BackForwardInstrument:  HEP-e 

Instrument details
Acronym HEP-e
Full name High-energy electron experiments
Purpose Measurement of high-energy electrons through the magnetosphere, specifically the Van Allen belts
Short description Spectrometer to observe electrons in the energy range 70-2,000 keV. Detailed description not yet available
Background Part of a package to measure low, medium, high and extremely-high energy electrons (LEP-e, MEP-e, HEP-e and XEP-e) and low and medium energy ions (LEP-i and MEP-i)
Scanning Technique Volumetric exploration of the magnetosphere as the satellite travels along the HEO with perigee 300 km and apogee 30,000 km whilst spinning at 1 round / 8 s
Coverage / Cycle Full magnetospheric volume, more frequently in low-middle latitudes, consistently with the 31° orbital inclination
Mass Power Data Rate


Providing Agency JAXA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2017 to 2033
Last update: 2021-10-02
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 2
  • Magnetospheric energetic particles and magnetometers
  • Electron sensor [cross magnetosphere]
Mission objectives
Primary mission objectives
  • Electron 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*2 - very highNo specific limitation.Magnetosphere, medium and high energy (over 40 to over 400 keV)