BackForwardInstrument:  SEM/HEPD 

Instrument details
Acronym SEM/HEPD
Full name Space Environment Monitor - High Energy Particle Detector
Purpose Space weather - Charged particles at platform level
Short description Spectrometer for electrons (0.15-5.7 MeV), protons (3-300 MeV) and alpha-particles (12-220 MeV)
Background Part of the Space Environment Monitor of FY-1 and FY-3 A/B satellites
Scanning Technique N/A (in-situ in the platform environment)
Resolution N/A
Coverage / Cycle N/A
Mass Power Data Rate


Providing Agency CMA
Instrument Maturity Flown on operational programme
Utilization Period: 1988 to 2024
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

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.
VariableRelevance for measuring this variableOperational limitationsExplanation
Electron differential directional flux*5 - marginalNo specific limitation.Platform environment, medium and high energy (over 40 to over 400 keV)
Proton differential directional flux*5 - marginalNo specific limitation.Platform environment, high energy (over 1000 keV)
Alpha particles differential directional flux*5 - marginalNo specific limitation.Platform environment. Low-medium energy range (<10 up to 100 MeV/n)