Development of the Internal Dosimetry Array for Gateway

The Gateway space station, to be built in orbit around the Moon in the mid-2020s, will not be protected by the Earth's magnetic field or the atmosphere; hence, astronauts could be exposed to up to 700 times the radiation dose of an average human on Earth from space radiation. The Internal Dosimeter Array (IDA) instrument suite is the very first internal ESA experiment on board Gateway. The IDA payload is accommodated inside the US HALO module within a Payload Bank and it is composed of the following already existing and flight proven instruments: - TRITEL 3D silicon detector telescope provided by Centre for Energy Research (EK); - European Active Dosimeter (EAD) provided by German Aerospace Center (DLR); - Medipix (MPX) detector provided by Advacam s.r.o. (AVD); - PADLES and D-SPACE provided by Japanese Space Agency (JAXA). IDA instruments provide, based on measurements of energy deposition and particle track analysis, particle fluxes and fluences, LET spectra, mean quality factors, absorbed dose and dose equivalent rates, as well as intergrated absorbed dose and dose equivalent from the charged particle component of space radiation. Besides charged particles (electrons, protons, He ions and HZE particles), X-rays and gamma-rays are also measured. The IDA instrument suite covers an overall LET range up to 1470 keV/μm in water (including the full range of 0.1 - 150 keV/μm relevant relevant to radiation protection from space radiation), and an absorbed dose rate range between nGy/h and a few hundred mGy/h. IDA data acquisition will start soon after HALO launch and will continue on a long term, including transit and on the final halo-like orbit around the Moon. This final orbit will also pass through the Van Allen radiation belts. Operations will be continuous even during uncrewed periods. The scientific radiation data provided by IDA will help the space dosimetry community to improve radiation physics models for cancer and non-cancer (cardio-vascular system, central nervous system) effects. These are of utmost importance in supporting crew risk assessment for deep space exploration missions, not only in the frame of the Artemis programme but for the future plans of human missions to Mars. Radiation data provided by the Instruments will serve also as inputs for studying radiation effects on electronics in deep space. The present paper gives a brief descripton of the scientific instruments in IDA and an overview of the system level concept of the IDA payload to integrate all required instruments within a Gateway Payload Bank and to provide a system interface between the instrumentation and Gateway onboard system from electrical and software point of view.