BackForwardInstrument:  EXIS 

Instrument details
Acronym EXIS
Full name Extreme Ultraviolet Sensor / X-Ray Sensor Irradiance Sensors
Purpose To monitor EUV and X-rays from the solar disk
Short description Two units: EUVS (EUV Sensor) and XRS (X-Ray Sensor). EUVS measures EUV flux in 5 channels of the 5-127 nm range [including Fe-XV at 28.4 nm, He-II at 30.4 nm and H-Lyman-alpha at 121.6 nm]. XRS measures soft-X-rays fluxes in two bands, 0.05-0.4 and 0.1-0.8 nm
Background Evolution of SXI on GOES 12 to 15
Scanning Technique Sun pointing from GEO
Resolution N/A (full disk)
Coverage / Cycle Full disc at 2 s intervals (X-ray) and 33 s (EUV)
Mass 30 kg Power 40 W Data Rate 7.2 kbps


Providing Agency NOAA
Instrument Maturity Backed by strong heritage
Utilization Period: 2017 to 2033
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
  • Solar activity monitor
WIGOS Subcomponents
  • Subcomponent 1
  • X-ray spectrograph on GEO orbit
  • X-ray spectrometer at GEO
  • Subcomponent 2
  • Solar magnetograph, solar EUV/X-ray imagery and EUV/X-ray irradiance, both on the Earth-Sun line and off the Earth-Sun line
  • Solar X-ray spectrometer [from L1, GEO, LEO]
  • Solar EUV spectrometer [from L1, GEO, LEO]
  • Subcomponent 3
  • UV spectral imagery (e.g. GEO, HEO, MEO, LEO)
  • X-ray spectrometer [from GEO, HEO, MEO, LEO]
  • EUV spectrometer [from GEO, HEO, MEO, LEO]
Mission objectives
Primary mission objectives
  • Solar EUV flux
  • Solar X-ray 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
Solar X-ray flux*3 - highNo specific limitation.Few channels, wide dynamic range
Solar EUV flux*1 - primaryNo specific limitation.Several channels, wide dynamic range