Abstract: The possible operation temperature of propellant xenon in electrical propulsion system  is between 30 ℃  and 45 ℃, which covers the xenon′s critical temperature. At the critical temperature, xenon′s state is sensitive to the operating pressure and the ambient temperature. The propellant may exhibit different forms. These characteristics make the traditional equation of state ineffective to calculate the p-V-T relationship in the above temperature  range (max error may rise to 30 %). To solve this problem, a new calculation method based on the corresponding state principle was put forward for physical property estimation. The theoretical outcomes were compared with experiment data and available database. The results show that among the whole temperature and pressure range, the method is capable to predict the xenon′s physical property in gas, liquid, supercritical state with an error less than 0.5 %.

Key words: electrical propulsion, xenon, supercritical, corresponding state principle, physical properties, equation of state