Data Set Information
DATA_SET_NAME NEW HORIZONS SDC JUPITER ENCOUNTER V2.0
DATA_SET_ID NH-J-SDC-2-JUPITER-V2.0
NSSDC_DATA_SET_ID
DATA_SET_TERSE_DESCRIPTION
DATA_SET_DESCRIPTION Data Set Overview : This data set contains Raw data taken by New Horizons Student Dust Counter instrument during the JUPITER mission phase. For the Jupiter encounter mission phase, SDC collected no science data during the Jupiter flyby, as the requisite spacecraft configuration prevented SDC from operating. There were some very sparse data taken from December, 2006 through April, 2007, and some of very short (or zero) duration after the Jupiter flyby from April, 2007 through June, 2007. Note that some SDC data files have the same stop and start time and a zero exposure time. The reason for this is that the start and stop time for SDC data files are the event times for the first and last events in the files, so for files that contain a single event, these two values are identical. Every observation provided in this data set was taken as a part of a particular sequence. A list of these sequences follows: Sequence IDs & start times (end times are the start times of the following Sequence IDs) for the SDC instrument during the JUPITER phase of the New Horizons Mission : Sequence ID: JESD_PLACEHOLDER Start UTC: 2007-01-01T00:00:00 Start SCLK: 1/0029915517:30912 Description: The SDC instrument did not have any sequenced data taken during Jupiter encounter. This entry is only a placeholder to cover any data that exist. For the list of observations and their parameters, refer to the data set index table (typically INDEX.TAB & CUMINDEX.TAB, initially in the /INDEX/ area of the data set). Time : There are several time systems, or units, in use in this dataset: New Horizons spacecraft MET (Mission Event Time or Mission Elapsed Time), UTC (Coordinated Universal Time), and TDB Barycentric Dynamical Time. This section will give a summary description of the relationship between these time systems. For a complete explanation of these time systems the reader is referred to the documentation distributed with the NAIF/SPICE toolkit from the NAIF PDS node. The most common time unit associated with the data is is the spacecraft MET. MET is a 32-bit counter on the New Horizons spacecraft that runs at a rate of about one increment per second starting from a value of zero at 19.January, 2006 18:08:02 UTC or JD2453755.256337 TDB. The leapsecond adjustment (DELTA_ET : ET - UTC) over this dataset is 65.184s. The data labels for any given product in this dataset usually contain at least one pair of common UTC and MET representations of the time at the middle of the observation. Other portions of the products, for example tables of data taken over periods of up to a day or more, will only have the MET time associated with a given row of the table. For the data user's use in interpreting these times, a reasonable approximation (+/- 1s) of the conversion between Julian Day (TDB) and MET is as follows: JD TDB : 2453755.256337 + ( MET / 86399.9998693 ) For more accurate calculations the reader is referred to the NAIF/SPICE documentation as mentioned above. Processing : The data in this data set were created by a software data processing pipeline on the Science Operation Center (SOC) at the Southwest Research Institute (SWRI), Department of Space Studies. This SOC pipeline assembled data as FITS files from raw telemetry packets sent down by the spacecraft and populated the data labels with housekeeping and engineering values, and computed geometry parameters using SPICE kernels. The pipeline did not resample the data. Data : The observations in this data set are stored in data files using standard Flexible Image Transport Sytem (FITS) format. Each FITS file has a corresponding detached PDS label file, named according to a common convention. The FITS files have image and/or table extensions; see the PDS label plus the DOCUMENT files for a description of these extensions and their contents. This Data section comprises the following sub-topics: - Filename/Product IDs - Other sources of information useful in interpreting these Data - CODMAC Level 2 SDC data details - Instrument description - Visit Description, Visit Number, and Target in the Data Labels - Unresolved Liens on the Data Filename/Product IDs -------------------- The filenames and product IDs of observations adhere to a common convention e.g. ALI_0123456789_0X0AB_ENG_1.FIT ^^^ ^^^^^^^^^^ ^^^^^ ^^^ ^\__/ | | | | | ^^ | | | | | | | | | | | +--File type (includes dot) | | | | | - .FIT for FITS file | | | | | - .LBL for PDS label | | | | | - not part of product ID | | | | | | | | | +-- Version number from the SOC | | | | (Science Operations Center) | | | | | | | +--ENG for CODMAC Level 2 data * | | | SCI for CODMAC Level 3 data * | | | | | +--Application ID (ApID) of the telemetry data | | packet from which the data come | | | +--MET (Mission Event Time) i.e. Spacecraft Clock | +--Instrument designator * For those datasets where the NH project is delivering CODMAC Level 1 & 2 data (REX & PEPSSI), ENG and SCI apply to CODMAC Level 1 & 2 data, respectively. Instrument Instrument designators ApIDs : : : SDC SDC 0X700 * Not all values in this range are used There are other ApIDs that contain housekeeping values and other values. See the documentation for more details. Here is a summary of the types of files generated by each ApID along with the instrument designator that go with each ApID: ApIDs Data product description/Prefix(es) : : 0x700 - SDC Science Data/SDC Other sources of information useful in interpreting these Data -------------------------------------------------------------- Refer to the following files for more information about these data NH Trajectory table: /DOCUMENT/NH_TRAJECTORY.* SDC Field Of View definitions: /DOCUMENT/NH_FOV.* /DOCUMENT/NH_SDC_V###_TI.TXT Instrument description ---------------------- Refer to the following files for a description of this instrument. CATALOG SDC.CAT DOCUMENTS SDC_SSR.* NH_SDC_V###_TI.TXT (### is a version number) SOC_INST_ICD.* Visit Description, Visit Number, and Target in the Data Labels --------------------------------------------------------------- The observation sequences were defined in Science Activity Planning (SAP) documents, and grouped by Visit Description and Visit Number. The SAPs are spreadsheets with one Visit Description & Number per row. A nominal target is also included on each row and included in the data labels, but does not always match with the TARGET_NAME field's value in the data labels. In some cases, the target was designated as RA,DEC pointing values in the form ``RADEC:123.45,-12.34'' indicating Right Ascension and Declination, in degrees, of the target from the spacecraft in the Earth Equatorial J2000 inertial reference frame. This indicates either that the target was either a star, or that the target's ephemeris was not loaded into the spacecraft's attitude and control system which in turn meant the spacecraft could not be pointed at the target by a body identifier and an inertial pointing value had to be specified as Right Ascension and Declination values. The PDS standards do not allow putting a value like RADEC:... in the PDS TARGET_NAME keyword's value; in those cases the PDS TARGET_NAME value is set to CALIBRATION. Unresolved Liens on the Data ---------------------------- None exist at the present time. Ancillary Data : The geometry items included in the data labels were computed using the SPICE kernels archived in the New Horizons SPICE data set, NH-X-SPICE-6-JUPITER-V1.0. Reference Frame : Geometric Parameter Reference Frame ----------------------------------- Earth Mean Equator and Vernal Equinox of J2000 (EMEJ2000) is the inertial reference frame used to specify observational geometry items provided in the data labels. Geometric parameters are based on best available SPICE data at time of data creation. Epoch of Geometric Parameters ----------------------------- All geometric parameters provided in the data labels were computed at the epoch midway between the START_TIME and STOP_TIME label fields. Software : The observations in this data set are in standard FITS format with PDS labels, and can be viewed by a number of PDS-provided and commercial programs. For this reason no special software is provided with this data set. Contact Information : For any questions regarding the data format of the archive, contact the person whose PDS_USER_ID is MHORANYI as described in PERSONNEL.CAT.
DATA_SET_RELEASE_DATE 2009-03-04T00:00:00.000Z
START_TIME 2007-01-01T12:00:00.000Z
STOP_TIME 2007-06-27T12:00:00.000Z
MISSION_NAME NEW HORIZONS
MISSION_START_DATE 2006-01-19T12:00:00.000Z
MISSION_STOP_DATE N/A (ongoing)
TARGET_NAME DUST
TARGET_TYPE DUST
INSTRUMENT_HOST_ID NH
INSTRUMENT_NAME STUDENT DUST COUNTER
INSTRUMENT_ID SDC
INSTRUMENT_TYPE DUST DETECTOR
NODE_NAME Small Bodies
ARCHIVE_STATUS ARCHIVED
CONFIDENCE_LEVEL_NOTE Confidence Level Overview : During the processing of the data in preparation for delivery with this volume, the packet data associated with each observation were used only if they passed a rigorous verification process including standard checksums. In addition, raw (Level 2) observation data for which adequate contemporary housekeeping and other ancillary data are not available are not reduced to calibrated (Level 3) data. This issue is raised here to explain why some data products in the raw data set, NH-J-SDC-2-JUPITER-V2.0, do not have corresponding data products in the calibrated data set, NH-J-SDC-3-JUPITER-V2.0. Review : The data have been reviewed and validated by the instrument team members, as well as by SOC personnel. SDC updates for Data Sets V2.0 : None of the formats for the Calibrated data will change. The data file will look the same, including the data formats. The changes are improvements to the processing code. There were 3 changes made to the code: Change to dust impact velocity assumption ----------------------------------------- An assumption is needed for the the dust impact velocity to calculate its mass. Before this update the pipeline used only the normal component of the total velocity between the dust and instrument (assuming the particle is in Keplerian orbit). Now this has been changed to the total relative velocity of the particle (still assumed to be in Keplerian orbit) and the instrument. Using multiple sensors for temperature correction ------------------------------------------------- There are two thermistors on the analog board. The analog board temperature is used for calibrating a particular channel on the board. Before this update, for a given channel the temperature of the closest thermistor to a that channel. Now a linear fit to the temperatures is used. New charge-velocity-mass calibration curve ------------------------------------------ The calibrated data contains the mass of the particle. The charge to mass curve used to be Q:3.18E17*m^1.3*v^3.0 where m is the mass, Q is the charge and v is the relative speed. This was the Simpson-Tuzzolino curve. The new curve is a function of detector temperature as well: Q:(1.15E15+6.75E12*T)*m^1.052*v^2.883 where T is the temperature. A paper with this new calibration curve will be submitted for publication in Spring, 2009.
CITATION_DESCRIPTION Horanyi, M., NEW HORIZONS SDC JUPITER ENCOUNTER V2.0, NH-J-SDC-2-JUPITER-V2.0, NASA Planetary Data System, 2007.
ABSTRACT_TEXT This data set contains Raw data taken by the New Horizons Student Dust Counter instrument during the Jupiter encounter mission phase.
PRODUCER_FULL_NAME JOSEPH PETERSON
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