Sun Monitoring on the External Payload Facility of Columbus -SOlar Variable and Irradiance Monitor (Solar-SOVIM) - 11.22.16

Overview | Description | Applications | Operations | Results | Publications | Imagery

ISS Science for Everyone

Science Objectives for Everyone
Sun Monitoring on the External Payload Facility of Columbus-SOlar Variable and Irradiance Monitor (Solar-SOVIM) measures solar spectral irradiance from the sun via filter-radiometers in the near-UV (402 nanometers), visible (500 nanometers) and near-IR (862 nanometers) regions, together with the total solar irradiance, using two types of radiometers covering the range from 200 nanometers to 100 micrometers.
Science Results for Everyone
Information Pending

The following content was provided by Claus Froehlich, Ph.D., and is maintained in a database by the ISS Program Science Office.
Information provided courtesy of the Erasmus Experiment Archive.
Experiment Details


Principal Investigator(s)
Claus Froehlich, Ph.D., Physikalisch-Meteorologisches Observatorium-World Radiation Centre, Davos, Switzerland

Information Pending

Oerlikon Contraves, Zurich, Switzerland

Sponsoring Space Agency
European Space Agency (ESA)

Sponsoring Organization
Information Pending

Research Benefits
Information Pending

ISS Expedition Duration
October 2007 - April 2009

Expeditions Assigned

Previous Missions
The predecessor to SOVIM, SOVA was operated on board of EURECA in 1992.

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Experiment Description

Research Overview

  • Solar-SOVIM (Sun Monitoring on the External Payload Facility of Columbus-SOlar Variable and Irradiance Monitor) is a re-flight of the SOVA experiment on-board Eureca-1. The investigation will observe and study the irradiance of the Sun, with high precision and high stability.

  • The total irradiance will be observed with active cavity radiometers and the spectral irradiance measurement will be carried out by one type of sun-photometer.

  • Solar-SOVIM is interested in the basic solar variability in itself or in using this variability to study other physical phenomena, as e.g. solar oscillations. The basic reasons for irradiance changes are crucially important for the understanding of solar and stellar evolution.

Solar-SOVIM (Sun Monitoring on the External Payload Facility of Columbus-SOlar Variable and Irradiance Monitor) will use the accurate time series of TSI (Total Solar Irradiance) and SSI (Spectral Solar Irradiance) to obtain quasi-continuous high quality measurements of the solar irradiance variation and determine with high accuracy the amount of spectral redistribution of the solar output. Solar-SOVIM will also search for the long periodicity or quasi-periodicity found in other solar parameters, study the influence of active regions and other large-scale solar structures on the solar irradiance and investigate the energy storage in the convection zone in connection with the energy blocking of active regions. Solar-SOVIM will continue investigations of the mechanisms of solar radiative forcing of climate change on seasonal to decade time scale and continue the historical TSI monitoring record by linking the present and future measurements.

TSI measurements can define the Sun's total radiative input to the Earth with at least an order of magnitude less uncertainty than the one achievable for narrow spectral bands. Geophysical investigations require the spectral irradiance itself. In particular, the UV radiation below 300nm varies by an order of magnitude more than the TSI and it contributes more than 10 percent of the TSI irradiance variations Solar UV radiation, absorbed in the Earth's atmosphere, controls the ozone process. This radiation is unavailable for direct radiative forcing of the climate but may contribute indirectly through its influence on the middle atmosphere. More generally, reliable knowledge of solar spectral irradiance and its variability is ultimately required for understanding the mechanisms of solar variability and the wavelength dependent physical processes through which it influences the terrestrial environment.

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Space Applications
Information Pending

Earth Applications
Information Pending

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Operational Requirements and Protocols
Solar-SOVIM will always be powered-on to avoid any possible drifts because of switch-on procedures. To determine changes of sensitive cavities and optical surfaces due to degradation, two sets of instruments within Solar-SOVIM are available. One set will be exposed all the time to the pointed sun; the other set, called the back-up units, will stay shaded and protected and will be used from time to time only. Time cycles for the back-up are variable and commanded from ground. This operation does not influence the Instrument operations, only Solar-SOVIM is responsible for it.

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Decadal Survey Recommendations

Information Pending

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Results/More Information

Information Pending

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Results Publications

    Mekaoui S, Dewitte S, Conscience C, Chevalier A.  Total solar irradiance absolute level from DIARAD/SOVIM on the International Space Station. Advances in Space Research. 2010 June; 45(11): 1393-1406. DOI: 10.1016/j.asr.2010.02.014.

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Ground Based Results Publications

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ISS Patents

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Related Publications

    Schmidtke G, Froelich C, Thuillier MG.  ISS-SOLAR: Total (TSI) and spectral (SI) irradiance measurements. Advances in Space Research. 2006 January; 37(2): 255-264. DOI: 10.1016/j.asr.2005.01.009.

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Related Websites
The information on this page is provided courtesy of the ESA Erasmus Experiment Archive.
Columbus Mission - European Experiment Programme

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