The present invention provides a means by which heat generated in an airtight container for a flying object flying at high altitude can be exhausted to the outside. Container 12 is a cabin of a gas balloon and comprises Main Body 121, which is an airtight container for accommodating Crew Member H1 and is filled with Air 122, Heat Transfer Member 125 made of a material that has a high thermal conductivity such as aluminum and that covers the inside of Main Body 121 and is partially in contact with Heat Absorber Holder 123, Heat Absorber Holder 123 that is a container made of a material that has a high thermal conductivity, such as aluminum, and is located outside of Main Body 121, and Heat Absorber 124 contained in Heat Absorber Holder 123. Heat generated by Crew Member H1 is transferred via Air 122 to Heat Transfer Member 125 and then to Heat Absorber Holder 123. Heat Absorber 124 absorbs heat from Heat Absorber Holder 123 as heat of vaporization and changes from a liquid to a gas.

A variable lift device includes a pressurized airtight enclosure accommodating air, a first airtight ballonet disposed inside the airtight enclosure accommodating a pressurized gas with a density lower than the density of air, the first airtight ballonet comprising a perforation means for perforating the first airtight ballonet.

A variable lift device includes a pressurized airtight enclosure accommodating air, a first airtight ballonet disposed inside the airtight enclosure accommodating a pressurized gas with a density lower than the density of air, the first airtight ballonet comprising a perforation means for perforating the first airtight ballonet.

A system for an unmanned aerial vehicle can include an altitude control system, which further includes a compressor assembly, a valve assembly, and an electronics assembly. The compressor assembly may include a driveshaft and a bearing assembly configured to rotate the driveshaft. The driveshaft may be formed from a first material and a compressor housing may be formed from a second material. The first and second materials may have different rates of thermal expansion. A dynamic preloading mechanism, such as a flexible plate, may be provided within the compressor assembly to exert a preloading force on the bearing assembly. Throughout the duration of the flight of the unmanned aerial vehicle, the preloading mechanism can continually compensate for differences in rates of thermal expansion between the first and second materials throughout.

A system for an unmanned aerial vehicle can include an altitude control system, which further includes a compressor assembly, a valve assembly, and an electronics assembly. The compressor assembly may include a driveshaft and a bearing assembly configured to rotate the driveshaft. The driveshaft may be formed from a first material and a compressor housing may be formed from a second material. The first and second materials may have different rates of thermal expansion. A dynamic preloading mechanism, such as a flexible plate, may be provided within the compressor assembly to exert a preloading force on the bearing assembly. Throughout the duration of the flight of the unmanned aerial vehicle, the preloading mechanism can continually compensate for differences in rates of thermal expansion between the first and second materials throughout.

A lighter-than-air craft including an envelope. A mixture of helium and hydrogen disposed within the envelope. The mixture having a ratio of helium to hydrogen such that the mixture is nonflammable during operating conditions for the lighter-than-air craft. The mixture provides buoyancy for the lighter-than-air craft. A hydrogen fuel cell fluidically coupled with the mixture and configured to utilize the mixture to generate electricity. A propulsion system is coupled to the envelope, and the propulsion system is configured to provide propulsion for the lighter-than-air craft. The propulsion system is electrically coupled with the hydrogen fuel cell and receives electricity generated by the hydrogen fuel cell. The propulsion system is configured to utilize the electricity in providing the propulsion to the lighter-than-air craft.

A lighter-than-air craft including an envelope. A mixture of helium and hydrogen disposed within the envelope. The mixture having a ratio of helium to hydrogen such that the mixture is nonflammable during operating conditions for the lighter-than-air craft. The mixture provides buoyancy for the lighter-than-air craft. A hydrogen fuel cell fluidically coupled with the mixture and configured to utilize the mixture to generate electricity. A propulsion system is coupled to the envelope, and the propulsion system is configured to provide propulsion for the lighter-than-air craft. The propulsion system is electrically coupled with the hydrogen fuel cell and receives electricity generated by the hydrogen fuel cell. The propulsion system is configured to utilize the electricity in providing the propulsion to the lighter-than-air craft.

A hydrogen boiloff capture system. The hydrogen boiloff capture system having a cryogenic tank for storing liquid hydrogen. The hydrogen boiloff capture system also includes an intermediate tank fluidically coupled with the cryogenic tank. The intermediate tank is configured to receive hydrogen gas boiloff from the cryogenic tank. The intermediate tank is further configured to provide the hydrogen gas boiloff to a lighter-than-air craft to regulate buoyancy of the lighter-than-air craft. The intermediate tank is also configured to provide the hydrogen gas boiloff to a hydrogen fuel cell coupled to the lighter-than-air craft.

A hydrogen boiloff capture system. The hydrogen boiloff capture system having a cryogenic tank for storing liquid hydrogen. The hydrogen boiloff capture system also includes an intermediate tank fluidically coupled with the cryogenic tank. The intermediate tank is configured to receive hydrogen gas boiloff from the cryogenic tank. The intermediate tank is further configured to provide the hydrogen gas boiloff to a lighter-than-air craft to regulate buoyancy of the lighter-than-air craft. The intermediate tank is also configured to provide the hydrogen gas boiloff to a hydrogen fuel cell coupled to the lighter-than-air craft.

According to one aspect, a reactor for generating lifting gas may include a first port, a second port, a coupling releasably securable in fluid communication with an aerostat, and a tank including a base and a crown defining at least a portion of a chamber therebetween, the first port and the coupling each supported on the crown, the second port supported on the tank away from the crown, the chamber in fluid communication with each one of the first port, the second port, and the coupling, the chamber expandable between the crown and the base from an uninflated state to an inflated state and, with the tank in the inflated state, a maximum height of the chamber less than a maximum dimension of the base.