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 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: 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.

Abstract: Aspects of the disclosure relate to high altitude or stratospheric balloon systems. For instance, a stratospheric balloon system may include a an upper structure, a lower structure, a platform associated with the lower structure, a stack of solar panels positioned on the platform, each solar panel coupled to an adjacent solar panel, at least one tension element connected, at a first end thereof, to the upper structure and, at a second end thereof, to the platform, and a first flexible tension member coupled, at a first end thereof, to the upper structure and to foremost solar panel of the stack of solar panels. Solar panels may be stacked in a “Z-fold” configuration with either solar cells of the adjacent solar panels facing one another or the frames of the adjacent solar panels facing one another. In this configuration, the adjacent solar panels are connected by a hinge system.

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 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 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 laminated load ring for a balloon assembly includes a plurality of ring stacking units stacked one on top of the other. Each of the ring stacking units can include a main body having a central opening, a plurality of arms, and at least one weld line. The plurality of arms may each extend away from the main body around a circumference of the main body. The at least one weld line can be formed on the main body. The plurality of arms of the plurality of ring stacking units may be aligned with one another. The weld line of each of the plurality of ring stacking units may be offset from the weld line of a directly adjacent ring stacking unit in a direction extending around the circumference of the laminated load ring.

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 technology relate to temperature regulation for high altitude, long duration balloons, such as balloons that operate in the stratosphere for weeks, months or longer. A balloon covering overlays the balloon envelope, providing an opaque or otherwise light-reflective layer with low emissivity that blocks or reflects optical and/or infrared light. Heat from within the envelope is reflected back from the covering toward the envelope, while light from the sun is reflected back towards the environment. An active venting system is employed to draw in cooler ambient air from the external environment while expelling warmer air from within the envelope. Vent and air intake assemblies of the active venting system are actuated in view of current and/or predicted balloon conditions to regulate internal balloon temperature. This approach reduces repeated pressure changes, which can put undue stress on the balloon envelope and adversely affect the operational lifespan of the system.

Abstract: Aspects of the disclosure relate to envelopes for aerial vehicle. The aerial vehicle may include an envelope including a plurality of gores. The aerial vehicle may also include a seal arranged between a pair of the plurality of gores, the seal including six layers of envelope material heat-sealed together.

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: Aspects of the disclosure relate to flight termination systems for tethered aerial vehicles having envelopes. For instance, a flight termination system may include a wire heating element arranged in a loop around the balloon envelope and connected to a strain relief connector, the strain relief connector, and an electrical cable connected to the strain relief connector. The electrical cable is configured to provide current to the wire in order to melt envelope material of the envelope and terminate a flight of the aerial vehicle.

Abstract: A high altitude or stratospheric balloon system may include a balloon envelope including envelope film, at least one tendon, and a suspender. The suspender may have a first end attached to the envelope film. The suspender is arranged to stretch such that the first end moves towards an equator of the balloon envelope as the balloon envelope pressurizes in order to control movement of the envelope film relative to the tendon and towards the equator as the balloon pressurizes.

Abstract: A fixed housing that is configured to be coupled to a balloon envelope and an impeller housing disposed within the fixed housing, wherein the impeller housing and the fixed housing form a seal in a closed position, wherein the impeller housing is moveable into the balloon envelope relative to the fixed housing in an open position, and wherein the impeller housing defines an unobstructed airflow passageway between an internal chamber in a balloon envelope and the atmosphere in the open position.

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 us 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.