Actively actuatable valves for aerostat buoyancy control

An aerostat comprising:

• an inflatable structure including a balloon and a neck collectively defining a volume;
• a valve including
• a funnel supportable in the neck and defining a first opening, a second opening, and a cavity therebetween, the cavity in fluid communication with the volume via the second opening,
• a stem defining a channel at least partially outside of the inflatable structure,
• a stopper disposed in the cavity,
• a rod coupled to the stopper, at least one portion of the rod formed of a ferromagnetic material;
• and
• an actuator including a metal coil disposed about the rod and electrically actuatable to move the rod in an axial direction relative to the channel such that the stopper moves relative to the first opening of the cavity to control fluid communication between the volume and the channel via the cavity.