The intention of these ‘Public Outreach Activity Days’ is the presentation of the ‘science background’, the ‘current state of research’ and the ‘further planned activities’ of the group to a scientific interested public audience. The place of the meetings is provided by the hosting co-investigators. The scientists will give talks about the baselines of radiation protection in space, the risks of long-duration space flight to humans, the scientific reason behind the MATROSHKA experiment, and the current status of the HAMLET project. The public outreach day will also include ‘hands-on experience’ for the general public to space radiation hardware, e.g. a training model of the MATROSHKA phantom.