DATA_SET_ID = "MESS-E/V/H/SW-EPPS-2-FIPS-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 FIPS portion of the data archive currently consists of four EDR data products. The data collected in one observation is downloaded at different times and in different packet formats. Therefore, different EDR formats have been developed, each of which presents a different grouping of the data. The following table shows the different FIPS data products and their files. Following is a description of each of the current FIPS 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 FIPS Data Products: High Priority FIPS Spectra (FIPS_HI_SPECTRA) Spectra Data file 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 Format updated by FSW5 on 9/6/2007 FIPS Pulse Height (FIPS_PULSE_HEIGHT) Contains FIPS Pulse Height Analysis data in binary table format. As of 8/18/2008 the PHA data product is generated from High or Low Priority spectra packets or from FIPS Scan packets. The file naming convention will identify the source packet. Format updated by FSW5 on 9/6/2007 FIPS SCAN (FIPS_SCAN) Contains rate counts sampled at each Deflection System High Voltage (DSHV) step in a FIPS scan. New FSW6 EDR. FIPS High Resolution Proton Velocity Distribution (FIPS_HIRES_PROTON_V) Contains a 32 x 32 high resolution proton velocity distribution, integrated over a 10 scan sequence. New FSW6 EDR. 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 which, in turn, changed the format of the FIPS EDRs. One significant change was the removal of housekeeping data stored in the FIPS High Priority Science Packet. The FIPS_HI_HOUSEKEEPING EDR is no longer generated for data collected on or after 9/6/2007. 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. This version introduced two new EDRs, the FIPS_SCAN and the FIPS_HIRES_PROTON_V. Prior to these changes the FIPS portion of the data archive consisted of four EDR data products, which corresponded to the three priorities of data produced by the FIPS instrument: high, medium, and low. As with the EPS the different priority modes result in the data being collected and downloaded in different packet formats. At high and medium priority, these packets contain multiple pieces of information, such as a spectral observation and housekeeping data. Therefore, different EDR formats have been developed, each of which captures 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: FIPS_HI_HOUSEKEEPING, High Priority FIPS Housekeeping (FSW5, 9/6/2007) FIPS_MED_SPECTRA, Medium Priority FIPS Spectra (FSW6, 8/18/2008) The following EDR types have changed in this version of the data set: FIPS_PULSE_HEIGHT, FIPS Pulse Height (FSW5, 9/6/2007) FIPS_HI_SPECTRA, High Priority FIPS Spectra (FSW5, 9/6/2007) The following EDR types are new in this version of the data set: FIPS_SCAN, FIPS SCAN (FSW6, 8/18/2008) FIPS_HIRES_PROTON_V, FIPS High Resolution Proton Velocity Distribution (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 FIPS 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. [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 High Priority FIPS Housekeeping EDR (FIPS_HI_HOUSEKEEPING) is an ASCII table file that contains 33 fields of housekeeping data taken from the High Priority Science Packet. [RETIRED, FSW5, 9/6/2007] [RETIRED] The Medium Priority FIPS Spectra EDR (FIPS_MED_SPECTRA) contains proton velocity distribution, 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] [CHANGED] The FIPS Pulse Height EDR (FIPS_PULSE_HEIGHT) contains FIPS Pulse Height Analysis data in binary table format. As of 8/18/2008 the PHA data product is generated from High or Low Priority spectra packets or from FIPS Scan packets. The file naming convention will identify the source packet. [CHANGED, FSW5 on 9/6/2007] [NEW] The FIPS Scan EDR (FIPS SCAN) contains rate counts sampled at each Deflection System High Voltage (DSHV) step in a FIPS scan. [NEW, FSW6, 8/18/2008] [NEW] The FIPS High Resolution Proton Velocity Distribution (FIPS_HIRES_PROTON_V) contains a 32 x 32 high resolution proton velocity distribution, integrated over a 10 scan sequence. [NEW, FSW6, 8/18/2008] [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. 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 was rotated 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) Venus 1 Cruise 27 Feb 2006 (058) 27 Feb 2006 (058) Venus 2 Cruise 01 Mar 2006 (060) 01 Mar 2006 (060) A dark count signature was discovered in the FIPS PHA data. These counts appear in a time-of-flight -- E/q histogram of PHA data as straight tracks in E/q, centered at about 8 different time-of-flights. These dark counts significantly complicate the analysis of FIPS PHA data, though not significantly for low mass ions (H+, He+ and He2+). All data since launch is affected. This situation has been well characterized by the FIPS team and models/algorithms for removing these counts have been developed. These algorithms are currently being refined and will be published and included in PDS documentation soon. A small bug was found in FSW v7 which causes only the high order 4 bits of the wedge, strip and zigzag values are transmitted in the data. This has the effect of reducing the position resolution for heavy ions in the FSW v7 data. A software patch has been created and is expected to be implemented by the end of 2009. Most of the Mercury_4_cruise phase was spent running flight tests in support of the dark counts investigation. As such, this data is not useful for scientific studies. There are two periods which are exceptions, but the instrument was run in somewhat different voltage configurations during those periods, so care should be taken during data analysis: Start End MCPHV PAHV Phase Name Date (DOY) Date (DOY) (V) (kV) ----------------- ---------------- ---------------- ----- --------- Mercury 4 cruise 09 Jul 2010 (190) 29 Jul 2010 (210) -2500 -10.5 Mercury 4 cruise 01 Nov 2010 (305) 31 Nov 2010 (335) -2520 -9.5 In orbit, FIPS is regularly taken out of nominal configuration for various spacecraft operations, such as commanded momentum dumps and eclipses, typically prevent possible high voltage discharge within FIPS or for power considerations. On occasion, the EPPS flight software autonomously takes FIPS out of nominal configuration in response to an anomaly. These intervals can be identified in the EPPS_LONG_STATUS data as periods where the MCPHV and PAHV levels are different from the nominal. FIPS regularly experiences penetrating radiation which serves as an additional noise source in the start and stop single-coincidence rates. These counts are identified in start and stop rate spectra as relatively constant streaks across the energy spectrum, because they bypass the electrostatic analyzer energy selction when they pass through the FIPS solid structures to trigger the detectors. Typically, these signals do not occur in double-coincidence and therefore do not affect the science data. (That is, they do not generate PHA events or add to the valid event or proton rate.) When double-coincidences do occur, they are often so short in duration (< 1 min) that they can be ignored in all but the most fine time scale analysis. Occasionally, events occur that are of sufficient intensity and duration as to make the double coincidence data unusable, such as long duration solar energetic particle (SEP) events. These events should be excluded from science analysis and marked as 'bad' in the data quality flag. For convenience, they are listed in the table below. Start time End time Description ----------------- ----------------- ------------------------ 2011-155T11:37:00 2011-161T07:00:00 High intensity SEP event 2011-155T15:00:00 2011-159T00:00:00 High intensity SEP event 2011-266T07:00:00 2011-266T12:00:00 High intensity SEP event 2011-277T01:00:00 2011-278T17:00:00 High intensity SEP event 2011-308T01:00:00 2011-308T20:00:00 High intensity SEP event 2012-028T01:00:00 2012-031T09:00:00 High intensity SEP event 2012-065T10:30:00 2012-071T10:30:00 High intensity SEP event 2012-148T11:00:00 2012-150T21:00:00 High intensity SEP event 2012-194T16:40:00 2012-196T05:20:00 High intensity SEP event As of PDS release 10, SEPs (above) are marked in the quality flag of the CDR data. Users are encouraged to use CDR data if they want to be able to automatically filter out SEPs and other events. For consistency, the above table will no longer be updated. From May-Sept 2013, MCP voltages higher than the nominal -2520V were tested on FIPS, with a goal of recovering counting efficiency lost through use thus far in the mission. Since the counting efficiency is a little different for each of these voltages, users are advised to consult the actual MCP voltage stored in housekeeping when using data from this period. During 05-07 Mar 2015, FIPS post-acceleration voltage was raised in steps from the 10.5 kV run throughout the orbital mission to 13 kV. This change was made to increase time-of-flight resolution and had been delayed until the end of mission for risk reduction. This new voltage needs to be included in any user processing which makes use of ion total energy in the time-of-flight telescope. 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)."