BackForwardInstrument:  SIS 

Instrument details
Acronym SIS
Full name Solar Isotope Spectrometer
Purpose To measure elemental and isotopic composition of solar energetic particles, anomalous cosmic rays, and interplanetary particles from H to Zn
Short description Z range: 1 to 30. Measurements are performed by a technique considering a particle's energy loss ΔE in a detector (multiple ΔE versus residual energy E). Energy range: 4-200 MeV/nucleon for Z > 2, 3.5-40 for alpha-particles, 7-20 for protons
Background Part of a package of instruments for solar observation
Scanning Technique Sun pointing from the L1 Lagrange libration point
Resolution N/A (full disk)
Coverage / Cycle Full Sun disk, nearly continuous
Mass 20.6 kg Power 21.5 W Data Rate 2 kbps

 

Providing Agency NASA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 1997 to 2026
Last update: 2021-11-10
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 1
  • Solar wind in situ plasma and energetic particles, magnetic field, at L1
  • Solar wind at L1 - Proton sensor
  • Solar wind at L1 - Alpha-particle sensor
  • Solar wind at L1 - Heavy ion sensor
  • Solar wind at L1 - Plasma density sensor
  • Solar wind at L1 - Plasma temperature sensor
  • Solar wind at L1 - Plasma velocity sensor
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*4 - fairNo specific limitation.Sun pointing, high energy (over 1000 keV)
Alpha particles differential directional flux*1 - primaryNo specific limitation.Sun-pointing. Low-medium energy range (<10 up to 100 MeV/n)
Solar wind density3 - highNo specific limitation.Solar viewing. Inferred from Proton and Alpha-particle spectroscopy
Solar wind temperature3 - highNo specific limitation.Solar viewing. Inferred from Proton and Alpha-particle spectroscopy
Solar wind velocity3 - highNo specific limitation.Solar viewing. Inferred from Proton and Alpha-particle spectroscopy
Heavy ion flux energy and mass spectrum*3 - highNo specific limitation.Sun-pointing. Extended energy range (<10 to >100 MeV/n)