Patent Publication Number: US-2021171197-A1

Title: Unmanned aircraft system with swappable components and shielded circuit board

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This patent application is a non-provisional patent application of, and claims priority to, U.S. Provisional Application No. 62/945,017 filed Dec. 6, 2019, titled “UNMANNED AIRCRAFT SYSTEM WITH SWAPPABLE COMPONENTS AND SHIELDED CIRCUIT BOARD,” the disclosure of which is hereby incorporated herein by reference in its entirety. 
    
    
     FIELD 
     The described embodiments relate generally to unmanned aerial vehicles, and more particular to unmanned aerial vehicles with swappable components. 
     BACKGROUND 
     Unmanned aerial vehicles (UAVs) are increasing in popularity for various applications. For example, UAVs are prevalent among hobbyists and enthusiasts for recreation, and are increasingly considered as viable package delivery vehicles. UAVs take many forms, such as rotorcraft (e.g., helicopters, quadrotors) as well as fixed-wing aircraft. UAVs may also be configured for different degrees of autonomy and may have varying complexity. For example, simple UAVs have only basic avionics may be controllable only by a human-operated remote control. More complex UAVs may be configured with sophisticated avionics and advanced computers, and may be configured for fully autonomous and/or semi-autonomous flight. 
     SUMMARY 
     An unmanned aerial vehicle may include a fuselage, an anchor structure coupled to the fuselage and comprising a wing retention structure and a power module retention structure, a wing releasably coupled to the wing retention structure, thereby coupling the wing to the fuselage, and a power module releasably coupled to the power module retention structure, thereby coupling the power module to the fuselage. 
     The anchor structure may include a monolithic metal frame that defines at least a portion of both the wing retention structure and the power module retention structure, the fuselage may define a cavity configured to receive the power module therein, and the monolithic metal frame may be mounted to the fuselage adjacent the cavity. The wing retention structure may include a retention pin, and the wing may include a mounting bracket defining a retention slot configured to slidably engage the retention pin. The retention pin may be a first retention pin, the power module retention structure may include a second retention pin, and the power module may be configured to slidably engage the second retention pin. The power module may be received within the cavity the power module prevents the mounting bracket of the wing from disengaging from the first retention pin. 
     The unmanned aerial vehicle may further include a circuit board attached to the anchor structure and a processor attached to the circuit board and configured to control flight operations of the unmanned aerial vehicle. The coupling between the wing and the wing retention structure may be the exclusive lift-transferring connection between the wing and the fuselage. The fuselage may include a load bearing frame and a closed-cell polymer foam body attached to the load bearing frame, and the anchor structure may be attached to the load bearing frame. 
     An unmanned aerial vehicle may include a fuselage and an integrated coupling and control unit coupled to the fuselage and comprising a frame member a circuit board coupled to the frame member, a processor attached to the circuit board, a first wing electrical connector, and a first power module electrical connector. The unmanned aerial vehicle may further include a wing comprising a second wing electrical connector configured to be removably coupled to the first wing electrical connector, and a power module comprising a second power module electrical connector configured to be removably coupled to the first power module electrical connector. 
     The wing may include a movable flight control surface and an actuator coupled to the flight control surface and configured to move the movable flight control surface, and the processor may be configured to send a signal to the actuator, via the first and second wing electrical connectors, to cause movement of the movable flight control surface. The frame member may include a wing retention structure and the wing may include a bracket configured to mechanically engage the wing retention structure. 
     The second wing electrical connector may be coupled to the wing in a fixed positional relationship to the bracket, thereby causing the first wing electrical connector to be electrically engaged with the second wing electrical connector when the bracket is at least partially mechanically engaged with the wing retention structure. The bracket may be a first bracket, the frame member may include a power module retention structure, and the power module may include a second bracket configured to mechanically engage the power module retention structure. 
     The second power module electrical connector may be coupled to the power module in a fixed positional relationship to the second bracket, thereby causing the first power module electrical connector to be electrically engaged with the second power module electrical connector when the second bracket is at least partially mechanically engaged with the power module retention structure. The power module may include a locking mechanism configured to retain the power module to the fuselage, thereby maintaining the mechanical engagement between the first bracket and the wing retention structure and between the second bracket and the power module retention structure. The locking mechanism may include a sliding cam mechanism. 
     The power module may include a handle movable between an open position and a locked position and a sliding cam coupled to the handle. The sliding cam may engage a locking pin as the handle is moved from the open position to the locked position. The wing may define a channel on a top side of the wing, the handle may be received in the channel when the handle is in the locked position, and an exposed portion of the handle and a portion of the wing adjacent the channel may define a substantially continuous exterior surface of the fuselage. 
     An unmanned aerial vehicle may include a fuselage including a substantially rigid frame and a polymer material attached to at least a portion of the substantially rigid frame to define an exterior surface of the fuselage. The unmanned aerial vehicle may also include an anchor structure attached to the fuselage via the substantially rigid frame, a wing releasably coupled to the fuselage via a mechanical engagement with the anchor structure, and a power module releasably coupled to the fuselage via a mechanical engagement with the anchor structure. The mechanical engagement between the wing and the anchor structure may be substantially the only connection for transferring lift forces from the wing to the fuselage. The anchor structure may include a wing retention structure, and the wing may include a mounting bracket configured to engage the wing retention structure by translating the wing along an installation path. When the wing and the power module are releasably coupled to the fuselage, the power module may prevent translation of the wing in a removal path that is opposite the installation path. 
     The fuselage may define a nose portion of the unmanned aerial vehicle and a cavity between the nose portion and the wing, and the power module may be received in the cavity. The unmanned aerial vehicle may include a deployable parachute coupled to the anchor structure via a cord. 
     A deployable parachute system for an unmanned aerial vehicle may include a body defining a cavity, a plunger within the cavity and dividing the cavity into a first chamber on one side of the plunger and a second chamber on a second side of the plunger opposite the first side a parachute positioned in the first chamber, and a propellant positioned in the second chamber. The propellant may be configured to expand within the first chamber to push the plunger along an ejection direction, thereby expelling the parachute from the cavity, and the plunger may be configured to remain within the cavity after the parachute has been expelled from the cavity. The propellant may include an explosive charge. The propellant may include compressed gas. 
     The body may define an opening at a first end of the body, the parachute may be expelled from the cavity through the opening, and the deployable parachute system may include a retention lip proximate the opening and configured to contact the plunger after deployment of the parachute to retain the plunger within the cavity. 
     The deployable parachute system may include a cap coupled to the body and substantially covering the opening, a first cord coupling the parachute to the cap, and a second cord configured to couple the cap to a parachute connection point of an unmanned aerial vehicle. The deployable parachute system may include a sleeve substantially surrounding the parachute, wherein the plunger is configured to expel the parachute by pushing the sleeve. 
     A battery pack for an unmanned aerial vehicle may include a body, a battery cell holder attached to the body and comprising a wall defining a first surface defining an exterior surface of the battery pack and a second surface defining an interior surface of a cavity, an electrical connector positioned at least partially within the cavity, and a battery cell positioned at least partially in the cavity and electrically connected to the electrical connector, wherein in the event of a battery cell failure the battery cell is configured to vent gasses towards the wall. 
     The first surface may define an exterior surface of an unmanned aerial vehicle. In the event of a battery cell failure, the battery cell may be configured to form an opening in the wall, through the interior surface of the cavity, thereby venting the gasses to an environment exterior to the battery pack. The wall may be formed from a polymer material configured locally fail in the event of a battery failure to allow the battery cell to form the opening in the wall. The battery cell holder may be configured to draw heat from the battery cell and transfer the heat, through the wall, to an environment exterior to the battery pack. 
     The battery pack may further include an additional battery cell holder attached to the housing and comprising an additional wall that defines a third surface defining an additional exterior surface of the battery pack and a fourth surface defining an additional interior surface of an additional cavity. The battery pack may further include an additional battery cell positioned at least partially in the additional cavity. The exterior surface may be configured to define a portion of a top surface of an unmanned aerial vehicle, and the additional exterior surface may be configured to define a portion of a bottom surface of an unmanned aerial vehicle. 
     An unmanned aerial vehicle may include a fuselage, an anchor structure coupled to the fuselage and comprising a battery pack retention structure, and a battery pack releasably coupled to the battery pack retention structure, thereby coupling the battery pack to the fuselage. The battery pack may include a battery cell holder comprising a wall defining a first surface defining at least part of an exterior surface of the unmanned aerial vehicle, and a second surface defining an interior surface of a cavity. The battery pack may also include a battery cell positioned at least partially in the cavity. The battery cell holder may be configured to draw heat from the battery cell and transfer the heat, through the wall, to air flowing along the exterior surface of the unmanned aerial vehicle during flight. In the event of a battery cell failure, the battery cell may be configured to form an opening in the wall, through the interior surface of the cavity, thereby venting gasses from the battery cell to the air flowing along the exterior surface of the unmanned aerial vehicle during flight. 
     The exterior surface of the unmanned aerial vehicle may be a top exterior surface of the unmanned aerial vehicle, and the battery pack may include an additional battery cell holder comprising an additional wall defining at least part of a bottom exterior surface of the unmanned aerial vehicle, the additional battery cell holder configured to draw heat from an additional battery cell and transfer the heat from the additional battery cell, through the additional wall, to air flowing along the bottom exterior surface of the unmanned aerial vehicle during flight. 
     An unmanned aerial vehicle may include a fuselage and an integrated coupling and control unit coupled to the fuselage and comprising a metal frame member having a cavity defined by a bottom wall and a side wall extending from the bottom wall, a circuit board coupled to the frame member, a processor attached to the circuit board and positioned at least partially within the cavity, a shielding material coupled to the circuit board, and a conductive deformable material compressed between the circuit board and the metal frame member. The conductive deformable material may be configured to form a water resistant seal between the circuit board and the metal frame member and conductively couple the metal frame member to the shielding material. The unmanned aerial vehicle may further include a wing mechanically retained to the frame member and electrically coupled to the processor. 
     The processor may be attached to a first surface of the circuit board and the shielding material may be attached to a second surface of the circuit board that is opposite the first surface. The processor may be substantially enclosed within a volume defined by the cavity, the conductive deformable material, and the circuit board. The conductive deformable material may be a polymer material with conductive particles embedded therein. The conductive deformable material may be positioned along a top side of the side wall. 
     The metal frame member may define an additional cavity, and the integrated coupling and control unit may include an additional processor attached to the circuit board and positioned at least partially within the additional cavity, wherein the additional cavity is distinct from the cavity and the additional processor is a redundant backup to the processor. 
     A system for operating an unmanned aerial vehicle may include a computer system configured to receive a service request specifying a destination site, configure an unmanned aerial vehicle to fly to the destination site, while the unmanned aerial vehicle is flying to the destination site receive route refinement information and generate updated navigation data based at least in part on the route refinement information, and send the updated navigation data to the unmanned aerial vehicle. The system may also include an unmanned aerial vehicle include a fuselage, an anchor structure coupled to the fuselage and comprising a wing retention structure, a circuit board, a wing electrical connector coupled to the circuit board, and a processor coupled to the circuit board and configured to control flight operations of the unmanned aerial vehicle. The unmanned aerial vehicle may further include a wing mechanically coupled to the wing retention structure and electrically coupled to the wing electrical connector and comprising an actuator for moving a movable flight control surface. The unmanned aerial vehicle may be configured to receive, at the processor, the updated navigation data and send a control signal, via the wing electrical connector, to the actuator to move the movable flight control surface and cause the unmanned aerial vehicle to navigate along a path defined by the updated navigation data. 
     In another example, a circuit board assembly for association with an aircraft, such as an unmanned aerial vehicle, is disclosed. The circuit board assembly includes a circuit board. The circuit board assembly further includes an electromagnetic interference component connected to the circuit board. The circuit board assembly further includes an enclosure having an electromagnetic signal permissive layer and an electromagnetic signal blocking layer. The electromagnetic signal permissive layer includes a housing that defines a volume or open space or void between the circuit board and the housing. The housing encloses the electromagnetic interference component on the circuit board. The electromagnetic signal blocking layer provides a conductive barrier about the electromagnetic interference component. 
     In another example, the electromagnetic signal permissive layer may include a thermoformed plastic substrate. The electromagnetic signal blocking layer may include a metallic layer that provides the conductive barrier. In some cases, the metallic layer may have a thickness of less than about  50  microns. Additionally, the metallic layer may have a metallic coating or metallic plating applied over the electromagnetic signal permissive layer. The metallic layer may include discontinuities, the discontinuities being shorter than a wavelength of a targeted electromagnetic signal blocked by the enclosure. The electromagnetic signal blocking layer may be structurally supported by the electromagnetic signal permissive layer. 
     In another example, the circuit board assembly may include a flange extending around a periphery of the enclosure. The flange may be configured to seat the enclosure on the circuit board. For example, the circuit board assembly may include an electromagnetic interference gasket having a conductive metallic exterior. The electromagnetic interference gasket may be configured to form a conductive bridge between the flange and the circuit board. The electromagnetic interference gasket may include a compressible foam core and a conductive pressure-sensitive adhesive along the conductive metallic exterior. 
     In another example, the circuit board assembly may include an environmental gasket having an exterior adhesive and proximal to the electromagnetic interference gasket at the periphery of the enclosure. The environmental gasket may have an environmental gasket height. Further, the electromagnetic interference gasket may have an electromagnetic interference gasket height that is greater than the environmental gasket height. In this regard, the flange may be adhered to the environmental gasket, thereby compressing the electromagnetic interference gasket and forming the conductive bridge. In some cases, the circuit board may include a metal trace that is configured to match a footprint of the flange. The metal trace may be electrically coupled to the electromagnetic signal blocking layer via the electromagnetic interference gasket to establish a common electrical potential between the electromagnetic interference component and the enclosure. 
     In another example, the circuit board assembly may further include a vent defined in the enclosure. The vent may be configured to permit air exchange between the volume and the external environment. The vent may further be configured to hinder liquid and debris from entering the volume or open space or void defined between the housing and the circuit board from the external environment. 
     In another example, a method is disclosed. The method includes providing an enclosure that defines an open space or void. The enclosure includes an electromagnetic signal permissive layer and an electromagnetic signal blocking layer. The method further includes enclosing an electromagnetic interference component on a circuit board with the enclosure. The method further includes coupling the enclosure to the circuit board to define a circuit board assembly. The method further includes attaching the circuit board assembly with a fuselage of an aircraft. The circuit board assembly may define an environmental barrier and a conductive barrier between the electromagnetic interference component and the fuselage. 
     In another example, the method may further include establishing a conductive bridge between the enclosure and the circuit board using an electromagnetic interference gasket. The electromagnetic gasket may include a conductive metallic exterior connected to the circuit board and a flange of the enclosure that extends about a periphery of the enclosure. Further, the electromagnetic interference gasket may include a foam core and a conductive pressure-sensitive adhesive along the exterior. In this regard, the coupling may further include compressing the electromagnetic interference gasket and adhering the electromagnetic interference gasket to the enclosure to the circuit board. 
     In another example, the bonding or coupling further comprises adhering an environmental gasket to the flange and the circuit board alongside the electromagnetic interference gasket at the periphery of the enclosure. The method may further include maintaining the compression of the electromagnetic interference gasket based in part on the environmental gasket having an environmental gasket height that is less than a height of the electromagnetic interference gasket. 
     In another example, the attaching or coupling may further include removably attaching the circuit board assembly to a mount structure of the aircraft using one or more standoff features. 
     In another example, an aircraft is disclosed. The aircraft includes a circuit board assembly, such as any of the circuit board assemblies described herein. The aircraft further includes a fuselage. The aircraft further includes one or more standoff features configured to removably attach the circuit board assembly to the fuselage or a mount structure housed within the fuselage. 
     In another embodiment, the aircraft further comprises the mount structure. Further, the one or more standoff features may define a ridge configured to define an offset between the circuit board and the mount structure to accommodate the enclosure therebetween. The aircraft may be an unmanned aerial vehicle. 
     In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the drawings and by study of the following description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which: 
         FIGS. 1A-1B  depict an example unmanned aerial vehicle (UAV); 
         FIGS. 2A-2B  depict side views of the UAV of  FIGS. 1A-1B ; 
         FIGS. 3A-3B  depict partial views of the UAV of  FIGS. 1A-1B , showing details of the internal structure of the UAV; 
         FIGS. 4A-4D  depict exploded views of the UAV of  FIGS. 1A-1B , showing the UAV with its wing structure and power module removed from the fuselage; 
         FIG. 5  depicts an exploded view of a portion of the UAV of  FIGS. 1A-1B , showing an anchor structure removed from a frame of the UAV; 
         FIGS. 6A-6C  depict a portion of the UAV of  FIGS. 1A-1B  at various stages of attaching the wing structure and power module to the fuselage; 
         FIGS. 7A-7C  depict a locking mechanism of a power module in various stages of engagement; 
         FIGS. 8A-8B  depict a portion of a UAV having an alternative mounting arrangement and locking mechanism for the wing structure and power module; 
         FIGS. 8C-8J  depict a portion of the UAV of  FIGS. 8A-8B  showing aspects of the mounting arrangement and locking mechanism for the wing structure and power module; 
         FIGS. 9A-9E  depict the locking mechanism of the UAV of  FIGS. 8A-8H  in various stages of engagement; 
         FIG. 10A  depicts a partial view of the engagement between a wing bracket and the anchor structure; 
         FIG. 10B  depicts a partial view of the engagement between a power module and the anchor structure; 
         FIG. 10C  depicts a partial view of the engagement between another example wing bracket and another example anchor structure; 
         FIGS. 10D-10E  depicts a partial view of the engagement between another example power module and the anchor structure of  FIG. 10C ; 
         FIG. 11A  depicts an integrated coupling and control unit; 
         FIG. 11B  depicts an exploded view of the integrated coupling and control unit of  FIG. 11A ; 
         FIG. 11C  depicts a bottom view circuit board of the integrated coupling and control unit of  FIG. 11A ; 
         FIGS. 12A-12B  depict the UAV of  FIGS. 1A-1B  during stages of parachute deployment; 
         FIG. 13  depicts a portion of the UAV of  FIGS. 1A-1B  after parachute deployment; 
         FIGS. 14A-14E  depict a deployable parachute system; 
         FIG. 15  depicts a power module for a UAV; 
         FIG. 16  depicts an exploded view of the power module of  FIG. 15 ; 
         FIGS. 17A-17B  depict partial cross-sectional views of the power module of  FIG. 15 ; 
         FIG. 18A  is a diagram illustrating the components of an unmanned aerial system (UAS) and entities that may interface with it; 
         FIG. 18B  is a diagram illustrating a UAV launch process; 
         FIG. 19A  is a diagram illustrating the components of a UAV; 
         FIG. 19B  is a diagram illustrating the process for rerouting a flight; 
         FIG. 20  is a diagram illustrating the components of a distribution center; 
         FIG. 21  is a diagram illustrating the components of the global services, according to one example embodiment; 
         FIG. 22A  depicts an example shielded circuit board assembly; 
         FIG. 22B  is a schematic cross-sectional exploded view of the shielded circuit board of  FIG. 22A  showing an electromagnetic interference gasket in an uncompressed state; 
         FIG. 22C  is a schematic cross-sectional view of the shielded circuit board assembly of  FIG. 22A  in an assembled configuration; 
         FIG. 22D  is a schematic cross-sectional view of an enclosure of the shielded circuit board assembly of  FIG. 22A ; 
         FIG. 22E  is a schematic cross-sectional view of an environmental gasket of the shielded circuit board assembly of  FIG. 22A ; 
         FIG. 22F  is a schematic cross-sectional view of an electromagnetic interference gasket of the shielded circuit board assembly of  FIG. 22A ; 
         FIG. 22G  is a detail view of a portion of the shielded circuit board assembly of  FIG. 22A ; 
         FIG. 22H  is a detail view of a circuit board of the shielded circuit board assembly of  FIG. 22A ; 
         FIG. 23A  depicts an exploded view of another example of a circuit board assembly; 
         FIG. 23B  depicts an exploded view of the circuit board assembly of  FIG. 23A  and a mounting structure; and 
         FIG. 23C  depicts an exploded view of the circuit board assembly and mounting structure of  FIG. 23B  and a fuselage; and 
         FIG. 24  depicts a flow chart for a method of assembling an aircraft, such as a UAV. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following description is not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims. 
     The embodiments described herein are generally directed to unmanned aerial vehicles (UAVs) with swappable components, and which use an integrated coupling and control unit to facilitate fast and efficient coupling and decoupling of components, while producing secure mechanical as well as electrical connections. Broadly, UAVs with swappable components may include wings and battery packs that can be securely attached to a fuselage to enable flight, but can also be removed from the fuselage quickly and easily, and without damaging the wings, battery packs, or fuselage. Using removable couplings for such components may provide numerous advantages. For example, if a wing is damaged or needs maintenance, it can be quickly and easily removed from the fuselage and repaired or replaced with another wing. As another example, swappable battery packs may allow faster turnaround between missions of a particular UAV, as spent batteries can be quickly replaced with pre-charged batteries, obviating the need to take an entire UAV out of commission to charge a more permanently affixed battery. 
     In order to maximize flight duration and payload capacity, UAVs may be designed to be as light as possible. Lightweight materials, however, may weaker than heavier materials. For example, building a fuselage largely from a polymer foam material may be lighter than one made from aluminum or other metals, but it also may be weaker or more susceptible to damage than metal. Moreover, such lightweight materials may be less capable of supporting structural connections with other components of the UAV, such as wings, battery packs (which may be up to 20%, 30%, 40% or more of the total weight of the UAV), and the like. 
     The UAVs described herein address these and other drawbacks of conventional UAV design. In particular, described is a UAV system in which a fuselage is built around an anchor structure that provides the principal load-bearing connection between the fuselage, the wings, and the battery pack. For example, an anchor structure, which may be a metal structure with retention structures (e.g., pins), is structurally attached to a lightweight fuselage. A battery pack is attached to the UAV via a releasable coupling with one of the attachment structures, and a wing is attached to the UAV via a releasable coupling with another of the attachment structures. Because the principal load-bearing connection between the wings and the fuselage and the battery and the fuselage is via the anchor structure, additional structural connections can be omitted. This may reduce the overall weight of the UAV, while also simplifying the mechanical interconnects between the components and facilitating simple, fast, and accurate coupling and decoupling of the components. 
     In addition to providing load-bearing mechanical coupling between the wing, battery pack, and fuselage, the anchor structure may provide a mount for the avionics of the UAV, including circuit boards, processors, antennas, communication circuitry, and the like. This may be a convenient location for the avionics for various reasons. For example, the wing and battery pack may couple directly to the anchor structure. When these components are removed, they may allow direct access to the avionics for inspection, repair, replacement, or the like. Further, while the anchor structure may be structurally coupled to the fuselage, it may be relatively simple to remove from the fuselage. Accordingly, an entire anchor structure can be removed as a single module to facilitate simple and efficient replacement and repair. The integration of the avionics with the anchor structure may also be designed so that the anchor structure forms part of an environmental seal and an electromagnetic shield for the avionics. Such features and benefits are described in greater detail herein. 
     Because the anchor structure carries the avionics of the UAV and also has a direct mechanical connection to the wing and the battery pack, electrical connectors may also be coupled to the anchor structure to facilitate electrical connections between the wing and the avionics, and the battery pack and the avionics. The electrical connectors may be coupled to the anchor structure such that mechanically securing the wing to the anchor structure results in a positive electrical connection between complementary electrical connectors on the wing and the anchor structure. More particularly, the mechanisms for physically attaching and retaining the wing to the anchor structure may have a high precision, self-aligning configuration that, when mated together, automatically aligns the corresponding electrical connectors with one another. A similar connection scheme may be used for electrically connecting the battery pack to the anchor structure. This allows both mechanical and electrical connections to be formed between the wing and fuselage (and battery pack and fuselage) with a single coupling process, further reducing the time and complexity of what would otherwise be a complicated and time-consuming process. Other types of connectors between the anchor structure and the battery pack or wing may also be included, such as to connect coolant tubes or other fluid conduits together. For example, a battery pack or a wing may have a heat exchanger, and fluid conduits may be used to draw heat from electrical or other components on the anchor structure to the heat exchanger. 
     The mechanisms for coupling the wing and battery pack to the anchor structure may be designed and manufactured with high precision and accuracy, thus facilitating highly accurate and repeatable alignment between all components, connectors, and the like. Further, such high-precision design and construction improves the interchangeability of the various components, allowing different battery packs, wings, and fuselages to be combined to produce a single UAV. Additionally, the high-precision design and construction reduces sloppy fitments between components that may contribute to vibrations, oscillations, rattles, or other phenomena that may be detrimental to the operation of a UAV (e.g., by causing unstable flight, unexpected detachment of components, or the like). 
     The anchor structure may act as a load-bearing structure for other components of the UAV as well. For example, UAVs as described herein may be fitted with parachutes for controlling the descent of the UAV in the event of a malfunction, a loss of power, or to otherwise produce a substantially controlled landing of the UAV. It may not be feasible to attach parachutes to the lightweight materials of a UAV fuselage, however, as they may not be suitable for or capable of supporting the weight of the entire UAV during a parachuting descent. Accordingly, a parachute may be attached to the anchor structure, which, as a load-bearing connection point to the fuselage, is capable of supporting the entire UAV via the parachute. 
     The combination of the anchor structure, the avionics, and the electrical connectors (as well as other possible components) may be referred to herein as an integrated coupling and control unit. As set forth above and described in greater detail herein, the integrated coupling and control unit provides numerous structural and electrical connections between components of a UAV. Additional features, benefits, and details of the integrated coupling and control unit are also described herein, along with additional details of UAVs that may be used alone or in conjunction with an integrated coupling and control unit. 
       FIGS. 1A-1B  depict an example UAV  100 . The UAV  100  may include a fuselage  102 , a wing structure  104 , a tail section  106 , and a motor module  108 . As described in greater detail herein, the fuselage  102  may be formed from a substantially rigid load bearing frame and a polymer foam body that at least partially encapsulates the frame. The fuselage  102  may also have a shape that provides lift to the UAV during flight, in addition to the wing structure  104 . (As used herein, flight may refer to sustained flight operations as well as takeoff and landing operations.) 
     The wing structure  104  may provide lift to the UAV during flight, and may be releasably coupled to the fuselage  102 . The wing structure  104  may be part of a single, integrated structure that includes a first wing segment  110  on one side of the fuselage  102 , a second wing segment  112  on an opposite side of the fuselage, and a central section  114  between and joining the first and second segments  110 ,  112 . As described herein, the wing structure  104  may be releasably coupled to the fuselage  102  via an integrated coupling and control unit. While the example in the current figures shows a single structure that includes two wing segments (or wings), in other examples a wing structure may include separate structures or components that are each releasably coupled to the integrated coupling and control unit. 
     The wing structure  104  may include movable flight control surfaces  116 , which may be or may resemble flaps. The flight control surfaces  116  may be configured to move to control and/or change the attitude of the UAV in flight (e.g., to change the pitch and/or roll of the UAV  100 ). The flight control surfaces  116  may be coupled to cause the movable flight control surfaces  116  to move to control the UAV  100 . More particularly, the avionics of the UAV  100  may send signals to the actuators that cause the actuators to move the flight control surfaces  116  in a particular way. The actuators may be or may include any suitable actuator or actuation technology, including servos, electric motors, hydraulic actuators, pneumatic actuators, piezoelectric actuators, or the like. The actuators may be mechanically coupled to the flight control surfaces  116  in any suitable way, including via linkages, push rods, cables, or the like. As described herein, the actuators may be electrically coupled to the avionics of the UAV  100  via a releasable electrical connection between the wing structure  104  and the integrated coupling and control unit. 
     The UAV may also include a power module  122  that is attached to the fuselage. The power module  122  may provide power and/or fuel for the UAV  100 . For example, the power module  122  may be or may include a battery pack that provides electrical power for the avionics and optionally any electric motors and/or other components on the UAV  100 . In cases where a UAV includes internal combustion motors for propulsion, the power module  122  may also or instead include a fuel tank or other fuel storage system. The power module  122  may also or instead include a capacitor or group of capacitors, fuel cell, or any other suitable fuel and/or power (e.g., electrical power) storage unit. The power module  122 , which may be removable from the fuselage  102  to facilitate easy swapping, may also define exterior surfaces  126  ( FIG. 1A ) and  128  ( FIG. 1B ) of the UAV  100 . As described herein, these exterior surfaces may provide various functionality, including acting as a heat exchanger (e.g., a heat sink) for batteries inside the power module  122 , and providing a sacrificial component in the event of a battery cell failure. Like the wing structure  104 , the power module  122  may be removably attached to the fuselage  102  via a releasable coupling with an integrated coupling and control unit. 
     The tail section  106  may also include movable flight control surfaces  118  that may move to control the attitude of the UAV  100  during flight. The movable flight control surfaces  118  are also moved by actuators, which may be similar to the actuators that move the flight control surfaces  116  of the wing structure  104 . The tail section  106  may be attached to the fuselage  102  via a tail support  107  that may be attached to an internal load bearing frame of the fuselage  102 . The tail support  107  may have a hollow interior channel that carries wires for electrically connecting the actuators and/or other tail-mounted electronics to the avionics of the UAV  100 . 
     The motor module  108  may include one or more motors for propelling the UAV  100  during flight. As shown, the motor module  108  includes two propellers, which are configured to act in concert to propel the UAV  100 . In other cases, more or fewer propellers may be used. Moreover, while the instant UAV  100  is described as using one or more electric motors and propellers for propulsion, other types of propulsion may also be used, including internal combustion motors with propellers, turbines, rockets (e.g., solid and/or liquid fuel rocket motors), or the like. Further, while the motor module  108  is shown positioned at a particular location on the UAV  100 , the motor module  108  may be positioned elsewhere, such as at a nose of the fuselage  102 , the wings, the tail (or any other suitable location). 
     As shown in  FIG. 1B , the UAV  100  may also include doors  124 . The doors  124  may be configured to open and close to allow access to an internal cargo bay. For example, the doors  124  may be opened (e.g., by actuators within the UAV  100  and attached to the doors  124 ) to allow a payload to be placed within the cargo bay. During flight, the doors  124  may be closed to contain the payload within the cargo bay. In order to deliver the payload to an intended recipient or location, the doors  124  may be opened, during flight, and the payload may be dropped to the ground. The payload may be attached to a parachute or other descent-controlling component so that the payload reaches the ground safely, and optionally to direct the payload to a particular location. The payload may be any suitable payload. For example, the payload may include medical supplies, pharmaceuticals, mail, blood for blood transfusions, or the like. In one embodiment the payload doors  124  may open to expose a fixed payload such as a camera, LIDAR, RADAR, or other instrument. The payload doors  124  can be opened for a portion of a flight so that the instrument can operate and then closed to protect the instrument for the remainder of the flight. 
     The UAV  100  may also include a capture hook  120 . The capture hook  120  may be attached to the UAV  100  via the tail support  107  or via any other suitable attachment point. The capture hook  120  may be used at the end of flight to engage a capture line of a UAV retrieval system. For example, the UAV  100  may be flown at or near a capture line that is positioned above the ground. The capture line may slow the UAV  100  to a complete stop and lower the UAV  100  to the ground after for safe retrieval. The capture hook  120  may be configured to pivot, extend, or otherwise move from a first (e.g., stowed) position to a capture (e.g., deployed) position prior to engaging a capture line. The capture hook  120  may be deployed in response to a signal, which may be based on a location of the UAV. In some cases, the UAV itself may generate the signal (e.g., based on a proximity to a retrieval system as determined by the UAV), or it may be sent from a retrieval system to the UAV. The capture hook  120  may be used in conjunction with a retrieval system such as that described in U.S. patent application Ser. No. 15/712,107, entitled “Automated Recovery System for Unmanned Aircraft,” which is incorporated by reference herein in its entirety. In some cases, instead of or in addition to the capture hook  120 , the UAV may include landing gears, wheels, or other landing systems or components. 
     The UAV  100  may also include a parachute access panel  130  that may cover a deployable parachute system. The parachute access panel  130  may be removed when the parachute is deployed. More particularly, in cases a deployable parachute system uses a propellant (e.g., an explosive charge) to rapidly deploy a parachute. The deploying parachute may force open the parachute access panel  130  to allow the parachute to exit the fuselage  102  and begin slowing the descent of the UAV  100 . 
       FIGS. 2A and 2B  depict side views of the UAV  100 , with  FIG. 2A  showing a representation of the UAV  100  during level flight (e.g., with an angle of attack of approximately zero), and  FIG. 2B  showing a representation of the UAV  100  at an increased angle of attack. Example airflow is shown by arrows  202  ( FIG. 2A ) and  204  ( FIG. 2B ). As shown in  FIG. 2A , the fuselage  102  may have a substantially symmetrical side cross-section. Accordingly, during level flight, the UAV  100  may rely substantially entirely on the wing structure  104  to provide lift to the UAV  100 , as the symmetrical shape of the fuselage  102  may result in little additional lift. 
     As shown in  FIG. 2B , when the angle of attack of the UAV  100  is increased, the fuselage  102  may generate lift (represented by arrow  206 ) that helps maintain the UAV  100  aloft during flight. Further, the increased lift may decrease the stall speed of the UAV  100 , allowing the UAV  100  to stay aloft at lower speeds. This may be particularly useful during low-speed maneuvers that may be critical to the success of UAV missions. For example, in order to accurately and safely deliver cargo to a particular location by dropping the cargo from the air, it may be particularly beneficial for the UAV  100  be able to maintain lift at as low a speed as possible. The shape of the fuselage  102  may allow the UAV  100  to decrease its stall speed (and thus fly at a lower speed) prior to and during a cargo delivery portion of a mission by simply changing its angle of attack. The UAV  100  may also decrease its stall speed at other times during a mission, such as prior to and during takeoff and/or landing. 
     Because the fuselage  102  is symmetrical, it may not generate substantial lift during level flight. This may make level flight more efficient, as lift-induced drag may be reduced or eliminated. At the same time, lift may be increased selectively by changing the angle of attack of the UAV  100 , as described above. Accordingly, the symmetrical wing shape of the fuselage  102  provides additional lift to the UAV  100  when it is needed, without adding substantial lift-induced drag during level flight. 
       FIGS. 2A-2B  also illustrate how the exterior surfaces  126 ,  128 , which may be defined by a part of a removable power module and/or battery pack, are positioned in the airflow that flows over the fuselage  102  when the UAV  100  is in flight. As described herein, these surfaces may be heat sink surfaces that are thermally coupled to heat-generating components within the fuselage  102 , such as battery cells. The airflow over the surfaces  126 ,  128  during flight may aid in removing heat from the power module. Further, in cases where the power module is configured to vent the gasses of failed battery cells through the surfaces  126 ,  128 , the vented gasses may be directed directly into the airflow. This may prevent and/or reduce the likelihood of the escaping gasses from damaging other battery cells or other portions of the UAV  100 . 
     UAVs in accordance with the concepts described herein may be formed using any suitable constructions. In some cases, UAVs—and in particular the fuselage of UAVs—may include a load bearing frame that is at least partially encapsulated and/or surrounded by a foam outer shell or body. The load bearing frame may be the main structural portion of the UAV, while the foam body may define the overall shape of the UAV and/or the fuselage. 
       FIG. 3A  is a partial top view of a portion of the UAV  100 , and  FIG. 3B  is a partial perspective view of a portion of the UAV  100 . In  FIGS. 3A-3B , the UAV  100  is shown with the motor module  108  and the wing structure  104  removed. The UAV  100  may include a frame  300  that is at least partially encapsulated by a body  301 . The frame  300  may be a rigid load-bearing frame that is configured to act as the primary structural member for the UAV  100 . For example, the wing structure  104  and the tail support  107  may be structurally attached to the frame  300  to allow forces from the wing structure  104  and the tail section  106  (e.g., lift and other flight-control forces) to be transferred to the fuselage  102 . 
     The frame  300  may include multiple struts, walls, plates, rods, and/or other structural members, that are secured to one another to form a substantially rigid structure. The structural members of the frame  300  may be secured to one another in any suitable manner, including fasteners (e.g., screws, bolts, rivets, etc.), adhesives, welding, brazing, soldering, or the like. The frame  300  may be formed from or include any suitable material, such as carbon fiber, fiberglass, metal (e.g., aluminum, titanium, etc.), plastics, or any other suitable material (or combination of materials). 
     The frame  300  may also be configured to interface with other structures and/or components of the UAV  100 . For example, as described herein, the UAV  100  may have an integrated coupling and control unit that provides a quick-release style coupling between the wing structure  104  and the fuselage  102  and between the power module  122  and the fuselage  102 . The integrated coupling and control unit may include an anchor structure that defines the retention structures to which the wing structure  104  and the power module  122  are coupled, and through which the loads from the wing structure  104  and the power module  122  are transferred to the rest of the UAV  100 . Accordingly, the frame  300  may include an anchor support member  302 . The anchor support member  302  may be configured to receive and securely attach the anchor structure to the frame  300 . For example, the anchor structure may be secured to the anchor support member  302  via fasteners, adhesives, or any other suitable attachment technique. 
     The body  301  of the fuselage may be attached to the frame  300  to define the outer shape of the fuselage  102 . The body  301  may be formed from or include any suitable material, such as a polymer foam material (e.g., expanded polystyrene or any other suitable open-cell or closed-cell polymer foam), wood (e.g., balsa wood), or the like. The body  301  may be attached to the frame  300  in any suitable way. For example, in cases where a polymer foam is used, the frame  300  may be placed into a mold, and the polymer foam (or a precursor material of a polymer foam) may be introduced into the mold and around the frame  300 . When expanded, the polymer foam may at least partially encapsulate the frame  300 . The encapsulation of the frame  300  by the foam may structurally secure the frame  300  and the foam, thus producing a structurally sound fuselage. 
     The body  301  may be attached in other manners as well. For example, one or more body panels may be retained to the frame  300  using fasteners, elastic members, interlocking structures (on either or both the frame  300  and the body panels), or the like. In some cases, the body  301 , and/or individual body panels that make up the body  301 , may be configured to detach from the frame  300  in the event of an impact such as may occur during a hard landing or a crash event. In such cases, the detachment of the body panels may distribute impact forces and prevent, limit, or reduce the likelihood of damage to the frame  300 . The panels defining the body  301  may be configured with quick-release style fasteners (e.g., elastic members, non-permanent fasteners, interference fit fasteners, etc.) for easy removal and replacement without damaging the panels or the frame  300 . 
     The body  301  also defines a cavity  304  between a nose portion of the UAV  100  and the wing structure  104  that is configured to receive the power module  122 . The cavity  304  and the power module  122  may be shaped so that when the power module  122  is received in the cavity  304 , exterior surfaces  126 ,  128  of the power module  122  form exterior surfaces of the fuselage  102 . Accordingly, the cavity  304  may extend completely through the fuselage  102  to define a first opening in a top surface of the fuselage  102  and a second opening in a bottom surface of the fuselage  102 . 
     The cavity  304  may be adjacent the anchor support member  302 . In particular, because the anchor support member  302  is configured to receive an anchor structure, the placement of the cavity  304  allows the power module  122  to easily mechanically and electrically couple to the anchor structure, as described herein. 
     The internal walls of the cavity  304  may be defined by portions of the frame  300 , and may include guiding mechanisms  308  that engage with corresponding guiding mechanisms on the power module  122  to facilitate proper alignment between the power module  122  and the frame  300  (and thus the anchor structure) when the power module  122  is inserted into the cavity  304 . The guiding mechanisms  308  are shown in  FIG. 3A  as channels that receive corresponding features (e.g., protrusions, pins, fins, tabs, etc.) on the power module, though other guiding mechanisms may be used, or the positions of the guiding mechanisms may be swapped. 
     The portions of the frame  300  that define the cavity  304  may also include load bearing features (e.g., the top edges of the frame portions that define the cavity  304 ) on which a portion of the power module  122  may rest when the power module  122  is in the cavity. By allowing a portion of the power module  122  to contact and/or rest on the load bearing features, some of the weight of the power module  122  can be transferred to the frame  300  via the walls of the cavity  304 , rather than through the anchor structure (to which the power module  122  is otherwise mechanically and electrically coupled, as described herein). 
     The body  301  also defines a wing channel  306 . The wing channel  306  is a channel that receives a portion of a wing structure  104 . The wing channel  306  may be positioned over the anchor support member  302  to allow the wing structure  104  access to the anchor structure (which may be mounted on the anchor support member  302 ) to mechanically and electrically couple to the anchor structure, as described herein. 
       FIGS. 4A-4D  depict the UAV  100  with the power module  122  and the wing structure  104  removed from the fuselage  102 . With the wing structure  104  and the power module  122  removed, an anchor structure  400  can be seen attached to the frame  300  of the UAV  100 . The anchor structure  400  may be a load-bearing component of an integrated coupling and control unit  401 , described in greater detail herein. 
     As noted above, the wing structure  104  and the power module  122  are releasably coupled to the UAV  100  via the anchor structure  400 . In particular, and as shown in greater detail herein, the anchor structure includes wing retention structures and power module retention structures. The wing structure  104  and the power module  122  include complementary retention structures that engage with the wing and power module retention structures and form a load bearing connection between the anchor structure and both the wing structure  104  and the power module  122 . 
     The power module  122  may be configured to assist in maintaining the wing structure  104  in engagement with the anchor structure  400 . For example, as shown in  FIGS. 4A-4D , a process of releasably securing the wing structure  104  and the power module  122  to the fuselage  102  may include first attaching the wing structure  104  to the UAV  100  by engaging retention structures of the wing structure  104  (e.g., a mounting bracket, as described herein) to the anchor structure  400 . As shown by the dotted lines in  FIGS. 4A-4C , this may include sliding the wing structure  104  aft, or towards the tail of the UAV  100 , which may cause the retention structures of the wing structure  104  to slidably engage with wing retention structures on the anchor structure  400 . The coupling between the retention structures of the wing structure  104  and the anchor structure  400  may represent the exclusive lift-transferring mechanical connection between the wing structure  104  and the fuselage. More particularly, the fuselage  102  and the wing structure  104  may not have any other engaging features that provide sufficient strength to hold the wing structure  104  to the fuselage  102  to enable sustained flight. Because it may be the exclusive (and sufficient) lift-transferring connection, attachment of the wing structure  104  to the fuselage  102  is ultimately extremely simple and efficient, as only one connection action is required in order to mechanically (and electrically and optionally fluidically) connect the wing structure  104  to the fuselage  102 . 
     Subsequent to attaching the wing structure  104  to the UAV  100 , the power module  122  may be inserted into the cavity  304  in such a way that retention structures on the power module  122  engage with power module retention structures on the anchor structure  400 . The weight of the power module  122  may be transferred to the UAV  100  via the anchor structure  400  and optionally additional load bearing structures or interfaces between the power module  122  and the frame  300  of the UAV  100 . 
     The power module  122  may be configured so that when it is positioned in the cavity  304  and engaged with the anchor structure  400 , the power module  122  prevents the wing structure  104  from disengaging from the anchor structure  400 . For example, a portion of the power module  122  may be positioned in a removal path of the wing structure  104 , thereby preventing the wing structure  104  from moving in a removal direction (e.g., forward, or towards the nose of the UAV) and becoming disengaged or decoupled from the anchor structure  400 . In some cases, as described in greater detail below, an interfacing side  402  of the power module  122  may be positioned adjacent a corresponding interfacing side  404  of the wing structure  104  and may impart a force (in the aft direction, or towards the tail of the UAV) to the corresponding interfacing side  404  of the wing structure. The force imparted on the wing structure  104  by the interfacing side  402  may bias the wing structure  104  in the aft direction, or otherwise prevent disengagement of the retention structures of the wing structure  104  and the anchor structure  400 . 
     The power module  122  may include a locking mechanism that is configured to securely retain the power module  122  to the fuselage. The locking mechanism may include any suitable mechanism that can retain the power module  122  in place during flight. For example, latches, cams, pins, detents, clips, spring-loaded mechanisms, or the like. Several example locking mechanisms are described in greater detail herein with respect to  FIGS. 6A-7C and 8A-9E . In some cases, the power module  122  includes a handle  406  that is movable between an open position (shown in  FIGS. 4A-4C ) and a locked or flight position (shown in  FIG. 1A ). The handle  406  may be attached to or may include a portion of the locking mechanism. When the handle  406  is rotated, it may cause the locking mechanism to engage to lock the power module  122  to the UAV  100 . For example, when the handle  406  is in an open position, the locking mechanism may be disengaged and the power module  122  may be removed or inserted into the cavity  304 . As shown, the open position of the handle corresponds to the handle  406  being in a convenient position to allow the power module  122  to be lifted into or out of the cavity  304 . When the handle  406  is in the closed or flight position (as shown in  FIG. 1A ), the locking mechanism is engaged or locked, thereby securing the power module  122  to the UAV  100 . 
     As described above, the process of installing and/or removing the wing structure  104  and the power module  122  to the fuselage  102  is an efficient and simple process, and requires few steps. For example, assembling these components may include sliding the wing structure  104  onto the anchor structure  400 , inserting the power module  122  into the cavity  304 , and engaging a locking mechanism to lock the power module  122  and/or the wing structure  104  to the UAV  100 . The locking mechanism thus provides sufficient mechanical security to both the power module  122  and the wing structure  104  to secure these components to the fuselage  102  during flight, while also allowing fast and efficient attachment and removal of the components. 
     In addition to allowing quick and efficient attachment and removal, the UAV  100  is configured so that the mechanical attachment and removal of the wing structure  104  and the power module  122  also causes electrical connectors that are coupled to the anchor structure  400 , the power module  122 , and the wing structure  104  to positively engage with one another, thereby forming a path through which electrical signals may be passed between the wing structure  104 , power module  122 , and circuitry and other components that are coupled to the anchor structure  400 . Such signals may include digital and/or analog communication signals as well as electrical power to provide energy to circuitry, servos, motors, or any other electrical component of the UAV  100 . The electrical connections between the anchor structure  400  (or more particularly to electrical components that are coupled to the anchor structure) and the power module  122  and wing structure  104  may be created as a direct result of the mechanical attachment of the power module  122  and the wing structure  104  to the anchor structure  400 , thus obviating the need to take additional steps to electrically connect components in the wing structure  104  and/or in the power module  122  to the UAV  100  (such as separately electrically connecting cables or wires between such components). 
       FIGS. 4C and 4D  illustrate additional details of an example configuration of electrical connectors on the anchor structure  400 . For example, wing electrical connectors  412  may be coupled to the anchor structure  400 , and may be configured to mechanically mate and thus electrically couple to corresponding electrical connectors on the wing structure  104 . The wing electrical connectors  412  and the corresponding electrical connectors on the wing structure  104  may be positioned relative to the mechanical retention structures so that when the wing structure  104  is being mechanically engaged with the anchor structure  400 , the wing electrical connectors  412  are aligned with the corresponding electrical connectors on the wing structure  104 . Accordingly, the mechanical attachment of the wing structure  104  to the anchor structure  400  results in a positive mate between the electrical connectors, thus forming both a mechanical and an electrical coupling to the wing structure  104 . Proper alignment between the electrical connectors when the wing structure  104  is being mechanically engaged with the anchor structure  400  may be ensured by having the electrical connectors in a fixed positional relationship with respect to the mechanical retention structures, as shown and described herein. In particular, because each of the electrical connectors on the anchor structure  400  is in a fixed positional relationship with respect to the retention structures (e.g., they are not free to move substantially relative to one another), and because the corresponding the connectors and retention structures on the wing structure  104  are similarly fixed, engagement of the mechanical retention structures may cause the electrical engagement of the electrical connectors. 
     The anchor structure  400  may also include (or have coupled thereto) power module electrical connectors  414  that are configured to electrically mate with corresponding electrical connectors on the power module  122 . The power module electrical connectors  414  may also be in a fixed positional relationship with respect to mechanical retention structures for the power module  122  and the anchor structure  400 , thus allowing a positive electrical coupling between the power module  122  and the components attached to the anchor structure  400  as a result of a mechanical coupling between the components. The power module electrical connectors  414  may be positioned on the anchor structure  400  so that they are exposed when the wing structure  104  is coupled to the fuselage, which allows the power module  122  to couple with them after the wing structure  104  has been attached. The power module electrical connectors  414  may be configured to transfer electrical power from the power module  122  (e.g., from batteries, fuel cells, capacitors, or other energy storage components) to electrical components of the anchor structure  400 . Such power may be used to provide energy to the propulsion system of the UAV  100  (e.g., electric motors), to avionics (e.g., processors, GPS systems, radios, etc.), flight control hardware (e.g., servos and/or other motors for moving flight control surfaces), and the like. The power module electrical connectors  414  may also be configured to transfer electrical signals between the power module  122  and electrical components coupled to the anchor structure  400 . Such electrical signals may be intended for communication between components rather than to provide motive power to the propulsion motors or flight control components. In some cases, there may be separate electrical connectors for power and for communications, and both types of connectors may be physically configured to facilitate engagement in the manner described above. 
     As noted above and described herein, the electrical connectors for the power module and the wing structure may not require direct manual manipulation in order to form the electrical connections. Moreover, the connectors may not be visible or accessible by a user&#39;s fingers once the wing structure  104  and the power module  122  begin to be coupled to the anchor structure  400 . Accordingly, the physical positioning of the connectors may be specifically configured to facilitate positive mating despite the lack of visibility or physical access by a user. More particularly, because each of the power module electrical connectors on the anchor structure  400  is in a fixed positional relationship with respect to the power module retention structures (e.g., they are not free to move substantially relative to one another), and because the corresponding the connectors and retention structures on the power module  122  are similarly fixed, engagement of the mechanical retention structures may cause the electrical engagement of the electrical connectors. 
     While the wing electrical connectors  412  and the power module electrical connectors  414  are described as being in a fixed positional relationship with respect to mechanical retention structures, the wing and power module electrical connectors  412 ,  414  may be configured to have some float so that small-scale misalignments between the wing and power module electrical connectors  412 ,  414  and corresponding connectors can be tolerated. The degree of float may be configured so that when the mechanical retention structures are correctly engaged, the electrical connectors cannot become misaligned significantly enough to damage the electrical connectors or otherwise not correctly engage each other. Thus, the float may be primarily for accommodating small misalignments due to component wear, manufacturing tolerances, or the like, and may not be significant enough to allow the electrical connectors to improperly couple if the mechanical retention structures are aligned. Further, each electrical connector may be configured to float independently of other electrical connectors, thus being more accommodating of slight misalignments between the electrical connectors. It will be understood that the floating configuration of the electrical connectors described herein is not inconsistent with the otherwise fixed positional relationship between the electrical connectors and the mechanical retention structures. 
     While the instant application refers in many cases to electrical connectors, other types of connectors may be used instead of or in addition to electrical connectors, such as optical connectors, fluidic connections (e.g., to deliver liquid or gaseous fuel to a propulsion system), or the like. For example, if a UAV includes an internal combustion engine, the power module may include fuel tanks that can be fluidly coupled to the UAV via releasable fluidic connections between the power module and the UAV. The releasable fluidic connections (as well as any other types of connectors) may operate in substantially the same way as the connectors described herein. 
     As noted above, the power module  122  may include a handle  406 . As shown in  FIG. 4D , the wing structure  104  may include or define a channel  408  on a top side of the wing structure  104  that is configured to receive the handle when the handle is in the locked or “flight” position. The channel  408  and the handle  406  may be configured so that when the handle  406  is in the channel  408 , an exposed portion of the handle  406  (e.g., a top surface of the handle  406 ) is substantially flush with adjacent portions of the fuselage  102  and/or the wing structure  104  (e.g., the top surface of the handle and an adjacent surface of the fuselage  102  and/or the wing structure  104  may define a substantially continuous exterior surface). In this way, undesirable aerodynamic drag on the UAV  100  from the handle  406  may be avoided or minimized during flight. 
     The channel  408  may also be configured to divert water or other liquids or debris generally away from the anchor structure  400  (and/or away from certain components that are coupled to the anchor structure  400 , such as circuit boards, processors, electrical connectors, etc.). An example water flow path defined by the channel  408  is shown by path  410  in  FIG. 4D . Water and other debris may be encountered by the UAV  100  during flight due to precipitation, condensation, or the like. 
       FIG. 5  shows the anchor structure  400  removed from the frame  300 , with electrical components (e.g., circuit boards, electrical connectors, processors, etc.) removed from the anchor structure  400 .  FIG. 5  shows examples of the wing and power module retention structures. In particular, in the example shown in  FIG. 5 , the anchor structure  400  includes wing retention structures  502  and power module retention structures  504  that are or include retention pins (or any other suitable retention protrusion). The retention pins (or protrusions) may be configured to slidably or otherwise mechanically engage with corresponding retention structures on the wing structure  104  and the power module  122 . In some cases, the retention structures may be swapped so that the retention structures  502  and/or  504  are slots, guides, channels, or the like, and the pins (or tabs, guides, protrusions, or other complementary mating structures) are coupled to or otherwise integrated with the wing structure  104  and/or the power module  122 . Other retention structures are also contemplated, including ball bearing guides, latches, detents, spring-loaded connectors, clips, or the like. 
     The retention structures  502 ,  504  may be formed or coupled to the anchor structure in any suitable manner. For example, in some cases the retention structures  502 ,  504  (including any pins, protrusions, tabs, fins, or the like) are machined or otherwise formed from a single piece of metal (e.g., forming a monolithic anchor structure  400 ). Where the retention structures include protrusions (such as the pins shown in  FIG. 5 ), the protrusions may be separate components that are coupled to a base of the anchor structure  400 . In such cases, the protrusions or pins may be configured as sacrificial components that are designed to break under a certain load or stress. For example, the protrusions may be configured to be the first point of failure in the event of a crash or other potentially damaging impact or force being applied to the UAV  100 . Thus, in the event of a crash or other potentially damaging impact, the wing structure  104  and/or the power module  122  may break the protrusions, resulting in the decoupling of the wing structure  104  and/or the power module  122  from the anchor structure  400 . This may help prevent other damage to the anchor structure  400  and/or the UAV  100  that may be more difficult or expensive to repair. The protrusions may be replaceable to facilitate quick and efficient repair of a UAV  100  with damaged or broken protrusions. For example, the protrusions may be threaded, interference fit, or otherwise secured using removable fastening techniques (or fasteners) to allow for easy replacement separate from the larger base portion of the anchor structure  400 . As noted, the protrusions of the retention structures are shown as retention pins, though other types of protrusions may be used instead or in addition to pins, such as fins, tabs, rounded bumps, etc. Moreover, while the retention pins are shown as cylindrical pins, other shapes are also possible (e.g., oblong pins, square pins, rectangular pins, etc.). 
       FIGS. 6A-6C  depict a portion of the UAV  100  at various stages of attaching the wing structure  104  and the power module  122  to the fuselage  102 . Some components of the UAV  100  are omitted in order to avoid obscuring certain aspects of the UAV  100 .  FIG. 6A  shows the UAV  100  at a state prior to the wing structure  104  and the power module  122  being coupled to the fuselage  102 . A mounting bracket  600  (which may be part of the wing structure  104 , which is largely omitted from  FIGS. 6A-6C  for clarity) is positioned above the anchor structure  400 . The mounting bracket  600  (referred to herein as a bracket) may include retention structures  602  that are configured to engage the retention structures  502  on the anchor structure  400 .  FIGS. 6A-6C  show the complementary retention structures  602  as retention slots, though this is merely one example retention structure that may be used for the wing structure  104 . Moreover, the retention structures  602  are shown as being located on a bracket  600  (of which there may be multiple for a given wing structure), though in other cases the retention structures  602  may be formed or otherwise incorporated with other components or structures of the wing structure  104 . Further, other bracket configurations other than that shown in  FIGS. 6A-6C  may be used. 
     As shown in  FIGS. 6A-6B , the wing structure  104  may be releasably coupled to the anchor structure  400  by engaging the retention structures  602  with the retention structures  502 . As shown in the instant figures, the retention structures are engaged by translating the wing structure  104  in an aft direction (e.g., along an installation path) to cause the pins and slots to slidably engage one another. In other examples, the installation path may be different than that shown, and it may depend at least in part on the type, shape, and/or configuration of the retention structures of the anchor structure  400  and the wing structure  104 . For example, the retention structures may be engaged by translating the wing structure  104  downwards (relative to the orientation shown in  FIGS. 6A-6C ), or diagonally, or along any other path that results in engagement of the retention structures. 
     After the wing structure  104  has been releasably coupled to the anchor structure  400  via the wing retention structures  502 , the power module  122  may be inserted into the cavity  304  and releasably coupled to the anchor structure  400  via the power module retention structure  504 . The power module  122  may include a complementary retention structure  604  that slidably or otherwise engages the power module retention structure  504 . The mass of the power module  122  may be transferred to the anchor structure  400  (and thus the UAV  100  as a whole) via the complementary retention structures  504 ,  604 . In some cases, as noted above, the power module  122  may also contact a portion of the frame  300  of the UAV  100 , thus transferring at least a portion of the mass load of the power module  122  to the UAV  100  via the frame  300 . 
     As shown in  FIGS. 6B-6C , when the power module  122  is within the cavity  304 , the interfacing side  402  of the power module  122  is in contact with (or otherwise positioned adjacent to) the corresponding interfacing side  404  of the wing structure  104 . Because the interfacing side  402  of the power module  122  is blocking the wing structure  104  from moving in the foreword direction (left, as shown in  FIGS. 6A-6C ), the wing structure  104  cannot be disengaged from the anchor structure  400  along the designed removal path when the power module  122  is installed (e.g., the power module  122  prevents the retention structures of the wing and anchor structures from disengaging one another). 
     As represented by  FIGS. 6B-6C , after the power module  122  is inserted into the cavity  304  and engaged with the anchor structure  400 , the power module  122  (and optionally the wing structure  104 ) may be locked to the fuselage  102 .  FIGS. 6A-6C  show an example embodiment in which a locking mechanism  606  is integrated with and/or actuated by the handle  406  of the power module  122 . In particular, as discussed in greater detail with respect to  FIGS. 7A-7C , the locking mechanism  606  may be or may include a sliding cam mechanism that secures the power module  122  to the UAV  100  when the handle  406  is rotated or moved into the flight or locked position. The locking mechanism  606  may provide sufficient force to maintain the handle  406  in the flight or locked position during flight, and also to securely hold the power module  122  (and the wing structure  104 ) to the anchor structure  400 . The locking mechanism  606 , in conjunction with the design of the retention structures on the wing structure  104 , the power module  122 , and the anchor structure  400 , may also provide sufficient locking and/or biasing forces to prevent or reduce vibration, rattling, or other undesirable movement between the wing structure, power module, and anchor structure. 
       FIGS. 7A-7C  depict the locking mechanism  606  that secures the power module  122  (and by extension the wing structure  104 ) to the UAV  100 , showing the locking mechanism  606  at different states of engagement. While the locking mechanisms  606  is one particular type of locking mechanism, others are also possible and contemplated. For example,  FIGS. 8A-9E  illustrate another example locking mechanism that may be used instead of or in addition to the locking mechanism  606 . 
     The locking mechanism  606  includes a body  700  that includes a channel  702 . The channel  702  may be a machined or forged feature of the body  700 , or it may be formed in any other suitable way. The body  700  may be coupled to the handle  406  such that rotation of the handle  406  results in rotation of the body  700  about a pivot  703 . The pivot  703  may be coupled to the power module  122 . 
       FIG. 7A  shows the locking mechanism  606  prior to engagement with a locking pin  704 . The locking pin  704  may be attached to or otherwise integrated with the UAV  100 , such as via the frame  300 . As the power module  122  is inserted into the cavity  304  while the handle  406  is in an open configuration (as represented by the configurations in  FIGS. 6B and 7A ), the locking pin  704  enters the channel  702 . As the handle  406  (or any other member or component that may be actuated by a user to rotate the body  700 ) is rotated about the pivot  703 , as represented by arrow  701  in  FIG. 7B , the pin  704  slides along the channel  702 . As it slides, the pin  704  may contact one or both sides of the channel  702 , which may apply a force that draws the power module  122  downward (e.g., into the cavity  304  and into a flight-ready position). Further, the channel  702  may be configured as a sliding cam so that as the body  700  is rotated about the pivot  703 , a force between the pin  704  and one or more walls of the channel  702  increases. This force may prevent and/or inhibit unintended counter-rotation of the body  700  during flight, thereby retaining the handle  406  in the flight position and securely coupling the power module  122  to the fuselage  102 . 
       FIG. 7C  shows the locking mechanism  606  in a fully locked configuration, corresponding to the handle  406  (or other actuating member) in a flight position. In some cases, the cam profile defined by the channel  702  varies along its length so that the force produced by the cam is somewhat reduced when the locking mechanism  606  is in the fully locked configuration. This may act as a tactile detent that may be felt by a user to indicate that the locking mechanism  606  is fully engaged or locked, and may also bias the locking mechanism  606  in the locked configuration. 
     Reversing the process shown and described with reference to  FIGS. 7A-7C  unlocks the locking mechanism  606 , allowing the power module  122  to be removed from the UAV  100 . In some cases, the interaction between the pin  704  and the channel  702  while the locking mechanism  606  is being unlocked applies a force on the power module  122  that lifts the power module  122  out of the UAV  100  (e.g., an upward force), or that otherwise tends to decouple the power module  122  from the UAV  100 . The upwards motion of the power module  122  (or a different decoupling motion caused by unlocking a locking mechanism) may result in the decoupling of one or more electrical connections between the power module  122  and the integrated coupling and control unit  401 . For example, as the power module  122  is raised upwards by the pin  704  and channel  702 , electrical connectors on the power module  122  (e.g., a power module electrical connector  1004 ,  FIG. 10B ) may become mechanically and/or electrically decoupled from the power module electrical connectors  414  of the anchor structure  400 . In this way, the action of moving the handle  406  from a flight position to an open position may unlock the locking mechanism  606 , lift the power module  122  at least partially out of engagement with the integrated coupling and control unit  401 , and disconnect the electrical connectors of the power module  122  and the integrated coupling and control unit  401 . 
       FIGS. 8A-8J  depict portions of a UAV  800  that includes a different mechanism for engaging and maintaining a wing structure and power module to a UAV. In this example, instead of the power module having a handle that actuates a locking mechanism, a different locking mechanism may be used, which may include one or more handles or levers that are part of or coupled to the fuselage of the UAV  800 . Additionally, the retention structures on the wing structure, power module, and anchor structure may have a different configuration to accommodate the operation of the different locking mechanism. 
       FIG. 8A  shows the UAV  800  in a flight mode. The UAV  800  may include a fuselage  802 , a wing structure  804 , and a power module  822 . Apart from the differences described herein, the UAV  800  may be the same as or similar to the UAV  100 . Accordingly, details of the UAV  100  that are described above are omitted here for clarity, but will be understood to apply equally and/or by analogy to the UAV  800 . 
     The UAV  800  may also include lock levers  830  that are part of or otherwise coupled to the fuselage  802  and remain on the fuselage  802  when the power module  822  and/or the wing structure  804  are removed. When the UAV  800  is in the flight mode, as represented in  FIG. 8A , the lock levers  830  may be substantially flush with surrounding areas of the fuselage  802  to minimize drag produced by the lock levers  830 . 
       FIG. 8B  shows a portion of the UAV  800  in a partially disassembled state in which the power module  822  and the wing structure  804  are removed from the fuselage  802 . In order to release or unlock the power module  822  and the wing structure  804  so that they can be removed from the fuselage  802 , the lock levers  830  are rotated or otherwise manipulated to cause an internal locking mechanism  818  ( FIG. 8C ) to release the power module  822  and wing structure  804 . Details of the locking mechanism  818  are described herein with respect to  FIGS. 8A-9E . 
       FIGS. 8C-8J  depict a portion of the UAV  800  at various stages of attaching the wing structure  804  and the power module  822  to the fuselage  802 . Some components of the UAV  800  are omitted in order to avoid obscuring certain aspects of the UAV  800 .  FIG. 8A  shows the UAV  800  at a state prior to the wing structure  804  and the power module  822  ( FIGS. 8A-8B ) being coupled to the fuselage  802 . A mounting bracket  806  (which may be part of the wing structure  804 , which is largely omitted from  FIGS. 8C-8J  for clarity) is positioned above an anchor structure  808 . The anchor structure  808  may be similar to the anchor structure  400 , except that it may have different mechanisms, retention structures, and other features to form the alternative locking mechanism used by the UAV  800 . For example, the anchor structure  808  may include a locking mechanism  818  that includes a locking shaft  817 . The locking shaft  817  may be coupled to an arm  816  that allows the locking shaft  817  to rotate, translate, or otherwise move in order to engage the mounting bracket  806  (as well as a portion of the power module  822 ), thereby retaining the wing structure  804  and the power module  822  to the fuselage  802 . The structure and operation of an example embodiment of the locking mechanism  818  are discussed in greater detail herein. 
     The mounting bracket  806  (also referred to herein as a bracket) may include a first retention structure  812  and a second retention structure  814  that are configured to engage corresponding retention structures (e.g., a third retention structure  813  and a fourth retention structure  815 , respectively) on the anchor structure  808 .  FIGS. 8C-8J  show the retention structures  812 ,  814  as retention slots, though this is merely one example retention structure that may be used for the wing structure  804 . Other example retention structures may include channels, recesses, detents, divots, blind or through holes, or the like. The retention structures  812 ,  814  are shown as being located on a bracket  806  (of which there may be multiple for a given wing structure), though in other cases the retention structures  812 ,  814  may be formed or otherwise incorporated with other components or structures of the wing structure  804 . The corresponding retention structures  813 ,  815  are shown as pins (e.g., solid cylindrical members), though other types of retention structures may also be used, such as hollow cylinders, protrusions, bumps, non-cylindrical bars, or any other suitable component or feature that engages the retention structures  812 ,  814  of the mounting bracket  806 . 
       FIG. 8D  shows the retention structure at a first stage of an engagement process. In particular, the first retention structure  812  has been engaged with the corresponding third retention structure  813 . The first and third retention structures  812 ,  813  are configured to allow the mounting bracket  806  to rotate after the initial engagement of the retention structures. Accordingly, the mounting bracket  806  may be initially engaged with the anchor structure  808  while the mounting bracket  806  (and thus the wing structure  804 ) is at an angle relative to the fuselage  802 . The wing structure  804  and mounting bracket  806  may then be rotated (e.g., as shown in  FIG. 8D ) to engage the second retention structure  814  with the fourth retention structure  815 . The mounting bracket  806  may also include a support surface  824  that contacts a corresponding support member  823  of the locking mechanism  818  when the mounting bracket  806  is in the engaged position. The act of engaging the mounting bracket  806  to the anchor structure  808  may also result in the alignment and coupling of electrical (or other) connectors between the wing structure  804  and an integrated coupling and control unit, as described herein. 
       FIG. 8E  shows the mounting bracket  806  in an engaged position, which may correspond to the wing structure  804  (to which the mounting bracket  806  is attached) being in an engaged, flight-ready position. As shown in  FIG. 8E , the locking mechanism  818  is not in a locked or secured configuration. As such, while the mounting bracket  806  is engaged with the anchor structure  808 , the mounting bracket  806  (and thus the wing structure  804 ) may not be retained to the anchor structure  808 . Nevertheless, the configuration of the first and third retention structures  812 ,  813  and the second and fourth retention structures  814 ,  815  may constrain the mounting bracket  806  in at least some directions. For example, the second and fourth retention structures  814 ,  815  may prevent the mounting bracket  806  from translating to the left (based on the orientation in  FIG. 8E , and thus may prevent the decoupling of the first retention structure  812  from the third retention structure  813 . 
     The retention structures  812 ,  813 ,  814 ,  815 , along with the support surface  824  and the corresponding support member  823  of the locking mechanism  818 , may be the primary and in some cases the only load-bearing connections between the wing structure  804  and the fuselage  802 . That is, all or substantially all of the lift produced by the wing structure  804  (as well as any other aerodynamic forces acting on the wing structure  804 ) may be transferred to the rest of the UAV  800  via the mechanical engagements of the retention structures  812 ,  813 ,  814 ,  815 , and the contact between support surface  824  and the corresponding support member  823 . 
       FIGS. 8C-8D  illustrate the mounting bracket  806  being correctly aligned with and coupled to the anchor structure  808 . During coupling of a wing structure to the fuselage, however, a user may not correctly align the mounting bracket  806  to the anchor structure, or may otherwise attempt to force the wing structure (and thus the mounting bracket  806 ) downwards before the retention structures  812 ,  813 ,  814 ,  815  are correctly aligned and/or engaged. Accordingly, the mounting bracket  806  and the anchor structure  808  may be configured to prevent damage to the system under such circumstances. For example, the mounting bracket may include a brace  832  that is positioned adjacent the second retention structure  814  and configured to contact the fourth retention structure  815  if the wing structure is translated or pivoted downward before the first retention structure  812  is fully engaged with the third retention structure  813  (e.g., before a pin is received or positioned at a terminal end of a slot or channel). This may produce an abrupt or hard stop to further motion of the wing structure, signaling to the user that the wing structure is not fully engaged and also preventing components on the wing structure and/or the anchor structure from being crushed. In particular, the brace  832  may have a dimension (e.g., a height, as depicted in  FIG. 8E ) that will prevent components such as wing electrical connectors, processors, circuit elements, circuit boards, or other mechanical and/or electrical components from contacting one another when the bottom surface of the brace  832  is in contact with the fourth retention structure  815 . Thus, if a user tries to force a misaligned wing structure  804  downward, the brace  832  may prevent the components from being crushed or damaged. 
       FIG. 8F  shows the retention structure engaged with the anchor structure  808 , and shows the power module  822  above the anchor structure  808  and aligned for engagement with the anchor structure  808 . As shown in  FIGS. 8F-8G , the power module  822  may be engaged with the anchor structure  808  by translating the power module  822  downward along a linear path. In other embodiments, the power module  822  may be engaged with the anchor structure  808  in other manners. 
     The power module  822  may include a fifth retention structure  819  that is configured to engage the fourth retention structure  815 , as well as a support surface  825  that is configured to contact the support member  823  of the locking mechanism  818 . The power module  822  may also include a sixth retention structure  826 , which may engage a corresponding retention structure on the fuselage  802  (e.g., in a cavity such as the cavity  304 ,  FIG. 3 ). Similar to the engagement of the mounting bracket  806  with the anchor structure  808 , the retention structures  819 ,  815 , and  826 , along with the support surface  825  and the corresponding support member  823  of the locking mechanism  818 , may be the primary and in some cases the only load-bearing connections between the power module  822  and the fuselage  802 . That is, all or substantially all of the weight of the power module  822  may be transferred to the rest of the UAV  800  via the mechanical engagements of the retention structures  819 ,  815 ,  826 , and the contact between support surface  825  and the corresponding support member  823 . Further, the retention structures  819 ,  815 , and  826  may be configured to align electrical connectors between the power module  822  and an integrated coupling and control unit, as described herein, thus allowing fast and accurate blind mating of the power module  822  with the UAV  800 . 
       FIG. 8G  shows the portion of the UAV  800  after the power module  822  has been initially engaged with the anchor structure  808  and prior to the locking mechanism  818  securing the power module  822  and the mounting bracket  806  to the anchor structure  808 . As noted above, the locking mechanism  818  may include a locking shaft  817  that is coupled to an arm  816 . The arm  816  may be coupled to the lock levers  830  ( FIGS. 8A-8B ) such that rotation or actuation of the lock levers  830  results in rotation or movement of the locking shaft  817 . More particularly, rotating the lock levers  830  from an unlocked position (as shown in  FIG. 8B ) to a stowed or flight position (as shown in  FIG. 8A ) may result in the arm  816  rotating or otherwise moving to cause the locking shaft  817  to engage locking surfaces  827 ,  820  of the mounting bracket  806  and the power module  822 , respectively. The locking shaft  817  may contact and slide along at least a portion of the locking surfaces  827 ,  820  as the lock levers  830  are rotated, and the locking shaft  817  may remain in contact with the locking surfaces  827 ,  820  (or a portion thereof) when the locking mechanism  818  is in a locked configuration. In this way, the locking shaft  817  may secure the power module  822  and the wing structure  804  to the fuselage  802 . In some cases, the locking shaft  817  does not contact and slide along the entire lengths of the locking surfaces  827 ,  820  as the locking mechanism  818  is moved from an unlocked position to a locked position. Instead, the locking shaft  817  may remain out of contact with one or both of the locking surfaces  827 ,  820  until the locking shaft  817  is proximate a locked position, at which point it may contact one or both of the locking surfaces  827 ,  820  (e.g., in a recess defined by the locking surfaces) in order to secure the power module  822  and the wing structure  804  to the fuselage  802 . 
     The locking mechanism  818  may be configured to be maintained in the locked configuration unless it is intentionally unlocked. For example, the locking surfaces  827 ,  820  (and the locking mechanism  818  more generally) may be configured to exhibit bistability, such that when the locking mechanism  818  is moved into the locked configuration it is moved into an over-centre state. The bistability may be produced by any suitable technique, including cams (e.g., defined by the shape of the locking surfaces  827 ,  820 , or components within the locking mechanism  818 ), actuators (e.g., electromechanical actuators), detents, latches, springs, or the like. As shown, the locking surfaces  827 ,  820  define recessed regions in which the locking shaft  817  may be received. The shape of the recesses may be such that the locking shaft  817  is retained as a result of contacting the portions of the locking surfaces  827 ,  820  that define the recesses. 
     Notably, the locking mechanism  818  locks both the power module  822  and the wing structure  804  to the fuselage  802 . Accordingly, similar to other UAV configurations described herein, the power module  822  and the wing structure  804  can both be secured to the fuselage  802  with a single process (e.g., rotating or otherwise actuating the lock levers  830 ). 
     In some cases, guides may be included on a UAV to help align and mate the various retention structures of the wing structure, power module, and anchor structure.  FIGS. 8I-8J  illustrate a side and top view, respectively, of an example guide  834  that may be configured to guide the first retention structure  812  into engagement with the third retention structure  813  during attachment of the wing structure to the fuselage. The guide  834  may include side walls  836  and a bottom wall  838 . The side walls  836  may be angled to define an entry opening  840  that is wider than an exit opening  842  and to guide the bracket  806  (and more particularly the first retention structure  812 ) into alignment with the third retention structure  813 . More particularly, the wider entry opening  840  may provide a larger area on which the bracket  806  may be placed during assembly, while still ensuring that the first and third retention structures will be properly engaged when the bracket  806  is translated towards an engaged orientation (e.g., to the right, as oriented in  FIG. 81 ). The guide  834  may be formed of or include any suitable material, such as plastic, metal, or the like. In some cases, the guide  834  (or at least the surfaces of the bottom and side walls  838 ,  836  that contact the bracket  806 ) is formed of a polymer material that has relatively low friction to allow the bracket  806  to glide along the material without binding or otherwise resisting assembly. 
       FIGS. 9A-9E  depict a portion of the locking mechanism  818  that secures the power module  822  and the wing structure  804  to the UAV  800 , showing the locking mechanism  818  at different states of engagement.  FIG. 9A  shows a portion of the locking mechanism  818  that includes the arm  816 , the locking shaft  817 , and the support member  823 , all of which may be coupled to other mechanisms (and ultimately to a lock levers  830 ) via a linkage member  902  (or by any other suitable mechanism, feature, or component). The lock lever  830  may be configured to rotate the arm  816  about a pivot defined by the support member  823 , thereby moving the locking shaft  817  into engagement with the locking surfaces  827 ,  820  of the mounting bracket  806  and the power module  822 , respectively. 
     The power module  822  and the locking mechanism  818  may be configured so that the process of locking the locking mechanism  818  (e.g., by moving the lock levers  830  from an unlocked position to a stowed or flight position) pulls the power module  822  into a stowed or flight position. For example, when the power module  822  is initially inserted into a fuselage, the locking mechanism, which would be in an unlocked configuration, may prevent the power module  822  from moving to its stowed or flight position.  FIG. 8G  may illustrate the initial rest position of the power module  822  before the locking mechanism  818  is manipulated to lock the power module  822  in place. As the lock levers  830  are moved into the stowed or flight position, the rotation of the arm  816  may cause the locking shaft  817  to engage the locking surface  820  (or any portion of a channel that is defined in part by the locking surface  820 ), and the shape of the locking surface  820  may be configured to force or pull the power module  822  into its final stowed or flight position. This configuration may also improve the process of removing the power module  822 . In particular, moving the lock levers  830  from the stowed to the unlocked position may cause the locking shaft  817  to push the power module  822  upwards (based on the orientation shown in  FIG. 8H ), thus forcing the power module  822  away from the fuselage and making it easier to grasp the power module  822  to remove it from the fuselage. In particular, this process may result in the power module  822  moving from the position shown in  FIG. 8H  to the position shown in  FIG. 8G , which may cause a gap to be formed between the power module  822  and the fuselage. This gap may allow a person to easily grasp an edge of the power module  822  and lift the power module  822  out of the fuselage. The partial ejection of the power module  822  may be achieved solely due to the action of the lock levers  830 , and without requiring a user or operator to apply additional force on the power module  822 . 
     As noted above with respect to  FIGS. 7A-7C , the partial ejection of the power module  822  may also result in the decoupling of one or more electrical connections between the power module  822  and the integrated coupling and control unit of the UAV  800  (which may be the same as or similar to the integrated coupling and control unit  401 ). For example, as the power module  822  is raised upwards by the locking shaft  817 , electrical connectors on the power module  822  (e.g., a power module electrical connector  1012 ,  FIG. 10E ) may become mechanically and/or electrically decoupled from the power module electrical connectors coupled to the anchor structure  808 . In this way, the action of moving the lock levers  830  from a flight position to an open position may unlock the locking mechanism  818 , lift the power module  822  at least partially out of engagement with the anchor structure (e.g., causing the fourth retention structure  815  to slide out of secure engagement with the fifth retention structure  819 ), and disconnect the electrical connectors of the power module  822  and the integrated coupling and control unit of the UAV  800 . 
       FIG. 9B  shows the locking mechanism  818  with the mounting bracket  806  aligned with the locking mechanism  818  and prior to the mounting bracket  806  being placed on the locking mechanism  818 .  FIG. 9C  shows the mounting bracket  806  placed on the locking mechanism  818 , with its support surface  824  in contact with or near the support member  823 . The placement of the mounting bracket  806  on the locking mechanism  818  as shown in  FIG. 9C  may result from the engagement process of the mounting bracket  806  illustrated with respect to  FIGS. 8C-8J . 
       FIG. 9D  shows the locking mechanism  818  with a portion of the power module  822  placed on the locking mechanism  818 , with its support surface  825  in contact with or near the support member  823 . The placement of the power module on the locking mechanism  818  as shown in  FIG. 9D  may result from the engagement process of the power module  822  illustrated with respect to  FIGS. 8F-8J . 
     As shown in  FIG. 9D , both of the locking surfaces  827 ,  820  are substantially flush or even, and define a surface that the locking shaft  817  may engage to lock the power module  822  and the wing structure  804  in place. For example, the action of moving one or both of the lock levers  830  into a locked configuration may cause the arm  816  to rotate or otherwise move, thereby sliding the locking shaft  817  along the locking surfaces  827 ,  820  and into a locked position.  FIG. 9E  shows the lock mechanism  818  in a locked position, with the locking shaft  817  positioned at an end of its travel relative to the locking surfaces  827 ,  820 . The locking surfaces  827 ,  820  may have a shape that acts as a cam lock, such that a force between the locking surfaces  827 ,  820  and the locking shaft  817  increases as the locking shaft  817  is slid towards a locked position. In some cases, as described above, the force may decrease slightly as the locking shaft  817  reaches its locked position (e.g., entering an over-centre state), thus helping to maintain the locking mechanism  818  in the locked configuration and reducing unintentional unlocking of the locking mechanism  818 . 
     In the figures and description relating to the components and/or mechanisms for attaching a power module and a wing structure to a fuselage (e.g.,  FIGS. 6A-7C, 8C-8J, 9A-9E ), a single example pair of each mating component and/or mechanism is shown. However, it will be understood that UAVs in accordance with the instant description may include more pairs of the mating components. For example, the wing structures  104 ,  804  may include one, two, three, or more mounting brackets that are the same as or similar to the mounting brackets  600 ,  806 . Similarly, the power modules  122 ,  822  may include one, two, three, or more instances of the engagement structures shown in the instant figures. Further, UAVs may have single or multiple instances of any other of the components, mechanisms, structures, and/or features shown or described herein, even if only one instance of such components, mechanisms, structures, and/or features is shown in any given figure. 
       FIGS. 10A-10B  depict details of how the mechanical attachment of the wing structure  104  and the power module  122  to the anchor structure  400  also results in forming positive electrical connections between the components.  FIG. 10A , for example, shows a partial cutaway view of the bracket  600  from the wing structure  104  prior to mechanical engagement with the anchor structure  400 . As described above, the anchor structure  400  may have wing electrical connectors  412  coupled thereto. For example, the wing electrical connectors  412  may be mounted on a circuit board that is coupled to the anchor structure  400 , as described herein. 
     As shown in  FIG. 10A , the process of attaching the bracket  600  to the anchor structure  400  results in the wing electrical connector  412  engaging and thereby electrically coupling to a corresponding wing electrical connector  1002  on the wing structure  104 . More particularly, the translation path used to slide the pins of the retention structure  502  into the slots  602  of the bracket  600  (e.g., the installation path of the wing structure  104 ) corresponds to a translation path that results the engagement of the corresponding wing electrical connectors  412 ,  1002 . 
     The corresponding wing electrical connector  1002  may be electrically coupled to electronic components in the wing structure  104 , and may be configured to facilitate the transfer of power and/or signals to and/or from the circuit board (e.g., signals to/from the avionics, power from the power module  122 , etc.) to the electronic components in the wing structure  104 . For example, the wing structure  104  may include actuators (e.g., servos, motors, etc.) or other components and the avionics may be configured to send and/or receive signals (e.g., communication signals, power signals, etc.) to the components via the electrical connectors. Where the wing structure  104  includes actuators for moving flight control surfaces, the signals transmitted via the wing electrical connectors may cause movement of the flight control surfaces. 
     As shown in  FIG. 10B , the process of attaching the power module  122  to the anchor structure  400  results in the power module electrical connector  414  engaging and thereby electrically coupling to a corresponding power module electrical connector  1004  on the power module  122 . More particularly, the translation path used to slide the pins of the retention structure  504  into the slot  604  of the power module  122  corresponds to a translation path that results the engagement of the corresponding power module electrical connectors  414 ,  1004 . 
       FIGS. 10C-10E  depict details of how the mechanical attachment of the wing structure  804  and the power module  822  to the anchor structure  808  also results in forming positive electrical connections between the components. The discussion of  FIGS. 10C-10E  is similar to that relating to  FIGS. 10A-10B , but relate to the different configuration of the components of the UAV  800 . 
       FIG. 10C  shows the bracket  806  prior to mechanical engagement with the anchor structure  808 . Similar to the anchor structure  400 , described above, the anchor structure  808  may have a wing electrical connector  1008  coupled thereto. For example, the wing electrical connector  1008  may be mounted on a circuit board that is coupled to the anchor structure  808 , as described herein. 
     As shown in  FIG. 10C , the process of attaching the bracket  806  to the anchor structure  808  results in the wing electrical connector  1008  engaging and thereby electrically coupling to a corresponding wing electrical connector  1006  on the wing structure  804 . More particularly, the rotation or pivoting motion used to engage the engagement structures of the bracket  806  with the anchor structure  808  (e.g., the installation path of the wing structure  804 ) corresponds to a movement that results the engagement of the corresponding wing electrical connectors  1008 ,  1006 . 
     Like the corresponding wing electrical connector  1002  (the discussion of which applies equally to the connector  1006 ), the corresponding wing electrical connector  1006  may be electrically coupled to electronic components in the wing structure  804 , and may be configured to facilitate the transfer of power and/or signals to and/or from the circuit board (e.g., signals to/from the avionics, power from the power module  822 , etc.) to the electronic components in the wing structure  804 . 
     As shown in  FIGS. 10D-10E , the process of attaching the power module  822  to the anchor structure  808  results in a power module electrical connector  1010  engaging and thereby electrically coupling to a corresponding power module electrical connector  1012  on the power module  822 . More particularly, the translation path used to engage the engagement structures of the power module  822  with those of the anchor structure  808  (and optionally the fuselage  802 , as described above) corresponds to a translation path that results the engagement of the corresponding power module electrical connectors  1010 ,  1012 . 
     While the foregoing examples show particular example assembly paths that result in mechanical and electrical couplings between the various illustrated components, it will be understood that the shape, type, and positioning of the electrical connectors on the various components may be determined by the shape, type, and positioning of the retention structures. Accordingly, the electrical connector coupling path may substantially match or otherwise correspond to whatever mechanical coupling path is used, thereby ensuring that the process of mechanically coupling the components results in the electrical coupling as well. In some cases, the electrical connectors (e.g.,  412 ,  414 ,  1002 ,  1004 ,  1006 ,  1008 ,  1010 ,  1012 ) may be configured to allow some degree of misalignment during the engagement process and still make a secure and sufficient electrical coupling between the complementary connectors. This may allow the electrical connectors to be securely coupled despite the type of common misalignment or jostling that may occur when attaching the wing structure and the power module to the fuselage. Moreover, the foregoing figures are shown in side views, and thus illustrate only one pair of complementary electrical connectors for the wing structures and the power modules. It will be understood that additional connectors may be used. For example, a UAV may include one, two, three, four, five, or more sets of complementary electrical connectors for each wing structure and power module. 
     As described above, the anchor structure  400  may be part of an integrated coupling and control unit that serves as both a principle component for mechanical couplings to the wing structure and power module, as well as a principle mounting location for avionics of a UAV.  FIGS. 11A-11C  depict the integrated coupling and control unit  401  in accordance with some example embodiments. 
     The integrated coupling and control unit  401  may include the anchor structure  400 , a circuit board  1102 , and a seal  1106  ( FIG. 11B ). The anchor structure  400  may be or may include a frame member  1103  that includes wing and power module retention structures  502 ,  504 , as described above, for rigidly (and releasably) engaging the wing structure  104  and the power module  122  to the fuselage of a UAV. The anchor structure  400 , or the frame  1103  of the anchor structure  400 , may also include parachute attachment features  1111 . As noted above and described herein, the anchor structure  400  may be a principal structure for transferring mechanical loads to the UAV  100 , including wing loads (e.g., lift), power module loads, and the like. Thus, the parachute attachment features may be coupled to the cords of parachute or parachute system to transfer the load from the parachute cords to the frame  300  of the UAV  100  in the event of a parachute deployment. While  FIG. 11A  shows the parachute attachment features  1111  at a particular location, they may be positioned at other locations in other embodiments, or they may be omitted and a parachute cord may be attached to another location or component of the anchor structure  400 , such as to the retention structures  502 ,  504 . The parachute cords may be anchored to the anchor structure  400  substantially directly above the center of gravity of the UAV  100 , so that the UAV  100  descends substantially horizontally during a parachute landing. In other cases it may be offset from the center of gravity. 
     The anchor structure  400  may be configured to be coupled to the fuselage of a UAV, as shown and described herein. For example, the anchor structure  400  may be attached to a rigid frame (e.g., the frame  300 ) of the UAV  100  at a position that is proximate the cavity  304  for receiving the power module  122 . 
     The frame  1103  of the anchor structure  400  may be formed from any material using any suitable process. For example, it may be machined from a single piece of metal or other material, or it may be produced by additive manufacturing (e.g., 3-D printing), molding, or any other suitable process. The frame  1103  may be formed from metal (e.g., aluminum, magnesium, titanium, metal alloys, etc.), composites (e.g., carbon fiber, fiberglass, metal matrix composites, etc.), polymers (e.g., polycarbonate, polyamide, etc.), or any other suitable material. Where the frame  1103  is formed of metal, it may be referred to as a metal frame. In some cases, the frame  1103  of the anchor structure  400  is a monolithic component (e.g., a monolithic metal frame). In some cases, the entirety of the load-bearing structure of the anchor structure  400  (e.g., the portions of the anchor structure  400  that carry the load of the power module  122  and the wing structure  104 ) includes only a monolithic frame  1103  and the pins of the retention structures (e.g., pins  1101 ), which may be attached to the monolithic frame  1103 . 
     The integrated coupling and control unit  401  may include a circuit board  1102  coupled to the anchor structure  400 . The circuit board  1102  may include electrical components attached thereto. For example, the circuit board  1102  may include wing electrical connectors  412  coupled to a top side of the circuit board  1102 , as shown in  FIG. 11A . The circuit board  1102  may also include avionics components. The avionics may include any and all electronic components for controlling the UAV and/or allowing the UAV to communicate with other devices such as other UAVs, ground-based controllers, or the like. Example avionics may include processors, memory, circuit components, global positioning systems (GPS), accelerometers, altimeters, barometric sensors, radar, sonar, communication radios, and the like. As described with respect to  FIGS. 11B-11C , such components may be mounted on a bottom side of the circuit board  1102  so that they are positioned in the interior volume of a cavity defined by the anchor structure  400  and the circuit board  1102 . Antennas and other avionics components  1104  may be coupled to the circuit board  1102  (and/or components on the circuit board), and may extend from the integrated coupling and control unit  401 . As shown, the antennas and other components  1104  extend from the rear or aft location of the integrated coupling and control unit  401 , though other positions are also contemplated. 
     The integrated coupling and control unit  401  may also include the power module electrical connectors  414  coupled thereto. The power module electrical connectors  414  may be coupled to the frame  1103  of the anchor structure  400 , and electrically connected to the circuit board  1102  (and/or a component on the circuit board) via one or more conductors. 
     As described above, the integrated coupling and control unit  401  may form an environmental and electromagnetic shield for the avionics and/or electronics of the UAV  100 . For example, the integrated coupling and control unit  401  may be configured so that electronic components such as GPS units, processors, memory, circuit elements, and the like, are positioned in sealed and shielded volumes within the integrated coupling and control unit  401 . The sealed and shielded volumes may be sealed against ingress of liquids, debris, or other contaminants, and may be shielded against electromagnetic interference.  FIG. 11B  depicts an exploded view of the integrated coupling and control unit  401 , illustrating elements of the sealing and shielding of the integrated coupling and control unit  401 .  FIG. 11B  shows the circuit board  1102  and a seal  1106  removed from the anchor structure  400 . 
     The anchor structure  400 , and in particular the frame  1103  of the anchor structure  400 , may define one or more cavities that are configured to form volumes in which electronic components on the circuit board  1102  may be received. For example,  FIG. 11B  shows an anchor structure  400  that defines three cavities,  1108 - 1 ,  1108 - 2 , and  1108 - 3 . The cavities may be defined by bottom walls  1114  and side walls  1116  extending from the bottom walls  1114 . The bottom and side walls  1114 ,  1116  may be part of a monolithic structure. For example, the bottom and side walls  1114 ,  1116  may be formed by machining the cavities  1108  from a single piece of metal. 
     The seal  1106  may be positioned between the circuit board  1102  and the anchor structure  400  and around the cavities  1108  to form the sealed and shielded volumes. The seal  1106  may perform both shielding and sealing functions. For example, the seal  1106  may be formed from a conductive deformable material that forms a mechanical seal between the circuit board  1102  and the anchor structure  400  and also forms a conductive path between the circuit board  1102  and the anchor structure  400 . The conductive deformable material may include, for example, an elastomer material with conductive elements, particles, wires, or the like, embedded in the elastomer material. For example, the conductive deformable material may be a silicone elastomer with carbon particles distributed within the silicone elastomer. 
     Due to the deformable nature of the seal  1106 , the seam or joint between the circuit board  1102  and the anchor structure  400  may be substantially sealed against ingress of liquids, debris, and/or other contaminants (e.g., a water resistant seal). This may be particularly advantageous in the context of UAVs, as they may need to be able to continue to function in numerous weather and environmental conditions. By sealing the electronic components in the sealed volumes of the integrated coupling and control unit  401 , the reliability and range of operating conditions of the UAV may be increased. 
     As noted above, the seal  1106  may be configured to form a conductive path between the circuit board  1102  and the anchor structure  400 . More particularly, the anchor structure  400  may include a metal (e.g., conductive) frame  1103 , and the circuit board  1102  may include one or more metal layers, traces, or other conductive materials extending over the area of the circuit board  1102 . By conductively coupling the metal frame  1103  of the anchor structure  400  (which may form the bottom and side walls of the cavities  1108 ) to the conductive materials of the circuit board  1102 , the metal frame  1103 , the seal  1106 , and the circuit board  1102  may cooperate to form a substantially continuous conductive covering around the sealed volume. (These conductive components may be coupled to or may form a ground plane for the electrical system of the UAV.) The substantially continuous conductive covering around the volumes may operate as a Faraday cage to prevent or reduce electromagnetic interference to the electronic components that are coupled to the circuit board  1102 . 
     In some cases, the circuit board  1102  may include one or more continuous conductive layers that are conductively coupled to the metal frame  1103  via the seal  1106 . In other cases, the circuit board  1102  may include traces, wires, or other discontinuous conductive paths that are spaced sufficiently close together to act as an electromagnetic shield. 
     As shown in  FIG. 11C , electrical components  1118  may be mounted to the circuit board  1102  at particular locations that result in the electrical components being positioned in the cavities  1108 . While  FIG. 11C  shows three electrical components ( 1118 - 1 - 1118 - 3 ), these are merely representative of the electrical components that may be coupled to the circuit board  1102 . More and/or different electrical components may be used in UAVs in accordance with the instant application. In some cases, the electrical components include redundant components, with the redundant components being positioned in different cavities in the frame  1103 . For example, the electrical components  1118 - 1  and  1118 - 2  (which may be processors, GPS units, radios, or any other suitable component) may be the same or similar components (or may provide the same or similar functions) and thus may act as redundant backup components for one another. 
     Because the components  1118 - 1  and  1118 - 2  are positioned in separately sealed and shielded volumes in the integrated coupling and control unit  401 , electrical components in other volumes may make up for any loss of functionality due to damage (or electromagnetic interference) of an electrical component in a breached volume. Moreover, because the internal volumes are distinct (e.g., defined by physically separate cavities) and are independently sealed, a breach in one volume may be contained to that volume and may not negatively affect other volumes. 
       FIG. 11C  also shows conductive traces  1120 - 1 - 1120 - 3  positioned on the underside of the circuit board  1102 . The conductive traces  1120  may be conductively coupled to additional conductive traces, layers, or other shielding components in the circuit board  1102 , and may contact the seal  1106  when the integrated coupling and control unit  401  is assembled. Thus, the seal  1106  may conductively couple the circuit board  1102  to the metal frame  1103  via the conductive traces  1120 . 
     As noted above, the UAV  100  may include a deployable parachute to help slow the UAV  100  during either a planned or unplanned descent. The parachute may be coupled to the UAV  100  via the anchor structure  400  of the integrated coupling and control unit  401 , as described herein.  FIG. 12A  shows the UAV  100  prior to the deployment of a parachute  1204  ( FIG. 12B ), and  FIG. 12B  shows the UAV  100  after deployment of the parachute  1204 . As described herein, the parachute may be deployed using a propellant to push the parachute  1204  out of a parachute housing and into the air surrounding the UAV  100 . 
     In order to limit aerodynamic drag, a deployable parachute system may be positioned under one or more body panels of the UAV  100 , and the body panels may be jettisoned or otherwise displaced as a result of the deployment of the parachute  1204 . For example, as shown in  FIGS. 12A-12B , body panels  1200 ,  1202 , and  1203  may be jettisoned as a result of the force of the parachutes deployment and/or forces applied to the body panels by parachute cords  1210  and/or  1206 . Once the parachute  1204  is deployed, it may fill with air as a result of the motion and/or descent of the UAV  100 , and thus slow the UAV  100 . As described herein, the parachute  1204  may be coupled to the UAV  100  via the parachute cords  1206  and  1210 , both of which may be coupled to a cap  1208  that is used to cover and/or enclose a sealed housing of a deployable parachute system. 
     The parachute system may be configured to deploy the parachute  1204  in response to any suitable event. For example, a flight plan for the UAV  100  (which may be stored by a flight controller onboard the UAV  100  or may be transmitted in real-time to the UAV  100  from a ground-based controller or another UAV) may include a scheduled parachute descent at a landing zone. In such cases, when the UAV  100  is detected at the landing zone (e.g., by the UAV  100 , by ground-based sensors, or using any other suitable system or technique), the UAV  100  may command the parachute system to deploy the parachute  1204 . In other cases, the UAV  100  may be configured to detect conditions indicative of or likely to produce an unplanned descent, and in response to detecting such conditions, cause the parachute system to deploy the parachute  1204 . Example conditions that may be indicative of or likely to produce an unplanned descent and may be detected by the UAV  100  (or a ground-based system or another UAV) include but are not limited to loss of motor function or propulsion, a loss of power or fuel, a loss of vehicle control, rapid descent and/or deceleration, or the like. 
       FIG. 13  depicts a portion of the UAV  100  with body panels removed, showing how the parachute of a parachute system may be coupled to the anchor structure  400 . For example, a cord  1210  may be coupled to a cap  1302  of the parachute system via a connection point  1304  (e.g., an eyelet or other feature). The cord  1210  may be laid along a path, and optionally within channels, in the fuselage  102  of the UAV  100 , and connected to the anchor structure  400 . The cord  1210  may split into multiple branches to attach to multiple points on the anchor structure  400 . Further, while  FIG. 13  shows a single cord  1210  connected to the cap  1302 , this is merely representative, and more cords may be connected to the cap  1302 . 
     As shown in  FIG. 13 , the cord  1210  is positioned under one or more body panels of the UAV  100 . When the parachute is deployed from the parachute system (which may be positioned towards a bottom of the fuselage  102 ), the tension on the cord  1210  and any optional branches may cause the first cord  1210  to force the overlying body panels off of the fuselage  102 . This allows the cord  1210  a clear vertical path to allow the parachute to be positioned above the UAV  100  and maintain the UAV  100  in a substantially horizontal attitude (or at least with the bottom of the UAV  100  generally facing downward). 
     The deployable parachute system of the UAV  100  may be configured so that, despite a rapid and possibly explosive deployment, internal components of the parachute system (other than the parachute and optional packing materials) remain captive in the parachute system and are not expelled from the parachute system. This may increase the safety of the parachute system, and also allow for greater reusability, as internal components, such as plungers, are not lost during parachute deployment and may be reused.  FIGS. 14A-14D  illustrate aspects of a deployable parachute system  1400  that may be used in the UAV  100  described herein. 
       FIG. 14A  depicts the deployable parachute system  1400  (referred to simply as a parachute system  1400 ). The parachute system  1400  may include a body  1401  and a cap  1302  that is coupled to an open end of the body  1401 . The body  1401  may be substantially tubular (e.g., a hollow cylinder) and may define an internal cavity. The cap  1302  may include the connection point  1304  to which the cord  1210  may be connected. As shown in  FIG. 13 , the cord  1210  may be routed along a path and connected to the anchor structure  400 . 
     The cap  1302  may be coupled to the body  1401  in any suitable way. In some cases, the cap  1302  is adhered to the body  1401 . In some cases, a seam between the cap  1302  and the body  1401  is sealed, such as with a plastic or polymer cover that extends over a seam. The cover may be adhered to the cap  1302  and/or the body  1401  to prevent moisture or other contaminants from entering the body  1401 . 
       FIG. 14B  shows a cross-sectional view of the parachute system  1400 , viewed along line A-A in  FIG. 14A . As shown, the parachute system  1400  is in an undeployed state. The parachute system  1400  includes a plunger  1402  positioned in the cavity and dividing the cavity into a first chamber  1405  on one side of the plunger  1402  and a second chamber  1406  on an opposite side of the plunger  1402 . The parachute system  1400  includes the parachute  1204  in the first chamber  1405 . The parachute  1204  may be folded or otherwise packed into a configuration that allows it to expand when deployed so that it can slow the descent of the UAV  100 . In some cases, the parachute  1204  is at least partially surrounded (e.g., wrapped) in a sleeve  1412 . The sleeve  1412  may help guide the parachute  1204  out of the body (e.g., through an opening in the body  1401 ) and may prevent the packed parachute  1204  from catching or snagging on any part of the parachute system  1400  during deployment. In some cases, the sleeve  1412  may be stiffer and/or more rigid than the parachute  1204  to help the parachute  1204  easily slide out of the opening during deployment. In some cases, the plunger  1402  may exclusively contact the sleeve  1412  to push the parachute  1204  out of the body  1401 . In other cases, then plunger  1402  may contact both the parachute  1204  and the sleeve  1412  to expel the parachute  1204 . The sleeve  1412  may become unwrapped from the parachute  1204  when it is deployed, and may simply be jettisoned. In some cases, the sleeve  1412  may be held captive to the UAV  100  via a parachute cord or other suitable tether or attachment mechanism. 
     The parachute  1204  may be coupled to the cap  1302  via the cord  1206 . The cord  1206  may be coupled to the cap  1302  at a parachute connection point  1410 . As noted above, because the cord  1206  couples the parachute  1204  to the cap  1302 , and the cord  1210  couples the cap  1302  to the anchor structure  400  (or another suitable connection point of the UAV  100 ), a continuous load bearing cord path is formed between the parachute  1204  and the UAV  100 . 
     The parachute system  1400  also includes a propellant module  1404  configured to provide a force to expel the parachute  1204  from the cavity. The propellant module  1404  may be positioned at least partially in the second chamber  1406 , and may be configured to expand (or introduce an expanding gas or other composition) within the second chamber  1406  to push a plunger  1402  along an ejection direction (e.g., to the right, as shown in  FIGS. 14A-14D ) to expel the parachute  1204  from the cavity. The propellant module  1404  may be removable and/or replaceable, thus allowing other components of the parachute system  1400  to be reused for multiple parachute deployments. 
     The propellant module  1404  may be or may include any suitable propellant. For example, the propellant module  1404  may include an explosive charge that produces a force (e.g., from rapidly expanding gases) on the plunger  1402 . In other cases, the propellant module  1404  may use compressed gas (e.g., air, carbon dioxide, nitrogen, etc.) as a propellant, which may be released into the second chamber  1406  such that the compressed gas expands and pushes the plunger  1402  along the ejection direction to expel the parachute  1204 . 
     As noted above, the parachute system  1400  may be configured so that, apart from the parachute  1204  and the optional sleeve  1412 , other components are not expelled or projected from the parachute system  1400  during deployment. For example, the parachute system  1400  may be configured to retain the plunger  1402  within the body  1401  after the parachute  1204  is expelled.  FIGS. 14B-14D  illustrate the structures that retain the plunger  1402  to the body  1401 . 
     As shown in  FIG. 14B , the parachute system  1400  includes a retention feature  1408  proximate the opening through which the parachute  1204  is expelled. The retention feature  1408  may be integrally formed with the body  1401 , or it may be a separate component that is attached to the body  1401  (as shown). 
     The retention feature  1408  may define a retention lip  1418  that extends into the first chamber  1405  and/or is otherwise configured to overlap a portion of the plunger  1402 . As shown in  FIG. 14D , when the parachute  1204  is deployed, the plunger contacts the retention lip  1418 , which prevents the plunger  1402  from exiting the cavity and/or otherwise retains the plunger  1402  to the body  1401 . In some cases, the plunger  1402  and the interior volume defined by the body  1401  is substantially circular. In such cases, the retention lip  1418  may be a circular feature that has a smaller inner diameter or opening than the diameter of the circular plunger. In some cases, the retention feature  1408  and/or the retention lip  1418  does not extend continuously around the opening in the body  1401 . For example, two, three, four, or more retention lips may be positioned at various locations around the opening. 
       FIGS. 14B-14D  show the parachute system  1400  at various stages of operation. For example,  FIG. 14B  shows the parachute system  1400  in an initial state, prior to the parachute being deployed.  FIG. 14B  may represent how the parachute system  1400  is configured during nominal flight of a UAV. 
       FIG. 14C  shows the parachute system  1400  while the parachute  1204  is being expelled. The propellant module  1404  is producing an expanding gas  1411  (e.g., from a reservoir of compressed gas or from an explosive charge or other chemical reaction) that is applying a force to the plunger  1402 . The plunger  1402 , in turn, is pushing the parachute  1204  and the sleeve  1412  out through the opening in the body  1401 . As shown in  FIG. 14C , the cap  1302  has already been decoupled from the body  1401 . 
       FIG. 14D  shows the parachute system  1400  after the parachute  1201  has been ejected from the body  1401 . Notably, the plunger  1402  has remained within the body  1401 , with the retention feature  1408  engaging a peripheral region of the plunger  1402  to prevent it from exiting the body  1401 . 
       FIG. 14E  shows how the parachute  1204  may be separated from the sleeve  1412  after the parachute  1204  and sleeve  1412  are ejected from the body  1401 . For example, the sleeve  1412  may unwrap or otherwise open to allow the folded or packed parachute  1204  to become free of the sleeve  1412  and freely expand due to the parachute  1204  being exposed to the airflow around the UAV. In some cases, a pilot parachute may be used to help unpack or unfold the parachute  1204  so that the parachute  1204  can begin slowing the descent of the UAV. 
     As described above, the UAV  100  may use a removable power module  122  to provide energy to one or more of its flight systems, including its avionics, motors, flight control surface actuators, and the like. The removable power module  122  described herein is configured to be quickly and easily coupled to and decoupled from the UAV  100 , and also provide additional advantages. For example, as noted above, the power module  122  may include heat sinks that define exterior surfaces of the fuselage  102  of the UAV  100  (and thus directly in the airflow over the fuselage  102  during flight) to transfer waste heat out of the power module  122  quickly and efficiently. Further, the power module  122  may be designed so that a failure of the power module  122 , or a component of the power module  122 , is less likely to damage other components of the power module  122 . 
       FIG. 15  shows an example embodiment of the power module  122 . As described above, the power module  122  may include a handle  406  that is pivotally or rotatably attached to a body  1501 . The power module  122  may also include an interfacing side  402 , which may be or may define a surface of the power module  122  that contacts or otherwise interfaces with a portion of a wing structure (such as the bracket  600  or another bracket embodiment). The interfacing side  402  may act as a mechanical interlock that imparts a force on the wing structure, or a component thereof, to prevent the wing structure from moving in a decoupling direction. As shown, the power module  122  is a battery pack that includes battery arrays  1502 ,  1504  that provide electrical power to the UAV  100 . The power module  122  also includes battery cell holders  1506 ,  1508  that define surfaces  126 ,  128  which form exterior surfaces of the fuselage  102  of the UAV  100  when the power module  122  is coupled to the UAV  100 . The battery cell holders  1506 ,  1508  also secure the battery arrays  1502 ,  1504  to the power module  122 . 
       FIG. 16  depicts an exploded view of a portion of the power module  122 . In particular,  FIG. 16  shows the battery cell holders  1506  and  1508  and the battery arrays  1502 ,  1504 . The battery arrays  1502 ,  1504  include multiple individual battery cells  1503 . The battery cells  1503  may be any suitable type of battery cell and may use any suitable chemistry or other electrical storage system including but not limited to nickel metal hydride (NiMH), lithium ion, nickel cadmium (NiCd), alkaline, and lead acid. The battery cells  1503  may be electrically coupled to one another via electrical connectors  1507 . The electrical connectors  1507  may couple the battery cells  1503  in any suitable way, such as in a series or parallel or series-parallel configuration. 
     The battery cell holders  1506 ,  1508  may include features  1604  that define cavities  1602 . The cavities  1602  may each be configured to receive a portion of a battery cell  1503 . The battery cells  1503  may be held securely in the cavities  1602  via fasteners, adhesives, clips, interference fits, clamps/clamping forces, or other retention structures or techniques. The electrical connectors  1507  or portions thereof may be disposed in the cavities  1602  when the battery cells  1503  are positioned in the cavities  1602 . In some cases, the electrical connectors  1507  are attached to the battery cell holders  1506 ,  1508  and are securely held within the cavities  1602 . 
     The battery cell holders  1506 ,  1508  may be configured to act as heat sinks for the battery cells  1503 . In particular, the battery cells  1503  may be thermally coupled to the battery cell holders  1506 ,  1508  due to the physical contact between the features  1604  and the battery cells  1503 , and the battery cell holders  1506 ,  1508  may be formed from or include a thermally conductive polymer material. For example, the battery cell holders  1506 ,  1508  may be formed from or include a polymer material having a thermal conductivity that is greater than 1 W/mK, greater than 5 W/mK, greater than 10 W/mK, greater than 20 W/mK, or the like. Example polymer materials include but are not limited to filled polymers (e.g., a polymer matrix with thermally conductive particles such as metals, graphite, ceramics, or the like, distributed therein). In some cases, the battery cell holders  1506 ,  1508  are formed from metal such as aluminum, magnesium, titanium, etc. 
     Due to the thermal coupling between the battery cells  1503  and the battery cell holders  1506 ,  1508 , heat generated by the battery cells  1503  may be drawn away from the battery cells  1503 . When the UAV  100  is flying, heat from the battery cells  1503  may be drawn through the material of the battery cell holders  1506 ,  1508  and transferred via the exterior surfaces  126 ,  128  to the air that is flowing over the fuselage  102 . Thus, the airflow resulting directly from the flight of the UAV  100  also acts as a forced-air cooling system that continually removes heat from the battery cells  1503  via the exterior surfaces  126 ,  128  to the exterior of the power module  122 . By directly physically coupling and retaining the battery cells  1503  to a thermally conductive structure that defines an exterior surface of the fuselage  102 , greater electrical efficiencies may be achieved during flight as compared to other battery arrangements. Moreover, coupling the battery cells  1503  to the thermally conductive battery cell holders  1506 ,  1508  in the removable power module  122  allows the thermal connection to be maintained even when the power module  122  is removed and replaced, obviating the need to separately secure the battery cells to a heat sink or other thermal component when coupling the battery cells to the UAV  100 . 
     In some cases, battery cells  1503  may be thermally coupled to a heat sink or other heat exchanger via other techniques. For example, the battery cells  1503  may be wrapped, jacketed, or otherwise thermally coupled to a fluid conduit that is in turn thermally coupled to a heat sink or other heat exchanger. Fluid inside the fluid conduit may draw or conduct heat away from the battery cells  1503  and towards the heat sink or other heat exchanger, where the heat may be drawn or conducted out of the fluid and into the air surrounding the UAV  100 . 
     One or both of the battery cell holders  1506 ,  1508  may also act as heat sinks for other components of the UAV  100 . For example, processors, motors, electronic circuitry, or other components (including, for example, components of the integrated coupling and control unit  401 ,  FIG. 11A ) may be thermally coupled to the battery cell holders  1506 ,  1508  via fluid conduits or other thermal couplings. In some cases, the fluid conduits or other thermal couplings may include complementary connectors on the power module  122  and the integrated coupling and control unit  401  (which may operate in an analogous manner to the power module electrical connectors  414 ,  1004 ) to facilitate the blind mating of the fluid conduits or other thermal conduits when the power module  122  is attached to the UAV  100 . In this way, the thermal connections may be formed as part of the same power module attachment process and without any extra steps or operations to complete the thermal connections. 
     In embodiments where fluid conduits are used to thermally couple components with heat sinks or other heat exchangers, a fluid pump may circulate fluid through the fluid conduits. The fluid pump may be any suitable type of pump or mechanism, and may be powered by the power module  122 . 
     While the power module  122  shown in  FIGS. 15-16  have two battery cell holders  1506 ,  1508  and two battery cell arrays  1502 ,  1504 , this is merely one example embodiment, and more or fewer battery cell holders and battery arrays may be used. For example, in some cases only one battery cell holder and corresponding battery cell array is used. In other cases, three or more battery cell holders and corresponding battery cell arrays are used. As used herein, a battery cell array relates to the group of battery cells that are coupled to a corresponding battery cell holder, and does not necessarily correspond to a particular electrical configuration or grouping. 
     Under some conditions battery cells may fail, which may result in the battery cell exploding, catching fire, or otherwise forcefully venting gasses and/or particles out of the cell. Where multiple battery cells are positioned in close proximity, the failure of one cell (e.g., venting of hot gasses or particles) may cause other cells to melt, overheat, and/or otherwise fail in a similar manner. Thus, the failure of one battery cell may cause a chain reaction that causes other battery cells to fail. Additionally, any components of a UAV that are in proximity to a failing battery may be destroyed or damaged by the failing battery cell. Due to these risks, the power module  122  may be configured to reduce the likelihood that a failure of one battery cell will cause damage to other battery cells or to other internal components of the UAV  100 .  FIGS. 17A-17B  depict partial cross-sectional views of a portion of the power module  122 , viewed alone line B-B in  FIG. 16 , showing how the damage from a failing battery cell may be limited or mitigated. In particular, the battery cells  1503  may be positioned in the battery cell holders  1506 ,  1508  such that a failing battery cell  1503  is likely to project any explosion or venting through the battery cell holders  1506 ,  1508  and to the exterior of the UAV  100 . While  FIGS. 17A-17B  show only a portion of one of the battery cell arrays, it will be understood that each battery array and battery cell holder may have the same or similar configuration. 
     With reference to  FIG. 17A , battery cells  1503  may be configured so that when they fail in a way that causes an explosion or other forceful venting of gasses and/or material, the venting is directed through a venting member  1706 . For example, the venting member  1706  may be a portion of the battery housing that is weaker than other portions. Thus, if there is an internal pressure rise in the battery cell  1503 , the venting member  1706  will fail or breach first, allowing the gasses and/or other material to escape through the venting member  1706  while the remaining portions of the battery housing stay intact and contain the gasses and/or other material. As shown in  FIGS. 17A-17B , the battery cells  1503  may be positioned in the battery cell holders  1506 ,  1508  so that the venting member  1706  is facing an interior surface of a wall  1702 , where the exterior surface of the wall  1702  defines the exterior surface  128  of the power module  122 . 
       FIG. 17B  illustrates the battery cell  1503 - 1  during a failure event in which gasses and/or other material  1704  is being ejected from the battery cell  1503 - 1 . Because the battery cell  1503 - 1  is positioned in its cavity such that the venting member  1706  is facing the wall  1702  (or otherwise configured to direct vent towards the wall  1702 ), the venting gasses/materials form a localized opening  1703  in the wall  1702 . In this way, the venting gasses/materials are directed away from other battery cells  1503  and away from other components of the UAV  100 . Moreover, the venting gasses/materials are directed through the wall  1702  and into the environment exterior to the UAV  100 , thus taking advantage of the airflow over the exterior surface  128  to help quickly remove heat and strip the venting gasses/materials away from the other battery cells  1503  and generally away from the UAV  100 . 
     The battery cell holder  1508  may be configured to locally fail in the event of a battery cell failure. For example, the battery cell holder  1508  may be formed from a material (and have a particular shape, thickness, or other dimension) that is configured to be breached in response to a typical venting event of a failing battery cell. More particularly, the material may have a strength, heat resistance, toughness, or other property that is below a threshold for containing the venting of a failing battery cell. Because the battery cell holder  1508 , and in particular the wall  1702 , is designed to locally fail, the battery cell holder  1508  can improve the likelihood that venting gasses/materials are expelled or otherwise directed outside the UAV  100 . 
     Thus, though a failing battery cell  1503  may damage the power module  122  by forming an opening in the wall  1702 , the damage may be limited and/or contained to the failed cell and the opening, rather than causing other cells to fail or damaging internal components. Indeed, a failure of a single cell (or even multiple individual cells) may be tolerated during flight and not substantially disrupt the flight or otherwise require an unplanned landing. By contrast, in a conventional configuration a failed cell may damage the structure or electronics of a UAV, or even cause a cascading effect that could destroy a significant portion or even all of the cells of a battery pack, either of which could cause the UAV to make an unplanned landing or even crash. 
     In addition to carrying battery cells, the power module  122  may include other electronic components, such as processors, memory, GPS radios, sensors (e.g., altimeters, pressure transducers), avionics, or other components. For example, the power module  122  may have a GPS radio that supplements or otherwise works with the processors on the integrated coupling and control unit of a UAV. The GPS radio may be configured to store a current location of the power module  122  even when the power module  122  is not coupled to a UAV, such as when the power module  122  is being charged. When the power module  122  is coupled to a UAV, the GPS radio (and/or other associated processors and circuitry) on the power module  122  may communicate with the processors of the UAV and provide GPS information (e.g., a current location, the location or identifiers of available GPS satellites, or the like) to the processors of the UAV. In this way, the UAV may be capable of flying more quickly after a power module  122  is attached. In particular, the GPS radios that are resident on the UAV may have been unpowered due to the lack of a power module. Providing GPS or other location information to the UAV from the power module  122  thus prepares the UAV for flight without requiring the UAV to wait until the UAV-mounted GPS system starts up and acquires suitable location information. 
     The power module  122  may also include memory that stores data about the UAV to which it is attached. For example, the UAV may capture and store, in the power module&#39;s memory, data relating to altitude, speed, received commands, motor speed, commands or signals issued to flight control surfaces, or any other suitable data. When the power module  122  is removed from the UAV for charging, it may also be coupled to a data recovery system that retrieves and optionally stores the data. 
     In some cases, the same electrical connectors that electrically couple the memory of the power module  122  to the integrated coupling and control system are also used to couple the memory of the power module  122  to the data recovery system. Similarly, the same electrical connectors that provide power from the power module  122  to the UAV are also used to charge the power  122 . For example, a charging system may include mechanical retention structures and electrical connectors that mimic or are otherwise similar to those on a UAV. Accordingly, the power module  122  may be easily and simply coupled to the charging system in the same manner that would be coupled to a UAV, and the mechanical coupling process may result in the electrical coupling between the power module  122  and the charging system (e.g., for the transfer of both power and data). 
     The foregoing description relates to the features and functions of a UAV. The UAV described herein may be part of an Unmanned Aerial System (UAS) that operates multiple UAVs (such as multiple ones of the UAV  100  and/or any other suitable UAVs). An example UAS is now described with reference to  FIGS. 18A-21 . The UAS may operate one or more UAVs to perform various functions, including, but not limited to, package delivery, data capture, mapping, surveillance, and infrastructure-provisioning. Additional details of a UAS that may include and/or use UAVs as described herein may be found, for example, in U.S. Pat. No. 9,489,852, entitled “Unmanned Aerial Vehicle Management System,” and in U.S. Pat. No. 9,488,979, entitled “System And Method For Human Operator Intervention In Autonomous Vehicle Operations,” U.S. patent application Ser. No. 14/966,265, entitled “Decentralized Air Traffic Management System For Unmanned Aerial Vehicles,” and U.S. patent application Ser. No. 15/229,099, entitled “Vision Based Calibration System for Unmanned Aerial Vehicles,” each of which are incorporated by reference herein in their entireties. 
       FIG. 18A  illustrates an embodiment of a UAS and interfacing entities. The UAS  1800  receives a service request from a service requestor  1804  and deploys a UAV  1802  (e.g., the UAV  100 ,  FIG. 1 ) to fulfill that request. In this embodiment, the UAS  1800  comprises a distribution center  1801 , a UAV  1802 , and global services  1803 . Although a single UAV  1802  is depicted in  FIG. 18A , there may be more than one UAV  1802  in a UAS  1800 . As noted above, the UAVs in a UAS may include multiple UAVs such as those described above, as well as other types of UAVs (e.g., multi-rotor aircraft, balloons, lighter-than-air vehicles, etc.). 
     The service requestor  1804  may be a human user or an autonomous system that issues a service request to the UAS  1800 . In the case where the service requestor  1804  is a human user, that user may use a remote client device such as a mobile phone, tablet, or personal computer to issue the request. A service request is an instruction to the UAS  1800  to provide some service at the destination site  1805 . The destination site  1805  may be any designated location, such as a portion of open ground, a building, a mailing address, a GPS coordinate, or a slice of airspace. In some embodiments, the destination site  1805  is the location of a beacon device. The beacon device may be any device that emits a signal that can be used to track or identify a location, such as for example a transponder, a mobile phone, etc. The destination site  1805  may also be designated by identifying a particular object, such as, for example, a designated vehicle, a mailbox, a delivery pad, or some other target object that can be tracked to indicate a target location for a service. In another embodiment, the destination site  1805  is the location of the service requestor  1804 , although this need not be the case. Although one service requestor  1804  and one destination site  1805  are illustrated in this embodiment, in practice there can be many service requestors  1804  and destination sites  1805 . 
     The requested service may be any service that can be provided from an airborne platform. For example, in one embodiment, the service request issued by the service requestor  1804  is a request to deliver a package containing a specific payload to the destination site  1805 . In another embodiment, the service request is a request to capture image data using a camera mounted on the UAV  1802 , at the destination site  1805  or along a route to and from the destination site  1805 . In yet another embodiment, the service request is a request to provide an Internet access point at the destination site  1805  using a Wi-Fi gateway mounted on the UAV  1802 . Many other services can be provided using the UAS  1800  at the destination site  1805 , such as package pickup, surveillance, mapping, data capture using UAV-mounted instruments, etc. 
     The distribution center  1801  may be a fixed or mobile facility that facilitates the launch, recharge, recovery, communications, repair, and payload logistics for the UAV  1802 . The distribution center  1801  is explained in further detail in the description for  FIG. 20 . Although a single distribution center  1801  is shown in  FIG. 18A , there may be more than one distribution center  1801  in the UAS  1800 . In one embodiment, each UAV  1802  in the UAS  1800  is based at a single distribution center  1801 , and is repaired, reloaded, and recharged at that distribution center  1801 . In another embodiment, each UAV  1802  can be repaired, reloaded, and recharged at any distribution center  1801  in the UAS  1800 , and UAVs  1802  may be routed between distribution centers  1801  based on the logistical requirements of current service requests and the projected requirements for future service requests. 
     The global services  1803  may be comprised of one or more computer server systems, running software services (i.e. computer software programs), accessible through the Internet, which provide offsite support, administration, air traffic control, communications, data storage and logistics functions for the distribution centers  1801  and the UAVs  1802 . In one embodiment, the global services  1803  route a service request from a service requestor  1804  to a distribution center  1801  that is geographically adjacent to (or in relative geographic proximity to) the destination site  1805 . The global services  1803  are explained in more detail in the description for  FIG. 21 . 
     The global system operator  1806  may be a human user that monitors and operates the UAS  1800  to ensure the correct and efficient functioning of the system. For example, in some embodiments, the global system operator  1806  may monitor the UAS  1800  through the computer servers of the global services  1803 , to ensure that a distribution center  1801  has the appropriate payload in stock to fulfill a service request from a service requestor  1804 . In one example embodiment, the global system operator  1806  may use the global services  1803  to route new stock of a particular payload to a distribution center  1801  in anticipation of that payload stock being depleted. 
     There may be more than one global system operator  1806 , and the global system operators  1806  may monitor and provide services for multiple distribution centers  1801 , UAVs  1802 , and service requesters  1804 . In some embodiments, one or more of the global system operators  1806  are trained UAV pilots, and the UAS  1800  may hand over control of a UAV  1802  to one such operator, temporarily or for the duration of a UAV mission. 
     The distribution center operator  1807  is a human user that monitors and operates the distribution center  1801 . The distribution center operator  1807  may ensure that the UAS  1800  components that are local to the distribution center  1801  function correctly. This includes the UAVs  1802  based at the distribution center  1801 , as well as other components such as launchers, rechargers, payloads, etc. The distribution center  1801  provides systems and methods to facilitate the tasks of the distribution center operator  1807 . For example, in some embodiments, the distribution center operator  1807  operating a distribution center  1801  is provided with an operator interface that allows her to determine the inventory of each type of payload at that distribution center  1801 , and that enables her to order more of any type of payload that is in short supply. The distribution center systems and methods that facilitate the distribution center operator  1807 &#39;s work are explained in more detail in the description for  FIG. 21 . 
       FIG. 18B  illustrates one embodiment of a UAV launch process implemented by the UAS  1800 . As an initial step the global services  1803  of the UAS  1800  receive  1850  a service request from a service requester  1804 . The service request specifies a destination site  1805 , which designates the location where the service is to be delivered. As described herein, the service request may also include payload information, corresponding to a payload requested by the service requester. The global services  1803  then select  1851  a suitable distribution center  1801  from which to fulfill the service request. In some embodiments, the global services  1803  select  1851  the distribution center  1801  from which to fulfill the service request by determining the distribution center  1801  that is closest to the location of the destination site  1805 . In another embodiment, the global services  1803  select  1851  a distribution center  1801  to fulfill the service request by taking into account both the proximity of the distribution center  1801  to the destination site  1805  as well as an inventory at the distribution center  1801  that indicates the availability of a payload specified in the service request. For example, if the service request is a request to deliver a specific type of item to the destination site  1805 , the global services  1803  will select the distribution center  1801  from those distribution centers that are near the destination site  1805  and have the requested item in their inventory. Other factors can also be used to select a distribution center  1801 , such as, for example, the local weather conditions and air traffic at the distribution centers  1801 . 
     Once a distribution center  1801  is selected  1851 , at least a portion of the information in the service request is sent  1852  to that distribution center  1801 . In addition to the destination site location and payload information, the service request may contain other information that is useful at the distribution center  1801  for the fulfillment of the service request. For example, in some embodiments, the service request further comprises a time designating when the service request should be fulfilled at the destination site  1805 . 
     A UAV  1802  can be selected  1853  to fly a mission to fulfill the request, either during the distribution center selection process or afterwards. The UAV  1802  that will fly the mission may be selected  1853  based on one or more criteria that are relevant to the service request and/or system efficiency. For example, in one embodiment, the UAV  1802  is selected  1853  based on the charge level of its battery and the distance to the destination site  1805 . In another embodiment, the UAV  1802  is selected  1853  based on the instruments that are installed on its airframe and a type of data capture specified in the service request. In yet another embodiment, the UAV  1802  is selected  1853  based on a package in its payload matching a package specified for delivery in the service request. 
     In an alternative embodiment, the UAS  1800  does not select from pre-configured UAVs for a given mission. Instead, either the distribution center  1801  or the global services  1803  determine a set of components that are required to complete the service request, and the distribution center  1801  causes a UAV comprising the required components to be assembled for the mission. For example, if the destination site  1805  is a certain distance from the distribution center  1801 , the UAV for the mission can be configured with a suitable battery pack to complete a round-trip flight to that destination. 
     The selection  1853  of the UAV  1802  may occur after the selection  1851  of the distribution center, or may be used as a factor in selecting  1851  the distribution center  1801 . For example, the distribution center  1801  may be selected  1851  from only those distribution centers that have a particular type of UAV airframe, UAV battery (e.g., power module  122 ,  FIG. 1A ), or UAV motor, based on the weight of a payload required by the service request. 
     Once the UAV  1802  is selected  1853  for the mission, mission data is generated  1854  for it. The mission data is information that enables the UAV  1802  to navigate to the destination site  1805  and fulfill the service request. In some embodiments, the mission data includes GPS coordinates for the destination site  1805  as well as flight corridor information facilitating navigation to those GPS coordinates. The flight corridor information is discussed in more detail in the descriptions for  FIG. 19A  and  FIG. 20 . Further details related to the mission data are discussed in the descriptions for  FIG. 19A ,  FIG. 20 , and  FIG. 21 . After the mission data is generated  1854 , it is uploaded into a database on the UAV  1802 . 
     Once the mission data is generated and uploaded  1854 , the UAV  1802  is launched  1855 . From the time the UAV  1802  is launched and until it lands again, it is considered to be on a mission to complete the service request. In one embodiment, the UAV  1802  may be launched with a mission to fulfill more than a single service request. In another embodiment, at least a part of the mission data is uploaded and perhaps even generated, after the UAV  1802  is launched  1855 . 
       FIG. 19A  is a block diagram of a UAV  1802  according to one example embodiment. The UAV  1802  is an aircraft system with hardware and software modules that enable it to fulfill service requests with little or no human supervision. In one embodiment, the UAV  1802  corresponds to the UAV  100 , described above. 
     The embodiment of the UAV  1802  illustrated in  FIG. 19A  comprises a mission planner  1900 , a flight controller  1901 , a sensor system  1902 , a communications system  1903 , an actuator control system  1904 , a propulsion management system  1905 , a payload management system  1906 , and a safety system  1907 . The foregoing systems (also referred to as modules) of the UAV  1802  may include and/or interact with physical components of the UAV  1802 . For example, the flight controller  1901  may be implemented at least in part by a processor that is part of an integrated coupling and control unit  401 , as described above. As another example, the sensor system  1902  may include sensors that are coupled to the fuselage of the UAV  100 , as well as a processor that is part of an integrated coupling and control unit  401 . Operations performed by the foregoing systems of the UAV  1802 , including algorithmic and/or logical operations, may be implemented at least in part by a processor, memory (e.g., non-transitory computer readable storage media), and/or other components that are part of the integrated coupling and control unit  401 . 
     Although not depicted in the figure, the modules of the UAV  1802  may be interconnected via at least one communications bus. The bus allows the modules to communicate with each other to receive and send information and commands. The bus may be implemented using any of the methods known to those with familiarity in aviation and vehicle engineering. For example, the bus may be implemented using the Controller Area Network (CAN) standard. To improve the reliability of the system, embodiments may use additional redundant buses. For example, a dual-CAN bus can be implemented to prevent a bus failure from causing the UAV to lose control. 
     The mission planner  1900  is a module that provides the other modules of the UAV  1802  with high-level directives and goals; the execution of these directives and goals causes the UAV  1802  to fulfill a service request. The goals and directives produced by the mission planner  1900  are communicated to the other modules of the UAV  1802 , which may then take other actions to complete a mission, including the generation of additional directives and goals for other modules of the system. 
     For instance, in one embodiment, the mission planner  1900  determines a set of waypoints that the UAV  1802  may traverse in order to reach a destination site  1805 , and provides the location of a first waypoint to the flight controller  1901  as a goal, along with a directive to fly to that location. In this embodiment, the flight controller  1901  may then, in turn, compute the orientation and propulsion needed to move the UAV  1802  towards the goal location; the flight controller  1901  may also generate further directives for other modules, such as, for example, for the actuator control system  1904  and for the propulsion management system  1905 . The directives sent to the actuator control system  1904  and the propulsion management system  1905  may cause them to take actions that change the orientation of the UAV  1802  and propel it towards the goal location. As a result of the actions taken by various modules in the UAV  1802  in response to the directives and goals of the mission planner  1900 , the UAV  1802  will fly to the designated first waypoint. Once that goal is achieved, the mission planner  1900  may send new goals and directives to the other modules, such that the UAV  1802  flies to a second waypoint, and a third waypoint, and so on, until the higher-level goal of reaching the destination site  1805  is fulfilled. 
     Besides movement directives, the mission planner  1900  may issue other directives to the modules of the UAV  1802  that cause actions such as dropping of a payload, capturing of image data, transmitting of data, etc. The mission planner  1900  may also receive commands from the global services  1803 , from human operators, or from third-party controllers (such as air traffic controllers), and may issue directives to the UAV  1802  modules based on these commands. For instance, in one example embodiment, the mission planner  1900 , on board a UAV  1802 , may receive a command from a human operator to fly back to a distribution center  1801  due to an approaching storm. In response to this command, the mission planner  1900  will produce new goals and directives that are sent to other modules in the UAV  1802 , and as a result of these new goals and directives, the UAV  1802  will change course and return to the distribution center  1801 . 
     The mission planner  1900  is provided with mission data prior to the launch of the UAV  1802  from the distribution center  1801 . The mission data includes information that enables the mission planner  1900  to locate the destination site  1805 , to determine an appropriate route to that location, and to perform any request-specific actions required to complete the service request. For example, in some embodiments, the mission planner  1900  is provided with a destination location, a route to the destination location, and a series of points along the route where images are to be captured with an on-board camera. 
     In some embodiments, the mission data includes a local skymap for an area of operation. The area of operation may be a geographic region that encompasses the distribution center  1801  and the destination site  1805 . The local skymap includes information about a plurality of flight corridors within the area of operation. In some embodiments, the local skymap is generated from a global skymap, which contains information about flight corridors within a wider geographic area, by selecting the information in the global skymap that pertains to flight corridors within the area of operation. 
     A flight corridor may be an area of airspace that is designated by the UAS  1800  for UAV flight. The local conditions in a flight corridor may be monitored by the UAS  1800 , and the flight corridors may be used by the UAVs  1802  to travel safely and efficiently between locations. The local skymap comprises information about each of a plurality of flight corridors. The information about each flight corridor may include, but is not limited to, data about the flight corridor&#39;s location, local wind conditions, local air traffic (i.e. other UAVs and aircraft within the flight corridor), precipitation, aerial hazards, geographic obstacles (e.g. Mountains), etc. 
     Using the information in the skymap, the mission planner  1900  develops a dynamic route from the distribution center  1801  to the destination site  1805 , prior to launch or soon after launch. The dynamic route takes into account the goals of the mission as well as the requirement of the UAV  1802  to return to a distribution center  1801  after fulfilling the service request. In some embodiments, the mission planner  1900  receives a pre-generated route from the distribution center  1801  or the global services  1803 , and modifies that route only as conditions in the skymap change over time. 
     The dynamic route may be a sequence of flight corridors that the UAV  1802  may traverse to fly from its present location to some goal location. As the UAV  1802  flies its mission, it may receive updates to the skymap from the UAS  1800 , including updates concerning local conditions of the flight corridors in the area of operation. The updates may be received from the global services  1803 , from the distribution centers  1801 , or from other UAVs  1802 . In some embodiments, updates may also be received from the service requestors  1804 , or from third-parties, such as weather information providers, news services, air traffic controllers, satellites, civil aviation authorities, law enforcement, military aviation authorities, etc. 
     The mission planner  1900  may modify the dynamic route during the mission as the flight corridor updates are received. For example, in some embodiments, the mission planner  1900  may alter the dynamic route to avoid flight hazards such as inclement weather, aircraft trespassing into a flight corridor, etc. When the route is modified, the mission planner  1900  will re-determine the sequence of flight corridors that will be traversed to reach the goal location. 
       FIG. 19B  illustrates one embodiment of the mission planner  1900 &#39;s dynamic routing process for a goal location. In the illustrated process the UAV  1802  first receives  1950  an initial local skymap. The skymap may be received prior to launch or after launch. In one embodiment, a skymap is received from the global services  1803  directly. In another embodiment, a skymap is received from the distribution center  1801 . 
     In one embodiment, the skymap that is provided to the UAV  1802  is a global skymap that contains data about the entire area that the UAS  1800  covers. In another embodiment, the skymap contains information about only the area of operation for the UAV  1802 &#39;s current mission. 
     Once the skymap is received  1950  the mission planner  1900  computes  1951  a traversal cost for each flight corridor in the area of operation. The traversal cost for a flight corridor is a measure of the suitability of the corridor&#39;s path for a flight to the goal location. The goal location may be any point that the UAV  1802  must traverse to complete its mission. For example, the destination site  1805  may be the goal location on the outward leg of the UAV  1802 &#39;s mission, while the distribution center  1801  may be the goal location on the return leg of the UAV  1802 &#39;s mission. The traversal cost of a flight corridor may take into account many factors, including but not limited to, the wind speed and weather in the flight corridor, the air traffic within the flight corridor, the length and elevation of the flight corridor, and the number and direction of maneuvers required to navigate the flight corridor. The traversal cost for a flight corridor may take into account the predicted energy consumption necessary to fly the UAV  1802  along the flight corridor&#39;s path. Flight corridors that are predicted to require greater energy to traverse may be assigned a greater traversal cost than flight corridors that require less energy. For example, a flight corridor that has a tailwind may have a lower traversal cost than a flight corridor with a headwind. The traversal cost may also take into account regulatory limits to flight paths. For example, if a flight corridor intersects an area that has been temporarily designated as a no-fly zone by the local aviation authority, the traversal cost for that flight corridor may be set to infinity until the no-fly restriction is lifted. 
     In some embodiments, the traversal cost for flight corridors is pre-computed by the global services  1803  or the distribution center  1801 , and is included in the skymap received  1950  by the UAV  1802 . 
     After the traversal cost for each flight corridor in the skymap is computed  1951  the mission planner  1900  determines  1952  a lowest cost route from the UAV  1802 &#39;s current position to the goal location, using the flight corridors. Any appropriate path-finding and/or graph traversal algorithms can be used to find the lowest cost route. 
     Once the lowest cost route is determined  1952 , the UAV  1802  may traverse  1953  the lowest cost route. As the UAV  1802  flies to the goal location, it may periodically receive information from the global services  1803 , the distribution centers  1801 , other UAVs  1802 , and third party information sources (such as weather services, aviation authorities, etc.). Any of the data received from such sources may constitute a local skymap update, in the sense that the traversal cost of one or more flight corridors in the area of operations may need to be changed. For example, if the weather in a particular region changes, the traversal cost of flight corridors in that region may increase or decrease depending on the wind in those flight corridors and the direction that the UAV  1802  must fly. 
     The mission planner  1900  will determine  1954  whether a given piece of data received by the UAV  1802  constitutes a local skymap update by applying rules and heuristics to the received information. For example, in some embodiments, if the mission planner  1900  receives information that pertains to regions outside the area of operations, it may determine that this information does not constitute a local skymap update. 
     Some information that the UAV  1802  receives may be filtered out from consideration because it is not related to factors that may affect the flight of an aircraft. For example, if the UAV  1802  receives information regarding inventory levels at a distribution center  1801 , this information may be stored or forwarded, but it will not influence the local skymap, since inventory levels will not influence the traversal cost of flight corridors. (Note, however, that changing inventory levels may influence the mission planner  1900 &#39;s selection of a goal destination. For example, after a service request has been fulfilled, a UAV  1802  may be routed to land at a distribution center  1801  where there are insufficient UAVs in the inventory for future missions, as opposed to the distribution center that it took off from.) 
     As long as the mission planner  1900  determines  1954  that no data requiring an update to the local skymap has been received, the UAV  1802  continues to fly on the lowest cost route that has already been determined  1952 . However, if a local skymap update has been received, then the mission planner  1900  will update  1955  the traversal cost for each affected flight corridor in the local skymap. 
     The mission planner  1900  may then re-determine  1952  the lowest cost route to the goal location based on the updated traversal costs of the flight corridors in the local skymap. 
     As illustrated in  FIG. 19A , the UAV  1802  also includes a flight controller  1901 . The flight controller  1901  provides the mission planner  1900  with guidance, navigation, and control functions. For example, the mission planner  1900  is required to know the location, orientation, altitude, and speed of the UAV  1802  at various times during the mission, and the flight controller  1901  provides this information through a process called state estimation. Similarly, when the mission planner  1900  requires the UAV  1802  to move from one point to another, it sends commands to the flight controller  1901  to achieve that goal. The flight controller  1901  communicates over the bus with the sensor system  1902 , the actuator control system  1904 , and the propulsion management system  1905 , to provide the guidance, navigation, and control functions. 
     The sensor system  1902  provides information from sensor instruments to the flight controller  1901 . In some embodiments, the sensor system  1902  comprises several instruments, such as, for example, a Global Positioning System (GPS) unit, an Inertial Measurement Unit (IMU), dynamic pressure sensor, static pressure sensor, air temperature reader, etc., any or all of which may be attached to the circuit board  1102  ( FIG. 11A ), or any other component of the integrated coupling and control unit  401 . 
     The actuator control system  1904  includes motorized actuators (or actuators that are moved by any other means, such as hydraulics) that control various moving parts on the UAV  1802 , including the flight control surfaces on the UAV  1802  (e.g., the flight control surfaces  116 ,  118 ,  FIGS. 1A-1B ). The actuator control system  1904  can change the state of the motorized actuators based on commands from the flight controller  1901 . The actuator control system  1904  can also report the current state of the motorized actuators back to the flight controller  1901 . 
     The propulsion management system  1905  controls the force exerted by the motor mounted on the UAV  1802  (e.g., the motor module  108 ,  FIG. 1A )—for example by adjusting the speed of propellers mounted on a propeller powered UAV—and monitors the amount of fuel and/or battery capacity remaining on the UAV. The flight controller  1901  can adjust the speed of travel of the UAV  1802  by communicating with the propulsion management system  1905 . 
     The flight controller  1901  receives information from the sensor management system  1902  and the actuator control system  1904 , and performs a state estimation that provides a best guess of the UAV  1802 &#39;s position, orientation, and speed to the mission planner  1900 . The state estimation is continuously updated and checked as the various systems of the UAV  1802  provide new information. 
     The mission planner  1900  determines the high-level goal location that the UAV  1802  must travel to and communicates the goal location to the flight controller  1901 . The mission planner  1900  may communicate commands and goals to the flight controller  1901  using any appropriate technique(s). For example, in one embodiment, the mission planner  1900  communicates movement goals to the flight controller  1901  via a sequence of waypoints. In another alternative embodiment, the mission planner  1900  communicates movement goals to the flight controller  1901  via splines. 
     The flight controller  1901  receives the movement goals—as waypoints, splines, or any other suitable form—and determines, based on rules or physics-based models, the commands that must be communicated to the actuator control system  1904  and the propulsion management system  1905  to achieve the movement goals. For example, according to some embodiments, the physics-based models output the required rudder and elevator state, and the motor thrust for the UAV  1802 , based on the current state estimation (i.e. the UAV  1802 &#39;s position, orientation, and speed), and the local conditions including wind and temperature. 
     The communication system  1903  comprises transmitters and receivers that enable the UAV  1802  to send and receive information using different communications protocols. The communication system  1903  may include transmitters and receivers for standard cellular radio technologies such as CDMA, GSM, 3G/4G, LTE, etc., as well as custom line-of-sight and mesh protocols that allow the UAV  1802  to directly communicate with a distribution center  1801  or another UAV  1802 . 
     Although the UAV  1802  is designed to operate autonomously, the mission planner  1900  is configured to receive instructions via the communications system  1903  that may override the mission planner  1900 &#39;s flight plans. For example, the UAV  1802  may receive instructions from a distribution center  1801  or the global services  1803  that command the UAV  1802  to return to base immediately due to bad weather or a passenger aircraft entering the area. On receiving such a command the mission planner  1900  will change the movement goals of the UAV  1802  and issue new directives to the other modules so that the UAV  1802  adjusts its flight path as necessary. 
     The payload management system  1906  performs various functions related to the payload carried by the UAV  1802 , depending on the nature of the service request and the payload. For example, when the payload is attached to the UAV  1802  prior to launch, the payload management system  1906 , will communicate that the attachment is successful to the mission planner  1900  and/or the distribution center  1801 . In the case where the service request is a package delivery, the payload management system  1906  also monitors the state of the payload—for example the temperature of the payload in the case where the payload is perishable—and manages the release of the payload at the destination site  1805 . In this example, the mission planner  1900  determines the location, altitude, speed, and orientation of the UAV  1802  required to drop the payload safely at the destination site  1805 , and communicates a command to release the payload at the appropriate time to the payload management system  1906 . The payload management system  1906  receives the command and releases the payload. 
     The payload management system  1906  may perform other functions depending on the nature of the payload. For example, in the case where the service request is related to surveillance or mapping, the payload management system  1906  may interface with a camera system included in the payload and can capture images or video based on instructions received from the mission planner  1900 . For instance, in this embodiment, the mission planner  1900  may issue a command to the payload management system  1906  to capture images when the UAV  1802  flies over some point of interest in its route. 
     The safety system  1907  manages various failsafe components mounted on the UAV  1802 . For example, in one embodiment, the safety system  1907  monitors and controls a parachute system (e.g., the deployable parachute system  1400 ,  FIG. 14A-14D ) that may be deployed based on a command received from the mission planner  1900 , or based on information received directly from the flight controller  1901  or sensor system  1902 . For instance, if the UAV  1802  enters a non-recoverable dive, the safety system  1907  may deploy the parachute based on data received from the sensor system  1902 . In another embodiment, the mission planner  1900  may instruct the safety system  1907  to deploy a parachute based on a message received from the global services  1803  or a distribution center  1801 . Parachute deployment on command may be useful in situations where an air traffic control process detects the possibility of imminent collision between multiple aircraft in an area with heavy air traffic. Forcing a UAV  1802  to deploy its parachute and descend may prevent it from entering the flight path of other aircraft. 
     The structure and functionality of the UAV  1802  described above has been divided into modules based on one example implementation, but the functionality of various modules may be merged or further split such that there are more or less components than have been illustrated in  FIG. 19A . It is also possible to devolve some of the functionality of the various modules directly into the actuators, sensors, and other hardware components of the UAV  1802 . For instance, the flight controller  1901  may communicate directly with a plurality of actuator motors, each of which has the functionality of the described actuator control system  1904 . Such a decentralization of hardware component control may be beneficial in some implementations from the point of view of fault-tolerance. 
     As noted above, the distribution center  1801  handles the local logistics for the UAS  1800 . When the global services  1803  receive a service request from a service requestor  1804 , the global services  1803  will select a distribution center  1801  to fulfill the service request according to criteria in the service request, including the location of the destination site  1805 . The global services  1803  will then send at least a portion of the information in the service request to the selected distribution center  1801 . 
     The distribution center  1801  is responsible for launching and recovering UAVs  1802 , maintaining and monitoring inventories of payloads and UAVs  1802 , and communicating local information to the global services  1803 . Other functions such as UAV or component selection for missions, mission data preparation, UAV monitoring and communication during the mission, and other tasks can be performed by either the distribution centers  1801  or the global services  1803 , depending on implementation and/or system status. A distribution center operator  1807  may be stationed at the distribution center  1801  to facilitate the distribution center operations. 
       FIG. 20  is a block diagram of a distribution center  1801 , according to one example embodiment. As mentioned previously, some of the functions performed by this embodiment of the distribution center  1801  could be performed by the global services  1803  instead. Similarly, some of the functions of the global services  1803  could be performed locally by the distribution center  1801 . System designers with skill in the art may divide the functionality of the global services  1803  and the distribution centers  1801  in any appropriate way based on the requirements of a particular UAS implementation. 
     In this embodiment, the distribution center  1801  is comprised of a propulsion inventory management system  2001 , a payload inventory management system  2002 , a verification and launch system  2003 , a distribution center management system  2004 , an operator interface  2012 , and a UAV inventory management system  2013 . 
     The distribution center management system  2004  serves as the hub of the distribution center  1801 . In this embodiment, the distribution center management system  2004  comprises a mission manager  2005 , sensor station  2006 , communications station  2007 , logistics system  2008 , skymap database  2009 , terrain map database  2010 , and interface handler  2011 . In one example embodiment, the distribution center management system  2004  is implemented using one or more computer servers that have specialized sensor and communications peripherals installed. 
     Some of the functions of the distribution center  1801  may require the assistance of a human distribution center operator  1807 . For example, UAV assembly, UAV repair, payload attachment and detachment, UAV recovery, battery replacement, and refueling are tasks that may require human involvement if they are not fully automated. The operator interface  2012  allows the distribution center operator  1807  to receive information and instructions from the distribution center management system  2004  and the global services  1803 , as well as to send information and instructions back to the distribution center management system  2004  and the global services  1803 . The distribution center management system  2004  communicates with the operator interface  2012  via the interface handler  2011 . In some embodiments, the operator interface  2012  is an application running on a smartphone, a tablet computer, or a personal computer, and the interface handler  2011  communicates with the application via a wireless communications protocol, such as IEEE  302 . 11 . 
     The mission manager  2005  is a module that is responsible for managing the local aspects of mission operations at the distribution center  1801 . In some embodiments, the mission manager  2005  receives service requests (or data derived from the service requests) from the global services  1803 , selects a UAV  1802  or UAV components that will be assembled into a UAV  1802 , prepares the mission data that will be utilized by the UAV  1802  during the mission, selects an appropriate payload for the mission, tests and launches the UAV  1802 , and monitors the status of the UAV  1802  and payload during the mission. The mission manager  2005  communicates with the distribution center operator  1807  via the operator interface  2012  during various stages of the mission to communicate both the status of the mission, as well as instructions indicating the actions to be taken to facilitate the preparation, loading, launch, and recovery of UAVs  1802 . 
     The mission manager  2005  utilizes the other components of the distribution center management system  2004  to monitor the status of the local environment and various local components of the UAS  1800 , including the UAVs  1802  and the local inventories. 
     The mission manager  2005  maintains contact with the global services  1803  and local UAVs  1802  through the communications station  2007 . Information about service requests is received from the global services  1803 , and information about local conditions, ongoing missions, inventories, etc., is transmitted back to the global services  1803 . The communications station  2007  may have transmitters and receivers for several different standard telecommunications protocols, including, but not limited to GSM, CDMA, GSM, 3G/4G, LTE, etc. In addition to these standard protocols, the communications station  2007  may also support line-of-sight or mesh protocols to enable direct communications with UAVs  1802  and other distribution centers  1801 . Finally, the communications station  2007  may also include a wired connection to the Internet for high-speed communication with the other components of the UAS  1800  and third-party information providers. The mission manager  2005  may send some of the information received via the communications station  2007  to the operator interface  2012 , so that the distribution center operator  1807  can monitor the status of UAVs  1802  or other components of the UAS  1800  that are relevant to a local mission. 
     The sensor station  2006  is primarily used to gather local weather data for the distribution center  1801 &#39;s location. The sensor station  2006  may include pressure sensors, thermometers, wind sensors, precipitation detectors, etc. The sensor station  2006  may also be used to detect and track UAVs  1802  using instruments such as radars, radio trackers, and optical object recognition systems. The mission manager  2005  may present information from the sensor station  2006  to the distribution center operator  1807  via the operator interface  2012 , so that the distribution center operator  1807  can take actions necessary to protect the UAVs  1802  and distribution center  1801  from inclement weather. For example, if the sensor station  2006  detects an approaching storm, the mission manager  2005  may display a notification to the distribution center operator  1807  via the operator interface  2012 , and the operator  1807  can follow procedures to recover UAVs  1802  that have already been launched, to abort missions that have not been launched, and the like. 
     The logistics system  2008  tracks the inventory levels of various components at the distribution center  1801 , and reports these inventory levels to the global services  1803  and the mission manager  2005 . This inventory information may be used when selecting a particular distribution center  1801  to fulfill a service request. 
     The logistics system  2008  interfaces with the propulsion inventory management system  2001 , the payload inventory management system  2002 , and the UAV inventory management system  2013  to determine the inventory levels of fuel/batteries, payloads, and UAVs/UAV components, respectively. The logistics system  2008  is capable of requesting deliveries of additional stock when inventory levels fall below a threshold level or when inventory levels are predicted to fall below a threshold level within a specified period of time. 
     The global services  1803  may monitor the inventory levels reported by the logistics system  2008  and may proactively dispatch additional inventory items to a distribution center  1801  based on current inventory levels or the predicted inventory levels in the future. The logistics system  2008  may also directly notify the distribution center operator  1807  of inventory shortages, or of errors with specific items in an inventory, via the operator interface  2012 . Based on these notifications, the distribution center operator  1807  may restock or repair items as needed. 
     Each item at the distribution center  1801  may be affixed with a tracking tag that can be monitored by the logistics system  2008 . Various technologies can be used to implement the tracking tags, including bar codes, RFID tags, NFC tags, etc. These tags may be affixed to every item at the distribution center  1801  that requires tracking, including UAVs  1802 , UAV components, payloads, batteries, spare parts, etc. The tags associate an object identifier with each tracked physical object at the distribution center  1801 . For example, each payload at the distribution center  1801  will have an object identifier associated with it that is indicated by the tag affixed to it. The object identifier may be read from the tag by way of a reader that is configured to scan the tag. For example, an RFID tag would be read using an RFID reader, an NFC tag using an NFC reader, etc. 
     The object identifiers can be used to determine the type of an object that has been scanned as well as its unique identity. For example, the tag affixed to a payload object will identify that the object is a payload of a specific type, as well as that it is a specific instance of that payload, different from other payloads of the same type in the inventory. In some embodiments, the object identifier can be used to determine a database entry associated with the object in an inventory database. 
     The logistics system  2008  reports the inventory levels for objects associated with each object identifier to the global services  1803 . 
     Propulsion related components of the UAV&#39;s, such as batteries and/or fuel, are stored and tracked by the propulsion inventory management system  2001 . The propulsion inventory management system  2001  also has means for recharging batteries, refilling fuel tanks, etc. The propulsion inventory management system  2001  reports the inventory levels and status of fuel and/or batteries to the logistics system  2008 . For example, the propulsion inventory management system  2001  may track not only the number of batteries stocked at a particular distribution center  1801 , but may also track the level of charge in each of those batteries and the expected time for each battery to reach full charge. Additional properties of batteries may also be tracked, such as battery capacity, charge retention over time, etc. 
     The mission manager  2005  is made aware, via the logistics system  2008 , of the battery charge levels and/or fuel available for UAVs prior to a mission launch. The mission manager  2005  determines the energy resources that are required for each UAV  1802  based on the service requests and may instruct the distribution center operator  1807  to replace batteries on a UAV  1802  or to refuel a UAV  1802  to ensure that the aircraft has sufficient energy to complete a mission. For example, the mission manager  2005  may instruct the distribution center operator  1807 , via the operator interface  2012 , to load a battery having a particular charge state onto a specific UAV  1802  prior to that UAV  1802  being launched on a mission. 
     The payload inventory management system  2002  tracks inventory levels and status for various payloads that may be mounted to the UAVs  1802 . The payload inventory management system  2002  may also provide recharging, refrigeration, and other maintenance related functions related to specific payloads. For instance, if the payload is a vaccine, then the payload inventory management system may provide a refrigerated storage container for vaccine doses and may monitor and report the temperature in the storage container and the number of doses stored in the container to the logistics system  2008 . The mission manager  2005  may notify the distribution center operator  1807  of the status of various payloads stored at the distribution center  1801  via the operator interface  2012 . For example, in some embodiments, the mission manager  2005  may send a notification to the operator interface  2012  to notify the distribution center operator  1807  that a particular vaccine stored in the payload inventory management system  2002  has expired. Based on this notification the distribution center operator  1807  may remove the expired vaccine from storage and replace it with new stock. 
     The UAV inventory management system  2013  tracks the assembled UAVs  1802  and UAV components stored at the distribution center  1801 , and reports this information to the logistics system  2008 . The mission manager  2005  or global services  1803  may query the logistics system  2008  to determine the UAV resources available for missions at a particular distribution center  1801 , and may allocate these resources based on the requirements of service requests received by the UAS  1800 . When a particular UAV configuration is required to fulfill a mission, the mission manager  2005  may send instructions to the distribution center operator  1807 , via the operator interface  2012 , to assemble a particular set of UAV components—stored in the UAV inventory management system  2013 —to construct a UAV suitable to complete that mission. As UAVs or UAV components are added and removed from the inventory, the UAV inventory management system  2013  tracks not only the availability of these resources, but also the status of components, such as their condition and need for replacement. This information may be used by the mission manager  2005  and the global services  1803  to order deliveries of new UAVs  1802  or components for the distribution center  1801 . 
     The mission data that will be uploaded to the UAV  1802  is prepared based on the requirements of the service request received from the global services  1803 . Although we discuss the preparation of the mission data by the mission manager  2005 , alternative embodiments are possible, where either the global services  1803  or the mission planner  1900  onboard the UAV  1802 , prepare the mission data. The mission data includes not only the location of the destination site  1805  and the payload required to satisfy the service request, but also information required to generate a flight route to the destination location. The information required for route generation is stored locally in the skymap database  2009  and the terrain map database  2010 . 
     The skymap database  2009  contains data about a plurality of flight corridors in the geographic region served by the distribution center  1801 . The skymap database  2009  may be at least partially synchronized with a global skymap database  2100  that is part of the global services  1803 . The flight corridor data includes information about the real-time conditions within the flight corridors, such as weather, air traffic, etc. The local skymap database  2009  updates the flight corridor data based on the latest information received from the global services  1803 , other distribution centers  1801 , and third parties (such as weather services and air traffic controllers). UAVs  1802  that have recently flown in a flight corridor may also send data to the distribution center  1801  about the last monitored conditions present in the flight corridor, and this information may be used by the skymap database  2009  to update the relevant flight corridor data. When the local skymap database  2009  at the distribution center  1801  has more recent information about a flight corridor than the global skymap database  2100 , the global skymap database  2100  is updated via the communications station  2007 . The reverse is also true, and the latest updates from the global skymap database  2100  are received via the communications station  2007  and incorporated into the local skymap database  2009 . 
     The terrain map database  2010  contains terrain data, which is information about the terrain and ground obstacles in the geographic region served by the distribution center  1801 . This terrain data can be stored in a number of ways, including but not limited to, as raw images, as a heightmap, and as a three-dimensional (3D) mesh. The global services  1803  also include a global terrain map database  2101 , which is at least partially synchronized with the local terrain map database  2010 . As in the case with the skymap databases, the terrain map database  2010  is updated based on data captured from UAVs  1802  during their mission flights. For example, if a UAV  1802  flies over a location and captures information regarding a new obstacle that was not present at that location in the terrain map database  2010 , the terrain map database  2010  will be updated with the new information via data received from the UAV  1802 , either during the mission, or after the UAV  1802  has been returned to the distribution center  1801 . 
     Although the information about the flight corridors from the skymap database  2009  may be sufficient to route the UAV  1802  to the destination site  1805 , information about the ground that the UAV  1802  is flying over can also be useful during various phases of the mission. For instance, during UAV launch and recovery, the terrain and obstacles near the launch and recovery sites are relevant. In addition, if the service request requires a package delivery, then the terrain and obstacles at the destination site  1805  are relevant, as the UAV  1802 &#39;s mission planner  1900  must determine a location from which to drop the payload such that the payload lands in an accessible place and does not damage local structures, objects, or persons. 
     The information from the terrain map database  2010  is also useful for fulfilling service requests that require surveillance or mapping. In some instances, the terrain data from the terrain map database  2010  can be used to fulfill a surveillance or mapping request without launching a UAV. For example, if a UAV  1802  has recently captured imagery at a destination site  1805  at a particular location, and a subsequent service request asks for image capture at the same location, within some threshold time limit, then the most recent information from the destination site  1805  that has been stored in the terrain map database  2010  can be sent to the service requestor  1804 . 
     To prepare the mission data locally, the mission manager  2005  first determines the location of the destination site  1805  from the service request information received from the global services  1803 . Based on this destination location, and the launch location, which is typically the location of the distribution center  1801 , the mission manager  2005  determines the relevant area of operations for the mission, and extracts the data associated with this geographic region from the skymap database  2009  and the terrain map database  2010 . The extracted information is sent to the UAV  1802  as part of the mission data. In some embodiments, the mission manager  2005  also provides the UAV  1802  with a lowest cost route to the destination site  1805  as part of the mission data. Depending on the implementation, the route can be dynamically updated by the global services  1803 , the mission planner  1900  in the UAV  1802 , and/or the mission manager  2005 . When the connectivity to the UAV  1802  cannot be guaranteed during the mission flight, the mission planner  1900  onboard the UAV  1802  may be allowed to dynamically update the route. The process for dynamic route generation is explained in more detail in the description for  FIG. 19B . In embodiments discussed in connection with  FIG. 19B , the UAV  1802  receives the skymap data and determines the lowest cost route to the destination site  1805  using the onboard mission planner  1900 , instead of receiving the route from the mission manager  2005 . 
     In some embodiments, the UAV  1802  stores complete mirrors of the skymap database  2009  and the terrain map database  2010 , instead of only subsets of the information in these databases. This can be done when the size of the databases is small enough that the storage resources on the UAV  1802  are sufficient to store the entire dataset. When this is not the case, a subset of the information may be stored in the UAV  1802 , as described earlier. Similarly, in the case where the local skymap database  2009  and local terrain map database  2010  have sufficient storage capacity, the entire global skymap  2100  and global terrain map  2101  may be stored locally at the distribution center  1801 . Subsets of the global data may be extracted and stored locally only when the global data sets are too large for complete local mirroring to be economical. 
     The verification and launch system  2003  is responsible for testing, verification, and launching of UAVs  1802 . The UAVs  1802  are loaded into the verification and launch system  2003 , and their components are tested to ensure that they will perform during the mission. Any faulty components are identified at this stage and brought to the attention of the distribution center operator  1807  via the operator interface  2012 . The verification and launch system  2003  also verifies, via the affixed tags, that each component in the assembled UAV  1802  is a component allocated by the mission manager  2005  for the current mission. For example, the verification and launch system  2003  detects the battery and motors attached to the UAV  1802 , and ensures that they have adequate charge and performance for the mission, prior to launch. Any discrepancies are brought to the attention of the distribution center operator  1807  for correction. Similarly, the verification and launch system  2003  verifies that the payload loaded onto the UAV  1802  is the right payload for the current mission. 
     Once the verification and launch system  2003  verifies the UAV  1802 , the UAV  1802  is launched, and the mission manager  2005  continues to monitor the aircraft during the mission flight. The mission manager  2005  receives status updates from the UAV  1802 , and these status updates enable the mission manager  2005  to track the progress of the mission at least intermittently. The mission manager  2005  may present information related to the UAV  1802 &#39;s status to the distribution center operator  1807  via the operator interface  2012 . In the event that there is some local event that requires a mission termination, such as, for example, an approaching storm, either the mission manager  2005  or the distribution center operator  1807  (or both), via the operator interface  2012 , can send a command to the UAV  1802 , through the communications station  2007 , to instruct the UAV  1802  to return to the distribution center  1801 . 
     The structure and functionality of the distribution center  1801  described above has been divided into modules based on one example implementation, but the functionality of various modules may be merged or further split such that there are more or fewer components than have been illustrated in  FIG. 20 . For instance, it is possible to implement many parts of the distribution center management system  2004 , including the mission manager  2005 , communications station  2007 , logistics system  2008 , and interface handler  2011  on a single piece of computer hardware, such as a computer server or embedded SOC. Similarly, the different inventory management systems could be merged under a single inventory manager, while the verification and launch system  2003  could be split into a separate verification system and launch system. 
     The UAS also includes global services  1803 , which are a collection of software services running on one or more computer servers, accessible through the Internet or another communications protocol. In one example embodiment, the global services  1803  are software modules running on virtual machines in a third-party data center, such as Amazon Web Services or Google Cloud. 
     One purpose of the global services  1803  is to provide a global infrastructure to coordinate, support, and manage multiple distribution centers  1801 , service requestors  1804 , and UAVs  1802 . However, in some embodiments, it is conceivable that the functionality of the global services  1803  is provided by a local computer server, and that the server serves a local set of UAVs  1802 , distribution centers  1801 , and service requestors  1804 —possibly only a single one of each. 
     One or more global system operators  1806  connect to the global services  1803  and provide human intervention for systems that cannot be fully automated (or are otherwise selected to not be fully automated). The global system operators  1806  typically connect to the global services  1803  through control devices. A control device may be a computer workstation, a personal computer, a tablet device, a smartphone, or any other computing device that can communicate through a network with the global services  1803 . For instance, in one example embodiment, a global system operator  1806  uses a laptop computer, with an Internet connection, to connect to the global services  1803  executing on a computer server, which is also connected to the Internet. 
     In the example embodiment illustrated in  FIG. 21 , the global services  1803  are configured to serve a plurality of distribution centers  1801 , UAVs  1802 , and service requestors  1804 . In this embodiment, the global services  1803  comprise a global skymap database  2100 , a global terrain map database  2101 , a data manager  2102 , a service request handler  2103 , a global logistics manager  2104 , an air traffic control system  2105 , and a system interface manager  2106 . 
     As discussed earlier, the global skymap database  2100  and the global terrain map database  2101  are global repositories for skymap and terrain map data in the UAS  1800 . As was the case with the local versions of these databases, the information in these databases can be represented in various ways depending on the needs of the UAS  1800 . Although these databases are represented as single units in the illustrated embodiment, in practice the databases may be implemented using several mirrored data stores to provide improved read speed, redundancy, and error recovery. 
     The data manager  2102  manages data-writes into, and data-reads out of the global databases. For example, as updates to the local skymap databases  2009  and local terrain map databases  2010  are communicated to the global services  1803 , the data manager  2102  ensures that the information is stored in the appropriate database and that the latest information is always available and is not overwritten by out-of-date information. The data manager  2102  also manages information received from outside of the UAS  1800  and integrates this information into the global databases. For instance, information received from third-party weather information providers, aviation authorities, and external air traffic controllers may be integrated into the global skymap database  2100 . Similarly, third-party topographical data, map imagery, and surveillance data may be integrated into the global terrain map database. 
     The data manager  2102  also manages the updates sent to the local databases at each distribution center  1801 . In one embodiment, as the global skymap database  2100  and global terrain map database  2101  are updated, the data manager  2102  will monitor the regions where those updates are relevant, and will send at least a portion of those updates to distribution centers  1801  that are in the relevant regions. In another embodiment, the mission manager  2005  at a distribution center  1801  in a particular region will periodically request information about that region from the global services  1803 , and the data manager  2102  will determine the set of information that is relevant to that region from the global databases, and will send that information to the distribution center  1801 , where the information may be integrated into the local databases. Similarly, a UAV  1802  in flight may request information about its current location from the global services  1803 , and the data manager  2102  may similarly determine the relevant information that should be sent back to the UAV  1802  based on the UAV  1802 &#39;s location. 
     The service request handler  2103  manages service requests sent by service requestors  1804  that are received by the global services  1803 . When a service request is received by the global services  1803 , the service request handler  2103  will communicate with the global logistics manager  2104  to determine a distribution center  1801  that is suitable for handling the service request locally. As mentioned previously, the selection of the distribution center  1801  may take into account not only the location of a destination site  1805  specified in the service request, but also the logistic requirements of the request, such as payload, UAV capability, etc. For instance, a service request may include information that specifies a payload type required to complete the request, and the distribution center  1801  may be selected based on the availability of that payload type at various distribution centers  1801 . 
     The payload type may be specified directly by means of a payload identifier associated with a type of payload, or it may be specified by implication. For example, a camera payload may be specified by implication if the service request is a request for image data at the destination site  1805 . 
     In some embodiments, the service request handler  2103  takes input from a global system operator  1806  to determine the distribution center  1801  that will be used to fulfill a service request. 
     Once the distribution center  1801  and UAV  1802  have been identified and reserved to fulfill a service request, the service request handler  2103  may notify the service requestor  1804  that the service request is in process. The service request handler  2103  may also receive information from the distribution center  1801  and/or the UAV  1802  that allows a predicted time of mission completion to be estimated and sent to the service requestor  1804 . 
     The service request handler  2103  is capable of communicating with the service requestor  1804  via the system interface manager  2106 . A human service requestor  1804  will typically send a service request to the global services  1803  by means of some remote client device such as a mobile phone, a tablet, or a personal computer. The system interface manager  2106  is capable of sending information to the client device operated by the service requestor  1804  that is configured to be displayed on the client device. For example, in one embodiment, the system interface manager  2106  functions as a web server, and the client device connects to the web server and displays a web page that is downloaded from the system interface manager  2106 . In this example, the system requestor  1804  can receive and send information to the global services  1803  via the displayed web page. In another embodiment, the system interface manager  2106  exposes an application interface over the Internet (such as a representational state transfer, or “REST” interface), and an application running on the client device is configured to display information received from the global services  1803  to the service requestor  1804 , and to send information inputted by the service requestor  1804  back to the global services  1803 . 
     The service request handler  2103  may also play an active part in determining the route a UAV  1802  takes on a mission to complete a service request. For example, the service request handler  2103  may use the system interface manager  2106  to query a service requestor  1804  for the precise location of the destination site  1805 , and the information provided by the service requestor  1804  may include route refinement information that may be used to refine the flight route used by the UAV  1802  in fulfilling the service request. 
     The service request handler  2103  utilizes the global logistics manager  2104  to obtain information required for distribution center  1801  and UAV  1802  selection. The global logistics manager  2104  tracks the inventory information in each local logistics system  2008  at each distribution center  1801 . The global logistics manager  2104  may proactively route additional stock to local distribution centers  1801  when supplies of any inventory item are depleted, are below some threshold quantity, or are predicted to be depleted within some threshold time. The global logistics manager  2104  may also notify a global system operator  1806  in the event of an inventory shortage at a distribution center  1801 . The global system operator  1806  may take actions outside the UAS  1800  to route new inventory items to the distribution center  1801 , such as, for example, ordering and shipping items from a third-party warehouse. 
     In one embodiment, the global logistics manager  2104  relocates UAVs  1802  from a first distribution center  1801  that has an excess of UAVs to a second distribution center  1801  that has a shortage of UAVs. In this embodiment, the global logistics manager  2104  may monitor the daily, monthly, or yearly patterns of service requests to determine the estimated UAV requirements at each distribution center  1801  over a period of time. Based on these estimated UAV requirements, the global logistics manager  2104  may preemptively relocate UAVs from one distribution center  1801  to another. The relocation of UAVs  1802  may be done using third-party shippers, or the relocation may be done by sending requests to the distribution centers  1801  to launch UAVs  1802  with destination sites  1805  set to other distribution centers  1801 . As an optimization, these relocation flights may be scheduled during times when the service request volume is low, for example, late at night or during holidays. 
     The air traffic control system  2105  is responsible for tracking the UAVs  1802  and aircraft that are known to be in flight in the area served by the UAS  1800 . The air traffic control system  2105  receives information from the distribution centers  1801 , the UAVs  1802  in flight, and from third party air traffic information providers. The information received by the air traffic control system  2105  includes the known positions of aircraft in the area of the UAS  1800 , as well as flight routes that are registered with the system. Distribution centers  1801  and/or UAVs  1802  may register flight routes for missions, with the air traffic control system  2105 . The air traffic control system  2105  may also allow UAVs and aircraft operated by third parties to register their flight routes. 
     The air traffic control system  2105  provides real-time information updates regarding the positions of aircraft and UAVs to UAVs  1802  that are flying missions. Using this information, the mission planners  1900  onboard the UAVs  1802  may modify their flight routes to avoid colliding with other aircraft. The air traffic control system  2105  may offer similar information updates to UAVs and other aircraft that are operating outside the UAS  1800  in order to maintain a safer airspace for all aircraft operations. 
     The air traffic control system  2105  also provides information to the service request handler  2103  and the global logistics manager  2104 . Information from the air traffic control system  2105  may be used to influence the selection of distribution centers  1801  for service requests and the relocation of UAVs  1802 . For example, a service request may be routed away from distribution centers  1801  where there is an excess of air traffic in the vicinity, and UAV relocation may be timed to avoid periods when air traffic is at its highest. 
     The structure and functionality of the global services  1803 , described above, has been divided into modules based on one example implementation, but the functionality of various modules may be merged or further split such that there are more or less components than have been illustrated in  FIG. 21 . For example, it is possible to merge the skymap and terrain map databases into a single data store. Some of the services illustrated can be moved outside the UAS  1800 , for example, the air traffic control system  2105  and the global logistics manager  2104  may be operated outside the UAS  1800  as independent services, accessible through an Application Programming Interface (API). These and other changes to the structure do not change the overall architecture of the system, and systems with such changes will be recognized by those with skill in the art as equivalent to the system disclosed. 
       FIG. 22A  illustrates an example shielded circuit board assembly  2200 , which may be used in UAVs as described herein. For example, the shielded circuit board assembly  2200  may be mounted to an anchor structure (e.g., the anchor structure  400 ,  FIG. 5 ). In some cases, a circuit board assembly  2200  as described with respect to  FIGS. 22A-22H  may be used instead of or in addition to the circuit board  1102  ( FIG. 11A ). The circuit board assembly  2200  may also be integrated with a UAV in a different manner, such as by being directly connected to a fuselage component, rather than being attached to an anchor structure.  FIG. 22B  is a schematic cross-sectional exploded view of the shielded circuit board assembly  2200  (along line  22 B- 22 B in  FIG. 22A ).  FIG. 22C  is a schematic cross-sectional view of the shielded circuit board assembly  2200  in an assembled configuration.  FIG. 22D  is a schematic cross-sectional view of an enclosure  2204  of the shielded circuit board assembly  2200 .  FIG. 22E  is a schematic cross-sectional view of an environmental gasket  2210  of the shielded circuit board assembly  2200 .  FIG. 22F  is a schematic cross-sectional view of an electromagnetic interference (EMI) gasket  2208  of the shielded circuit board assembly  2200 .  FIG. 22G  is a detail view of area  22 H ( FIG. 22A ) of the shielded circuit board assembly  2200 , showing a seam between a printed circuit board assembly (PCBA)  2202  and the enclosure  2204 .  FIG. 22H  is a detail view of the PCBA  2202 , showing an example configuration of an electromagnetic interference (EMI) component  2206 , the EMI gasket  2208 , and the environmental gasket  2210 . 
     The shielded circuit board assembly  2200  offers a lightweight solution to protect the PCBA  2202  from both solid and liquid ingress and from EMI. Ingress protection is provided by creating a physical barrier to the environment, and EMI protection is provided by creating a conductive encapsulation around sensitive components (e.g., mounted to the PCBA  2202 ), which shares an electrical potential to those components&#39; electrical ground. 
     The enclosure  2204  may include multiple layers. The enclosure  2204  may include an electromagnetic signal permissive layer  2220  and an electromagnetic blocking layer  2230 , as shown in  FIG. 22D . The electromagnetic signal permissive layer  2220  may be a structural component of the enclosure  2204  that includes or otherwise defines a housing or housing structure  2207 , as shown in  FIG. 22A . While many implementations are possible, the housing structure  2207  may generally include five sides (a base, such as a top or bottom, and four walls or sides extending from the base) the five sides defining an open space or void or volume extending into the housing structure  2207 . The housing structure  2207  of the electromagnetic signal permissive layer  2220  and at least a portion of the circuit board  2202  may cooperate to define a volume  2225 . The electromagnetic signal blocking layer  2230  may be structurally supported or otherwise attached to the electromagnetic permissive layer  2220  and generally operate to define a conductive barrier about the volume  2225 . In this regard, the enclosure  2204  may enclose the EMI component  2206  on the circuit board  2202  with the electromagnetic permissive layer  2220 , while providing a conductive barrier about the EMI component  2206  with the electromagnetic blocking layer  2230 . 
     The electromagnetic permissive layer  2220  may be formed from thin plastic stock, which is then thermoformed into the desired shape. For example and as shown in  FIG. 22D , the electromagnetic permissive layer  2230  may be a thermoformed plastic substrate  2222  (i.e. a substrate formed of a thermoplastic). The base of the enclosure  2204  features a flange  2205 , which is used to attach it to the PCBA  2202 . After the thermoformed plastic substrate  2222  is formed, a conductive metallic coating is then applied to define the electromagnetic blocking layer  2230 . An electroless nickel process is used, and a coating containing a specific proportion of Phosphorous is applied to provide corrosion resistance to the plating. In the example of  FIG. 22D , the electromagnetic blocking layer  2230  is shown as including a metallic layer  2232 , such as a metallic plating. The plating is applied in a sufficient thickness such that its EMI-blocking performance is sufficient for the intended application. The plating can have discontinuities  2236  or otherwise be discontinuous, so long as any discontinuity is shorter than the wavelength of the frequencies being protected against. The enclosure  2204  may be hermetic, such that no air is exchanged between the inside of the enclosure  2204  and the environment. It may also feature a vent  2212  to exchange air and vapor with the environment, but disallow liquid water and solid debris from entering. This may be desirable to allow the equalization of air pressure, if the assembly  2300  is operated at an altitude different from that at which it was assembled. 
     The PCBA  2202 , whose components may either produce EMI or be negatively affected by EMI, is designed with an exposed metal trace  2218  encompassing and/or surrounding the area of the PCBA  2202  where environmental and EMI protection is needed (e.g., extending about a perimeter of the PCBA  2202  or about a perimeter of a portion of the PCBA). The shape of this metal trace  2218  is configured to match or substantially match the footprint of the enclosure&#39;s flange. 
     The environmental gasket  2210  between the PCBA  2202  and enclosure  2204  may be formed from or include a double-sided adhesive  2252  with a foam core  2250 , as shown in  FIG. 22E . This environmental gasket  2210  may be a continuous piece of material, such that there are no gaps through which water or debris may enter the enclosure. 
     The EMI gasket  2208  between the PCBA  2202  and enclosure  2204  is made from segments of fabric-over-foam gasket. This may include a compressible foam core  2240 , a conductive metallic fabric exterior  2242 , and a conductive pressure-sensitive adhesive along its base  2244 , as shown in  FIG. 22F . The height hi of the EMI gasket  2208  is greater than a height h 2  of the environmental gasket  2210 , as illustrated in the exploded view of  FIG. 22B . When the enclosure  2204  is pressed or seated on the EMI gasket  2208 , the EMI gasket  2208  is compressed ( FIG. 22C ), and thereby forms a conductive bridge between the PCBA  2202  and enclosure  2204 , when the environmental gasket  2210  adheres to each. The EMI gasket  2208  may be discontinuous, so long as any discontinuity is shorter than the wavelength of the frequencies being protected against. 
     The advantages to the circuit board assembly  2200  as described herein are numerous. Firstly, the mass of the enclosure  2204  is minimized or reduced as compared to other shielding options (e.g., a sold metal enclosure). The thickness ti of the metallic shield/plating on the plastic of the enclosure  2204  can be very thin, on the order of about 5 microns to about 50 microns, to provide adequate EMI shielding, but if metal alone were used in this thickness, it would not be mechanically robust and could easily be damaged. By using a thin plastic substrate  2220 , adequate physical protection can be provided for the PCBA  2202 , and the metallic plating  2230  used for EMI shielding can be as thin and light as is required. 
     The use of the environmental gasket  2210  (with its adhesive properties) and fabric-over-foam gaskets also offers several advantages. Mass can be reduced or minimized thanks to the low density of both materials. Further, the evenly distributed adhesion of the environmental gasket  2210  may eliminate the need for screws or other fasteners, which, in conventional applications may be used at regular intervals to maintain compression on an elastomeric gasket. Finally, the enclosure  2204  can be rapidly assembled onto the PCBA  2202 . Assembly may aided by use of a press, which applies pressure along the flange  2205  of the enclosure  2204 , above the environmental gasket  2210 . This bond is intended to last the lifetime of the assembly; however, if high-value components within the enclosure, like radios or other modules, are desired, the enclosure can be removed without specialized tools. 
     While the shielded circuit board assembly  2200  is described as being integrated into the UAV  100 , this is merely one example type of vehicle that may include a shielded circuit board assembly as described herein, and it may be used in other types of vehicles as well, including any other suitable UAV, aircraft, road vehicle (e.g., car, truck), or the like. For example, turning to  FIGS. 23A-23C , an example shielded circuit board assembly  2300  is shown, which may be associated with an aircraft  2390 , such as a UAV. The shielded circuit board assembly  2300  may be substantially analogous to the shielded circuit board assembly  2200  and include a circuit board  2302 , an EMI component  2304 , one or more enclosures  2320 , an enclosure volume  2322 , an EMI gasket  2324 , and a vent  2328 ; redundant explanation of which is omitted for clarity. 
     Notwithstanding the foregoing similarities, the circuit board assembly  2300  is shown as having standoff features  2340 . The standoff features  2340  may be configured to removably attach the circuit board  2302  to a mount structure, fuselage, or other structure of the aircraft  2390 . Further, the standoff features  2340  may be configured to define an offset between the circuit board  2302  and the mount structure to accommodate the enclosure  2320 . To facilitate the foregoing, as shown in  FIG. 23A , the standoff features  2340  include a ridge  2342 , a board connection feature  2344 , and a mount connection feature  2348 . The ridge  2342  may extend the width or length of the circuit board  2302 . The ridge  2342  may have a height that is greater than a height of the enclosure  2320  from the circuit board  2302 . The greater height of the standoff feature  2340  may be used to define the offset of between the circuit board  2302  and the mount structure to accommodate the enclosure  2320  therebetween. The board connection feature  2344  may be a pin, latch, threaded feature or other structure that allows for the attachment of the circuit board  2302  to the standoff features  2340 . The mount connection feature  2348  may be a protrusion, clip, or the like that allows the standoff features  2340  to be removably received by one or more structures of the aircraft  2390 . This may facilitate modular construction of the aircraft  2390 , with the circuit board assembly  2300  being pressed into place during manufacturing and swappable with a replacement assembly as needed during use. 
     With reference to  FIG. 23B , the circuit board assembly  2300  is shown associated with a mount structure  2350  of the aircraft  2390 . The mount structure  2350  may include a landing  2354  and receiving features  2358 . The landing  2354  may be configured to accommodate a footprint of the circuit board  2302 . The receiving features  2358  may be configured to engage the standoff features  2340  in order to secure the circuit board assembly  2300  into a desired position. For example, the receiving features  2358  may be configured to receive protrusions, clips, or the like of the mount connection feature  2348  in order to releasably secure the circuit board assembly  2300  to the mount structure  2350 . 
     With reference to  FIG. 23C , the circuit board assembly  2300  is shown with the aircraft  2390 . The aircraft  2390  may be substantially analogous to any of the aircrafts described herein, such as the UAV  100  of  FIGS. 1A-5 . In this regard, the aircraft  2390  is show as including a fuselage  2360 , a motor module  2364 , a tail section  2368 , flight control surfaces  2370 , and tail support  2372 ; redundant explanation of which is omitted for clarity. 
     To facilitate the reader&#39;s understanding of the various functionalities of the embodiments discussed herein, reference is now made to the flow diagram in  FIG. 24 , which illustrates process  2400 . While specific steps (and orders of steps) of the methods presented herein have been illustrated and will be discussed, other methods (including more, fewer, or different steps than those illustrated) consistent with the teachings presented herein are also envisioned and encompassed with the present disclosure. 
     At operation  2404 , an enclosure is provided. For example and with reference to  FIG. 22D , the enclosure  2204  may be provided. The enclosure  2204  may be provided with the electromagnetic interference permissive layer  2220  and the electromagnetic interference blocking layer  2230 . The electromagnetic interference permissive layer  2220  may be defined by the thermoformed plastic substrate  2222 . The electromagnetic interference blocking layer  2230  may be defined by the metallic layer or plating  2232 . 
     At operation  2408 , an electromagnetic interference (EMI) component is enclosed with the enclosure. For example and with reference to  FIGS. 22B and 22C , the enclosure  2204  may enclose the EMI component  2206  on the circuit board  2202 . For example, the enclosure  2204  may enclose the EMI component  2206  within the volume  2225 . 
     At operation  2412 , the enclosure is coupled to the circuit board about the EMI component to define a circuit board assembly. For example and with reference to  FIGS. 22B and 22C , the enclosure  2204  may be pressed into the EMI gasket  2208 . The enclosure  2204  may adhere to the EMI gasket  2208  using the adhesive  2244 . The enclosure  2204  may be further pressed to compress the EMI gasket  2208  until the enclosure  2204  contacts the environmental gasket  2210 . The enclosure  2204  may contact the environmental gasket  2210  at the adhesive  2252 . The enclosure  2204  may therefore be bonded to the circuit board  2202  with the EMI gasket  2208  in a compressed state. 
     At operation  2418 , the circuit board assembly is attached with an aircraft. For example and with reference to  FIGS. 23A-23C , the circuit board assembly  2300  may be associated with the aircraft  2390 . Standoff features  2340  may be provided to removably attach the circuit board assembly  2300  to mount structure  2350 . For example, standoff features  2340  may be pressed into one or more receiving features  2358  on the landing  2354  to secure the circuit board assembly  2300  into a desired position within the fuselage  2360 . The standoff features  2340  may be configured to define an offset between the assembly  2300  and the landing  2354  in order to accommodate the enclosure  2320  therebetween. 
     The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it will be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not targeted to be exhaustive or to limit the embodiments to the precise forms disclosed. It will be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings. Also, when used herein to refer to positions of components, the terms above and below, or their synonyms, do not necessarily refer to an absolute position relative to an external reference, but instead refer to the relative position of components with reference to the figures.