To store xenon propellant onboard the spacecraft, xenon is typically compressed and stored at high pressures (75-300 bar) between 20 • C and 50 • C, in a supercritical state . The pressure vessel must have thick walls to safely contain the xenon at these high pressures, making it heavy. Because the cost of launching a payload into Earth's orbit is ca. 10 000 USD/lb , it is desirable to reduce the mass of storage materials required to store xenon propellant onboard spacecraft.