August 23, 2016


The Soho satellite was built in Europe by an industrial consortium led by Matra, while the scientific instruments were provided by European and American scientists and funded by their national institutions.

SOHO undergoes integration in 1995 in Toulouse. Credits: ESA.

Soho is constituted of two modules. The Service Module, lower part of the satellite, provides the power, the thermal control, the pointing and the telecommunications for the entire satellite, it also supports the solar panels. The Payload Module is above; it contains the 12 following scientific instruments:

  • GOLF (Global Oscillations at Low Frequencies) and VIRGO (Variability of Solar Irradiance and Gravity Oscillations) conduct long and uninterrupted measurements of the solar disk oscillations respectively integrated in velocity and intensity. Information about the solar core will therefore be obtained.

  • SOI/MDI (Michelson Doppler Imager/Solar Oscillations Investigation) measures the Sun's surface oscillations with a high angular resolution in order to obtain accurate information on the Sun's convective zone, the most external layer of the solar interior.

  • SUMER (Solar Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostics Spectrometer), EIT (Extreme ultraviolet Imaging Telescope), UVCS (Ultraviolet Coronagraph Spectrometer) and LASCO (Large Angle and Spectrometric Coronagraph) provide a combination of telescopes, spectrometers and coronographs which observe the Sun's hot atmosphere, the corona, which extends very far away from the visible surface.
    SUMER, CDS and EIT observe the internal corona, while UVCS and LASCO observe the external corona. They obtain measurements of the coronal temperature, density, composition and velocity, and survey structure evolution with a high resolution.

  • CELIAS (Charge, Element, and Isotope Analysis System), COSTEP (Comprehensive Suprathermal and Energetic Particle Analyzer) and ERNE (Energetic and Relativistic Nuclei and Electron experiment) analyze in situ the charge and isotopic composition state of the solar wind ions, and the charge and isotopic composition of the particles emitted by the Sun.

  • SWAN (Solar Wind Anisotropies) maps the hydrogen density from 10 solar diameters in the heliosphere. It uses sensitive telescopes at a specific wavelength of the hydrogen, enabling to measure the large scale structure of solar wind jets.