MESSENGER RADIO SCIENCE DERIVED DATA ARCHIVE VOLUME SOFTWARE INTERFACE SPECIFICATION Version 1.4 August 27, 2013 Susan Slavney TABLE OF CONTENTS 1. Introduction 1 1.1. Purpose and Scope 1 1.2. Content Overview 1 1.3. Applicable Documents and Constraints 1 1.4. Relationships with Other Interfaces 1 2. Archive Volume Contents 2 2.1. Root Directory Contents 2 2.2. Data Directory Contents and Naming 2 2.3. Index Directory Contents 2 2.4. Document Directory Contents 3 2.5. Catalog Directory Contents 3 3. Archive Volume Format 4 3.1. File Formats 4 3.1.1. Document File Format 4 3.1.2. Tabular File Format 4 3.1.3. PDS Label Format 5 3.1.4. Catalog File Format 5 3.1.5. Science Data File Formats 5 4. Archive Volume Generation 6 4.1. Data Transfer and Validation Methods 6 4.2. Data Product Sizes and Delivery Rates 6 4.3. Interface Media Characteristics 6 4.4. Backup and Duplicates 6 4.5. Labeling and Identification 6 5. Support Staff and Cognizant Persons 6 TABLES AND FIGURES Table 1 Index table contents. 3 Table 2 Standard product sizes and delivery rates. 6 DOCUMENT CHANGE LOG Change Date Affected Portions Initial draft 10/15/12 All Rev. 1.1. MRR: Removed references to RSDMAP products. Added names for SH*DR products. 1/25/13 Multiple. Rev. 1.2. MRR: Added SHADR, SHBDR, and OCC subdirectories to DATA directory. Added acronyms. Correct file names in Document directory. 2/13/13 Sec. 2.2 Data Directory Contents and Naming, Acronyms section. Sec. 2.4 Document Directory Contents Rev. 1.3. MRR: Changed naming convention for spherical harmonics (SHADR/SHBDR) products. 2/20/13 Sec. 2.2 Data Directory Contents and Naming. Rev. 1.4. MRR: Minor modifications from peer review. 8/27/13 Multiple. TBD ITEMS Section Description None ACRONYMS AND ABBREVIATIONS ASCII American Standard Code for Information Interchange CD-ROM Compact Disk - Read-Only Memory CD-WO Write-Once Compact Disk IEEE Institute of Electrical and Electronics Engineers ISO International Standards Organization JPL Jet Propulsion Laboratory MESSENGER Mercury Surface, Space Environment, Geochemistry, and Ranging MLA Mercury Laser Altimeter NSSDC National Space Science Data Center OCC Occultation Summary PDF Portable Document Format PDS Planetary Data System PSG Project Science Group RS Radio Science SDVT Science Data Validation Team SHADR Spherical Harmonics ASCII Data Record SHBDR Spherical Harmonics Binary Data Record SIS Software Interface Specification TBD To Be Determined GLOSSARY Archive - An archive consists of one or more data sets along with all the documentation and ancillary information needed to understand and use the data. An archive is a logical construct independent of the medium on which it is stored. Archive Volume, Archive Volume Set - A volume is a unit of media on which data products are stored; for example, one CD-ROM or DVD-ROM. An archive volume is a volume containing all or part of an archive; that is, data products plus documentation and ancillary files. When an archive spans multiple volumes, they are called an archive volume set. Usually the documentation and some ancillary files are repeated on each volume of the set, so that a single volume can be used alone. Catalog Information - Descriptive information about a data set (e.g. mission description, spacecraft description, instrument description), suitable for loading into the PDS catalog. Data Product - A labeled grouping of data resulting from a scientific observation, usually stored in one file. A product label identifies, describes, and defines the structure of the data. An example of a data product is a planetary image, a spectrum table, or a time series table. Data Set - An accumulation of data products. A data set together with supporting documentation and ancillary files is an archive. Standard Data Product - A data product generated in a predefined way using well-understood procedures, processed in "pipeline" fashion. Data products that are generated in a nonstandard way are sometimes called special data products. 1. 1. Introduction 1.1. Purpose and Scope This Software Interface Specification is intended to be used by those who wish to understand the format and content of the MESSENGER Radio Science Derived Data Archive, including Spherical Harmonics and Occultation products. Typically, these individuals would be software engineers, data analysts, or planetary scientists. The specifications in this document apply to all MESSENGER Radio Science Derived Data standard product archive volumes that are generated by the MESSENGER Project. 1.2. Content Overview This Software Interface Specification (SIS) describes the format, content, and generation of the MESSENGER Radio Science Derived Data Archive. Section 2, Archive Volume Generation, describes the procedure for transferring data products to archive media. Section 3, Archive Volume Contents, describes the structure of the archive volumes and the contents of each file. Section 4, Archive Volume Format, describes the file formats used on the archive volumes. Finally, Section 5, Support Staff and Cognizant Persons, lists the individuals responsible for generating the archive volumes. 1.3. Applicable Documents and Constraints This Archive Volume SIS is intended to be consistent with the following documents: 1. MESSENGER Data Management and Archive Plan, Rev. B, Feb. 15, 2012, Johns Hopkins University Applied Physics Laboratory. 2. Software Interface Specification, Spherical Harmonics ASCII Data Record (SHADR), Frank Lemoine, version 1.0, Jun. 29, 2006, NASA/Goddard Space Flight Center. 3. Software Interface Specification, Spherical Harmonics Binary Data Record (SHBDR), Frank Lemoine, version 1.0, Jun. 29, 2006, NASA/Goddard Space Flight Center. 4. Software Interface Specification, MESSENGER Radio Science Reduced Data Record Archive For Radio Occultation Summaries (OCCSUM) Files, Mark Perry, version 0.91, Jan. 25, 2013, Johns Hopkins University Applied Physics Laboratory. 5. Planetary Data System Archive Preparation Guide, April 1, 2010, Version 1.4, JPL D-31224. 6. Planetary Data System Standards Reference, February 27, 2009, Version 3.8. JPL D-7669, Part 2. 7. Planetary Science Data Dictionary Document, October 20, 2008, JPL D-7116, Rev. F. 1.4. Relationships with Other Interfaces This Archive Volume SIS could be affected by changes to the design of the MESSENGER Radio Science derived standard data products (Applicable Documents 2, 3, 4, and 5). 2. Archive Volume Contents This section describes the contents of the MESSENGER Radio Science Derived Data archive volume, including the file names, file contents, file types, and organization responsible for providing the files. 2.1. Root Directory Contents Files in the Root Directory include an overview of the archive, a description of the volume for the PDS Catalog, and a list of errata or comments about the archive. The following files are contained in the Root Directory. File Name File Contents File Provided By AAREADME.TXT Volume content and format information RS Team ERRATA.TXT A cumulative listing of comments and updates concerning all archive volumes published to date RS Team VOLDESC.CAT A description of the contents of this volume in a PDS format readable by both humans and computers Geosciences Node 2.2. Data Directory Contents and Naming The Data Directory contains the derived Radio Science products and their PDS labels. Under the Data Directory are three subdirectories named SHADR, SHBDR, and OCC, which store the Spherical Harmonics ASCII Data Record, Spherical Harmonics Binary Data Record, and the Occultation Summary Data Record. in the filenames is a numeric version ID range 01...99. File Name File Contents File Provided By SHADR/GGMES_20V_SHA.TAB, SHADR/GGMES_20V_SHA.LBL Gravity Spherical Harmonics ASCII Data Record (SHADR) RS Team SHBDR/GGMES_20V_SHB.DAT, SHBDR/GGMES_20V_SHB.LBL Gravity Spherical Harmonics Binary Data Record (SHBDR) SHADR/GTMES_24V_SHA.TAB, SHADR/GTMES_24V_SHA.LBL Shape Spherical Harmonics ASCII Data Record (SHADR) (ASCII product only) MLA Team OCC/MESS_RS_OCC_V.CSV, OCC/MESS_RS_OCC_V.LBL Occultation Summary Product (OCC) RS Team 2.3. Index Directory Contents Files in the Index Directory are provided to help the user locate products on this archive volume and on previously released volumes in the archive. The following files are contained in the Index Directory. File Name File Contents File Provided By INDXINFO.TXT A description of the contents of this directory Geosciences Node INDEX.TAB A table listing all data products on this archive volume RS Team INDEX.LBL A PDS detached label that describes INDEX.TAB RS Team The index table contains one row for each product in the archive. Table 1 lists the columns of the index table. Table 1 Index table contents. Column Name Description Source VOLUME_ID PDS archive volume on which a data product is stored Always MESSRS_1001 DATA_SET_ID Unique identifier for data set to which the data product belongs PDS label PRODUCT_ID Unique identifier for data product PDS label PRODUCT_TYPE Type of product, e.g. SHADR, SHBDR, OCC PDS label FILE_SPECIFICATION_NAME Directory path and file name of label file for data product PDS label file name PRODUCT_CREATION_TIME Date and time of data product creation PDS label START_TIME UTC date and time of start of observation PDS label STOP_TIME UTC date and time of end of observation PDS label PRODUCT_VERSION_ID Version number of data product PDS label 2.4. Document Directory Contents The Document Directory contains documentation to help the user understand and use the archive data. The following files are contained in the Document Directory. File Name File Contents File Provided By DOCINFO.TXT A description of the contents of this directory Geosciences Node OCCSUM.TXT Occultation Summary Product Software Interface Specification RS Team MESS_RS_RDR_OCC_AVSIS.TXT, MESS_RS_RDR_OCC_AVSIS.PDF, MESS_RS_RDR_OCC_AVSIS.LBL Archive Volume SIS (this document) in text and PDF formats, with detached PDS label Geosciences Node SHADR.TXT Spherical Harmonics ASCII Data Record Software Interface Specification RS Team SHBDR.TXT Spherical Harmonics Binary Data Record Software Interface Specification RS Team 2.5. Catalog Directory Contents The files in the Catalog Directory provide a top-level understanding of the mission, spacecraft, instruments, and data sets. The files in this directory are coordinated with the PDS data engineer, who is responsible for loading them into the PDS catalog for online searching. The following files are found in the Catalog Directory. File Name File Contents File Provided By CATINFO.TXT A description of the contents of this directory Geosciences Node RSRDR_DS.CAT Description of the Radio Science derived data set RS Team INST.CAT Description of the Radio Science subsystem RS Team INSTHOST.CAT Description of the MESSENGER spacecraft MESSENGER Project MISSION.CAT Description of the MESSENGER mission MESSENGER Project PERSON.CAT Contact information for personnel responsible for creating this archive Geosciences Node REF.CAT References mentioned in other *.CAT files Geosciences Node 3. Archive Volume Format This section describes the format of the MESSENGER Radio Science Derived Data Archive Volume. Data that comprise the archive will be formatted and described in accordance with Planetary Data System specifications and definitions [Applicable Documents 6 and 7]. 3.1. File Formats This section describes file formats for the kinds of files contained on Archive Volumes. 3.1.1. Document File Format Document files with the .TXT suffix exist in the Root, Index, Catalog, and Document directories. They are ASCII files which may have embedded PDS labels. Lines in a .TXT file end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be readable under various operating systems. Documents in the Document directory may contain formatting and figures that cannot be rendered as ASCII text. Such documents are also provided in PDF form. The PDF (Portable Document Format) is frequently used for distributing documents and may be read with free PDF reader software. 3.1.2. Tabular File Format Tabular files (.TAB suffix) exist in the Index directory. Tabular files are ASCII files formatted for direct reading into many database management systems on various computers. In the case of the INDEX.TAB file, all fields are separated by commas, and character fields are enclosed in double quotation marks ("). (Character fields are padded with spaces to keep quotation marks in the same columns of successive records.) Character fields are left justified, and numeric fields are right justified. The "start byte" and "bytes" values listed in the labels do not include the commas between fields or the quotation marks surrounding character fields. The records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. This allows a table to be treated as a fixed length record file on computers that support this file type and as a text file with embedded line delimiters on those that don't. The MD5.TAB file contains only two space-delimited fields, a numeric (hexadecimal) MD5 hash value and a file specification. The file specification is not enclosed in quotes. All tabular files are described by detached PDS labels. Each PDS label files has the same name as the data file it describes, but with the extension .LBL; for example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory. 3.1.3. PDS Label Format All data files in the archive have PDS labels, either embedded at the beginning of the file or detached in a separate file. For examples of PDS labels for each type of data product, see the Data Product SISes [Applicable Documents 2, 3, and 4]. A PDS label, whether embedded or detached from its associated file, consists of lines of ASCII text in the form of keyword = value statements that provide descriptive information about the data file. The label is intended to be readable both by humans and by software. Details of the syntax and semantics of PDS labels can be found in the PDS Standards Reference [Applicable Document 6], and definitions of the keywords used in the label can be found by using the PDS Data Dictionary Lookup web service at http://pds.jpl.nasa.gov/tools/ddlookup/data_dictionary_lookup.cfm. Lines of text in detached labels end with a carriage return character (ASCII 13) and a line feed character (ASCII 10). This allows the files to be read under various operating systems. 3.1.4. Catalog File Format Catalog files (suffix .CAT) exist in the Root and Catalog directories. Like PDS labels, they are text files formatted as keyword = value statements. They contain descriptions of the data set, instrument, spacecraft, and mission, as well as personnel contact information and references to published literature. They are called Catalog Files because they are loaded into the PDS online catalog to make the information available to users searching for data. 3.1.5. Science Data File Formats The Radio Science SHADR product is an ASCII text file containing two tables, a header table and a coefficient table. The SHBDR product is a binary file containing four tables: a header, a names table, a coefficients table, and a covariance matrix. The OCC product is an ASCII text table stored in Comma-Separated Value (CSV) format. For more information about the format and content of the data products, see the relevant Data Product SIS [Applicable Documents 2, 3 and 4]. 4. Archive Volume Generation 4.1. Data Transfer and Validation Methods MESSENGER Radio Science Derived Products are generated by the MESSENGER Radio Science Team and delivered to the PDS Geosciences Node according to the schedule for data releases determined by the MESSENGER Project [Applicable Document 1]. The products are validated for PDS compliance by the Team before delivery and by PDS upon receipt. 4.2. Data Product Sizes and Delivery Rates Table 2 summarizes expected sizes and production rates for the Radio Science Derived Products. Table 2 Standard product sizes and delivery rates. Product Typical Product Size Production Rate Expected Total Data Volume for Entire Mission SHADR 441 KB Two products (gravity and shape), revised as needed (GGMES_20V_SHA.TAB,, GTMES_24V_SHA.TAB) 441 KB SHBDR 164 MB One product (gravity), revised as needed (GGMES_20V_SHB.DAT) 164 MB OCC 32 KB One product, revised as needed (MESS_RS_OCC_V.CSV) 32 KB 4.3. Interface Media Characteristics All volumes in the archive conform to ISO 9660 standards [ISO 9660, 1988]. 4.4. Backup and Duplicates The Radio Science Team will maintain its own backup copies of the archive at least until it has been released by PDS. PDS will maintain at least three copies, including a copy at the National Space Science Data Center (NSSDC), according to PDS policy and agreements with NSSDC. 4.5. Labeling and Identification All MESSENGER Radio Science derived data products are archived on a single PDS archive volume with the unique identifier MESSRS_1001. 5. Support Staff and Cognizant Persons Mark Perry (Mark.Perry@jhuapl.edu) and Michael Reid (Mike.Reid@jhuapl.edu) are the MESSENGER Radio Science data providers. David Smith (dsmith@tharsis.gsfc.nasa.gov) is the MESSENGER Radio Science Principal Investigator. Susan Slavney (Susan.Slavney@wustl.edu) is the PDS Geosciences Node representative for Radio Science archives.