Simultaneous Mitigation of Communication Blackout and Aerothermal Heating through Film Cooling

Abstract

The advancement of space transportation critically depends on addressing key challenges during atmospheric reentry, notably severe aerodynamic heating and radio frequency communication blackout caused by plasma formation. During reentry, high-velocity flight through the atmosphere induces extreme gas temperatures, which promote gas ionization, generating a plasma sheath that significantly attenuates electromagnetic waves. Therefore, this study investigates the effectiveness of gas film cooling as a simultaneous mitigation method for both aerodynamic heating and communication blackout. Experiments were performed in a large-scale arc-heated wind tunnel, producing high-enthalpy, weakly ionized flows representative of reentry conditions. A test model equipped with a gas injector and an onboard communication antenna was exposed to two freestream conditions: pure argon and an argon–nitrogen mixture. The pure argon flow produced a sufficiently high electron number density to reproduce a communication blackout. The addition of nitrogen reduces the electron number density in the plasma flow, thereby effectively suppressing communication blackout. Under pure argon flow, significant signal attenuation due to plasma was observed. Gas injection led to a measurable reduction in surface temperature and a marked improvement in signal strength. These findings demonstrate that gas injection offers a promising dual-purpose mitigation strategy, enhancing the safety and reliability of future atmospheric reentry missions.