Infrasonic Wave-Induced Variations of Ionospheric HF Sounding Echoes Radio Science

We conducted ionospheric observations during several Orbital Corporation International Space Station Resupply missions from the Mid-Atlantic Regional Spaceport at National Aeronautics and Space Administration Wallops Flight Facility in Virginia. These observations were made under different ionospheric and thermospheric conditions using different variations of an experimental sounding mode of the Wallops Vertical Incidence Pulsed Ionospheric Radar. We present an analysis of variations in signal strength (fading), range (signal delay), and echo arrival angle as the rocket-generated High Altitude Acoustic Waves propagate in the thermosphere and through the plasma layers being observed. The results improve our understanding of the effects of infrasonic waves on remote sensing of the ionosphere and on radio wave propagation through the ionosphere and thermosphere.