One of the main issues in assessing air breathing systems is to test the concept on ground, with a suitable flow generator which shall be as representative as possible of atmospheric flow rates encountered by the spacecraft at VLEO.
The AETHER team refined a particle flow generator (PFG) which relies on electric propulsion to accelerate a mixture of Oxygen and Nitrogen representative of what can be found at so low orbits.
Detailed results of a characterization test campaign on the PFG have been discussed at the 2022 IEPC, the paper can be found here:
CharacterizationofanAtmosphericPropellant-fedHallThrusterasaVLEOSimulator.
