DATA_SET_ID = "MESS-E/V/H/SW-EPPS-2-EPS-RAWDATA-V2.0" DATA_SET_NAME = "EPPS UNCALIBRATED (EDR) DATA E/V/H V2.0" DATA_SET_COLLECTION_MEMBER_FLG = "N" DATA_OBJECT_TYPE = TABLE START_TIME = 2004-257T00:00:00 STOP_TIME = 2015-120T18:54:31 DATA_SET_RELEASE_DATE = 2015-10-09 ARCHIVE_STATUS = "ARCHIVED" PRODUCER_FULL_NAME = "GEORGE HO" DETAILED_CATALOG_FLAG = "N" CITATION_DESC = "G. C. Ho (APL), EPPS UNCALIBRATED (EDR) DATA E/V/H V1.0, NASA Planetary Data System, 2008" DATA_SET_TERSE_DESC = "The MESSENGER EPPS uncalibrated observations consist of energetic particle and plasma data collected by the EPPS instrument during fly-by and orbital operations of Mercury. Also included are cruise observations for calibration purposes." ABSTRACT_DESC = " Abstract ======== This data set consists of the MESSENGER Energetic Particle and Plasma Spectrometer (EPPS) uncalibrated observations, also known as EDRs. The system encompasses 2 instrument subsystems - the Energetic Particle Spectrometer (EPS) and the Fast Imaging Plasma Spectrometer (FIPS). EPS covers the energy range of 25 to > 500 keV for electrons, and 10 keV/nucleon to ~3 MeV total energy for ions. FIPS covers the energy/ charge range of < 50 eV/q to 20 keV/q. There are nine EDR data products, four of science and ancillary data for the EPS and the FIPS, and one of engineering and status for the total EPPS instrument." DATA_SET_DESC = " Data Set Overview ================= The data set consists of uncalibrated observations, also known as EDRs. For all the EDR 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 binary (or 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 currently consists of five EDR data products. The EPS instrument creates all of its different science data packets during one observation, but the packets are telemetered to the ground at different times. The different formats of these data packets do not lend themselves to standardization into one EDR file format. Therefore, different EDR formats have been developed, each of which captures one specific data grouping such as spectra or PHA data. A given EDR data file will contain all the observations obtained on same earth day. The following table shows the different EPS data products. Following is a description of each of the current EPS EDRs. A more complete description of each may be found in the EPPS EDR SIS document, located in the DOCUMENT directory of the document volume. Current EPS Data Products: EPS Pulse Height (EPS_PULSE_HEIGHT) Contains Pulse Height Analysis data in binary table format. The PHA EDR format was changed by FSW6 on 8/18/2008 There is no longer a priority level associated with the PHA EDRs since the PHA data product is generated from PHA data packets and the high, medium, and low priority packets were retired. EPS_High Resolution Spectra (EPS_HIRES_SPECTRA) High resolution (energy channels) ion and electron energy spectra. New FS W6 EDR introduced on 8/18/2008, replaces EPS_HI_SPECTRA. EPS_Low Resolution Spectra (EPS_LORES_SPECTRA) Low resolution (energy channel) ion and electron energy spectra and rate counters. New FSW6 EDR introduced on 8/18/2008, replaces EPS_MED_SPECTRA. EPS Summary Spectra (EPS_SUMMARY_SPECTRA) Contains a subset of rate counters and low resolution energy spectra. New FSW6 EDR introduced on 8/18/2008 EPS Scan (EPS_SCAN_RATES) Contains the integrated hardware counters over four energy thresholds. Each threshold setting and integration lasts 1/4 second. New FSW6 EDR introduced on 8/18/2008 In addition to the science data, associated instrument parameters are included. EPPS Engineering and Status Data Product The EPPS_LONG_STATUS EDR data product contains the engineering and status information for the EPPS instrument. This data product consists of an external PDS label file and its pointer to an ASCII table file. The data product is in ASCII to facilitate the browsing of instrument status parameters with commonly available text readers during mission operations. New FSW5 EDR introduced on 9/6/2007 Previous Data Set Overview ========================== On 9/6/2007, version 5 of the EPPS flight software (FSW5) was uploaded to the MESSENGER spacecraft. FSW5 implemented several changes to the FIPS science telemetry. One significant change was the removal of FIPS housekeeping data stored in the FIPS High Priority Science Packet and its inclusion in the EPPS engineering and status data. Due to this change the EPPS_STATUS EDR has been replaced by the EPPS_LONG_STATUS as noted below. On 8/18/2008, version 6 of the EPPS flight software (FSW6) was uploaded to the MESSENGER spacecraft and installed on the EPPS instrument on 8/19/2008. FSW6 changed the packet formatting such that two EPS EDRs had to be retired and replaced by two new EDRs. Two additional EDRs had to be created to store data from two new instrument packets. Finally, the format for the EPS PHA EDR has been updated to support slight changes in the PHA data. Prior to these changes, the EPS portion of the data archive consisted of four EDR data products, which correspond to the different types of science data packets generated by the instrument at high priority, medium priority, and low priority. The EPS instrument created all of its different science data packets during one observation, but the packets were telemetered to the ground at different times based on priority. The different formats of the data packets did not lend themselves to standardization into one EDR file format. For example, the high priority science data packet contained the EPS high priority spectra, housekeeping information, and Pulse Height Analysis (PHA) data. Therefore, different EDR formats were developed, each of which captured one specific data grouping spectra, housekeeping information, or PHA data. Due to these changes the following EDR types have been retired in this version of the data set and will no longer be included in future archives: EPS_HI_SPECTRA, High Priority EPS Spectra (FSW6, 8/18/2008) EPS_HI_HOUSEKEEPING, High Priority Housekeeping (FSW6, 8/18/2008 EPS_MED_SPECTRA, Medium Priority EPS Spectra (FSW6, 8/18/2008) EPPS_STATUS, EPPS Engineering and Status () The following EDR types have changed in this version of the data set: EPS_PULSE_HEIGHT, EPS Pulse Height (FSW6, 8/18/2008) The following EDR types are new in this version of the data set: EPS_HIRES_SPECTRA, EPS High Resolution Spectra (FSW6, 8/18/2008) EPS_LORES_SPECTRA, EPS Low Resolution Spectra (FSW6, 8/18/2008) EPS_SUMMARY_SPECTRA, EPS Summary Spectra (FSW6, 8/18/2008) EPS_SCAN_RATES, EPS Scan (FSW6, 8/18/2008) EPPS_LONG_STATUS, EPPS Engineering and Status (FSW5, 9/6/2007) These changes are described in detail in the EPPS EDR SIS Document, contained in the DOCUMENT directory of the DOC_VOL. 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. The 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 FIPS consists of an electrostatic analyzer (ESA), located at the entrance to the sensor, a post-acceleration chamber between the output of the ESA and the carbon foil, and a time-of-flight telescope. The ESA at the entrance to the FIPS acts as a wide-angle lens for ions. It only allows ions with a specific energy/charge band to enter through its output plane. See the EPPSINST.CAT file for more information and [ANDREWSETAL2007] for full details. Calibration Overview ==================== This data set is NOT calibrated; it only provides the uncalibrated sensor measurements. Parameters ========== The principal parameters during normal science operations when observing with the EPPS are as follows: * EPS Medium-Priority Integration Interval (N2): This parameter sets the integration interval for medium-priority data (commonly 30 s). * EPS High-Priority Integration Interval (N1): This parameter sets the integration interval for high-priority data (commonly 300 s). N1 is an integer-multiple of N2. * EPS Detector Selection: EPS possesses 24 detectors: 12 for ions and 12 for electrons. Half are large-pixel, and half are small-pixel. Only 12 detectors can be used simultaneously, so the operational detectors can be set by command. * FIPS Mode Selection: This command allows selection of the mode of operation: normal, burst, and pick-up ion. The EPPS also includes modes for testing the instrument and maintenance activities. Data ==== The EPS EDR data set products are described as follows (the STANDARD_ DATA_PRODUCT_ID value is given in parentheses). The notes provided in brackets give the current status of the data product in version 2 of the data set. [RETIRED] The High Priority EPS Spectra EDR (EPS_HI_SPECTRA) contains spectral data, hardware and software rate counters in binary table format. Data and counter values are taken from the High Priority Science Packet. [RETIRED, FSW6, 8/18/2008] [RETIRED] The High Priority Housekeeping EDR (EPS_HI_HOUSEKEEPING) is an ASCII table file that contains 33 fields of housekeeping data. [RETIRED, FSW6, 8/18/2008] [RETIRED] The Medium Priority EPS Spectra EDR (EPS_MED_SPECTRA) contains contains spectral data, hardware and software rate counters in binary table format. Data and counter values are taken from the Medium Priority Science Packet. [RETIRED, FSW6, 8/18/2008] [NEW] The EPS High Resolution Spectra (EPS_HIRES_SPECTRA) contains high resolution (energy channels) ion and electron energy spectra. [NEW, FSW6, 8/18/2008] [NEW] EPS Low Resolution Spectra (EPS_LORES_SPECTRA) contains Low resolution (energy channel) ion and electron energy spectra and rate counters. [NEW, FSW6, 8/18/2008] [NEW] EPS Summary Spectra (EPS_SUMMARY_SPECTRA) contains a subset of rate counters and low resolution energy spectra. [NEW, FSW6, 8/18/2008] [NEW] EPS Scan (EPS_SCAN_RATES) contains the integrated hardware counters over four energy thresholds. Each threshold setting and integration lasts 1/4 second. [NEW, FSW6, 8/18/2008] [CHANGED] The EPS Pulse Height EDR (EPS_PULSE_HEIGHT) contains Pulse Height Analysis data in binary table format. The PHA data product is generated from the high, medium, or low priority science packet. The priority level will be identified within the PDS label. [CHANGED, FSW6, 8/18/2008) [CHANGED] The High Priority FIPS Spectra EDR (FIPS_HI_SPECTRA) contains spectral and velocity distribution, hardware and software rate counters in binary table format. Data and counter values are taken from the High Priority Science Packet. [CHANGED, FSW5, 9/6/2007] [RETIRED] The EPPS Status EDR contains engineering and status information for the EPPS instrument. The data product is in ASCII to facilitate the browsing of instrument status parameters with commonly available text readers during mission operations. [RETIRED, FSW5, 9/6/2007] [NEW] The EPPS Engineering and Status EDR (EPPS_LONG_STATUS), contains engineering and status information for the EPPS instrument. The data product is in ASCII to facilitate the browsing of instrument status parameters with commonly available text readers during mission operations. [NEW, FSW5, 9/6/2007] " CONFIDENCE_LEVEL_NOTE = " Confidence Level Overview ========================= The EPPS EDR data are the least processed data set released for the EPPS. Data presented here are an accurate representation of the EPPS data as received from the spacecraft, with minimal timing and no spatial processing. Review ====== The EPPS EDR was reviewed internally by the EPPS team prior to release to the PDS. PDS also performed an external review of the EPPS EDR. Data Coverage and Quality ========================= Data reported are the minimally processed data received from the spacecraft during the following 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 03 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) 09 Oct 2006 (282) Venus 1 Flyby 10 Oct 2006 (283) 07 Nov 2006 (311) Venus 2 Cruise 08 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) No EPPS data were collected during Venus_1_Flyby phases. The EPPS was on for brief periods during the other six mission phases. During these planned operational periods, the EPS sensor on the EPPS did not have high voltage enable, hence no Time-of-flight data and only spectra data were collected. The EPS was turned on for the Venus_2_Flyby and to be remained on throughout the remainder of the mission phases. EPPS data were collected during the Mercury_1_Flyby. EPS High Ion Sector 1 and 5 have malfunction detectors and do not produce any data product. The lowest energy channel (32 to 55 keV) on the High Ion Sector 3 and 5 have periodic high count that are due to flight software interaction with the instrument and should not be used. User of EPS data should consult with the instrument team at JHU/APL to verify the quality of specific data in certain time interval prior to publication. During orbital phase, a certain sector in the EPS field-of-view has a direct view of the sunlit side of the planet. During these periods, the single event data (Fast, Scanned, etc) may be susceptible to photon contamination. The science event data (all rate and spectra data) have additional on-board software processing that should eliminate 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, EPS instrument temperature can raise to level that affect the low energy channels. We have noticed during some of these orbits, the temperature induced noise render 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 factor during one integration period and remain so for a few minutes to hours. The EPS team is currently investigating 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, EPS routinely switches between large and small pixel on both the ion and electron detector. User should check the pixel size flag in the data to know which pixel the detectors are using. On 18 Aug 2008 (231), a new Flight Software (FSW) was uploaded to EPPS. This new FSW (v6) enhances the energy resolution for EPS and adds a high- resolution proton distribution data packet on FIPS. Description of these new data products are included in the FMT file. In addition, the new FSW v6 fixed the data spikes in the EPS data (as mentioned in the previous paragraph). As always, user of the EPS data should consult with the instrument team at JHU/APL to verify the quality of specific data prior to publicaion. On 18 August 2009 (230), another new FSW was uploaded to EPPS. This new FSW (v7) only affects the FIPS data. In the nominal flight configuration, the FIPS sensor on the EPPS field-of-view will not measure the solar wind. Periodically, the spacecraft will rotate such that the FIPS field-of-view can detect the nominal radial flowing solar wind. These periods typically lasted less than 3 hours and are identified as: Start time End time Phase Name Date (DOY) Date (DOY) ----------------- ---------------- ---------------- Earth_Cruise 05 Apr 2005 (105) 05 Apr 2005 (105) Earth_Flyby 02 Aug 2005 (214) 02 Aug 2005 (214) 07 Aug 2005 (219) 07 Aug 2005 (219) Venus_1_Cruise 27 Feb 2006 (058) 27 Feb 2006 (058) 06 Sep 2006 (249) 10 Sep 2006 (253) Venus_1_Flyby No Data Venus_2_Cruise 01 Mar 2006 (060) 01 Mar 2006 (060) Venus_2_Flyby 05 Jun 2007 (156) 05 Jun 2007 (156) There are gaps in the EPS scan spectra (EPS_SCAN_SPECTRA) products inclusively spanning 2014-078 through 2014-083 and 2014-246 through 2014-254. There are data gaps in the EPS scan spectra (EPS_SCAN_RATES) products inclusively spanning 2014-334 to 2014-350 (production halted to reduce data volume during a low speed downlink during a solar conjunction), 2014-352 to 2015-022 (production halted for a high voltage check), and 2015-092 to end of mission on 2015-120 (production halted to reduce solid state recorder load during a solar conjunction). Limitations =========== This data set is minimally processed data. The data are received from the spacecraft telemetry and ingested into the MESSENGER Science Operations Center (SOC). "