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Data Access
Virtual Magnetospheric Observatory
Explorer 43 Measurement of Magnetic Fields (MMF) data at 15.36 s Resolution
var authors='Ness, Norman F.';
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(2025).
Explorer 43 Measurement of Magnetic Fields (MMF) data at 15.36 s Resolution.
[Data set].
University of California, Los Angeles.
https://doi.org/10.48322/mhq4-fp67. Accessed on document.write(currentDateStr);.
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ResourceID
spase://NASA/NumericalData/Explorer43/MMF/PT2S
Description
The Explorer 43 Measurement of Magnetic Fields (MMF) data at 15.36 s resolution in various coordinate systems. These data consists of magnetic field vectors, variances, and spacecraft position measurements in several coordinate systems.
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/Explorer43/MMF/PT2S
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
Explorer 43 Measurement of Magnetic Fields (MMF) data at 15.36 s Resolution
AlternateName
IMP 6 MMF data
AlternateName
IMP I MMF data
AlternateName
IMP EYE MMF data
DOI
https://doi.org/10.48322/mhq4-fp67
ReleaseDate
2025-12-04 13:29:12Z
RevisionHistory
RevisionEvent
ReleaseDate
2025-05-06 21:14:33Z
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2025-11-14 16:03:09Z
Note
Added PublicationInfo. Added ResourceType and NamingAuthority. Changed http to https in top-level schemaLocation attribute. Fixed version number separator in top-level schemaLocation attribute. Matched version number in schemaLocation attribute to updated value in Version tag. ZCB
RevisionEvent
ReleaseDate
2025-12-04 13:29:12Z
Note
Added MetadataRightsList. Updated to 2.7.1. ZCB
Description
The Explorer 43 Measurement of Magnetic Fields (MMF) data at 15.36 s resolution in various coordinate systems. These data consists of magnetic field vectors, variances, and spacecraft position measurements in several coordinate systems.
Acknowledgement
NASA-Office of Space Science Applications (United States); Dr. Norman F. Ness
PublicationInfo
Authors
Ness, Norman F.
PublicationDate
2025-11-14 16:03:09Z
PublishedBy
University of California, Los Angeles
Contacts
Role
Person
StartDate
StopDate
Note
1.
PrincipalInvestigator
spase://SMWG/Person/Norman.F.Ness
2.
MetadataContact
spase://SMWG/Person/James.M.Weygand
InformationURL
Name
IMP I/Explorer 43 Spacecraft Information
URL
https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1971-019A
Description
Information about the magnetometer and other instruments onboard Explorer 43.
Language
en
PriorIDs
spase://VMO/NumericalData/Explorer/43/MMF/PT2S
spase://VSPO/NumericalData/Explorer/43/MMF/PT2S
spase://VSPO/NumericalData/Explorer43/MMF/PT2S
AccessInformation
RepositoryID
spase://SMWG/Repository/UCLA/VMO
Availability
Online
AccessRights
Open
AccessURL
Name
Virtual Magnetospheric Observatory
URL
http://vmo.igpp.ucla.edu/data1/Explorer/43/
Description
Direct link to the Explorer 43 MMF data in ascii format.
Format
Text.ASCII
Encoding
None
Acknowledgement
NASA; Dr. Norman F. Ness
ProcessingLevel
Calibrated
ProviderResourceName
Explorer 43 MMF
ProviderProcessingLevel
Level-2
InstrumentIDs
spase://SMWG/Instrument/IMP6/MMF
MeasurementType
MagneticField
TemporalDescription
TimeSpan
StartDate
1971-03-11 00:00:00
StopDate
1974-08-29 23:59:00
Note
Time format in data files is year, day-of-year, and milliseconds of the day.
Cadence
PT15.34S
ObservedRegion
Earth.Magnetosheath
ObservedRegion
Earth.Magnetosphere
ObservedRegion
Earth.Magnetosphere.Magnetotail
Caveats
Flag value is unknown. All of the descriptions for the parameters are taken from original notes on the data. Not all the descriptions are clear.
Keywords
15.36 s
Explorer
IMP I
Parameter #1
Name
Universal Time
ParameterKey
Time
Description
Universal time columns from left to right are: year, day of year, and milliseconds of the day.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. for all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Cadence
PT1S
Structure
Size
3
Description
Universal Time expressed using a 3-column year, day of year (Jan 1 = 0), and Millisec (Elapsed millisec in the day).
Element
Name
Year
Index
1
ParameterKey
Column_1
Element
Name
Day of Year
Index
2
ParameterKey
Column_2
Element
Name
Milliseconds of the Day
Index
3
ParameterKey
Column_3
Support
SupportQuantity
Temporal
Parameter #2
Name
Data Quality Flag
Description
8 bit counts. Order: from left to right: 2^7, 2^6,2^5,...2^0. Flags: from left to right: black, 90 degrees, 0 degrees, Heater, CAL, AUTO, range 2, and range, 1.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
InstrumentMode
Parameter #3
Name
Orbit Number
Description
Orbit number of Explroer 43 from the beginning of the mission.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
Other
Parameter #4
Name
Bit Rate Flag
Description
No description given.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
Other
Parameter #5
Name
Pseudo Sequence Count
Description
No description given.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
Other
Parameter #6
Name
Actually Satellite Clock from spacecraft
Description
No description given.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
Temporal
Parameter #7
Name
House Keeping data
Description
No description given.
Caveats
This parameter is for the last sequence included in the 15.36 s statistical computation. For all data processed prior to 01/28/72 these quantities are for the sequence following the statistical computations.
Support
SupportQuantity
Other
Parameter #8
Name
Field Magnitude (F1)
Description
Averaged over 15.36 s. F1 = (1/N)*Sum to n of F_i where F_i is computed by the PAYAVG subroutine over 1.28 seconds. The PAYAVG subroutne was not available with the data or data descriptio.
Units
gamma
Field
Qualifier
Magnitude
FieldQuantity
Magnetic
Parameter #9
Name
Field Magnitude (F2)
Description
Averaged over 15.36 s. Fl = SQRT( ((1/N) ∑ X_i)^2 + ((1/N) ∑ Y_i)^2 + ((1/N) ∑ Z_i)^2 ) where X_i, Y_i, and Z_i are computed by the PAYAVG subroutine over 1.28 seconds. Sum from i=1 to N.
Units
gamma
Field
Qualifier
Magnitude
FieldQuantity
Magnetic
Parameter #10
Name
Theta
Description
Averaged over 15.36 s. Theta is sin^{-1}(Bz/B_manitude).
Units
degrees
ValidMin
-90
ValidMax
+90
Field
Qualifier
DirectionAngle.ElevationAngle
FieldQuantity
Magnetic
Parameter #11
Name
Phi
Description
Averaged over 15.36 s.
Units
degrees
ValidMin
0
ValidMax
360
Field
Qualifier
DirectionAngle.AzimuthAngle
FieldQuantity
Magnetic
Parameter #12
Name
Variance from Averages
Description
Variance matrix over 15.36 s. [Vxx,--,--;Vyx,Vyy,--;Vzx,Vzy,VZZ]. e.g., Vxx = ( (N ∑ X^{2}_{i}) - ∑ X_{i} ∑ X_{i} )/(N(N-1)). Vzy = ( (N ∑ Z_{i}Y_{i}) - ∑ Z_{i} ∑ Y_{i} )/(N(N-1)). Sum from i=1 to N.
Structure
Size
6
Description
Only includes 6 elements of the 3 by 3 matrix since three elements are repeated..
Element
Name
Variance XX from averages.
Index
1
ParameterKey
Column_14
Units
gamma^2
Element
Name
Variance YY from averages.
Index
2
ParameterKey
Column_15
Units
gamma^2
Element
Name
Variance ZZ from averages.
Index
3
ParameterKey
Column_16
Units
gamma^2
Element
Name
Variance YX from averages.
Index
1
ParameterKey
Column_17
Units
gamma^2
Element
Name
Variance ZX from averages.
Index
1
ParameterKey
Column_18
Units
gamma^2
Element
Name
Variance ZY from averages.
Index
1
ParameterKey
Column_19
Units
gamma^2
Support
Qualifier
Variance
SupportQuantity
Other
Parameter #13
Name
N
Description
Number of sequences over which statistics were comuted.
Support
Qualifier
Total
SupportQuantity
Other
Parameter #14
Name
ND
Description
Number of detail points over which statistics were comuted.
Support
Qualifier
Total
SupportQuantity
Other
Parameter #15
Name
Trajectory Day
Description
Jan 1 = 0.
Units
day
Support
SupportQuantity
Temporal
Parameter #16
Name
Trajectory Millisec of the Day
Units
millisec
Support
SupportQuantity
Temporal
Parameter #17
Name
Geomagnetic Latitude Satellite position
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #18
Name
Geomagnetic Longitude Satellite position
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #19
Name
Geocentric Solar Ecliptic Satellite Position
Description
Location of the spacecraft in GSE coordinates in units of kilometers.
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
X-GSE
Index
1
ParameterKey
Column_26
Units
km
Element
Name
Y-GSE
Index
2
ParameterKey
Column_27
Units
km
Element
Name
Z-GSE
Index
3
ParameterKey
Column_28
Units
km
Support
SupportQuantity
Positional
Parameter #20
Name
Radial Distance to Satellite from Earth's center
Units
km
Support
Qualifier
Magnitude
SupportQuantity
Positional
Parameter #21
Name
Geocentric Solar Magnetospheric Satellite Position
Description
Location of the spacecraft in GSM coordinates in units of kilometers.
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSM
Structure
Size
2
Element
Name
Y-GSM
Index
1
ParameterKey
Column_30
Units
km
Element
Name
Z-GSE
Index
2
ParameterKey
Column_31
Units
km
Support
SupportQuantity
Positional
Parameter #22
Name
Geomagnetic Latitude Sun position
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #23
Name
Geomagnetic Longitude Sun position
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #24
Name
Theoretical Geomagnetic Field Geocentric Solar Ecliptic
Description
Theoretical geomagnetic field but the magnetic field model is unclear.
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
GSE
Structure
Size
3
Element
Name
BX-GSE
Index
1
ParameterKey
Column_34
Units
gamma
Element
Name
BY-GSE
Index
2
ParameterKey
Column_35
Units
gamma
Element
Name
BZ-GSE
Index
3
ParameterKey
Column_36
Units
gamma
Field
Qualifier
Vector
FieldQuantity
Magnetic
Parameter #25
Name
Rotation Matrix
Description
Rotation matrix from GSE to GSM
Structure
Size
9
Element
Name
1st row, 1st column
Index
1
ParameterKey
Column_37
Element
Name
1st row, 2nd column
Index
2
ParameterKey
Column_38
Element
Name
1st row, 3rd column
Index
3
ParameterKey
Column_39
Element
Name
2nd row, 1st column
Index
4
ParameterKey
Column_40
Element
Name
2nd row, 2nd column
Index
5
ParameterKey
Column_41
Element
Name
2nd row, 3rd column
Index
6
ParameterKey
Column_42
Element
Name
3rd row, 1st column
Index
7
ParameterKey
Column_43
Element
Name
3rd row, 2nd column
Index
8
ParameterKey
Column_44
Element
Name
3rd row, 3rd column
Index
9
ParameterKey
Column_45
Support
Qualifier
Array
SupportQuantity
Other
Parameter #26
Name
Rotation Matrix
Description
Rotation matrix from celestial inertial to GSE
Structure
Size
9
Element
Name
1st row, 1st column
Index
1
ParameterKey
Column_46
Element
Name
1st row, 2nd column
Index
2
ParameterKey
Column_47
Element
Name
1st row, 3rd column
Index
3
ParameterKey
Column_48
Element
Name
2nd row, 1st column
Index
4
ParameterKey
Column_49
Element
Name
2nd row, 2nd column
Index
5
ParameterKey
Column_50
Element
Name
2nd row, 3rd column
Index
6
ParameterKey
Column_51
Element
Name
3rd row, 1st column
Index
7
ParameterKey
Column_52
Element
Name
3rd row, 2nd column
Index
8
ParameterKey
Column_53
Element
Name
3rd row, 3rd column
Index
9
ParameterKey
Column_54
Support
Qualifier
Array
SupportQuantity
Other
Parameter #27
Name
Geocentric Latitude Satellite Position
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #28
Name
Geocentric Longitude Satellite Position
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #29
Name
Right Ascension
Description
Not clear what this is the right ascension of. Celestial Equatorial Coordinate System?
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #30
Name
Declination
Description
Not clear what this is the right ascension of. Celestial Equatorial Coordinate System?
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #31
Name
Theta Solar Ecliptic
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #32
Name
Theta Solar Magnetic
Units
degrees
Support
Qualifier
DirectionAngle.ElevationAngle
SupportQuantity
Positional
Parameter #33
Name
Phi Solar Ecliptic
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #34
Name
Phi Solar Magnetic
Units
degrees
Support
Qualifier
DirectionAngle.AzimuthAngle
SupportQuantity
Positional
Parameter #35
Name
Magnetic Field Vector Solar Ecliptic
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
SE
Structure
Size
3
Element
Name
BX-SE
Index
1
ParameterKey
Column_63
Units
gamma
Element
Name
BY-SE
Index
2
ParameterKey
Column_64
Units
gamma
Element
Name
BZ-SE
Index
3
ParameterKey
Column_65
Units
gamma
Field
Qualifier
Vector
FieldQuantity
Magnetic
Parameter #36
Name
Magnetic Field Vector Solar Magnetic
CoordinateSystem
CoordinateRepresentation
Cartesian
CoordinateSystemName
SM
Structure
Size
3
Element
Name
BX-SM
Index
1
ParameterKey
Column_66
Units
gamma
Element
Name
BY-SM
Index
2
ParameterKey
Column_67
Units
gamma
Element
Name
BZ-SM
Index
3
ParameterKey
Column_68
Units
gamma
Field
Qualifier
Vector
FieldQuantity
Magnetic