WMO OSCAR | Details for Instrument SEM/SSJ4

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Instrument: SEM/SSJ4

Instrument details

Acronym	SEM/SSJ4
Full name	SEM / Special Sensor Precipitating Electron and Ion Spectrometer - 4
Purpose	Measurement of transfer energy, mass, and momentum of charged particles through the magnetosphere-ionosphere in the Earth's magnetic field
Short description	Electrostatic analyzer for electrons protons and alpha-particles in the energy range 0.03-30 keV
Background	Part of the SEM (Space Environment Monitor) package
Scanning Technique	N/A (in-situ in the platform environment)
Resolution	N/A
Coverage / Cycle	N/A
Mass		Power	Data Rate

Providing Agency	DoD
Instrument Maturity	Flown on operational programme
Utilization Period:	1976 to 2020
Last update:	2022-07-25

Detailed characteristics

Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Defense Meteorological Satellite Program - Block 5D-1 (DoD)
- DMSP-F01 (see instrument status) Sep 1976 - Sep 1979
- DMSP-F02 (see instrument status) Jun 1977 - Mar 1978
- DMSP-F03 (see instrument status) Apr 1978 - Dec 1979
- DMSP-F04 (see instrument status) Jun 1979 - Aug 1980
- DMSP-F05 (see instrument status) Oct 1980 - Jul 1980
Defense Meteorological Satellite Program - Block 5D-2 (DoD)
- DMSP-F06 (see instrument status) Mar 1983 - Nov 1997
- DMSP-F07 (see instrument status) Feb 1984 - May 1988
- DMSP-F08 (see instrument status) Sep 1987 - Oct 2006
- DMSP-F09 (see instrument status) May 1988 - Aug 1994
- DMSP-F10 (see instrument status) Mar 1991 - Oct 1997
- DMSP-F11 (see instrument status) Feb 1992 - Aug 2000
- DMSP-F12 (see instrument status) Nov 1994 - Oct 2008
- DMSP-F13 (see instrument status) Jun 1995 - Feb 2015
- DMSP-F14 (see instrument status) Jul 1997 - Feb 2020
Defense Meteorological Satellite Program - Block 5D-3 (DoD)
- DMSP-F15 (see instrument status) Mar 2000 - Dec 2020

Instrument classification

Solar and space environment monitors
Energetic particle spectrometer

WIGOS Subcomponents

Subcomponent 1
In-situ plasma probes, and energetic particle spectrometers and magnetometers at GEO and LEO, and magnetic field at GEO
Electron sensor at LEO
Proton sensor at LEO
Alpha-particle sensor at LEO

Mission objectives

Primary mission objectives

Alpha particles differential directional flux
Electron differential directional flux
Proton differential directional flux

Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.

Variable	Relevance for measuring this variable	Operational limitations	Explanation
Electron differential directional flux*	5 - marginal	No specific limitation.	Platform environment, low energy (up to 40 keV)
Proton differential directional flux*	5 - marginal	No specific limitation.	Platform environment, low energy (up to 40 keV)
Alpha particles differential directional flux*	5 - marginal	No specific limitation.	Platform environment. Low-medium energy range (<10 up to 100 MeV/n)