PDS_VERSION_ID = PDS3 RECORD_TYPE = STREAM OBJECT = TEXT PUBLICATION_DATE = 2010-03-15 NOTE = "AAREADME.TXT describes this volume." END_OBJECT = TEXT END MESSENGER Energetic Particle and Plasma Spectrometer Calibrated Data Archive Prepared for the Planetary Plasma Interactions Node of the Planetary Data System ======================================================================== Introduction ======================================================================== This volume contains data from the MESSENGER Energetic Particle and Plasma Spectrometer (EPPS) calibrated data volume set. There are three EPPS volumes: one for documentation, one for EDR data, and one for CDR data. This is the CDR data volume, which contains the actual data. Note that the EPPS is made up of two instrument subsystems, the Fast Imaging Plasma Spectrometer (FIPS), and the Energetic Particle Spectrometer (EPS). Thus two data sets are delivered within this data volume, the FIPS and the EPS. In some cases one file will be relevant to both data sets, in which case the data set id for both are included in the one label. A complete description of the design of this volume is given in the EPPS CDR software interface specification. An electronic copy of this document is located in the /DOCUMENT directory on the DOCUMENT volume (not on this volume). This volume is intended for the use of scientists and students in the study of the of the planet Mercury. The data may be used for research and publication. ======================================================================== Known Issues In Data ======================================================================== Some of the EPS Data Types have unusual or unexpected values users should be aware of: - The Time of Flight segment of the instrument is no longer operational. Early observations (2006) were made in a mode such that rates and fluxes for all ION and Electron channels are all zero in the early files. Only FAST and SHAPED rates are nonzero. -The "Delta" values in SCAN mode data are often negative due to low count rate statistics. -Certain PHA events are excluded by default in standard instrument team analysis as they are of indeterminate analytical value: * Events for which the multi-hit flag is set. * Events with a negative RAW Energy. * Events with Maximum (= 4095) RAW Energy. Users are advised to discard these events as well unless they have strong reasons to do otherwise. See the EPPS CDR SIS document for a more detailed explanation of these issues. ======================================================================== Volume Format ======================================================================== The volume is organized into a hierarchical directory structure. It is transferred from the MESSENGER SOC to the Planetary Plasma Interactions Node via the TCP/IP File Transfer Protocol (FTP) and thus the physical characteristics of the final storage media are unknown to the SOC. All science data are located under the DATA directory. The INDEX directory contains a listing of all of the data products included on this volume. The CATALOG directory on the DOCUMENT volume contains PDS documentation describing the instrument and data set. These include: INSTRUMENT.CAT EPPS instrument description EPPSEPSDATASET.CAT EPPS EPS uncalibrated data set description EPPSFIPSDATASET.CAT EPPS FIPS uncalibrated data set description EPPSEPSDATASET_CDR.CAT EPPS EPS calibrated data set description EPPSFIPSDATASET_CDR.CAT EPPS FIPS calibrated data set description Note that these files are NOT on this, the DATA volume, but are instead included in the DOCUMENT volume. Additional information on volume organization is given in the CDR SIS on the DOCUMENT volume. ======================================================================== File Formats ======================================================================== The data files on this volume are provided in ASCII text format (extension .TAB). Each data file is also accompanied by a detached PDS label file (extension .LBL), an ASCII file containing information describing the data file and data record format. Catalog files (extension .CAT) are provided in ASCII format. Document files describing the volume and the data are included in the DOCUMENT volume. Refer to the AAREADME.TXT file on that volume. Text files and detached label files contain 80-byte fixed-length ASCII records, with a carriage-return character (ASCII 13) in the 79th byte and a line-feed character (ASCII 10) in the 80th byte. This format allows the files to be read by MacOS, DOS, UNIX and VMS operating systems. Note that while both label and catalog files are ASCII, some operating systems will not recognize the .LBL and .CAT extensions as ASCII types. It may be necessary to either remap these extensions as ASCII in the system or text browser, or else to open the files from within the text browser. ======================================================================== Volume Set Information ======================================================================== The MESSENGER EPPS calibrated volume sets (EPPS_2XXX) includes the following volumes: Volume ID. Contents ----------------- ----------------------------------------------------- MESSEPPS_CDR This volume. MESSENGER EPPS calibrated data. This volume contains EPPS data at Earth, Venus and Mercury over the interval 2004-216 (3 Aug) to 2009-287 (Oct 14). MESSEPPS_DOC MESSENGER EPPS documentation for uncalibrated and calibrated data. ======================================================================== Volume Contents ======================================================================== Directory Structure and Contents for EPPS CDR Data Archive Volume The following illustration shows the directory structure overview for the EPPS CDR Data Archive Volume. This volume contains the EPPS CDR data products and any additional files required for the volume to be compliant with PDS standards. It does not contain supporting documentation, which is contained on the DOCUMENT volume. The content of the volume is expected to be updated with periodic releases according to the schedule found in the MESSENGER Data Management and Archiving Plan (DMAP). Revised CDRs (if needed) will also be delivered according to the same schedule. Revised CDRs will have an incremented version number in the PDS label. Data Volume Directory Structure Overview ___________________________________|________ ____________ | | | |