Abstract: Aspects of the disclosure provide for controlling orientation of a payload of a balloon through a despin mechanism. In one instance, a system may include a flexible coupling configured to reduce effects of a balloon envelope tilting on a payload, a sensor configured to measure rotational displacement of the flexible coupling, a despin mechanism including a motor configured to rotate the payload, and a controller. The controller may be configured to use receive the measured rotational displacement and to use the despin mechanism to rotate the payload towards a preferred orientation based on the measured rotational displacement.

Abstract: A valve assembly for use with an unmanned aerial vehicle is provided and includes an inlet tube, a shuttle, a base plate, a screw assembly, and a spacer block. The shuttle is partially disposed within the inlet tube and is configured to be placed in a first position where the shuttle abuts the inlet tube and a second position where the outer surface is disposed in spaced relation to the inlet tube. The base plate extends between a first end portion that defines a cavity therein and a second end portion. The screw assembly is disposed within the cavity of the base plate and is coupled to a portion of the shuttle. The spacer block is interposed between the second end portion of the inlet tube and the first end portion of the base plate and is configured to maintain the inlet tube and the base plate in spaced relation.

Abstract: Aspects of the disclosure relate to manufacturing a balloon envelope for use in a stratospheric balloon system. For instance, a stream of polyethylene mixture is extruded through an extruder in order to orient molecules of polymer chains of polyethylene and to provide an oriented film. The oriented film is passed through an electron beam and thereby crosslinking the polymer chains to provide a cross-linked film. The cross-linked film is heat sealed to form the balloon envelope.

Abstract: The technology relates to a telescoping support structure which can be suspended between two objects. The telescoping support structure uses projections between adjacent tubular sections in order to prevent the adjacent tubular sections from falling away from one another. Although the telescoping support structure may be utilized in various different environments and circumstances, it may be of particular usefulness in the field of high-altitude ballooning. For instance, when used in a balloon system, the telescoping support structure may be suspended between two objects such as an upper payload structure and a lower payload structure. As another example, the telescoping support structure may be suspended between a balloon envelope and a payload which, in some examples, may include an upper and a lower payload structure.

Abstract: Aspects of the technology relate to rotational electromechanical systems, in which data and or power are supplied to components while one part of the system is rotating relative to another part of the system. Repeated rotation may create strain on or otherwise cause the cables to intermittently or permanently fail. A helical cable management system is provided that enables full rotation to the extent permitted. One or more cables are wound in a helical shape around the axis of rotation, which distributes the deformation of the cable along the helical length. Rotation in one direction causes the helix diameter to increase, while rotation in the other direction causes the helix diameter to decrease. A structure is used to maintain the distance between helical turns, while permitting the increase and decrease of the helix diameter. This reduces the overall strain on the cables, which can significantly extend their useful lifetime.

Abstract: Aspects of the disclosure provide for controlling orientation of a payload of a balloon through a despin mechanism. In one instance, a system may include a flexible coupling configured to reduce effects of a balloon envelope tilting on a payload, a sensor configured to measure rotational displacement of the flexible coupling, a despin mechanism including a motor configured to rotate the payload, and a controller. The controller may be configured to use receive the measured rotational displacement and to use the despin mechanism to rotate the payload towards a preferred orientation based on the measured rotational displacement.

Abstract: Aspects of the technology relate to propulsion systems for high altitude, long duration balloons, such as balloons that operate in the stratosphere for weeks, months or longer. A propeller assembly is used to provide lateral directional adjustments, which allows the balloon to spend more time over a desired region, reduce the return time to the desired region, reduce fleet overprovisioning, and increases the safety case by additional controls and avoidance abilities. A control assembly manages operation of the propeller assembly, including setting the pointing direction, speed of rotation and determining when to turn on the propeller and for how long. The propulsion system including the control and propeller assemblies is rotatable around a connection member of the balloon. Such rotation is independently adjustable from any rotation of the balloon's payload. The propeller blades may be made of plastic, which reduces weight and cost while providing sufficient speed at stratospheric altitudes.

Abstract: A valve assembly for use with an unmanned aerial vehicle is provided and includes an inlet tube, a shuttle, a base plate, a screw assembly, and a spacer block. The shuttle is partially disposed within the inlet tube and is configured to be placed in a first position where the shuttle abuts the inlet tube and a second position where the outer surface is disposed in spaced relation to the inlet tube. The base plate extends between a first end portion that defines a cavity therein and a second end portion. The screw assembly is disposed within the cavity of the base plate and is coupled to a portion of the shuttle. The spacer block is interposed between the second end portion of the inlet tube and the first end portion of the base plate and is configured to maintain the inlet tube and the base plate in spaced relation.

Abstract: The technology relates to techniques for drogue deployment for a lighter than air (LTA) vehicle descent. A drogue deployment system for an LTA vehicle descent can include a drogue comprising a drogue parachute coupled to a carrier. A spring can be configured to launch the drogue from a launch tube directed outward from an apex of the LTA vehicle in an acute angle from a horizontal plane. A core can be placed around the launch tube and placed around the spring, the core compressing the spring and holding the spring in a compressed state prior to deployment, and a riser can couple the carrier to the envelope of the LTA vehicle. In some cases, the drogue deployment system can comprise two or more drogues, wherein intervals between the two or more drogues can be selected such that horizontal components of drogue deployment forces approximately cancel out.

Abstract: Aspects of the disclosure relate to flight termination systems for tethered aerial vehicles. For instance, a flight termination system for a tethered aerial vehicle including an envelope may include a tool and a tether. The tool may include a first piece configured for attachment to an interior surface of the envelope and including a cutting blade. The tool may also include a second piece configured for attachment to an exterior surface of the envelope. The tether may be attached to the first piece such that when in use, a force on the tether causes the tool to cut an opening into the envelope.

Abstract: A system for an unmanned aerial vehicle can include an altitude control system 320, which further includes a compressor assembly 400, a valve assembly 500, and an electronics control assembly 600. The compressor assembly may include a compressor housing 410 that includes a compressor inlet 402, an outlet 202, and a cavity 414 extending therethrough and joining the inlet to the outlet. A diffuser 408 may be coupled to the compressor housing. A motor housing 407 may be disposed within the central cavity at the inlet of the compressor housing, and a compressor motor 406 may be disposed within the motor housing. An impeller 412 disposed within the compressor housing may be coupled to a driveshaft 444 for rotation therewith. The valve assembly may be coupled to an opening 416 of the compressor inlet. The valve head 502 may be configured to move into and away from the inlet opening so as to change a size of the circumferential area of the inlet opening.

Abstract: Aspects of the technology relate to lateral propulsion systems in lighter-than-air (LTA) platforms configured to operate in the stratosphere. One or more motor assemblies are used to actuate the lateral propulsion system and to make directional changes, for instance using one or more propellers. This can include a pointing axis motor assembly for orienting the lateral propulsion system along a particular heading, and a drive motor assembly for causing a propeller assembly or other propulsion mechanism to turn on and off Corrective actions may be necessary to adjust the alignment of the lateral propulsion system. A stepper motor control module may be used to control operation of the pointing axis motor assembly, for instance by causing it to rotate in a clockwise (or counterclockwise) direction. A motor current control approach may be used, in which the motor voltage is adjusted until a measured motor current reaches a selected current level.

Abstract: Aspects of the disclosure provide a flex connection for high altitude balloon applications. During operation flex connection allows a payload of a high-altitude balloon to remain level when an envelope of the balloon is tilted, in order to change the direction of the balloon. As an example, a system may include a balloon envelope, a payload, a cable between the balloon envelope and the payload, and a flex connection on the cable. The flex connection enables the payload to remain level relative to the ground when the balloon is in flight and the balloon envelope is tilted relative to the payload. The flex connection includes a top portion, a plurality of discs, and a bottom portion.

Abstract: A stratospheric balloon may include an upper structure having a pulley, a lower structure, at least one solar panel suspended between the upper structure and the lower structure, and a first orientation control member connected, at a first end thereof, to a first transverse edge of the at least one solar panel and, at a second end thereof, to a second transverse edge of the at least one solar panel. The first orientation control member is wound about the pulley such that rotating the pulley changes the orientation of the at least one solar panel relative to the upper structure and the lower structure. In another example, the pulley may be replaced by first and second support mechanisms and the system may include a second orientation control member. The first and second orientation control members are connected to the first and second support mechanisms, respectively, and to the solar panel.

Abstract: Aspects of the technology relate to a braking assembly for a lateral propulsion system of a high altitude platform (HAP) configured to operate in the stratosphere. Power is supplied to a propeller assembly as needed during lateral propulsion so that the HAP can move to a desired location or remain on station. When lateral propulsion is not needed, power is no longer supplied to the propeller assembly and it may slowly cease rotating. However, in certain situations, it may be necessary to cause the propeller assembly to stop rotating as soon as possible. This can include an unplanned descent. Rapid braking can avoid the propeller blades from entangling in the envelope, parachute or other parts of the HAP. A reusable brake is employed to prevent uncontrolled rotation of the propeller on descent, or otherwise to prevent the propeller from spinning freely when not being used to propel the HAP laterally.

Abstract: 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.

Abstract: A lighter than air platform an unfinned envelope having two or more propulsion elements coupled with the unfinned envelope proximate to the center of gravity. At least one navigation sensor is configured to monitor an actual flight path of the unfinned envelope, and at least one perturbation sensor is configured to monitor one or more perturbations of the unfinned envelope. A navigation controller is configured to guide the unfinned envelope with coordinated propulsion of the two or more propulsion elements. The navigation controller includes a navigation comparator that compares the actual flight path with a specified flight path of the unfinned envelope and determine a navigation instruction. A perturbation comparator compares the navigation instruction with the monitored one or more perturbations to determine a perturbation compensation. A propulsion coordinator controls propulsion values of each of the propulsion elements based on the navigation instruction and the perturbation compensation.

Abstract: A system for forming a tendon sleeve on an atmospheric balloon is described herein, the system comprising a coupling assembly including a seam coupling mechanism that forms a seam joint between a first gore panel and a second gore panel, the seam joint is spaced from respective first and second lateral edges of the first and second gore panels to form first and second edge flanges, and an edge coupling mechanism that forms an edge joint between the first and second edge flanges and closes a tendon sleeve, the edge joint spaced from the seam joint, the tendon sleeve includes a tendon sleeve passage between the seam joint and the edge joint and between the first and second edge flanges. The system also includes a tendon positioning mechanism that positions a tendon within the tendon sleeve passage. A tendon sleeve formed by this system is also described herein.

Abstract: A lighter than air platform an unfinned envelope having two or more propulsion elements coupled with the unfinned envelope proximate to the center of gravity. At least one navigation sensor is configured to monitor an actual flight path of the unfinned envelope, and at least one perturbation sensor is configured to monitor one or more perturbations of the unfinned envelope. A navigation controller is configured to guide the unfinned envelope with coordinated propulsion of the two or more propulsion elements. The navigation controller includes a navigation comparator that compares the actual flight path with a specified flight path of the unfinned envelope and determine a navigation instruction. A perturbation comparator compares the navigation instruction with the monitored one or more perturbations to determine a perturbation compensation. A propulsion coordinator controls propulsion values of each of the propulsion elements based on the navigation instruction and the perturbation compensation.

Abstract: A buoyant aerial vehicle includes: a balloon configured to store a gas; a payload coupled to the balloon; and a propulsion unit coupled to the payload by a tether. The propulsion unit includes: a fuselage having a substantially longitudinal shape, a first end, and a second end; a primary airfoil coupled to the fuselage; a secondary airfoil coupled to the fuselage at one of the first end or the second end; and a thrust generating device disposed at one of the first end or the second end and configured to move the propulsion unit relative to the payload along a propulsion flight path. The movement of the propulsion unit imparts movement of the buoyant aerial vehicle along a vehicle flight path.