BackForwardInstrument:  FUV/SI 

Instrument details
Acronym FUV/SI
Full name Far Ultraviolet Imager / Spectrographic Imager
Purpose To image the whole Earth proton aurora from satellite distances greater than 4 Earth radii to the center of the Earth
Short description Spectrometer to select the Doppler shifted Lyman H-alpha line at 121.82 nm in the ultraviolet part of the optical spectrum and to reject the non-Doppler shifted Lyman H-alpha from the geocorona at 121.567 nm. Temporal resolution between two images: 120 s
Background Associated to FUV / WCI (Wideband Imaging Camera and FUV / GEO (Geocorona Photometer)
Scanning Technique A field of view of 15º x 15º is imaged by 128 x 128 pixels. The satellite spin and the motion along the polar highly elliptical orbit provide volumetric scanning of the magnetosphere
Resolution 1.12° corresponding to 100 km at apogee distances
Coverage / Cycle Full magnetosphere at 2-min intervals
Mass Power Data Rate


Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2000 to 2005-12-15
Last update: 2017-05-21
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
  • Space radiometer or spectrometer
WIGOS Subcomponents No WIGOS subcomponents have been defined.
Mission objectives
Primary mission objectives
  • Aurora
  • UV flux
  • UV sky image
Opportunity objectives
  • Heliospheric image
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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
UV flux2 - very highNo specific limitation.Earth's limb and surface observed, moderate dynamic range
UV sky image2 - very highNo specific limitation.Earth's limb observed, coarse spatial resolution
Heliospheric image2 - very highNo specific limitation.Interplanetary space viewing in the UV band (121.6-393.4 nm)
Aurora2 - very highNo specific limitation.Observed down to Earth's surface in UV (121.6-393.4 nm)