AERO & VISTA: Demonstrating HF Radio Interferometry with Vector Sensors

The Auroral Emission Radio Observer (AERO) and Vector Interferometry Space Technology using AERO (VISTA) are twin 3U CubeSats, funded by NASA’s H-TIDeS program, that will study radio emissions of Earth’s aurora from a polar low earth orbit. Each CubeSat carries a radio science payload featuring a deployable vector sensor antenna that measures the electric and magnetic field in each of three orthogonal directions. The six electromagnetic field values are processed to estimate the angle of arrival and polarization of incoming signals from 100 kHz to 15 MHz to better than 10 degrees. This localization capability will enable AERO and VISTA to answer fundamental questions about the nature of auroral energy production and dissipation through refinement of source spatial distribution and physical mechanisms for auroral kilometric radiation (AKR), mid frequency bursts (MFB), and auroral roar and hiss phenomena.

Together, AERO and VISTA will also demonstrate low frequency interferometry to further improve radio localization ability by a factor of 10. A key goal is to validate theoretical modeling that shows interferometric arrays composed of vector sensors will be able to maintain sensitivity even in the presence of terrestrial interference. This capability would relax the requirement that space-based low frequency interferometers be placed far from the Earth in GEO or lunar orbits, significantly increasing the data volume returned from such a telescope. The interferometry demonstration, to be performed at 10-20 km separation between the spacecraft, requires high fidelity knowledge of relative position and timing, and will use differential drag to control spacecraft separation.