Propagation Modeling Inside the International Space Station for the Automatic Monitoring of Astronauts by Means of Epidermal UHF-RFID Sensors

The monitoring of Astronaut's health is one of the most impacting aspects of long-duration Space missions, especially for the high involvement required to the crew members in the daily acquisition of body parameters. Automatic procedures based on wireless systems would grant undeniable benefits, especially if lightweight and battery-less devices could be adopted. The possibility and the reliability of a communication link inside the International Space Station (ISS) is here investigated when the UHF-RFID epidermal technology is adopted. A Ray Tracing asymptotic method is hence proposed to evaluate the coverage area and the read probability inside the Harmony module. The analysis is referred to up to two astronauts simultaneously present in the module and to the presence of multiple reader antennas, in case purely passive epidermal tags are adopted. Simulations revealed that it is possible to identify some simple operating conditions that allow to obtain a reliable RFID link, also thanks to the advantageous propagation characteristics of the module itself.