Just like a submarine floats by displacing a volume of water. Likewise, our drone floats up by displacing a volume of air.
A submarine sinks by drawing water into it’s ballast tanks. Likewise, our drone sinks by drawing air into it’s “ballast tanks”
(Everything Assumed to be at STP)
The idea is that in theory, Air, with a density of 1.225 Kg/m3 is significantly heavier then helium. Drawing in air should bring the drone down. Previous experiments carried out with helium balloon drones used droplets of water to bring it down. Considering the sensitivity to weight changes a helium balloon has, we hope that air, is light enough to effect a gradual but significant change in height compared to water droplets. And with air, the evacuation and collection of it is so much simpler compared to water.