Mars Exploration Rover (MER) Software Interface Specification

Interface Title: Mössbauer Experiment Data Record (EDR) Mission: MER Date: September 27, 2005 Module ID: SIS-SCI009-MER Module Type (REFerence Only or MISsion-specific info included): MIS

Signatures GDS Generating Elements: Ops Product Generation Subsystem (OPGS) Justin Maki ______________________________________________________ Subsystem Engineer Date Concurrance: MössbauerPayload Element Lead Göstar Klingelhöfer, ______________________________________________________ PEL Date MER Mössbauer Investigation Scientist Albert Yen ______________________________________________________ Investigation Scientist Date MER Science Manager John Callas ______________________________________________________ Manager Date PDS Geosciences Node Manager Raymond Arvidson ______________________________________________________ Manager Date MER MIPL Cognizant Engineer Doug Alexander ______________________________________________________ Cognizant Engineer Date

Mars Exploration Rover (MER) Project

MB EDR Software Interface Specification (SIS)

Version 2.1

Prepared by:

Edward A. Guinness

MER MB SIS Custodian

Helen Mortensen

Paper copies of this document may not be current and should not be relied on for official purposes. The current version is in the MER Project Library at http://mars03-lib.jpl.nasa.gov, in the Controlled Documents and Records folder.

JPL D-22849

SEPTEMBER 27, 2005

Jet Propulsion Laboratory

California Institute of Technology

CHANGE LOG

TBD ITEMS

SECTION

DESCRIPTION

CONTENTS

CHANGE LOG.............................................................................................................................. iii

TBD ITEMS................................................................................................................................... vi

CONTENTS................................................................................................................................. vii

LIST OF FIGURES..................................................................................................................... viii

LIST OF TABLES....................................................................................................................... viii

ACRONYMS AND ABBREVIATIONS....................................................................................... ix

GLOSSARY.................................................................................................................................. xi

1. INTRODUCTION....................................................................................................................... 1

1.1 Purpose and Scope........................................................................................................... 1

1.2 Contents............................................................................................................................... 1

1.3 Applicable Documents and Constraints........................................................................... 1

1.4 Relationships with Other Interfaces................................................................................... 2

2. Data Product Characteristics and Environment........................................ 2

2.1 Instrument Overview............................................................................................................ 2

2.2 Data Product Overview...................................................................................................... 3

2.3 Data Processing................................................................................................................. 3

2.3.1 Data Processing Level............................................................................................... 3

2.3.2 Data Product Generation............................................................................................ 4

2.3.3 Data Flow..................................................................................................................... 4

2.3.4 Labeling and Identification.......................................................................................... 4

2.4 Standards Used in Generating Products......................................................................... 7

2.4.1 PDS Standards........................................................................................................... 7

2.4.2 Time Standards........................................................................................................... 7

2.4.3 Coordinate System Standards.................................................................................. 7

2.4.4 Data Storage Conventions......................................................................................... 9

2.5 Data Validation................................................................................................................... 9

3. Detailed Data Product Specifications............................................................... 9

3.1 Data Product Structure and Organization........................................................................ 9

3.2 Data Format Descriptions............................................................................................... 10

3.3 Label and Header Descriptions...................................................................................... 13

3.3.1 PDS Label................................................................................................................. 13

3.3.1 PDS Data Objects.................................................................................................... 13

4. Applicable Software.................................................................................................. 14

4.1 Utility Programs................................................................................................................ 14

Appendix A - Example of A MÖSSBauer EDR Label CONTAINING ALL 5 BLOCKS 15

Appendix B - Example of A MÖSSBauer EDR Label, SINGLE BLOCK............. 25

APPENDIX C - PDS LABEL ITEMS....................................................................................... 29

LIST OF FIGURES

Figure 1: S, S_R, and R Frame Coordinate Systems.................................................................. 8

Figure 2: The MB EDR consists of two files............................................................................... 9

Figure 3: Data structure for a MB binary file............................................................................ 10

Figure 4: SRAM structure (only scientific data shown)........................................................... 11

LIST OF TABLES

Table 1: Product and Software Interfaces to this SIS............................................................... 2

Table 2: Processing Levels for Science Data Sets................................................................. 3

Table 3: Coordinate Frames Used for MER Surface Operations.......................................... 7

Table 4: MB Instrument Parameters........................................................................................ 12

ACRONYMS AND ABBREVIATIONS

ASCII	American Standard Code for Information Interchange
APSS	Activity Planning and Sequencing Subsystem
CODMAC	Committee on Data Management and Computation
EDR	Experiment Data Record
EEPROM	Electronically Erasable Programmable Read-Only Memory
FEI	File Exchange Interface
FRAM	Ferroelectric Random Access Memory
ICD	Interface Control Document
IDD	Instrument Deployment Device
ISO	International Standards Organization
JPL	Jet Propulsion Laboratory
Kbytes	Kilobytes
LSB	Least Significant Byte
MB	Mössbauer Spectrometer
MB	Mega Bytes
MER	Mars Exploration Rover
MIPL	Multimission Image Processing Laboratory
MSB	Most Significant Byte
NASA	National Aeronautics and Space Administration
ODL	Object Description Language
OPGS	Operations Product Generation Subsystem
OSS	Operation Storage Server
PDS	Planetary Data System
PEL	Payload Element Lead
PPPCS	Pointing, Positioning, Phasing & Coordinate Systems
RAM	Random Access Memory
RDR	Reduced Data Record
RSVP	Rover Sequence and Visualization Program
SAP	Science Activity Planner
SFDU	Standard Formatted Data Unit
SIS	Software Interface Specification
SRAM	Static Random Access Memory
SSW	System Software
TBD	To Be Determined
TDS	Telemetry Delivery Subsystem
URL	Universal Resource Locator

GLOSSARY

1. INTRODUCTION

1.1 Purpose and Scope

The purpose of this data product Software Interface Specification (SIS) is to provide users of the Mössbauer Spectrometer (MB) Experiment Data Record (EDR) with a detailed description of the product and a description of how it was generated, including data sources and destinations. A MB EDR contains data from a measurement session. The MB EDR data are stored in binary format. The MB science team will produce a set of MB Reduced Data Record (RDR) products in ASCII format. The RDR's will be described in a separate SIS document.

This SIS is intended to provide enough information to enable users to understand the MB EDR data product. The users for whom this SIS is intended are software developers of the programs used in generating the EDR products and scientists who will analyze the data, including those associated with the Mars Exploration Rover (MER) Project and those in the general planetary science community.

1.2 Contents

This data product SIS describes how the MER MB instrument acquires its data, and how the data are processed, formatted, labeled, and uniquely identified. The document discusses standards used in generating the product and software that may be used to access the product. The data product structure and organization is described in sufficient detail to enable a user to read the product. Finally, an example of a product label is provided, along with the definitions of the keywords in the label.

1.3 Applicable Documents and Constraints

This data product SIS is responsive to the following MER documents:

1. Mars Exploration Program Data Management Plan, R. E. Arvidson, S. Slavney and S. Nelson, Rev. 3, March 20, 2002.

2. Mars Exploration Rover Project Archive Generation, Validation and Transfer Plan, R. E. Arvidson and S. Slavney, JPL D-19658, March 22, 2002.

3. MER Flight-Mission Systems ICD (FMICD), Vol. 4 Command Dictionary, MER 420-3-15.04, JPL D-20616.

4. MER Flight-Mission Systems ICD (FMICD), Vol. 7 Telemetry Dictionary, MER 420-3-15.047 JPL D-20617.

5. Pointing, Positioning, Phasing & Coordinate Systems Master (PPPCS), S.R. Doudrick, JPL D-19720, June 28, 2001.

This SIS is also consistent with the following Planetary Data System documents:

6. Planetary Data System Data Preparation Workbook, Version 3.1, JPL D-7669, Part 1, February 1, 1995.

7. Planetary Data System Data Standards Reference, Version 3.6, JPL D-7669, Part 2, August 1, 2003

8. Planetary Science Data Dictionary Document, JPL D-7116, Rev. D, August 28, 2002

Finally, this SIS is meant to be consistent with the contract negotiated between the MER Project and the Athena Principal Investigator (PI) in which experiment data records and documentation are explicitly defined as deliverable products.

1.4 Relationships with Other Interfaces

Changes to this MB EDR SIS document affect the products, software, and/or documents listed in Table 1.

Table 1: Product and Software Interfaces to this SIS

Name	Type P=product S=software D=document	Owner
MB EDRs	P	OPGS/MIPL
Mertelemproc	S	MIPL
MIPL database schema	P	MIPL
MB RDRs	P	MB Science Team
MB RDR SIS	D	MB Science Team
Other MB Programs/Products/Documents	P/S/D	MB Science Team
mb2asc	S	Geosciences Node

2. Data Product Characteristics and Environment

2.1 Instrument Overview

The MER Mössbauer (MB) spectrometer is designed to characterize the oxidation states of iron and the relative abundance of iron-bearing mineral phases on the martian surface. The MB spectrometer uses a vibrationally-modulated ⁵⁷Co source to illuminate a target with gamma rays. Backscattered gamma radiation is binned by source velocity to determine the hyperfine splitting of ⁵⁷Fe nuclear levels. Targets for Mössbauer measurements include soils and rocks (including rocks that have been abraded with the Rock Abrasion Tool), rover-mounted magnets designed to capture atmospheric dust, and a magnetite-rich calibration target mounted on the rover. The instrument consists of a sensor head mounted on the rover's Instrument Deployment Device (IDD), and electronics mounted in the rover's Warm Electronics Box. The sensor head contains the ⁵⁷Co radiation source, the Mössbauer drive unit, a radiation collimator, x-ray and gamma ray detectors, temperature sensors, a calibration source, and contact plate and switches. The MB has three temperature sensors that monitor the temperature of the electronics board, sensor head, and target sample.

Mössbauer measurements are made by placing the instrument directly on a target. Each measurement will usually take approximately 12 hours. Shorter integration times can be used to analyze the major iron minerals in a target. Mössbauer spectra are temperature dependent. Therefore, spectra are collected in thirteen temperature windows. The temperature limits for the windows can be changed with commands sent to the instrument.

2.2 Data Product Overview

Each MB EDR will consist of two files. The first file is an ASCII formatted, detached PDS label. The second file is a binary data file. The MB EDR binary data file is a copy of the Mössbauer memory buffer. That is, the EDR consists of unprocessed experiment data stored in binary format. The instrument has three sections of memory: SRAM, FRAM, and EEPROM. These memory sections comprise 5 blocks of data, each of which is 32 kilobytes in size. The SRAM, which is volatile memory, contains temperature dependent Mössbauer spectra, drive error signal data an energy spectrum, and temperature data. Mössbauer spectra are measured as counts per channel, where the channels represent velocity bins. The drive error signal measures the difference between the actual and expected velocities of the MB drive unit. The energy spectrum is collected during each MB observation to support a ground analysis of detector performance. The FRAM contains copies of the instrument parameter block and logbook. The EEPROM contains compressed Mössbauer spectra as a backup in case SRAM data are lost. The compressed spectra are contingency spectra to protect against certain instrument anomalies. They are not intended for science analysis and are not needed for any science analysis.

2.3 Data Processing

2.3.1 Data Processing Level

This SIS uses the Committee On Data Management And Computation (CODMAC) data level numbering system to describe the processing level of EDR data products. MB EDR data products are considered CODMAC "Level 2" or "Edited Data" (equivalent to NASA level 0) products. The EDR data files are generated from "Level 1" or "Raw Data", which are the telemetry packets within the project specific Standard Formatted Data Unit (SFDU) record. Refer to Table 2 for a breakdown of the CODMAC and NASA data processing levels.

Table 2: Processing Levels for Science Data Sets

2.3.2 Data Product Generation

The MB EDR data products will be generated by the MIPL (Multimission Image Processing Laboratory) at JPL under the OPGS using the telemetry processing software, mertelemproc. The EDR data products will be raw uncalibrated data reconstructed from telemetry data products generated by the SSW team and formatted according to this EDR SIS. Meta-data acquired from the telemetry data headers will be used to populate the PDS label. There will not be multiple versions of an MB EDR. If telemetry data is missing partial data sets will be created and the missing data will be filled with zeroes. The data will be reprocessed after all data are received and the original version will be overwritten.

2.3.3 Data Flow

The MB EDR data products generated by MIPL during operations are created collectively from: a) SSW data products and b) SPICE kernels. They are created on the OSS and then deposited into MIPL's File Exchange Interface (FEI) for electronic distribution to remote sites via a secure subscription protocol. After a data validation period, the MB EDR data products are collected with other science data and written to physical media for archiving with the Planetary Data System [see reference 2].

The size of the Mössbauer Spectrometer EDR binary data file is 0.160 MB. The Mössbauer Spectrometer EDR will be generated 60 seconds after the last packet SFDU for the EDR has been received by MIPL from the MER TDS. Mössbauer Spectrometer data will be reprocessed only if packets in the original downlink are not received. Partial files are created with missing data filled with zeroes. The MB EDR will be reprocessed after all data is retransmitted and received and the original version will be overwritten and placed into FEI for distribution.

2.3.4 Labeling and Identification

There is a file naming scheme adapted for the MER image and non-image data products. The scheme applies to the EDR and several RDR data products. The file naming scheme adheres to the Level II 27.3 filename convention to be compliant with PDS standards.

Each MER EDR or RDR data product can be uniquely identified by incorporating into the product filename the Rover Mission identifier, the Instrument identifier, the Starting Spacecraft Clock count (SCLK) of the camera event, the data Product Type, the Site location, the rover Position within the site, the Sequence number, the camera "Eye", the spectral Filter, the product Creator identifier and a Version number. For non-camera data, several fields do not apply.

Each MB EDR has a detached PDS label associated with the MB binary data file. The file naming scheme for the MB EDR and RDR data products is formed by:

<rover><inst>< sclk><prod><site>< pos><seq><eye>< filt><who><ver> .<ext>

2.4 Standards Used in Generating Products

2.4.1 PDS Standards

The MB EDR complies with Planetary Data System standards for file formats and labels, as specified in the PDS Standards Reference [Ref 7] and the Planetary Data Dictionary Document [Ref 8].

2.4.2 Time Standards

The PDS label of a MB EDR uses keywords containing time values such as start time, stop time, start spacecraft clock count and stop spacecraft clock count. Each time value standard is defined according to the keyword description. See Appendix C.

2.4.3 Coordinate System Standards

The coordinate systems defined for MER surface operations are listed in Table 3 and illustrated in Figure 1 below. Refer to the Pointing, Positioning, Phasing and Coordinate Systems document [Ref 5].

Table 3: Coordinate Frames Used for MER Surface Operations

Figure 1: S, S_R, and R Frame Coordinate Systems

2.4.4 Data Storage Conventions

The MB EDR data files contain binary data. Mössbauer and energy spectra are 24-bit integers stored in LSB first order. The drive error signal data are 16-bit integers stored in LSB first order. Temperature data are 16-bit integers stored in MSB first order. The detached PDS labels for MB EDR's are stored as ASCII text.

2.5 Data Validation

Validation of the MER EDRs will fall into two primary categories: automated and manual. Automated validation will be performed on every EDR product produced for the mission. Manual validation will only be performed on a subset.

Automated validation will be performed as a part of the archiving process after data has been received, and will be done simultaneously with the archive volume validation. Validations performed, will include such things as verification that the checksum in the label matches a calculated checksum for the data product (i.e., that the data product included in the archive is identical to that produced by the real-time process), a validation of the PDS syntax of the label, a check of the label values against the database and against the index tables included on the archive volume, and checks for internal consistency of the label items. The latter include such things as verifying that the product creation date is later than the earth received time, and comparing the geometry pointing information with the specified target. As problems are discovered and/or new possibilities identified for automated verification, they will be added to the validation procedure.

Manual validation of the data will be performed both as spot-checking of data throughout the life of the mission, and comprehensive validation of a subset of the data (for example, a couple of days' worth of data). These products will be viewed by a human being. Validation in this case will include inspection of the image or other data object for errors (like missing lines) not specified in the label parameters, verification that the target shown / apparent geometry matches that specified in the labels, verification that the product is viewable using the specified software tools, and a general check for any problems that might not have been anticipated in the automated validation procedure.

3. Detailed Data Product Specifications

3.1 Data Product Structure and Organization

The MB EDR consists of a detached ASCII PDS label and a binary data file as shown in Figure 2.

3.2 Data Format Descriptions

A MB EDR data product consists of five contiguous blocks of binary data or a single block and a detached ASCII PDS label (see section 3.3.1). Each data block is 32 Kbytes long for a total size of 160 Kbytes or 32 Kbytes. The five data blocks are a copy of the instrument's memory buffer (Figure 3). The EDR file contains Mössbauer spectra for a given target measured in thirteen temperature windows, along with temperature data, an energy spectrum, a drive error signal spectrum, copies of the instrument parameter block and logbook. In addition, the file contains ten compressed Mössbauer spectra stored in the EEPROM as backup in case the instrument loses power. These backup spectra are updated during data acquisition, approximately every 6 minutes. The MB spectrum stored at location 5400h-71FFh in the fifth block is for backup (a copy of data from one of main temperature windows) and contains no new data.

Data from the instrument's SRAM occupy the first four blocks in the Mössbauer EDR data product. The SRAM structure is shown in Figure 4. It contains three copies of the instrument parameter block, a drive error signal, temperature data, an energy spectrum, and Mössbauer spectra from 13 temperature windows. Sections of the SRAM that are not described in Figure 4 contain internal instrument variables and temporary data, which should be considered as spare bytes.

Each copy of the instrument parameter block in the SRAM is 512 bytes long. Table 4 lists the contents of the instrument parameter block. The SRAM has three copies of the parameter block for a total of 1536 bytes. The drive error signal, which monitors the operation of the MB drive unit, has 512 channels with two bytes per channel. The drive error signal values are stored in LSB first order. The MB EDR file contains temperature data recorded by three sensors: one on the electronics board (located inside the rover's Warm Electronics Box), one on the sensor head, and one on the reference sensor. Each temperature value is scaled and stored as a two byte integer in MSB first order. The file contains 256 temperature records. Within each record, the order of values is board sensor, sample sensor, and reference sensor. The following equations contain the conversion of the scaled temperatures into Kelvin:

Board sensor = 273.2 + 25 + (scaled value * 1.638*2500/4096 - 608)/2

Sample sensor = (scaled value)/10

Reference sensor = (scaled value)10

The energy spectrum, which monitors the operation of the detectors, contains 256 channels of data for each of 5 detectors. Each value is a three byte integer stored in LSB first order. The data are aggregated so that data for the first detector are followed by data for the second detector and so on. The instrument has four counters to store eight measurements from the detectors (4 detectors with 2 energies each). As a result, the measurements from pairs of detectors are added together and stored in one counter. These four summed spectra are included in the EDR data products. In the generation of the Reduced Data Record (RDR) products, the two 6.4 keV spectra are summed, as are the two 14.4 keV. These summed spectra exist, and are labeled as separate products in the RDR data set.

Mössbauer data collected during a measurement are divided into temperature windows defined by a selectable lookup table. Each Mössbauer temperature window consists of five spectra (one for each detector). One spectrum contains 512 channels with three bytes per channel stored in LSB first order. The first channel of each spectrum gives the measurement lifetime, where lifetime is the number of cycles that the MB drive unit has executed during the measurement. The collection of MB spectra can be described as a three-dimensional array with axes of temperature window, detector, and channel, with the channel axis varying the fastest.

The fifth data block of the MB EDR data file contains a copy of the instrument FRAM and EEPROM memory, along with copies of one Mössbauer temperature window, the drive error signal, instrument parameter block, and temperature data. The FRAM consists of three copies of the instrument parameter block (Table 4) and the instrument logbook. The logbook has 256 records with eight bytes in each record. The logbook contains information on the engineering status of the instrument during a measurement. The information in the logbook is not needed and not useful for calibration or science data analysis. The EEPROM contains ten compressed MB spectra. The data are compressed by combining data from several temperature windows or from several detectors. Each compressed MB spectrum has 512 channels with three bytes per channel stored in LSB first order.

The integration times for each MB measurement are listed in the observation table provided to the PDS. This table can be found in the document directory of both the EDR and RDR data sets. Integration time is calculated by division of drive cycles by drive frequency. As noted, the number of drive cycles is included with each spectrum in the EDR data files. The drive frequency is about 25 Hz. It can also be derived from the FG_PRESCALER parameter stored in the instrument parameter block. The stored FG_PRESCALER value is converted to drive frequency as follows: fdrive = 900 Hz / FG_PRESCALER. So, for example, a prescaler value of 37 yields a drive frequency of 900/37 = 24.3 Hz.