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Data Access
S3-3 Data Files
FTPS from SPDF (not with most browsers)
HTTPS from SPDF
S3-3 Magnetic Electron Spectrometers (MES) Data Set
ResourceID
spase://NASA/NumericalData/S3-3/MES/PT1S
Description
This data set includes all processed electron, proton, and alpha particle data from the S3-3 Magnetic Electron Spectrometer (MES). The electron data were sampled at 1/16 second intervals and include differential counts for twelve channels at the following mean energies, determined from calibrations for flat spectra: 12, 33, 70, 120, 170, 235, 433, 654, 880, 1110, 1350, and 1600 keV. The counts for 433 to 654 keV electrons are provided with and without corrections for saturation effects. Proton data consists of integral counts per channel for incident energies above 80, 150, 350, 770, and 1550 keV. Counts for 4 - 12 MeV alphas were sampled in one channel at 1/4 second intervals. Pitch angle information was provided for computation of directional fluxes at intervals of 1/16 second for electrons and 1/4 second for protons. At a spacecraft spin rate of 18 degrees per second this gave 1.1-degree sampling intervals for electrons and four-degree intervals for protons. Pitch-angle values may be in error by as much as one degree at times due to the fact that the raw magnetometer data was fitted to a field model and the calculations of pitch-angle were then performed using that field model. The aperature half-angle was two degrees for the five lowest electron channels (12 - 170 keV) and five degrees for the ion and higher energy electron channels. The full MES data files are reformatted in this data set from the data provider's 'VAX tape format' into Intel-PC 32-bit words with 164 words per one-second data 'frame' and 200 frames per data set record. All of the 32-bit words include two INTEGER*2 parameters, except that Universal Time and L are stored in INTERGER*4 words. Each data frame also includes time tags along with ephemeris, and geomagnetic coordinate data. The ephemeris and geomagnetic data include values pertaining to the intersection points of the local field line on which the satellite is situated and conjugate mirror points at 100-km altitude in the northern and southern hemispheres. Detailed information on the MES sensors and the data file formats are provided in ascii text format. The data set includes FORTRAN source codes, and some Intel-PC executables, used to process the proton and electron data and for calculation of geometric factors.
Metadata Rights
CC0-1.0:
Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available SPASE metadata descriptions. The actual data/software may be subject to a different license.
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Details
Version:2.7.1
NumericalData
ResourceID
spase://NASA/NumericalData/S3-3/MES/PT1S
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
S3-3 Magnetic Electron Spectrometers (MES) Data Set
ReleaseDate
2026-06-26 13:27:45Z
RevisionHistory
RevisionEvent
ReleaseDate
2020-07-07 21:15:17Z
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2025-12-04 13:31:22Z
Note
Added MetadataRightsList and RightsList(s). Added ResourceType and NamingAuthority. Updated to 2.7.1. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. ZCB
RevisionEvent
ReleaseDate
2026-06-26 13:27:45Z
Note
Add 'Z' to TemporalDescription:TimeSpan:StartDate, TemporalDescription:TimeSpan:StopDate. ZCB
Description
This data set includes all processed electron, proton, and alpha particle data from the S3-3 Magnetic Electron Spectrometer (MES). The electron data were sampled at 1/16 second intervals and include differential counts for twelve channels at the following mean energies, determined from calibrations for flat spectra: 12, 33, 70, 120, 170, 235, 433, 654, 880, 1110, 1350, and 1600 keV. The counts for 433 to 654 keV electrons are provided with and without corrections for saturation effects. Proton data consists of integral counts per channel for incident energies above 80, 150, 350, 770, and 1550 keV. Counts for 4 - 12 MeV alphas were sampled in one channel at 1/4 second intervals. Pitch angle information was provided for computation of directional fluxes at intervals of 1/16 second for electrons and 1/4 second for protons. At a spacecraft spin rate of 18 degrees per second this gave 1.1-degree sampling intervals for electrons and four-degree intervals for protons. Pitch-angle values may be in error by as much as one degree at times due to the fact that the raw magnetometer data was fitted to a field model and the calculations of pitch-angle were then performed using that field model. The aperature half-angle was two degrees for the five lowest electron channels (12 - 170 keV) and five degrees for the ion and higher energy electron channels. The full MES data files are reformatted in this data set from the data provider's 'VAX tape format' into Intel-PC 32-bit words with 164 words per one-second data 'frame' and 200 frames per data set record. All of the 32-bit words include two INTEGER*2 parameters, except that Universal Time and L are stored in INTERGER*4 words. Each data frame also includes time tags along with ephemeris, and geomagnetic coordinate data. The ephemeris and geomagnetic data include values pertaining to the intersection points of the local field line on which the satellite is situated and conjugate mirror points at 100-km altitude in the northern and southern hemispheres. Detailed information on the MES sensors and the data file formats are provided in ascii text format. The data set includes FORTRAN source codes, and some Intel-PC executables, used to process the proton and electron data and for calculation of geometric factors.
Contacts
Role
Person
StartDate
StopDate
Note
1.
GeneralContact
spase://SMWG/Person/T.Paul.OBrien
InformationURL
Name
ViRBO web page for this dataset
URL
http://virbo.org/S33
Description
Top-level web page for S3-3 data
PriorIDs
spase://ViRBO/NumericalData/S33/MES/PT1S
spase://VSPO/NumericalData/S3-3/MES/PT1S
AccessInformation
RepositoryID
spase://SMWG/Repository/ViRBO
Availability
Online
AccessRights
Open
AccessURL
Name
S3-3 Data Files
URL
http://mag.gmu.edu/ftp/users/obrien/s33/cd/
Description
ftp directory for this dataset for this dataset
Format
Binary
Encoding
None
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
Availability
Online
AccessRights
Open
RightsList
Rights
SchemeURI
https://spdx.org/licenses/
RightsIdentifierScheme
SPDX
RightsIdentifier
CC0-1.0
RightsURI
https://spdx.org/licenses/CC0-1.0.html
RightsName
Creative Commons Zero v1.0 Universal
Note
CC0 1.0 Universal is the Creative Commons license applicable to all publicly available NASA Heliophysics data products
AccessURL
Name
FTPS from SPDF (not with most browsers)
URL
ftps://spdf.gsfc.nasa.gov/pub/data/s3/s3-3/energetic_electron_magnetic_spectrometer/1-sec_avg_electron_proton_mass/
Description
In Binary via ftp from CDAWeb
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/s3/s3-3/energetic_electron_magnetic_spectrometer/1-sec_avg_electron_proton_mass/
Description
In Binary via HTTP from SPDF
Format
Binary
Acknowledgement
Please acknowledge the CDAWeb team at GSFC/SPDF.
InstrumentIDs
spase://SMWG/Instrument/S3-3/MES
MeasurementType
EnergeticParticles
TemporalDescription
TimeSpan
StartDate
1976-07-12 03:17:16.00000Z
StopDate
1979-04-25 21:58:15.99999Z
Cadence
PT1S
ObservedRegion
Earth.NearSurface