NSSDCA ID: PSSB-00588
Availability: Archived at NSSDC, accessible from elsewhere
This description was generated automatically using input from the Planetary Data System.
This data set contains Raw data taken by New Horizons Solar Wind Around Pluto instrument during the PLUTOCRUISE mission phase. This is VERSION 1.0 of this data set. SWAP comprises electro-optics and detectors to obtain count rate measurements of the the solar wind; measuring the solar wind before, during and after the Pluto encounter will allow characterization of the atmospheric escape rate of Pluto. The SWAP electro-optic elements select the angles and energies of the solar wind and pickup ions to be measured; ions thus selected are registered with a coincidence detector system. SWAP measures the energy spectrum of ions in its environment by varying (also called scanning or sweeping) voltages of the electro-optics over many steps during a short time period. SWAP can also immediately follow a sweep of coarse voltage steps with a sweep of finer steps, centered on the peak measurement of the coarse sweep, to obtain a higher resolution of that portion of the energy spectrum. There are three types of SWAP science data: real-time; summary; histogram. Real-time data, at rates up to 1Hz, provide the most detailed science measurements since they contain the full count rate distribution as a function of energy (speed). For science summary and science histogram modes, the full distribution is not recorded. Instead, parameters are derived from the count rate distribution stored by SWAP. These derived parameters require less memory than storing the whole distribution. The science summary and science histogram modes are primarily used during the cruise phase of the mission. For science data, the common data product is usually a binary table; for calibrated real-time data, spectrograms as images are also provided. Typically the tables have instrument parameters and measurements in the columns and measurement times in the rows, but the actual format depends on the type of data and the processing level (raw vs. calibrated). Other tables containing houskeeping and other parameters are also provided. This data set includes documentation for all data types and formats. Per the original mission plan for cruise operations, the SWAP instrument was off for the first 460+ days of Pluto Cruise. After that the operations were sporadic (just a few days in 2009) and mostly Science, alternating with Channel Electron Multiplier gain tests during Annual CheckOuts. After extensive testing in early 2012, in July of that year the project approved daily science operations for the SWAP and PEPSSI instruments throughout the rest of the cruise to Pluto. Every observation provided in this data set was taken as a part of a particular sequence. A list of these sequences has been provided in file DOCUMENT/SEQ_SWAP_PLUTOCRUISE.TAB For a list of observations, refer to the data set index table; this is typically INDEX.TAB initially in the INDEX/ area of the data set; there is also a file SLIMINDX.TAB in INDEX/ that summarizes key information relevant to each observation, including which sequence was in effect and what target was likely intended for the observation. 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 Navigation and Ancillary Information Facility (NAIF) SPICE toolkit from the PDS NAIF node, (see http://naif.jpl.nasa.gov/). The most common time unit associated with the data 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. Version ======= This is VERSION 1.0 of this data set. See the CONFIDENCE_LEVEL_NOTE for more information about this version. Data ==== The observations in this data set are stored in data files using standard Flexible Image Transport System (FITS) format. Each FITS file has a corresponding detached PDS label file, named according to a common convention. The FITS files may 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 SWAP data details - Instrument description - Visit Description, Visit Number, and Target in the Data Labels 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 =========== ================================== ============= SWAP SWA 0X584 - 0X587 * * Not all values in this range are in this data set 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) ===== =================================== 0x584 - SWAP Science Real-Time/SDC 0x585 - SWAP Science Summary/SWA 0x586 - SWAP Science Histogram Header/SWA 0x587 - SWAP Science Histogram Data/SWA Other sources of information useful in interpreting these Data -------------------------------------------------------------Refer to the following files for more information about these data NH Trajectory tables: /DOCUMENT/NH_MISSION_TRAJECTORY.* - Heliocentric /DOCUMENT/NH_TRAJECTORY.* - Jupiter-centric SWAP Field Of View definitions: /DOCUMENT/NH_FOV.* /DOCUMENT/NH_SWAP_V###_TI.TXT SWAP Data summary plots: /DOCUMENT/DATA_SUMMARY_PLOTS/SWAP_###DAY_YYYYMMDDHH_#.* Instrument description ---------------------Refer to the following files for a description of this instrument. CATALOG SWAP.CAT DOCUMENTS SWAP_SSR.* NH_SWAP_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. 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-PLUTOCRUISE-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 DMCCOMAS as described in PERSONNEL.CAT.
These data are available on-line from the Planetary Data System (PDS) at:
http://pdssbn.astro.umd.edu/holdings/nh-x-swap-2-plutocruise-v1.0/
Questions and comments about this data collection can be directed to: Dr. David R. Williams
Name | Role | Original Affiliation | |
---|---|---|---|
Dr. David J. McComas | Data Provider | Southwest Research Institute | dmccomas@pppl.gov |
Dr. Joseph Peterson | General Contact | Southwest Research Institute | joe@boulder.swri.edu |