SUN MONITORING ON THE EXTERNAL PAYLOAD FACILITY OF COLUMBUS – SOLAR AUTO-
CALIBRATING EUV/UV SPECTROPHOTOMETERS (SOLAR-SOLACES)
Research Area: Heliophysics
Expedition(s): 16-ongoing
Principle Investigator(s): ● Gerhard Schmidtke, Fraunhofer-IPM, Freiburg, Germany
RESEARCH OBJECTIVES
The Solar Auto-Calibrating EUV/UV Spectrophotometers (SOLACES) measures the extreme-
ultraviolet/ultraviolet (EUV/UV) solar spectrum (17 nm to 220 nm) with moderate spectral
resolution from the sun. The SOLACES instrument has been active since 2008, being located on
the SOLAR facility on the external surface of the European Columbus Laboratory.
EARTH AND SPACE BENEFITS
The awareness of the environment of the
Earth and of the sun radiation level and
spectrum is of importance to both Earth-
based and space-borne systems as well as to
advanced studies on climate. Monitoring the
sun radiation outside of the Earth
atmosphere over a large electromagnetic
spectrum and correlating with parallel
observations with other space missions and
on ground helps provide the accurate data
required to support predictive models and
anticipate on the influence of sun radiation
on our environment.
RESULTS
The period of the solar Extreme-UV minimum between solar cycles 23 and 24 continued over
an unexpected long period (roughly 2 years instead of 1 around 2008-2009 timeframe) with
SOLACES showing a distinct minimum in August/November 2009. During the beginning of solar
cycle 24 measurements were showing abnormally low characteristics of the EUV spectral
irradiance. The maximum of the solar cycle was also predicted for late 2013. However, in
SOLACES measurements up to now, the maximum of the Solar cycle appeared in late 2011.
After that, the solar cycle subsided and is stagnating at a lower level, though measurements
continue, which does not exclude another strong increase of solar activity within the near
future.
Data from the SOLAR facility on the International Space Station together with data from the
Solar EUV Experiment (SEE) aboard the NASA TIMED satellite (which measures Solar spectra in
the wavelength range from 0.1 nm to about 200 nm) have helped to confirm the improvement
in the EUV-TEC model. SOLACES has been measuring the short-wavelength solar EUV irradiance
Sun monitoring on the External Payload Facility of
Columbus – SOLar Auto-Calibrating EUV/UV
Spectrophotometers external facility mounted
outside the Columbus module. ESA/NASA image.