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SolACES - Auto-calibrating EUV/UV spectrometers for measurements onboard the International Space Station (ISS)

Presentation held at the 37th COSPAR Scientific Assembly, 13-20 July 2008, Montréal, Canada
SolACES - SOLar Auto-Calibrating EUV / UV Spectrophotometers on the International Space Station
: Brunner, R.; Schmidtke, G.; Konz, W.; Nikutowski, B.

Volltext urn:nbn:de:0011-n-1193186 (1.7 MByte PDF)
MD5 Fingerprint: 6d25d46455ddc00292bb4ddd43bc948a
Erstellt am: 12.3.2010

2008, 16 Folien
Committee on Space Research (COSPAR Scientific Assembly) <37, 2008, Montréal>
Vortrag, Elektronische Publikation
Fraunhofer IPM ()
SolACES; International Space Station (ISS); EUV/UV spectrometer; solar irradiance; thermosphere; ionosphere; climate change

In the field of terrestrial climatology the most important goal is the quasi-continuous measurement of the solar irradiance with highest possible accuracy within the ISS (ESA) SOLAR mission. SolACES as a part of it will contribute to the solar EUV/UV irradiance aspects. These data will be provided to investigate further the impact of the solar irradiance variability on the Earth's climate changes as well as the thermospheric/ionospheric interactions that are pursued in the TIGER program, too. The four grating spectrometers of SolACES cover the wavelength range from 16 nm to 220 nm. 42 band pass filters are used to select EUV photon fluxes within wavelength subranges in order to determine their irradiances within three-signal recording ionisation chambers that are considered as primary dete ctor standards. . Since spectrometers are not stable with respect to radiometric efficiency, re-measuring the filter transmissions and repeat the determination of the spectrometer efficiencies allow very accurate irradiance observations (2 The concept has been successfully tested with line emissions in the laboratory. Further, broadband as well as monochromatic synchrotron radiation has been used in the PTB laboratory of BESSY II electron synchrotron. There is good agreement with the BESSY II intercomparison. Still, the necessity to apply a re-calibration device showed up strongly. After the successful launch with the shuttle mission STS-122 on February 7th 2008 and the planned activation and commissioning of SolACES at the end of February 2008 we will extensively test all spectrometers an d ionization chambers, i.e., we will repeatedly determine all filter transmissions and spectrometer efficiencies in the new environment and compare the results of the laboratory and BESSY II measurements. Additionally, a compare with SOVIM and SOL- SPEC of the SOLAR payload on the Columbus laboratory will help to perform measurements of high quality. First results of the EUV irradiance measurements will be presented in view of the scientific goals.