{ "Spase": { "xmlns": "http://www.spase-group.org/data/schema", "xmlns:xsi": "http://www.w3.org/2001/XMLSchema-instance", "xsi:schemaLocation": "http://www.spase-group.org/data/schema http://www.spase-group.org/data/schema/spase-2_6_1.xsd", "_Note": "Nodes prefixed with a _ are not valid SPASE, but are included for debugging. Values prefixed with a x_ are not valid SPASE but may considered for addition for completeness.", "Version": "2.6.1", "_MasterURL": "https://cdaweb.gsfc.nasa.gov/pub/software/cdawlib/0JSONS/hk_h0_vlf_00000000_v01.json (from all.xml)", "NumericalData": { "ResourceID": "spase://NASA/NumericalData/Hawkeye/VLF/PT22S", "_ResourceID": "Source: https://github.com/rweigel/cdawmeta-spase/blob/main/ResourceID.json", "ResourceHeader": { "ResourceName": "Hk Electric and Magnetic Field Radio Frequency Spectrum Analyzer High Time Resolution", "_ResourceName": "Source: Master/CDFglobalAttributes/Logical_source_description", "AlternateName": "hk_h0_vlf", "_AlternateName": "Source: Master/CDFglobalAttributes/Logical_source", "Description": "BUILD_DATE: 1974-01-01INSTRUMENT_MASS: 0.23 (LESS BOOMS) kgINSTRUMENT_HEIGHT: 0.058 mtINSTRUMENT_LENGTH: 0.140 mtINSTRUMENT_WIDTH: 0.140 mtINSTRUMENT_MANUFACTURER_NAME: UNIV IOWAINSTRUMENT_SERIAL_NUMBER: VLF-05 Electric AntennaThe electric antenna on HAWKEYE consisted of two extendible beryllium copper elements 0.025 inch in diameter which could be extended to a maximum tip-to-tip length of 42.7 m. Except for the outermost 6.1 m of each element, which had a conducting surface, the antenna was coated with Pyre-ML to electrically insulate the antenna from the surrounding plasma. The insulating coating was required to insulate the antenna from the perturbing effects of the plasma sheath surrounding the spacecraft body. At high altitudes, the thickness of the plasma sheath surrounding the spacecraft body was quit large, on the order of 9 m. Since the conducting portion of the antenna must extend beyond the plasma sheath, it was necessary that the antenna be rather long, at least 30 m. tip-to-tip. The antenna mechanism used on HAWKEYE was the Dual-Tee extendible antenna manufactured by Fairchild Industries. The antenna length was 42.49 meters after final deployment until the last orbit, when an attempt was made to retract the antenna to reduce the spacecraft drag. Magnetic Antenna The magnetic antenna for this experiment consisted of a search coil with a high permeability core mounted on a boom approximately 1.5 m. from the centerline of the spacecraft body. The boom was a three element telescoping device developed at the University of Iowa. The boom supporting the flux gate magnetometer on the opposite side of the spacecraft was the same type. Both booms were extended simultaneously by an electric motor. The search coil core was .305 m. long and was wound with approximately 20,000 turns of copper wire. The axis of the search coil was parallel to the spin axis of the spacecraft. A preamplifier was located with the sensor to provide low-impedance signals to the main electronics package in the spacecraft body. The frequency range of the search coil antenna was from 1.0 Hz to 10.0 kHz. Electronics The potential difference between the electric antenna elements was amplified by a high input impedance differential amplifier to provide a 0 to 5 volt analog voltage, V-Diff, to the spacecraft encoder. As the spacecraft rotated the potential difference between the antenna elements varied sinusoidally at the spacecraft rotation rate, with an amplitude proportional to the electric field strength and a phase determined by the direction of the electric field. The frequency response of the differential amplifier was 0.05 Hz to 10 Hz and included the entire range of spin rates expected as the antenna was deployed. The V-Diff signal was sampled 6 times each frame by the encoder. The gain of the differential amplifier could be controlled by command to provide dynamic ranges of +/-0.5 and +/-8.0 volts for the antenna potential difference measurements. Signals from the electric antenna in the frequency range from 10 kHz to 200 kHz were analyzed by the narrow band step frequency receiver. The primary purpose of this receiver was to provide very good frequency resolution in the neighborhood of the electron plasma frequency and upper hybrid resonance frequency. The step frequency receiver consisted of 8 narrow band filters (+/-5% band-width) which were sequentially switched into a log compressor. The log compressor provided a 0 to 5 volt analog voltage, SFR, to the spacecraft encoder. The switch (S4) position was controlled by clock lines from the spacecraft encoder and was stepped through 8 frequencies, 13.3, 17.8, 23.7, 31.1, 42.2, 56.2, 100, and 178 kHz, at a rate of four frequencies per telemetry frame (5.76 seconds). The log compressor provided a 0 to 5 volt analog voltage, SFR, to the spacecraft encoder which was proportional to the logarithm of the signal strength over a dynamic range of 100 db. The 8-channel spectrum analyzer provided relatively coarse frequency spectrum measurements of both electric and magnetic fields over a broad frequency range of 1.0 Hz to 10.0 kHz. The primary purpose of the 8-channel spectrum analyzer was to provide field strength measurements to complement the high-resolution frequency-time spectra from the wide-band receiver. Switches S1 and S2 were controlled by clock lines from the spacecraft encoder and commutate the filter outputs to two log compressors which provided field strength measurements SA-1 and SA-2 (0 to 5 volts) to the spacecraft encoder. These outputs were sampled twice per telemetry frame. Switch S3, which was controlled by a clock line, commutates the electric and magnetic field signals to the 8-channel spectrum analyzer. Approximately every 5 minutes the impedance of the electric antenna was determined at a frequency of 17 Hz by driving a small AC current into the antennas and measuring the resultant voltage on the antennas with the 8-channel spectrum analyzer. The 17 Hz oscillator was gated on for 1 frame out of every 64 frames by a clock line. Immediately following the impedance measurement the pulser circuit produced a 10 volt pulse with a duration of 20 micro- seconds. This pulse was to stimulate local plasma resonances, such as plasma oscillation, from which the electron density could be determined. A pulse of +10 volts was applied to one antenna element and a -10 volt pulse was applied to the opposite antenna element. The pulser was switched on by command. The pulser was on when the experiment was in VLF45 mode and off when the experiment was in the VLF10 mode. The pulser voltage was coupled to the antenna through a 220 pf capacitor which would have allowed some meaningful data to be obtained from the experiment even if the pulser output were to short to ground. The pulse was applied at the end of the impedance measurement frame. The potential difference between the electric antenna elements was amplified by a high input impedance differential amplifier to provide a 0 to 5 volt analog voltage, V-Diff, to the spacecraft encoder. As the spacecraft rotated the potential difference between the antenna elements varied sinusoidally at the spacecraft rotation rate, with an amplitude proportional to the electric field strength and a phase determined by the direction of the electric field. The frequency response of the differential amplifier was 0.05 Hz to 10 Hz and included the entire range of spin rates expected as the antenna was deployed. The V-Diff signal was sampled 6 times each frame by the encoder. The gain of the differential amplifier could be controlled by command to provide dynamic ranges of +/-0.5 and +/-8.0 volts for the antenna potential difference measurements. Signals from the electric antenna in the frequency range from 10 kHz to 200 kHz were analyzed by the narrow band step frequency receiver. The primary purpose of this receiver was to provide very good frequency resolution in the neighborhood of the electron plasma frequency and upper hybrid resonance frequency. The step frequency receiver consisted of 8 narrow band filters (+/-5% band-width) which were sequentially switched into a log compressor. The log compressor provided a 0 to 5 volt analog voltage, SFR, to the spacecraft encoder. The switch (S4) position was controlled by clock lines from the spacecraft encoder and was stepped through 8 frequencies, 13.3, 17.8, 23.7, 31.1, 42.2, 56.2, 100, and 178 kHz, at a rate of four frequencies per telemetry frame (5.76 seconds). The log compressor provided a 0 to 5 volt analog voltage, SFR, to the spacecraft encoder which was proportional to the logarithm of the signal strength over a dynamic range of 100 db. The 8-channel spectrum analyzer provided relatively coarse frequency spectrum measurements of both electric and magnetic fields over a broad frequency range of 1.0 Hz to 10.0 kHz. The primary purpose of the 8-channel spectrum analyzer was to provide field strength measurements to complement the high-resolution frequency-time spectra from the wide-band receiver. Switches S1 and S2 were controlled by clock lines from the spacecraft encoder and commutate the filter outputs to two log compressors which provided field strength measurements SA-1 and SA-2 (0 to 5 volts) to the spacecraft encoder. These outputs were sampled twice per telemetry frame. Switch S3, which was controlled by a clock line, commutates the electric and magnetic field signals to the 8-channel spectrum analyzer. Approximately every 5 minutes the impedance of the electric antenna was determined at a frequency of 17 Hz by driving a small AC current into the antennas and measuring the resultant voltage on the antennas with the 8-channel spectrum analyzer. The 17 Hz oscillator was gated on for 1 frame out of every 64 frames by a clock line. Immediately following the impedance measurement the pulser circuit produced a 10 volt pulse with a duration of 20 micro- seconds. This pulse was to stimulate local plasma resonances, such as plasma oscillation, from which the electron density could be determined. A pulse of +10 volts was applied to one antenna element and a -10 volt pulse was applied to the opposite antenna element. The pulser was switched on by command. The pulser was on when the experiment was in VLF45 mode and off when the experiment was in the VLF10 mode. The pulser voltage was coupled to the antenna through a 220 pf capacitor which would have allowed some meaningful data to be obtained from the experiment even if the pulser output were to short to ground. The pulse was applied at the end of the impedance measurement frame.", "_Description": "Source: Master/CDFglobalAttributes/TEXT", "Acknowledgement": "University of Iowa and NSSDC", "_Acknowledgement": "Source: Master/CDFglobalAttributes/Acknowledgement", "_Rights": { "Name": "SPDX", "Description": "Creative Commons Zero v1.0 Universal", "URL": "https://spdx.org/licenses/CC0-1.0.html", "SchemeURI": "https://spdx.org/licenses/" }, "InformationURL": [ { "Name": "Hawkeye Spacecraft", "URL": "https://spdf.gsfc.nasa.gov/pub/data/hawkeye/documents/archived_website/hawkeye.html", "Description": "Hawkeye page maintained by NASA GSFC with science and instrument descriptions, data, software, and publication lists", "Language": "en", "_Note": "Source: InformationURL.json" }, { "Name": "NSSDC's Master Catalog", "URL": "https://nssdc.gsfc.nasa.gov/nmc/experiment/display.action?id=1974-040A-03", "Description": "Information about the ELF/VLF Receivers experiment on the Hawkeye 1 mission.", "_Note": "Source: InformationURL.json" } ] }, "ProviderResourceName": "Electric and Magnetic Field Radio Frequency Spectrum Analyzer Data ", "Caveats": "public", "_Caveats": "Source: Master/CDFglobalAttributes/Rules_of_use", "DOI": "https://doi.org/10.48322/etz7-wx98", "_DOI": "Source: https://github.com/rweigel/cdawmeta-spase/blob/main/DOI.json", "AccessInformation": [ { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "CDF" ], "Style": "Listing", "AccessURL": { "Name": "HTTPS from SPDF", "URL": "https://cdaweb.gsfc.nasa.gov/pub/data/hawkeye/h0/vlf", "Description": "In CDF via HTTP from CDAWeb", "AccessFilenameTemplate": "hk_h0_vlf_%Y%m%d_%Q.cdf", "AccessDirectoryTemplate": "%Y", "ProductKey": "HK_H0_VLF" } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "CDF" ], "Style": "Listing", "AccessURL": { "Name": "FTPS from SPDF", "URL": "ftps://cdaweb.gsfc.nasa.gov/pub/data/hawkeye/h0/vlf", "Description": "In CDF via HTTP from CDAWeb", "AccessFilenameTemplate": "hk_h0_vlf_%Y%m%d_%Q.cdf", "AccessDirectoryTemplate": "%Y", "ProductKey": "HK_H0_VLF" } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "CDF", "CSV", "GIF", "NetCDF", "PNG", "PS", "PDF", "XML", "x_Script.IDL", "x_Script.Python", "Text.ASCII", "x_WAV" ], "AccessURL": { "Name": "CDAWeb Web Service", "URL": "https://cdaweb.gsfc.nasa.gov/WebServices/", "Style": "WebService", "Description": "Instructions for using web services to access this dataset an other other metadata and options for CDAWeb datasets. The ProductKey here corresponds to the query parameter 'dataset' in the tables at the AccessURL in a dataset-related request can be made.", "ProductKey": "HK_H0_VLF" } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "CDF", "GIF", "PDF", "Text.ASCII", "x_WAV" ], "AccessURL": { "Name": "CDAWeb Web Service user interface", "URL": "https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?index=sp_phys&dataset=HK_H0_VLF", "Style": "WebService", "ProductKey": "HK_H0_VLF", "Description": "Web service user interface for this product." } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "x_Script.IDL", "x_Script.Python" ], "AccessURL": { "Name": "CDAWeb Python Script", "URL": "https://cdaweb.gsfc.nasa.gov/WS/cdasr/1/dataviews/sp_phys/datasets/HK_H0_VLF/clientLibraryExample/", "ProductKey": "HK_H0_VLF", "Style": "WebService", "Description": "Web service that generates a Python script to access this product." } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/SSCWeb. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "HTML" ], "AccessURL": { "Name": "4D Orbit Viewer", "URL": "https://sscweb.gsfc.nasa.gov/4dorbit/?sc=HK_H0_VLF", "ProductKey": "HK_H0_VLF", "Style": "x_Visualization", "Description": "Web Service to this product." } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb and the HAPI project. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "CSV", "JSON", "Binary" ], "AccessURL": { "Name": "CDAWeb HAPI Server", "URL": "https://hapi-server.org/servers/#server=CDAWeb&dataset=HK_H0_VLF", "Style": "HAPI", "ProductKey": "HK_H0_VLF", "Description": "Web Service to this product using the HAPI interface." } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb and the HAPI project. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "x_Script.IDL", "x_Script.Javascript", "x_Script.MATLAB", "x_Script.Python", "x_Script.Autoplot", "x_Script.curl", "x_Script.wget" ], "AccessURL": { "Name": "CDAWeb HAPI Script in Multiple Languages", "URL": "https://hapi-server.org/servers/#server=CDAWeb&dataset=HK_H0_VLF&return=script", "Style": "HAPI", "ProductKey": "HK_H0_VLF", "Description": "Web Service user interface that generates scripts in IDL, Javascript, MATLAB, Python, Autoplot, curl, wget to access this product. See https://hapi-server.org/servers/api for the API." } }, { "RepositoryID": "spase://SMWG/Repository/NASA/GSFC/SPDF", "Availability": "Online", "AccessRights": "Open", "Acknowledgement": "SPDF/CDAWeb and the HAPI project. Please also acknowledge the data producer: D. Gurnett at University of Iowa", "Format": [ "PNG", "PDF", "SVG" ], "AccessURL": { "Name": "HAPI visualizations", "URL": "https://hapi-server.org/plot/?server=https://cdaweb.gsfc.nasa.gov/hapi&dataset=HK_H0_VLF&format=gallery", "Style": "x_Visualization", "ProductKey": "HK_H0_VLF", "Description": "Web Service that generates plots. See https://hapi-server.org/plot/ for the API." } } ], "_AccessInformation": "Source: https://github.com/rweigel/cdawmeta-spase/blob/main/AccessInformation.json", "TemporalDescription": { "TimeSpan": { "StartDate": "1974-06-08T06:45:10Z", "StopDate": "1978-04-26T15:59:05Z" }, "_TemporalDescription": "Generated from all.xml/@timerange_start and all.xml/@timerange_stop", "Cadence": "PT23.04S", "_Cadence": "Counts based on variable 'Epoch' in https://cdaweb.gsfc.nasa.gov/sp_phys/data/hawkeye/vlf/vlf_h0/1974/hk_h0_vlf_19740608_v01.cdf. The most common cadence, 23040 [ms] = PT23.04S, occurred for 97.4779% of the 2203 timesteps. " }, "Keyword": [ "Hawkeye (from all.xml/observatory/description/@short)", "Electric and Magnetic Field Radio Frequency Spectrum Analyzer (from all.xml/instrument/description/@short)", "Space Physics (from Master/CDFglobalAttributes/Discipline)", "Magnetospheric Science (from Master/CDFglobalAttributes/Discipline)", "HK (from Master/CDFglobalAttributes/Source_name)", "Hawkeye (from Master/CDFglobalAttributes/Source_name)", "H0 (from Master/CDFglobalAttributes/Data_type)", "High Time Resolution (from Master/CDFglobalAttributes/Data_type)", "VLF (from all.xml/instrument/@ID)" ], "ObservedRegion": [ "Heliosphere.Inner", "Earth.Magnetosphere", "Earth.NearSurface.Ionosphere", "Earth.NearSurface.AuroralRegion", "Earth.NearSurface.PolarCap", "Earth.Magnetosphere.Polar" ], "_ObservedRegion": "Source: https://github.com/rweigel/cdawmeta-spase/blob/main/ObservedRegion.json", "ProcessingLevel": null, "_ProcessingLevel": "Processing level is not available in the master file; it should be there instead of, say, https://github.com/rweigel/cdawmeta-spase/blob/main/ProcessingLevel.json", "InstrumentID": "spase://SMWG/Instrument/Hawkeye/VLF", "MeasurementType": [ "Waves.Passive", "Spectrum" ], "Parameter2": [ { "Name": "Time Line", "ParameterKey": "Epoch", "Description": "CATDESC: 'Center TIme of 22 sec averaging period'. Notes not in Master CDF: 'The units are the units in CDF files. For other web services, this variable is may be represented as a time string.'", "Units": "ms", "Support": { "Qualifier": "Scalar", "SupportQuantity": "Temporal" } }, { "Name": "Magnetic Field Spectral Power Density", "ParameterKey": "b_spd", "Description": "Master CDF CATDESC: 'Magnetic Field Spectral Power Density at 8 Freq (2 - 5620 Hz)'. Master CDF VAR_NOTES: ''. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "Units": "nT**2/Hz", "FillValue": -1e+31, "Structure": { "Size": [ 8 ] } }, { "Name": "Electric Spectral Power Density", "ParameterKey": "e_spd", "Description": "Master CDF CATDESC: 'Electric Spectral Power Density at 16 Frequencies (2 Hz - 178 kHz)'. Master CDF VAR_NOTES: ''. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "Units": "(V/m)(V/m)/Hz", "FillValue": -1e+31, "Structure": { "Size": [ 16 ] } }, { "Name": "Average Magnetic Field Magnitude", "ParameterKey": "BAVE", "Description": "Master CDF CATDESC: 'Average magnetic Field Magnitude'. Master CDF VAR_NOTES: ''. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "FillValue": -1e+31 }, { "Name": "s/c position in SM lat/local time", "ParameterKey": "pos_mag", "Description": "Master CDF CATDESC: 'Hawkeye position in Earth radii, SM magnetic latitude, SM magnetic local time'. Master CDF VAR_NOTES: ''. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "Units": [ "Re", "Deg", "Hour" ], "FillValue": -1e+31, "Structure": { "Size": [ 3 ] } }, { "Name": "Cartesian Position GSM", "ParameterKey": "pos_GSM", "Description": "Master CDF CATDESC: 'Cartesian Position GSM'. Master CDF VAR_NOTES: ''. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "Units": "RE", "FillValue": -1e+31, "Structure": { "Size": [ 3 ] } }, { "Name": "Active vs Passive Indicator", "ParameterKey": "activity_index", "Description": "Master CDF CATDESC: 'Active (=1) vs Passive (=0) Indicator'. Master CDF VAR_NOTES: 'Active emissions only affect the Electric Field measurements at 17.8 Hz and 56.8 Hz'. Notes not in Master CDF: 'The time index (the ISTP DEPEND_0 variable) for this parameter is Epoch.'", "FillValue": -128 } ] } } }