Measurement of solar and cosmic radiation during spaceflight

The external platform of the International Space Station (ISS) will provide a unique opportunity for exobiological studies under space conditions, e. g., space vacuum, solar UV radiation, cosmic radiation, and temperature extremes. In order to facilitate this research, ESA is developing the EXPOSE facility to be attached to the External Pallet of the truss structure of the ISS. The experiment is planned for a duration of 18 months during the ISS early utilization period. Experiments on the Responses of Organisms to the Space Environment (ROSE) will study the survival of spores from bacteria, fungi, ferns, etc., under space conditions and thus investigate whether life could potentially survive extended travel through space. In parallel to the exposure of the biological material, the charged particle and solar extraterrestrial radiation will be measured with a multichannel dosimeter. This instrument is based on two separate developments. The dosimeter which determines solar radiation in four channels is based on the ground-based ELDONET (European light dosimeter network) instrument which has been developed to measure solar UV and visible radiation in three channels. The other part of the instrument is based on a 256 channel dosimeter of cosmic radiation which was developed and used on the Russian space station Mir. A final miniature prototype has been developed to fit the space available. The instrument incorporates the latest technologies such as Surface Mounted Devices (SMDs), switchable amplifiers, as well as on-board microprocessor control. Several software packages have been developed to record the solar visible and UV, and charged particle, radiations, to display them in graphical form and to store them for future analysis. All recorded data will be made available to the public via the Internet.