An altitude control system for an unmanned aerial vehicle includes a compressor assembly defining a plenum therein, a passive valve assembly coupled to a first portion of the compressor assembly and in fluid communication with the plenum, and an active valve assembly coupled to a second portion of the compressor assembly and in fluid communication with the plenum. A method of controlling an altitude of an unmanned aerial vehicle and an unmanned aerial vehicle are also provided.

An altitude control system for an unmanned aerial vehicle includes a compressor assembly defining a plenum therein, a passive valve assembly coupled to a first portion of the compressor assembly and in fluid communication with the plenum, and an active valve assembly coupled to a second portion of the compressor assembly and in fluid communication with the plenum. A method of controlling an altitude of an unmanned aerial vehicle and an unmanned aerial vehicle are also provided.

A Rapid Air Ballast System that generates ballast for an airship relatively quickly by compressing air at low pressures into a ballonet inside a large volume tank. The air pressure inside the ballonet being roughly equal to the lifting gas pressure outside the ballonet but inside the tank. The system comprising a controllable air compression device to achieve the desired air pressure and valves in the system to direct the flow of air into or out of the system. This is particularly useful for quickly and efficiently controlling aerostatic lift for an airship, especially while performing on-loading and off-loading of payload operations.

A Rapid Air Ballast System that generates ballast for an airship relatively quickly by compressing air at low pressures into a ballonet inside a large volume tank. The air pressure inside the ballonet being roughly equal to the lifting gas pressure outside the ballonet but inside the tank. The system comprising a controllable air compression device to achieve the desired air pressure and valves in the system to direct the flow of air into or out of the system. This is particularly useful for quickly and efficiently controlling aerostatic lift for an airship, especially while performing on-loading and off-loading of payload operations.

Aspects of the technology relate to lighter-than-air (LTA) high altitude platforms configured to operate in the stratosphere. Such platforms can generate operate for weeks, months or longer. Shaped envelope LTA platforms may support a payload that provides telecommunications and/or other services to remote regions around the world. The payload may be arranged with other components on a modular bus-type chassis. One or more components may be moveable along the chassis to change the pitch of the vehicle for more effective flight operation. The modular chassis may include a truss configuration assembled from one or more subunits. The subunits may be preassembled with different equipment packages. Trusses formed using sets of struts may have two or more struts terminating at one interconnection node. Node connection elements, such as compound dovetail interconnects, facilitate a reliable, repeatable and quick mounting method for structural interconnections, which can lead to faster assembly and disassembly times.

Described herein are features for a high altitude lighter-than-air (LTA) system and associated methods. A zero-pressure balloon (ZPB) is attached in tandem with one or more air super-pressure balloons (SPB). The ZPB provides lift for the system while the SPB may provide a variable amount of ballast air by pumping in or expelling out ambient air. Various advanced performance targets relating to ascent rate, descent rate, range and maximum altitude are achievable with various scaled versions of the basic design of the LTA system. Advanced navigation and control techniques, such as more efficient high altitude station-keeping approaches, made possible with the LTA system are also described.

Described herein are features for a high altitude lighter-than-air (LTA) system and associated methods. A zero-pressure balloon (ZPB) is attached in tandem with one or more air super-pressure balloons (SPB). The ZPB provides lift for the system while the SPB may provide a variable amount of ballast air by pumping in or expelling out ambient air. Various advanced performance targets relating to ascent rate, descent rate, range and maximum altitude are achievable with various scaled versions of the basic design of the LTA system. Advanced navigation and control techniques, such as more efficient high altitude station-keeping approaches, made possible with the LTA system are also described.

Devices, systems, and methods are directed to controlling lifting gas in a volume defined by an inflatable structure of an aircraft. For example, controlling lifting gas in the volume of the inflatable structure may account for variations in ambient and tactical conditions experienced by the aircraft over the course of flight, as may be useful for lifting the aircraft to a target altitude and/or carrying out a particular mission. Additionally, or alternatively, controlling lifting gas in the volume of the inflatable structure may facilitate lifting the aircraft using lifting gas generated by reacting stable materials with one another at a launch site in the field. As an example, aluminum may react with water to form a lifting gas including hydrogen and steam. As the steam condenses to water in the inflatable structure, a valve may expel water from the inflatable structure to assist in maintaining buoyancy of the aircraft.

Devices, systems, and methods are directed to controlling lifting gas in a volume defined by an inflatable structure of an aircraft. For example, controlling lifting gas in the volume of the inflatable structure may account for variations in ambient and tactical conditions experienced by the aircraft over the course of flight, as may be useful for lifting the aircraft to a target altitude and/or carrying out a particular mission. Additionally, or alternatively, controlling lifting gas in the volume of the inflatable structure may facilitate lifting the aircraft using lifting gas generated by reacting stable materials with one another at a launch site in the field. As an example, aluminum may react with water to form a lifting gas including hydrogen and steam. As the steam condenses to water in the inflatable structure, a valve may expel water from the inflatable structure to assist in maintaining buoyancy of the aircraft.

Devices, systems, and methods are directed to controlling lifting gas in a volume defined by an inflatable structure of an aircraft. For example, controlling lifting gas in the volume of the inflatable structure may account for variations in ambient and tactical conditions experienced by the aircraft over the course of flight, as may be useful for lifting the aircraft to a target altitude and/or carrying out a particular mission. Additionally, or alternatively, controlling lifting gas in the volume of the inflatable structure may facilitate lifting the aircraft using lifting gas generated by reacting stable materials with one another at a launch site in the field. As an example, aluminum may react with water to form a lifting gas including hydrogen and steam. As the steam condenses to water in the inflatable structure, a valve may expel water from the inflatable structure to assist in maintaining buoyancy of the aircraft.