where 2^32 is a full second."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 5

   NAME = dataLength

   DATA_TYPE = ASCII_INTEGER

   BYTES = 6

   START_BYTE = 43

   UNIT = BYTES

   DESCRIPTION = "The length of the following record (and all

   records in this product), not including this header."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 6

   NAME = cols

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 50

   UNIT = POINTS

   DESCRIPTION = "The width (number of points per line) of the AFM image."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 7

   NAME = lines

   DATA_TYPE = ASCII_INTEGER

   BYTES = 3

   START_BYTE = 54

   UNIT = LINES

   DESCRIPTION = "The height (number of lines) of the AFM image."

END_OBJECT = COLUMN

OBJECT = COLUMN

   COLUMN_NUMBER = 8

   NAME = direction

   DATA_TYPE = ASCII_INTEGER

   BYTES = 1

   START_BYTE = 58

   DESCRIPTION = "The scan direction, 1 = forward, 2 = backward."

END_OBJECT = COLUMN

OBJECT = COLUMN