BackForwardInstrument:  IMPACT/SWEA 

Instrument details
Full name IMPACT / Solar Wind Electron Analyzer
Purpose To measure the distribution function of the solar wind core and halo electrons with high spectral and angular resolution over practically the full spherical range
Short description Consists of a hemispherical top hat ElectroStatic Analyzer (ESA) that provides a 360º FOV in a plane, combined with electrostatic deflectors to provide nearly 4 pi coverage when SWEA is mounted at the end of the STEREO boomfrom. Energy range: 0.001-10 keV
Background Part of the IMPACT (In-situ Measurements of Particles and CME Transients) instrument package
Scanning Technique Interplanetary space observation from two variable positions along the Earth’s orbit around the Sun to implement stereoscopy
Resolution N/A
Coverage / Cycle Full interplanetary space
Mass Power Data Rate


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2007-01-21 to 2014-10-01
Last update: 2021-12-16
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
  • Electron sensor [at solar orbit, ecliptic, L5]
  • Subcomponent 3
  • Electron sensor [from solar orbit, ecliptic, L5]
Mission objectives
Primary mission objectives
  • Electron differential directional flux
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Tentative 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
VariableRelevance for measuring this variableOperational limitationsExplanation
Electron differential directional flux3 - highNo specific limitation.Interplanetary space, low energy (up to 40 keV)