Data Set Information
DATA_SET_NAME MESSENGER V/H RADIO SCIENCE SUBSYSTEM 1 EDR V1.0
DATA_SET_ID MESS-V/H-RSS-1-EDR-RAWDATA-V1.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : The MESSENGER Radio Science (RS) Raw Data Archive (RDA) is a time-ordered collection of raw and partially processed data collected during the MESSENGER mission to Mercury. This data set was collected during the cruise and orbital phases of the MESSENGER mission; the earliest data are from 2006. This period includes the three Mercury flybys and the orbit-phase data from Mercury orbit insertion (MOI) on 11 March 2011 to 17 March 2014. This data set includes four primary data types. Tracking and Navigation Files (TNFs) are the raw product of the closed-loop tracking system. Orbit Data Files (ODFs) are edited versions of TNFs, specifically targeted to spacecraft navigators and scientists interested in gravity fields. Radio Science Receiver (RSR) data are the raw product of the open-loop receiver. Delta-Differential One-way Ranging (DDOR) use two DSN stations and a quasar to provide additional position information normal to the line of sight. The data set also includes ancillary data or supporting data to be used in analyzing the primary data. Please see documentation in the DOCUMENT directory for additional information on the data files and their format. First-time users of the data set should begin with the MESSENGER_EDR_SIS, which is found in the DOCUMENT directory. Parameters : See individual SIS documents, which are located in the DOCUMENT directory, for detailed descriptions of each file contained in this data archive. Processing : Typical TNFs contain data from a 24-hour period and combine data from several antennas if there were multiple passes during the 24-hour period. ODFs are abstracted from subsets of TNF data. A full PDS label accompanies each ODF file and gives a bit-level description of the content and format. RSR data were modified during Ground Data System handling so that MISSION_ID in the Primary Header CHDO was set to 5. Data : Users should consult listings in the INDEX.TAB file to ascertain full coverage of each data type. The DATA directory contains ODF and TNF data for each DSN pass. During the cruise phase of the mission, there were usually three DSN contacts per week. During flybys, and the weeks preceding and following, there are more DSN contacts, and usually continuous for the four days centered on close approach. There are TNF and ODF data for each contact. DDOR data are infrequent, and concentrated near flybys. There are no DDOR data after MOI. RSR data were archived for a 6-month period starting late in 2006. These data span a long superior conjunction and were collected for potential use for studying the solar corona. RSR data are also collected at each occultation event during the cruise phase of the mission. During the Mercury orbital phase of the mission, there were one or two DSN contacts per 24 hours. MESSENGER orbited Mercury every 12 hours for the first 12 months of orbit operations. Each 24 hours, one contact included data obtained using MESSENGER's high-gain antennas (HGAs) and low-gain antennas (LGAs). The LGA data usually included the periapsis portion of the orbit and 75 minutes on either side of the periapsis. The HGA data were farther from Mercury and usually 6-9 hours in duration. If there was a second contact in a 24-hour span, it was usually LGA data that covered the second periapsis portion of the orbit. If there was an Earth occultation during the orbit, it was usually observed using the LGAs and there were usually RSR data collected for several minutes during both ingress and egress. During the first two weeks after MOI, DSN contact was nearly continuous. Starting in April 2012, thirteen months after MOI, MESSENGER began orbiting Mercury with an eight-hour period. The timing and frequency of contacts changed as described in the DATA COVERAGE AND QUALITY section, below. ODFs are stored in the ODF directory on archival volumes. File names are described in MESSENGER_EDR_SIS.html. The typical ODF contains under 2 Mbytes of data. ODFs during cruise are primarily 10-sec Doppler X-band data, but there are some ODFs with 1-second integration periods (during flybys) and some with 60-second integration periods. During the orbital phase of the mission most ODFs have 5-second integration periods. Every file in the directory has a PDS label. Except for files in the root directory and in the CATALOG directories, the label is a separate file in the same directory with the same name but a LBL extension. The TNF labels are embedded, not detached. Ancillary Data : An extensive set of ancillary files is provided for detailed analysis and interpretation of the primary (tracking) data. Users should refer to the INDEX.TAB listing to locate ancillary files and to the MESSENGER RS Raw-Data SIS for a description of the ancillary data files, their data formats, and their naming conventions. Coordinate System : The NAIF reader routines enable the raw data and ancillary data to be converted into a wide range of reference frames. Most of the data are linked to time and are independent of reference frame. The user chooses their reference frame. Software : Software for parsing, reducing, and analyzing data such as these must usually operate at the bit-level and is written for a narrow range of platforms. It is not suitable for general distribution. No software is included with this archival data set. Media/Format :
DATA_SET_RELEASE_DATE 2015-03-06T00:00:00.000Z
START_TIME 2006-10-18T12:00:00.000Z
STOP_TIME N/A (ongoing)
MISSION_NAME MESSENGER
MISSION_START_DATE 2004-08-03T12:00:00.000Z
MISSION_STOP_DATE 2015-04-30T12:00:00.000Z
TARGET_NAME MERCURY
TARGET_TYPE PLANET
INSTRUMENT_HOST_ID MESS
INSTRUMENT_NAME RADIO SCIENCE SUBSYSTEM
INSTRUMENT_ID RSS
INSTRUMENT_TYPE RADIO SCIENCE
NODE_NAME Geosciences
ARCHIVE_STATUS ARCHIVED_ACCUMULATING
CONFIDENCE_LEVEL_NOTE Overview : Data in this data set include the three flybys of Mercury, Mercury Orbit Insertion (MOI) and the first forty-two months of MESSENGER's orbital phase. The ODF data have been processed by the navigation team and by the gravity science team during the course of their analyses. This processing shows the data to be of good quality, sufficient for analysis of Mercury's gravitational field. Most of the cruise data were obtained using the spacecraft's high-gain antennas. There are periods within a few days of the closest approach to Mercury where the low-gain antennas were used. The gain of the low-gain antennas is typically 20-25 dB lower than the high-gain antennas, so the data encompass a wide range of RF power levels, and the signal-to-noise ratio therefore has a wide range. Variations in the proximity of the RF path to the Sun also contribute to a wide variation in the signal-to-noise ratio. Due to occultations and the availability of DSN stations, the tracking data are not continuous and may have several gaps during a single MESSENGER orbit. Review : This archival data set was reviewed by the MESSENGER RS Team prior to submission to the Planetary Data System (PDS). Prior to creation of the final version of the archival data set, key elements of the archive were distributed for preliminary review. These included electronic versions of example PDS labels, CATALOG files, and Software Interface Specifications. These materials were distributed to PDS personnel, the experiment investigator, and others, as appropriate. Data Coverage and Quality : Data reported are the minimally processed data received from the spacecraft during the 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 and Mercury Orbit Year 4. 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) There are RSR files for 6 months starting in late 2006 to cover the long solar conjunction for potential use for solar-corona studies. There are data for the second flyby of Venus, after which there are no data until late in 2007, after which the data are archived for all DSN contacts. There are three differences in the data for the flybys: 1) DSN coverage increases for the four weeks centered on each flyby, including nearly-constant coverage for +/-24 hours; 2) for most of the period within three days of close approach, the RF power is at least 20 dB below nominal because the low-gain antennas are used; 3) if there is an Earth occultation (M1 and M3), there are RSR data. RSR data are collected only for occultations and for a solar-conjunction investigation in 2006/2007. During flyby occultations, RSR data are recorded on multiple antennas, channels, and subchannels in multiple sample rates, bit rates, and frequency ranges; the data from each of these recordings is in a separate file which is identified by the channel and subchannel. ODF and TNF data are collected during each DSN contact. There are both 10-s and 1-s ODF data during portions of each flyby. DDOR data are collected irregularly, usually before and after critical events such as flybys or propulsive maneuvers. There are no DDOR data after MOI. Except for the safe mode that occurred near close approach during the third flyby of Mercury, periods of off-nominal operations are not documented, here. During the first twelve months of the orbital phase of the mission, there is usually one contact using a high-gain antenna (HGA) every other orbit. Each MESSENGER orbit lasts 12 hours. Each HGA contact lasts 6-8 hours and is during the portions of the orbit where MESSENGER is farther from Mercury. There is a low-gain antenna (LGA) contact either before or after the HGA contact, and the LGA contact includes the periapsis portion of the orbit. The LGA contact also includes any Earth occultations that may occur during the orbit. The LGA contact varies from 2 to 4 hours. Occasionally, an occultation will occur during HGA transmissions. For periods that total approximately 50% of the orbital mission, there was a second LGA contact during the second orbit that occurred during a 24-hour timespan. These second LGA contacts occur during weeks and months when the geometry is particularly favorable for high-quality Doppler or when there are occultations in Mercury's southern hemisphere, which is not reachable by the laser altimeter. Spacecraft activities such as orbit-correction maneuvers or momentum-dumping maneuvers may cause modifications to this nominal plan. After switching to an eight-hour orbit period, contacts are less frequent, and the HGA data are usually six hours per day or less. Most 24-hour periods contain at least one contact that includes LGA data for one of the three periapsis passes each 24 hours. There are periods when MESSENGER uses the HGA during the periapsis pass; these occur when the Earth-Mercury-Sun angle is near 90 degrees, which is a geometry that has particularly poor signal on the LGAs. RSR data for occultation measurements are captured predominantly when the viewing geometry produces good signal-to-noise observations, when the range to Earth is less than 1 AU. YY/DDD Comments ------ ---------------- 06/291 Start of RSR solar-conjunction campaign 07/139 End of RSR solar-conjunction campaign 07/156 Second flyby of Venus 07/347 Beginning of complete data archive 08/014 First flyby of Mercury (M1) Includes an occultation 08/280 Second flyby of Mercury(no occultation) 09/272 Third flyby of Mercury (M3) Includes an occultation. RF interrupted by safe mode at 21:57:21 UTC 11/077 Mercury orbital insertion (MOI). 12/111 Orbital period reduced to 8 hours. 13/260 Last data to be included in the delivery 11 data set. 14/076 Last data to be included in the delivery 12 data set. 14/260 Last data to be included in the delivery 13 data set. The start and stop days of the periods when Mercury occults RF transmissions to Earth are YY/DDD to YY/DDD 11/077 to 11/129 11/190 to 11/293 12/045 to 12/120 12/241 to 12/278 13/030 to 13/121 13/231 to 13/264 14/015 to 14/120 14/223 to 14/253 14/361 to 15/086 Limitations : The limitations in this data set follow from the quality of the execution, which is described above under Data Coverage and Quality.
CITATION_DESCRIPTION Perry, M.E., Solomon, S.C., Lemoine, F.G., Smith, D.E., Zuber, M.T., MESSENGER Radio Science Raw Data (MESS-V/H-RSS-1-EDR-RAWDATA-V1.0), NASA Planetary Data System, 2010.
ABSTRACT_TEXT This data set contains archival raw, partially processed, and ancillary/supporting radio science data acquired during the MESSENGER mission. The radio observations were carried out using the MESSENGER spacecraft and Earth-based receiving stations of the NASA Deep Space Network (DSN). The observations were designed to be part of a data set that is of sufficient quality and quantity to generate high-resolution gravity field models of Mercury. Of most interest are likely to be the Orbit Data Files in the ODF directory. The data range from 2006 to 2014; there are gaps in the data.
PRODUCER_FULL_NAME MARK E. PERRY
SEARCH/ACCESS DATA
  • Geosciences Web Services
  • Mercury Orbital Data Explorer
  • Geosciences Online Archives
    		•