An official website of the United States government
Here's how you know v
Official websites use .gov
A .gov websites belongs to an official government organization in the United States
Secure .gov website use HTTPS
A lock () or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Data Access
FTPS from the MMS SDC (not with most browsers)
HTTPS from the MMS SDC
FTPS from SPDF (not with most browsers)
HTTPS from SPDF
CDAWeb
WebService:
CDAWeb Programmatic Data Access
HAPI: CDAWeb HAPI Server
MMS 2 Active Spacecraft Potential Control (ASPOC), Sensors 1 and 2, Level 2 (L2), Survey Mode, 1 s Data
var authors='Nakamura, Rumi; Torkar, Klaus, M.; Jeszenszky, Harald; Burch, James, L.';
document.write(authors);
(2022).
MMS 2 Active Spacecraft Potential Control (ASPOC), Sensors 1 and 2, Level 2 (L2), Survey Mode, 1 s Data.
[Data set].
Laboratory for Atmospheric and Space Physics; Space Physics Data Facility.
https://doi.org/10.48322/9712-0x57. Accessed on document.write(currentDateStr);.
Note: Proper references, including
Copy BibTeX Citation
or other formats, should include the "Accessed on date" to identify the version of the resource being cited in a given publication.
ResourceID
spase://NASA/NumericalData/MMS/2/ASPOC/Survey/Level2/PT1S
Description
MMS 2 Active Spacecraft Potential Control (ASPOC) - Sensors 1 and 2 Ion Beam Current Rates, Beam Energies, and Instrument Status variables. In tenuous plasma regions, the floating potential of a sunlit spacecraft is positively charged, reaching up to tens of Volts. The corresponding electric field disturbs the ambient plasma measurements obtained from electron and ion sensors and the large fluxes of attracted photo-electrons can significantly reduce the lifetime of the micro-channel plate. The electric field measurements can be also contaminated by the high spacecraft potential values. The Active Spacecraft Potential Control neutralizes the spacecraft potential by releasing positively charged Indium ions. The ASPOCs neutralize the electrical potential of the spacecraft, limiting or eliminating spurious electric fields that can contaminate measurements. This allows observations of the more scientifically important low-energy ions and electrons.
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.
View XML |
Edit
Details
Version:2.7.1
NumericalData
ResourceID
spase://NASA/NumericalData/MMS/2/ASPOC/Survey/Level2/PT1S
NamingAuthority
NASA
ResourceType
NumericalData
ResourceHeader
ResourceName
MMS 2 Active Spacecraft Potential Control (ASPOC), Sensors 1 and 2, Level 2 (L2), Survey Mode, 1 s Data
AlternateName
MMS2_ASPOC_SRVY_L2
DOI
https://doi.org/10.48322/9712-0x57
ReleaseDate
2025-12-04 13:29:59Z
RevisionHistory
RevisionEvent
ReleaseDate
2021-04-27 15:38:11
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2022-08-04 12:34:56.789
Note
Added DOI and PublicationInfo minted by LFB, updated the RepositoryID, updated the SPDF MetadataContact Person to Robert M. Candey, metadata updated to SPASE 2.4.1, reviewed by LFB 20220803
RevisionEvent
ReleaseDate
2023-03-04 12:34:56.789
Note
Standardized the ResourceName Format, Set AlternateName equal to the ProductKey, Revised the Acknowledgement, PublicationInfo Authors, and Contact Person list per request of the MMS ASPOC team, metadata updated to SPASE 2.5.0, reviewed by LFB 20230304
RevisionEvent
ReleaseDate
2025-10-02 15:12:08Z
Note
Updated PublishedBy name to match ROR Registry. 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 13:29:59Z
Note
Added MetadataRightsList and RightsList(s). Updated to 2.7.1. ZCB
Description
MMS 2 Active Spacecraft Potential Control (ASPOC) - Sensors 1 and 2 Ion Beam Current Rates, Beam Energies, and Instrument Status variables. In tenuous plasma regions, the floating potential of a sunlit spacecraft is positively charged, reaching up to tens of Volts. The corresponding electric field disturbs the ambient plasma measurements obtained from electron and ion sensors and the large fluxes of attracted photo-electrons can significantly reduce the lifetime of the micro-channel plate. The electric field measurements can be also contaminated by the high spacecraft potential values. The Active Spacecraft Potential Control neutralizes the spacecraft potential by releasing positively charged Indium ions. The ASPOCs neutralize the electrical potential of the spacecraft, limiting or eliminating spurious electric fields that can contaminate measurements. This allows observations of the more scientifically important low-energy ions and electrons.
Acknowledgement
Please acknowledge R. Nakamura, K.M. Torkar, H. Jeszenszky, and J.L. Burch for use of these data
PublicationInfo
Authors
Nakamura, Rumi; Torkar, Klaus, M.; Jeszenszky, Harald; Burch, James, L.
PublicationDate
2022-01-01 00:00:00
PublishedBy
Laboratory for Atmospheric and Space Physics; Space Physics Data Facility
Contacts
Role
Person
StartDate
StopDate
Note
1.
InstrumentLeadCoInvestigator
spase://SMWG/Person/Rumi.Nakamura
2.
InstrumentLeadCoInvestigator
spase://SMWG/Person/Klaus.M.Torkar
Retired
3.
TechnicalContact
spase://SMWG/Person/Harald.Jeszenszky
4.
PrincipalInvestigator
spase://SMWG/Person/James.L.Burch
5.
HostContact
spase://SMWG/Person/MMS_SDC_POC
6.
MetadataContact
spase://SMWG/Person/Robert.M.Candey
7.
MetadataContact
spase://SMWG/Person/Lee.Frost.Bargatze
InformationURL
Name
The Magnetospheric Multiscale (MMS) Mission home page at Goddard Space Flight Center (GSFC)
URL
https://mms.gsfc.nasa.gov/
Description
The Magnetospheric Multiscale (MMS) Mission Home Page hosted by the Goddard Space Flight Center (GSFC).
InformationURL
Name
Data Caveats and Current Release Notes at LASP MMS SDC
URL
https://lasp.colorado.edu/mms/sdc/public/datasets/aspoc/
Description
The Magnetospheric Multiscale (MMS) Mission home page hosted by the Laboratory of Atmospheric and Space Physics, Science Data Center (LASP, SDC) at the University of Colorado, Boulder.
InformationURL
Name
The MMS Graz ASPOC Team home page at IWF, OAW
URL
https://www.oeaw.ac.at/en/iwf/research/space-missions/current-missions/magnetospheric-multiscale/aspoc
Description
The Magnetospheric Multiscale (MMS) ASPOC home page hosted by the Graz ASPOC team located at the Institut fur Weltraumforschung (IWF), Osterreichische Akademie der Wissenschaften (OAW).
PriorIDs
spase://VSPO/NumericalData/MMS/2/ASPOC/Survey/Level2/PT1S
AccessInformation
RepositoryID
spase://SMWG/Repository/UCOLO/LASP/MMS_SDC
Availability
Online
AccessRights
Open
AccessURL
Name
FTPS from the MMS SDC (not with most browsers)
URL
ftps://lasp.colorado.edu/mms/sdc/public/data/mms2/aspoc/srvy/l2/
Description
In CDF via ftp from the MMS Science Data Center
AccessURL
Name
HTTPS from the MMS SDC
URL
https://lasp.colorado.edu/mms/sdc/public/data/mms2/aspoc/srvy/l2/
Description
In CDF via http from the MMS Science Data Center
Format
CDF
Encoding
None
Acknowledgement
Please acknowledge R. Nakamura, K.M. Torkar, H. Jeszenszky, and J.L. Burch. Also please acknowledge the data providers and CDAWeb when using these data.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
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/mms/mms2/aspoc/srvy/l2/
Description
In CDF via ftp from SPDF
AccessURL
Name
HTTPS from SPDF
URL
https://spdf.gsfc.nasa.gov/pub/data/mms/mms2/aspoc/srvy/l2/
Description
In CDF via http from SPDF
AccessURL
Name
CDAWeb
URL
https://cdaweb.gsfc.nasa.gov/cgi-bin/eval2.cgi?dataset=MMS2_ASPOC_SRVY_L2&index=sp_phys
ProductKey
MMS2_ASPOC_SRVY_L2
Description
Access to ASCII, CDF, and plots via NASA/GSFC CDAWeb
Format
CDF
Encoding
None
AccessDirectoryTemplate
https://cdaweb.gsfc.nasa.gov/pub/data/mms/mms2/aspoc/srvy/l2/$Y/$m
AccessFilenameTemplate
mms2_aspoc_srvy_l2_$Y$m$d_$v.cdf
Acknowledgement
Please acknowledge R. Nakamura, K.M. Torkar, H. Jeszenszky, and J.L. Burch. Also please acknowledge the data providers and CDAWeb when using these data.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF
Availability
Online
AccessRights
Open
AccessURL
Name
CDAWeb Programmatic Data Access
URL
https://cdaweb.gsfc.nasa.gov/WS/cdasr/1/dataviews/sp_phys/datasets/MMS2_ASPOC_SRVY_L2/clientLibraryExample/
Style
WebService
ProductKey
MMS2_ASPOC_SRVY_L2
Description
Access to this data from common programming environments. Note: this AccessInformation element was added by HDPWS.
Format
Binary
Acknowledgement
Please acknowledge R. Nakamura, K.M. Torkar, H. Jeszenszky, and J.L. Burch. Also please acknowledge the data providers and CDAWeb when using these data.
AccessInformation
RepositoryID
spase://SMWG/Repository/NASA/GSFC/SPDF/CDAWeb
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
CDAWeb HAPI Server
URL
https://cdaweb.gsfc.nasa.gov/hapi
Style
HAPI
ProductKey
MMS2_ASPOC_SRVY_L2
Description
Web Service to this product using the HAPI interface
Format
CSV
Acknowledgement
Please acknowledge R. Nakamura, K.M. Torkar, H. Jeszenszky, and J.L. Burch. Also please acknowledge the data providers and CDAWeb when using these data.
ProcessingLevel
Calibrated
InstrumentIDs
spase://SMWG/Instrument/MMS/2/InstrumentControl/ASPOC
MeasurementType
InstrumentStatus
TemporalDescription
TimeSpan
StartDate
2015-05-06 00:00:00.000
RelativeStopDate
-P2M
Cadence
PT1S
ObservedRegion
Earth.Magnetosheath
ObservedRegion
Earth.Magnetosphere
ObservedRegion
Earth.Magnetosphere.Magnetotail
ObservedRegion
Earth.Magnetosphere.Main
ObservedRegion
Earth.Magnetosphere.RadiationBelt
ObservedRegion
Earth.NearSurface.EquatorialRegion
ObservedRegion
Earth.NearSurface.Plasmasphere
ObservedRegion
Heliosphere.NearEarth
Parameter #1
Name
Epoch
ParameterKey
Epoch
Description
Interval centered time tag rounded to nearest msecond
Caveats
This parameter exhibits an increasing monotonic progression.
Cadence
PT1S
Units
ns
UnitsConversion
1.0e-9>s
RenderingHints
DisplayType
TimeSeries
AxisLabel
Epoch
ScaleMin
6.2798349819904e+13
ScaleMax
6.6269642620904e+13
ScaleType
LinearScale
ValidMin
1990-01-01T00:00:00.000000000
ValidMax
2100-01-01T00:00:01.000000000
FillValue
9999-12-31T23:59:59.999999999
Support
SupportQuantity
Temporal
Parameter #2
Name
Beam Current Sum
Set
Time series defined by using: EPOCH
ParameterKey
mms2_aspoc_ionc
Description
ASPOC Ion Emission Current Sum
Cadence
PT1S
Units
uA
UnitsConversion
1.0e-6>A
RenderingHints
DisplayType
TimeSeries
AxisLabel
I_ion
ValueFormat
f5.1
ScaleMin
0.0
ScaleMax
100.0
ScaleType
LinearScale
ValidMin
0.0
ValidMax
100.0
FillValue
-1.0e+31
Particle
ParticleType
Ion
Qualifier
Median
ParticleQuantity
CountRate
Parameter #3
Name
Beam Current, Unit 1
Set
Time series defined by using: EPOCH
ParameterKey
mms2_asp1_ionc
Description
ASPOC Unit 1 Ion Emission Current
Cadence
PT1S
Units
uA
UnitsConversion
1.0e-6>A
RenderingHints
DisplayType
TimeSeries
AxisLabel
I_ion
ValueFormat
f5.1
ScaleMin
0.0
ScaleMax
100.0
ScaleType
LinearScale
ValidMin
0.0
ValidMax
100.0
FillValue
-1.0e+31
Particle
ParticleType
Ion
Qualifier
Median
ParticleQuantity
CountRate
Parameter #4
Name
Beam Current, Unit 2
Set
Time series defined by using: EPOCH
ParameterKey
mms2_asp2_ionc
Description
ASPOC Unit 2 Ion Emission Current
Cadence
PT1S
Units
uA
UnitsConversion
1.0e-6>A
RenderingHints
DisplayType
TimeSeries
AxisLabel
I_ion
ValueFormat
f5.1
ScaleMin
0.0
ScaleMax
100.0
ScaleType
LinearScale
ValidMin
0.0
ValidMax
100.0
FillValue
-1.0e+31
Particle
ParticleType
Ion
Qualifier
Median
ParticleQuantity
CountRate
Parameter #5
Name
Beam Energy, Unit 1
Set
Time series defined by using: EPOCH
ParameterKey
mms2_asp1_energy
Description
ASPOC Unit 1 Emitted Beam Energy
Cadence
PT1S
Units
kV
UnitsConversion
1.0e3>V
RenderingHints
DisplayType
TimeSeries
AxisLabel
Energy
ValueFormat
f5.2
ScaleMin
0.0
ScaleMax
12.5
ScaleType
LinearScale
ValidMin
0.0
ValidMax
12.5
FillValue
-1.0e+31
Particle
ParticleType
Ion
Qualifier
Median
ParticleQuantity
Energy
Parameter #6
Name
Beam Energy, Unit 2
Set
Time series defined by using: EPOCH
ParameterKey
mms2_asp2_energy
Description
ASPOC Unit 2 Emitted Beam Energy
Cadence
PT1S
Units
kV
UnitsConversion
1.0e3>V
RenderingHints
DisplayType
TimeSeries
AxisLabel
Energy
ValueFormat
f5.2
ScaleMin
0.0
ScaleMax
12.5
ScaleType
LinearScale
ValidMin
0.0
ValidMax
12.5
FillValue
-1.0e+31
Particle
ParticleType
Ion
Qualifier
Median
ParticleQuantity
Energy
Parameter #7
Name
Instrument Status
Set
Time series defined by using: EPOCH
ParameterKey
mms2_aspoc_status
Description
ASPOC Instrument Status
Cadence
PT1S
RenderingHints
DisplayType
TimeSeries
ValueFormat
i3
ScaleType
LinearScale
Structure
Size
4
Element
Name
Data Quality
Index
1
RenderingHints
AxisLabel
Data Quality
Element
Name
Unit 1 Mode
Index
2
RenderingHints
AxisLabel
Unit 1 Mode
Element
Name
Unit 2 Mode
Index
3
RenderingHints
AxisLabel
Unit 2 Mode
Element
Name
On/Off Status
Index
4
RenderingHints
AxisLabel
On/Off Status
ValidMin
0
ValidMax
254
FillValue
255
Support
SupportQuantity
InstrumentMode
Parameter #8
Name
Half Interval
ParameterKey
mms2_aspoc_var
Description
Half width of measurement interval
Cadence
PT1S
Units
ns
UnitsConversion
1.0e-9>s
RenderingHints
AxisLabel
Half_int
ValueFormat
f13.1
ValidMin
0.0
ValidMax
1.275e+10
Support
SupportQuantity
Temporal