DATA_SET_ID = "MESS-E/V/H/SW-EPPS-3-EPS-DDR-V1.0" DATA_SET_NAME = "MESSENGER E/V/H/SW EPPS CALIBRATED EPS DDR V1.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_OBJECT_TYPE = TABLE START_TIME = 2004-257T00:00:00 STOP_TIME = 2015-120T15:08:14 DATA_SET_RELEASE_DATE = 2017-05-12 ARCHIVE_STATUS = "ARCHIVED" PRODUCER_FULL_NAME = "GEORGE HO" DETAILED_CATALOG_FLAG = "N" CITATION_DESC = "{George C. Ho}, MESSENGER E/V/H/SW EPPS CALIBRATED EPS V1.0, MESS-E/V/H/SW-EPPS-3-EPS-DDR-V1.0, NASA Planetary Data System, 2009." DATA_SET_TERSE_DESC = "The MESSENGER EPPS DDR observations consist of energetic particle and plasma data collected by the EPPS instrument during orbital operations of Mercury." ABSTRACT_DESC = " Abstract ======== This data set consists of the MESSENGER Energetic Particle and Plasma Spectrometer (EPPS) advanced data products, also known as DDR/DAPs. The system encompasses 2 instrument subsystems - the Energetic Particle Spectrometer (EPS) and the Fast Imaging Plasma Spectrometer (FIPS). This data set contains EPS instrument data. EPS covers the energy range of 25 to > 500 keV for electrons, and 10 keV/nucleon to ~3 MeV total energy for ions. There is one DDR data product for EPS" DATA_SET_DESC = " Data Set Overview ================= The data set consists of advanced data products, also known as DDR/DAPs. For all the DDR products there is a detached PDS label file that describes the contents of one data file. Each label file will have the same base name as the data file it is describing, with the extension .LBL to denote a label file. The label file defines the start time and end of the observation, product creation time, and the structure of the ASCII tables. Each data product is identified within the PDS label by a STANDARD_DATA_PRODUCT_ID value, shown in parentheses in the table below. The EPS portion of the data archive consists of three DDR data products. These are tables of pitch-angle values, select pitch-angle distribution function spectrograms provided as image plots, and daily pitch-angle distribution function spectrograms provided as image plots covering the entire EPS data set during the Mercury Orbit phases. The pitch angle value table DDRs are included in both releases 9 and 11. The pitch angle value tables in release 11 include the entire EPS data set covering the Mercury Orbit Year 2. A set of EPS pitch angle spectrogram plot products were included in release 9. They cover selected time periods within the years 2011 and 2012 that the instrument team determines to be of particular interest. These were a one-time delivery containing plots in PNG format (.PNG). These may be found in the EPS_PITCH_ANGLES_SPECTROGRAM directory within the archive volume. In release 16, the complete set of pitch angle spectrograms containing both plots in PNG format and also data points in text format (.TAB files) were released. These are daily products covering the entire Mercury orbit years instead of just selected time periods. These may be found in the EPS_PA_DAILY_SPECTROGRAM directory within the archive volume. These products are summarized in the data table below. A more complete description of each product may be found in the EPPS DDR SIS document, located in the DOCUMENT directory of the document volume. Instrument Overview =================== The EPS sensor consists of a 60-mm diameter, tuna-can-like cylinder, in which a start foil and stop foil, wrapped around opposite curved sides of the cylinder, constitute the TOF chamber. Please note that the TOF section suffered a failure shortly after launched, hence no flight TOF data are included in any data release. The solid-state detectors are arranged so that each detector senses the events within a given range of incidence angles. Each of the 6 detector modules is composed of 4 pixels: large and small ion and large and small electron. The reported energies are the deposited particle energy. See the EPPSINST.CAT file for more information and [ANDREWSETAL2007] for full details. Calibration Overview ==================== This data set is normalized and background subtracted. Please refer to Livi et al. for full description of the EPS calibration. [Livi et al., 'MESSENGER Energetic Particle Spectrometer (EPPS/EPS) Calibration Report', 2004 (at PDS Geosciences node messgc_0001/EPS/ EPS_CAL_RPT)] Parameters ========== The accumulation times for each event are 120 seconds for the EPS Pitch Angle Spectrogram. Calibration parameters are described in the Calibration Implementation document. Data ==== EPS Pitch Angle table (EPSP_A) The pitch angle values tables contain the pitch angle for each of the six look directions reported at the same cadence as the EPS LoRes Spectral rate measurements (see EPPS CDR document). Each file thus has a one-to-one relationship with a corresponding LoRes spectral file. EPS Pitch Angle Spectrogram (EPS_PAS) Contains a plot of the pitch angle spectrogram as an image in PNG format (.PNG) for the EPS odd-numbered shaped channels (ion=1,5,7,9). A given pitch angle spectrogram DDR data file contains all the observations obtained on one electron event. The particle measurement is 120 seconds averaged. 0 denotes the same direction as the measured magnetic field, and 180 is opposite to the local field. The color scale is normalized to the maximum flux for the time interval covered in the plot. EPS_PA_DAILY_SPECTROGRAM (EPS_PASD) Contains pitch angle spectrogram products as described above, but as daily products covering the full orbital phases of the mission. Furthermore, these also contain text data files (.TAB) for each spectrogram in addition to the plots (.PNG)." CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview ========================= The EPPS DDR data are the processed data set released for the EPPS. Data presented here are an accurate representation of the EPPS data as received from the spacecraft and have been processed from instrument unit to physical unit. Review ====== The EPPS DDR was reviewed internally by the EPPS team prior to release to the PDS. PDS also performed an external review of the EPPS CDR. Data Coverage and Quality ========================= Data reported are the processed data received from the spacecraft during the sixteen mission phases: Launch, Earth Cruise, Earth Flyby, Venus 1 Cruise, Venus 1 Flyby, Venus 2 Cruise, Venus 2 Flyby, Mercury 1 Cruise, Mercury 1 Flyby, Mercury 2 Cruise, Mercury 2 Flyby, Mercury 3 Cruise, Mercury 3 Flyby, Mercury 4 Cruise, Mercury Orbit, Mercury Orbit Year 2, Mercury Orbit Year 3, Mercury Orbit Year 4, and Mercury Orbit Year 5. These mission phases are defined as: Start time End time Phase Name Date (DOY) Date (DOY) ----------------- ---------------- ---------------- Launch 3 Aug 2004 (216) 12 Sep 2004 (256) Earth Cruise 13 Sep 2004 (257) 18 Jul 2005 (199) Earth Flyby 19 Jul 2005 (200) 16 Aug 2005 (228) Venus 1 Cruise 17 Aug 2005 (229) 9 Oct 2006 (282) Venus 1 Flyby 10 Oct 2006 (283) 7 Nov 2006 (311) Venus 2 Cruise 8 Nov 2006 (312) 22 May 2007 (142) Venus 2 Flyby 23 May 2007 (143) 20 Jun 2007 (171) Mercury 1 Cruise 21 Jun 2007 (172) 30 Dec 2007 (364) Mercury 1 Flyby 31 Dec 2007 (365) 28 Jan 2008 (028) Mercury 2 Cruise 29 Jan 2008 (029) 21 Sep 2008 (265) Mercury 2 Flyby 22 Sep 2008 (266) 20 Oct 2008 (294) Mercury 3 Cruise 21 Oct 2008 (295) 15 Sep 2009 (258) Mercury 3 Flyby 16 Sep 2009 (259) 14 Oct 2009 (287) Mercury 4 Cruise 15 Oct 2009 (288) 03 Mar 2011 (062) Mercury Orbit 04 Mar 2011 (063) 17 Mar 2012 (077) Mercury Orbit Year 2 18 Mar 2012 (078) 17 Mar 2013 (076) Mercury Orbit Year 3 18 Mar 2013 (077) 17 Mar 2014 (076) Mercury Orbit Year 4 18 Mar 2014 (077) 17 Mar 2015 (076) Mercury Orbit Year 5 18 Mar 2015 (077) 30 Apr 2015 (120) The EPS pitch angle distribution data have been corrected for priority scheme in the instrument processor. During orbital phase, a certain sector in the EPS field-of-view had a direct view of the sunlit side of the planet. During these periods, the single event data (Fast, Scanned, etc) may have been susceptible to photon contamination. The science event data (all rate and spectra data) had additional on-board software processing that should have eliminated this photon contamination, but the user should always consult with the instrument team at JHU/APL to verify the quality of specific data prior to publication. During spacecraft noon-midnight orbits, the EPS instrument temperature can rise to levels that affect the low energy channels. We have noticed during some of these orbits, the temperature induced noise rendered those energy channels below 100 keV to be useless. In addition, the higher than normal temperature also induced a data 'drop-out' where the count in all rate drops by a factor during one integration period and remains so for a few minutes to hours. The EPS team has investigated the cause of this 'drop-out'. Users should always consult the instrument team at JHU/APL to verify the quality of specific data prior to publication. During orbital phase, the EPS routinely switched between large and small pixels on both the ion and electron detectors. Users should check the pixel size flag in the data to know which pixel the detectors were using. EPS Shaped channel Sector 3 and 11 had malfunctioning detectors and did not produce any data products. As always, users of the EPPS data should consult with the instrument team at JHU/APL to verify the quality of specific data prior to publication. Limitations =========== This data set is fully processed, science quality data. It has been reviewed at high level by the EPS instrument team. It has not been, however, manually validated on a point by point. Users are encouraged to contact the EPS instrument team when questions about the data arise. Some analysis of this data requires detailed knowledge of EPS pointing which can be extracted from SPICE."