The microwave electromagnetic background as measured onboard the International Space Station

This paper presents an attempt to experimentally evaluate the actual radiofrequency exposure levels onboard the International Space Station in terms of absorbed energy (power) density, which is essential for the confirmation of manned space flight safety. The measurements were made with the use of compact stand-alone electromagnetic dosimeters, capable for recording the absorbed energy (power) density in the frequency band 0.8-8.0 GHz once per minute. As a result of experimental data analysis for two representative locations at the MLM module of the ISS, it is possible to establish that the absorbed energy (power) densities can reach the following levels: 0.7 nW/cm² on average per day with maximal possible value of 119.8 nW/cm² in the Crew cabin; and 1.4 nW/cm² on average per day with maximal possible value of 207.8 nW/cm² at Central post. Though the maximal exposure levels recommended for the ISS electromagnetic hardware in the similar frequency band aren't exceeded so far, the existing recommendations for the ISS electromagnetic hardware with frequencies above 8.0 GHz makes us believe such equipment can pose an excessive radiofrequency exposure in some of the locations at ISS, so the further experimental electromagnetic measurements are still necessary in the extended frequency band.