BackForwardInstrument:  EPIC 

Instrument details
Acronym EPIC
Full name Energetic Particle and Ion Composition Experiment
Purpose To measure the charge, mass, and energy of ions; and to study the relative importance of ion sources and mechanisms for acceleration, transport and loss of particles, the formation and dynamics of magnetospheric boundary layers
Short description Assemblage of a Supra-Thermal Ion Composition Spectrometer (STIC) to measure charge state, mass and energy of ions with energies of 30-230 keV/charge; and a Ion Composition Subsystem (ICS) to measure mass and energy properties of energetic ions with energies from < 50 keV to 3 MeV. Z from 1 to 8
Background Part of a package of instruments to observe the Magnetosphere by navigating across its tail
Scanning Technique Travelling cross the Magnetosphere in a highly-elliptical orbit
Resolution N/A
Coverage / Cycle Magnetospheric volume
Mass Power Data Rate


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1992-10-02 to ≥2022
Last update: 2022-08-02
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
  • Heavy ion sensor [cross magnetosphere]
  • Subcomponent 3
  • Neutral and Ion Mass Spectrometer
  • Heavy ions mass spectrometer [from LEO and HEO]
Mission objectives
Primary mission objectives
  • Alpha particles differential directional flux
  • Heavy ion flux energy and mass spectrum
  • 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
Proton differential directional flux*2 - very highNo specific limitation.Magnetosphere, low, medium and high energy (up to over 1000 keV)
Alpha particles differential directional flux*4 - fairNo specific limitation.Cross-magnetosphere. Low-medium energy range (<10 up to 100 MeV/n)
Heavy ion flux energy and mass spectrum*2 - very highNo specific limitation.Cross-magnetosphere. Low-medium energy range (<10 up to 100 MeV/n)