This document provides access to most files in the archive. Note that some links in this document require Internet access.
This document provides an overview to the Viking Lander Labeled Release Experiment archive, including a complete listing of the volume contents (see Section 2 below). The Labeled Release (LR) instrument used two solid-state beta counters to measure carbon-14 labeled gas evolved from soil samples as a function of time. Martian soil samples were housed in one of four test cells and were moistened with an aqueous nutrient solution. The scientific objective of the experiment was to test for the presence of heterotrophic metabolism due to microbial organisms in the soil. Viking Lander 1 performed four analysis cycles, whereas Viking Lander 2 performed five cycles.
The Labeled Release data set was reconstructed from computer listings provided by Co-Investigator Patricia Ann Straat and from microfilm archived at the National Space Science Data Center (NSSDC). LR data files contain raw and background-corrected radioactivity counts as a function of time. Also included are temperature measurements for the test cell and detectors. Data collected during each analysis cycle are stored in separate files and are sorted in a time sequential format.
This archive, including supporting documentation and file labels, conforms to the Planetary Data System (PDS) Standards, Version 3.3, Jet Propulsion Laboratory (JPL) Document JPL D-7669 Part 2 (7/1/1999) and the Planetary Science Data Dictionary, JPL Document JPL D-7116, Rev D (7/15/1996). These documents are available from the PDS web site (http://pds.jpl.nasa.gov). Known errors, anomalies, and comments about the archive are documented in the ERRATA.TXT file in the root-level directory of this volume.
The organization of this volume and the contents of each directory are described below.
AAREADME.TXT, AAREADME.HTM, AAREADME.LBL
AAREADME.TXT and AAREADME.HTM are the plain text and HTML versions of the file you are currently reading. AAREADME.LBL is a detached PDS label that describes the other two files.
This file lists known errors and anomalies on this volume. It is occasionally updated if additional notes about the archive are needed.
This text file is a description of the volume contents as PDS objects. It is a required file on PDS archive volumes.
Files in the CATALOG directory are text files in PDS object description language. The files contain information about the Viking mission and spacecraft, the Labeled Release instrument, data set, personnel, and references. See the file CATINFO.TXT for details.
The DATA directory contains Labeled Release data products. There are separate files (and PDS labels) for the radioactivity, and head-end and detector temperature measurements. Data are also separated by analysis cycle. See the file DATAINFO.TXT for details.
The DOCUMENT directory contains the volume documentation file. See the file DOCINFO.TXT for details.
The EXTRAS directory contains files for the HTML-based description of the Labeled Release experiment known as the Experimenter's Notebook. See Section 5 of this document for more information about the Notebook.
The INDEX directory contains an index table, which lists all products on this volume, along with some catalog information for each product such as time range, file name, etc. See the file INDXINFO.TXT for details.
The volume has been formatted so that a variety of computer systems (e.g., PC, Macintosh, and Sun) may access the data. Specifically, it is formatted according to the ISO-9660 level 1 Interchange Standard. For further information, refer to the ISO-9660 Standard Document: RF# ISO 9660-1988, April 15, 1988.
This volume does not contain any Extended Attribute Records (XAR). Thus, VAX/VMS users may have some problems accessing files on this volume.
All document, detached PDS label, and HTML files are ASCII stream format files. Stream files consisting of ASCII text are delimited with a carriage return (CR) and line feed (LF) sequence. Stream files in this format can be read by MacOS, Windows, Unix, and VMS operating systems. Different computers interpret these codes differently. For example, PC/Windows systems use the two-byte CR/LF sequence to terminate a line of text. UNIX systems only use a line feed, whereas a Macintosh uses only a carriage return. VAX computers support these various formats as stream files, but prefer to store text files internally as variable length records. PDS has adopted the CR/LF as the standard line delimiter for archival products. Note that CR/LF is the required line terminator for all PDS labels and catalog files. This is the only line terminator sequence that insures text files will be viewable on all computer systems. System utilities are available on the various computer types to convert this format to the internal format if necessary.
Macintosh - Apple File Exchange, MS-DOS to Mac option.
Unix - Translate utility (tr -d'\15' <input_file >output_file)
The LR data files on this archive are stored as table objects. PDS tabular files are formatted so that they may be read directly into many database management systems (DBMS), spreadsheet, or plotting programs on various computers. All fields are separated by commas, and character fields are enclosed in double quotation marks ("). Character fields are left justified, and numeric fields are right justified. The "start byte" and "bytes" values listed in a PDS label do not include the commas between fields or the quotation marks surrounding character fields. Records are of fixed length, and the last two bytes of each record contain the ASCII carriage return and line feed characters. Table files can be treated as fixed length record files on computers that support this file type and as normal text files on other computers. All tabular files are described by PDS labels, which are detached label files having the same base name as the data files they describe, with the extension .LBL. For example, the file INDEX.TAB is accompanied by the detached label file INDEX.LBL in the same directory.
PDS labels are object-oriented. The object to which the label refers (e.g., IMAGE, TABLE, etc.) is denoted by a pointer statement of the form:
^object = location
in which the carat character (^, also called a pointer in this context) indicates that the object starts at the given location. For an object in the same file as the label, the location is an integer representing the starting record number of the object (the first record in the file is record 1). For an object located outside the label file, the location denotes the name of the file containing the object, along with the starting record or byte number. For example:
^IMAGE = ("C102.IMG",3)
indicates that the IMAGE object begins at record 3 of the file C102.IMG, in the same directory as the detached label file. Below is a list of the possible formats that use the ^object keyword.
^object = n
^object = n<BYTES>
^object = ("filename.ext",n)
^object = ("[dirlist]filename.ext",n)
^object = ("filename.ext",n<BYTES>)
^object = ("[dirlist]filename.ext",n<BYTES>)
where n starting record or byte number of the object,
counting from beginning of the file (record 1,
byte 1); default is record number.
<BYTES> indicates that number given is in units of bytes.
filename upper-case file name.
ext upper-case file extension.
dirlist period-delimited path-list of parent directories,
in upper case, that specifies the object file
directory (used only when the object is not in the
same directory as the label file).
The LR Experimenter's Notebook provides a HTML interface into the LR data set. The Notebook contains a timeline of important activities for the LR experiment, along with information about the instrument. The Notebook also includes images and maps of the Viking landing sites that show where the soil samples were acquired. The LR data are shown in a series of graphs. The main sections of the Notebook include: an overview of the experiment, soil sample collection, overview of the Viking biology experiment, detailed description of the LR instrument and experiment, a timeline of important LR activities, and references.
For questions concerning this data set:
PDS Geosciences Node
Washington University
Dept. of Earth and Planetary Sciences
1 Brookings Drive
St. Louis, MO 63130
314-935-5493
Geosciences Node Web Site: http://wwwpds.wustl.edu
Geosciences Node Email: geosci@wunder.wustl.edu
The Principal Investigator for the Viking Lander Labeled Release experiment was Dr. Gilbert V. Levin of Biospherics, Inc. Co-Investigator Dr. Patricia Ann Straat provided copies of data listings and notes about the LR experiment. Drs. Joseph King and David R. Williams of the NSSDC, Goddard Space Flight Center, NASA supervised the recovery of LR data from NSSDC's microfilm archive.
This volume was designed and produced by Dr. Edward A. Guinness, Planetary Data System Geosciences Node, Washington University, St. Louis, Missouri. Guinness also supervised the data entry from computer listings. Phillip G. Valko, Washington University, designed the Experimenter's Notebook.
The LR data set published on this volume may be cited in scientific literature using the following reference.
Levin, G. V., P. A. Straat, E. A. Guinness, P. G. Valko, J. H. King, and D. R. Williams, "Viking Lander Labeled Release Data Archive", NASA Planetary Data System, VL1/VL2-M-LR-2-EDR-V1.0, 2001.