In recent years, radiation shielding for astronauts has become an increasing priority among international space agencies, including the European Space Agency (ESA). As international efforts advance again towards exploration beyond the magnetosphere, the risks posed by Solar Particle Events (SPEs) to crew health resurface, with threats including acute radiation sickness, increased cancer risk, and damage to internal organs.

This thesis, developed at the European Astronaut Centre (EAC), presents the design of the FLARE suit, a personal radiation shielding system for astronauts in microgravity intravehicular environments. The suit uses 36 liters of on-board water and reduces the effective radiation dose by 36 ± 4.5%, with targeted protection for vital organs and a human-centered design. Simulation and accelerator testing demonstrated shielding effectiveness, while astronaut feedback refined its usability and comfort. In final review, FLARE offers a promising solution for radiation protection in future long-duration deep-space missions.

Keywords: Radiation Shielding, Solar Particle Event, Astronaut Protection Suit, Radiation Emergency Scenario, Human-Centered Space Design.

Humans are embarking on a new era of space exploration with the plan of sending crewed spacecraft beyond Low Earth Orbit (LEO), to the Moon, Mars and beyond. NASA is committed to land astronauts on the lunar surface by the year 2024. The goal of NASA's lunar exploration program - Artemis, a collaboration with commercial and international partners including the European Space Agency (ESA), is to establish sustainable exploration by the end of this decade. The plan is to use what is learned on and around the Moon to take the next giant leap, namely sending astronauts to Mars. Activities planned during the Artemis missions, especially in the early phases, involve finding critical resources needed for long-term exploration, and acquiring more knowledge on Moon, Earth and the universe by carrying out experiments. All these activities will involve extensive lunar geological field work, which is orders of magnitude more complex than field geology on Earth. Extravehicular activities (EVAs) will become increasingly more complicated than the tasks executed during the early Artemis missions and generally during human spaceflight missions so far. EVA systems and crewmember skills that currently do not exist will be required. This plan entails many challenges as real-time support from ground control cannot be provided to astronauts who thus need to become more autonomous. Hence, modern human-machine interfaces have to be designed to support astronauts during their deep space missions. Augmented reality (AR) and the internet-of-things (IoT) are changing the way industries work, especially AR has found application for space applications, specifically for procedural work. Nevertheless, only one AR space-related study focused on the use of AR for future human planetary exploration, namely on navigation and traverse planning. While cuff-checklists guided Apollo astronauts on the Moon, wrist displays and tablets represent the standard tools during today's astronaut analog planetary EVA missions. However, these are often operationally unfeasible as crew has to handle several tools simultaneously and/or repeatedly look at the display and thus gets distracted from the surroundings leading to a potential loss of situational awareness, affecting their safety. Based on the research that is currently being performed on IoT technologies in combination with AR for visualisation and enhanced situational awareness purposes, the benefits obtained through the use of these technologies applied to future human planetary EVAs, more specifically geological site inspections, were explored in this research. The AR-IoT surface exploration tool developed for this research introduces a new approach for astronauts to carry out geological site inspections. The tool enables hands-free operations such as data logging, detailed photo-documentation, taking site coordinates, descriptions of sites through the presence of a verbal “field notebook”, as well as mapping and highlighting features during a traverse by creating waypoints, while providing crew with suit diagnostics. A user-centered design method was adopted to design the AR-IoT tool deployed on the Microsoft HoloLens. This highly iterative design process involved two to three expert reviews for each of the first three concepts, and three heuristic evaluations for the fourth concept until the subsequent generation of the first prototype. Key usability and user interaction aspects, pertinent capabilities determining the adoption of innovative interfaces, essential insights into future human-machine interaction and design requirements for AR meant for EVA astronauts were gathered through semi-structured interviews held with four ESA astronauts and astronaut geological field activities experts. The interviews together with the qualitative and quantitative data collected through the questionnaires were then used to assess the usability of the AR-IoT tool. Moreover, these data provided with additional knowledge on user-centered design AR studies in general but also and particularly on user-centered AR space-related studies. Valuable insights into interface design and user interaction aspects were gained. Results from the qualitative content analysis of the interviews stressed the importance of user satisfaction (32% of 139 quotes) as a usability aspect. Key design factors identified were: displaying solely important information in the field-of-view while adjusting it to the user's visual acuity, easy usage, simplicity, helpfulness and extensibility. User interaction was the second most mentioned (24% of 139 quotes) aspect. While multimodal interaction was considered feasible, no conclusions could be drawn on the most suitable combination of inputs. Nonetheless, most experts defined voice the most intuitive input. Based on the positive feedback from ESA astronauts and other experts, the AR-IoT proof of concept proved to be a potentially usable tool for future geological site inspection activities. The AR-IoT tool is therefore a promising asset for analogue training missions, such as Caves & Pangaea, and in the future for lunar geological field work. While limitations in both research and design are outlined, a set of recommendations aimed at warranting future testing and development of a more advanced AR-IoT tool for astronaut geological field activities is provided.