Abstract: Provided herein are various enhanced antenna structures for radio frequency communications. In one example, an antenna includes a single-arm spiral antenna having an antenna element configured to couple to a radio frequency link at a central node of the spiral. A ground element is disposed proximate to the central node of the spiral and configured to couple to a ground reference for the radio frequency link.

Abstract: Provided herein are various improvements to communication systems and satellite-carried communications. In one example, a method provides communication coverage for at least an endpoint device within a cell. The method includes detecting access preamble communications transferred by the endpoint device during a random access slot of a base station by at least applying a selected quantity of successive sets of processing windows in accordance with a round-trip minimum communication delay expected between the base station and the cell, with each of the successive sets shifted in time by a selected duration.

Abstract: Multiple collimated laser beams can be arranged in a tightly packed non-overlapping array the goes through a telescope system to reduce the size of the beams and also the separation between the beam centers. The beams in the resulting smaller array then diverge until they reach a nonlinear lens, which collimates each of the beams individually so that all of the beams are collimated, pointing in the same direction and overlapping. The pulses in the beams are temporally separated from each other such that the nonlinear lens acts as a different lens for each of the beams. Such an arrangement facilitates scaling the far field average intensity by combining multiple temporally interleaved pulsed laser beams, allowing diverging pulsed laser beams to be collimated individually by utilizing the large nonlinear refractive index of certain materials.

Abstract: A monolithic fiber-lens array includes a number of optical fibers integrated into a fiber block and multiple lens elements integrated into a lens block. The fiber block is coupled to the lens block via a transparent adhesive layer, and the tips of the optical fibers are aligned with respective focal points of the lens elements.

Abstract: In one embodiment, a pixel for an image sensor includes a first subpixel and a second subpixel. Each of the first and second subpixels include a polygon shape. Each of the first and second subpixels include an emissive layer, a transparent cathode layer, and a transparent anode layer.

Abstract: A gear system for a rotary wing aircraft includes a first gear including an inner gear portion having a first pitch and an outer gear portion having a second pitch that is distinct from the first pitch. A second gear includes a third pitch driven at a driving rotational speed. An actuator member is coupled to the second gear while driven at the driving rotational speed. The actuator member shifts the second gear along the first gear to engage with one of the inner gear portion and the outer gear portion to drive the first gear at a first rotational speed and engage with other one of the inner gear portion and the outer gear portion to drive the first gear at a second rotational speed. A controller is operable to control the actuator member to shift the second gear between the inner gear portion and the outer gear portion.

Abstract: An aircraft, damper assembly for an aircraft and method for reducing a vibration in a rotating shaft. The damper assembly includes a damper element, a first plate and a second plate. The damper element has a damper opening shaped to surround the shaft. The first plate has a first opening shaped to surround the shaft and a recess receptive to the damper element, the damper element being rotatable within the recess. The second plate has a second opening shaped to surround the shaft and secured to the first plate to close the recess and secure the damper element between the first plate and second plate. The damper element rotates within the closed recess.

Abstract: A TE20 launch guidance waveguide hybrid coupler includes a waveguide body, a cavity, a plurality of ports, and a bend along the H-plane. The waveguide body includes a hybrid center portion which is disposed between and is in direct communication with the plurality of ports. The bend along the H-Plane is defined within the hybrid center portion, assists in the launching of the TE20 mode, and results in typically half the axial ratio and mass when compared to traditional hybrid approaches.

Abstract: According to an aspect, a method of assembling a mandrel includes assembling a plurality of members via interlocking features arranged at opposing edges of each member of the plurality of members to form a compartment, the assembled members having a collective outer surface that conforms to an inner surface of the spar. A support member is inserted into the compartment formed radially inward from the assembled members, the support member making contact with a portion of each member of the plurality of members.

Abstract: An aircraft pilot incapacitation detection system includes a controller configured to determine, based on an input received from a flight control computer, a current flight parameter. The controller compares the current flight parameter to a corresponding predetermined flight metric associated with at least one of a predetermined flight plan or a benchmark for a predetermined flight stage. The controller determines, responsive to the comparison, that the aircraft is in an abnormal state and causes a first prompt by a user interface in communication with the controller, the first prompt being associated with a first time threshold. The controller determines whether the first time threshold is satisfied and, if so, subsequently initiates an emergency protocol and causes a second prompt associated with a second time threshold. Upon determining that the second time threshold has been satisfied, the controller carries out the emergency protocol.

Abstract: Provided herein are various enhancements to spacecraft or other vehicles, including spacecraft docking mechanisms and vehicle mating systems. In one example, a vehicle mating mechanism includes a latch assembly of a vehicle having soft capture elements and hard capture elements. The soft capture elements accept a bar element of a mating vehicle and retain the bar element to within an envelope that provides a soft capture with the mating vehicle. The hard capture elements move within the envelope to engage the bar element and draw the bar element toward the vehicle to provide a hard capture with the mating vehicle. The vehicle mating mechanism can also include a cup-cone interface element of the vehicle that mates with a cup-cone interface element of the mating vehicle during the hard capture to establish an alignment between the vehicle and the mating vehicle.

Abstract: An asymmetric, broadband, compact and low-PIM orthomode transducer comprised of two parts is presented. Mating of the two parts results in the formation of a choke flange as well as a critical impedance step which suppresses unwanted modes and enables broadband matching of the junction between the two parts. Furthermore, a cruciform-quatrefoil waveguide type is utilized that transitions to an aperture. This waveguide configuration can lead to a lower overall part length, an improved reflection, and reduced manufacturing costs.

Abstract: A rotor blade retention assembly includes a central hub, a rotor blade including an upper outer surface, a lower outer surface, a blade hole, and a proximal end coupled to the central hub, a strap member extending along a portion of the rotor blade such that a distal end receiving portion extends into the blade hole, and a retainer assembly disposed within the blade hole and coupled to the strap member. The retainer assembly includes an upper bushing and a lower bushing slidably disposed within the blade hole. The upper bushing includes a counterbored portion. The retainer assembly also includes an outboard blade pin disposed within the distal end receiving portion and includes a blade pin inner cavity.

Abstract: A bushing assembly for a structure having a first aperture is provided. The bushing assembly includes a first component configured to be received by the first aperture and having a second aperture. A maximum width of the first component defines an outer diameter. The bushing assembly further includes a second component positioned outside of the first aperture and coupled to the first component, the second component having a third aperture extending through the second component. The third aperture is dimensioned so as to be equivalent to the outer diameter of the first component, and the first component and the second component are formed as discrete components of the bushing assembly.

Abstract: An actuation system for an aircraft can include an actuator and a plurality of clutches connected to and structured to be moved by the actuator. The actuation system can include a plurality of control levers connected to the plurality of clutches and structured to be moved by the plurality of clutches when the plurality of clutches are moved by the actuator. The actuation system can include a processor connected to the actuator and to the plurality of clutches. The processor can identify one or more clutches connected to one or more control levers of the plurality of control levers for controlling an operation of the aircraft, and cause the one or more clutches connected to the one or more control levers to be in an engaged stat. The processor can activate the actuator to cause movement of the one or more control levers via the one or more clutches.

Abstract: Provided herein are various enhanced arrangements for arrays of aperture antennas, such as horn antennas or short backfire antennas. Examples include an array of aperture antennas having a wall thickness between apertures, and a conductive mesh positioned above the apertures such that openings of the conductive mesh are aligned with the apertures and positioned having a selected spacing between the conductive mesh and the apertures.

Abstract: A system for providing instructions directed to facilitating the completion of an aerial mission in an environment includes one or more sensors mounted on a vehicle; a transceiver configured to transmit an instruction directed to facilitating the completion of the mission to an electronic display; and a server comprising a processor coupled to memory of the vehicle containing processor-readable instructions. The instructions causing the processor to, responsive to receiving a factor associated with the mission, compute the instruction directed to facilitating the completion of the mission based on adjusting a cost function, the factor being at least one of a boundary condition of the cost function or a constraint of the cost function.

Abstract: A wind estimation system for an aircraft includes a first sensor configured to sense a first position associated with an aircraft control component in a wind condition, a second sensor configured to sense a first configuration associated with a rotor system of the aircraft in the wind condition, and at least one controller in communication with at least one of the first sensor or the second sensor. The at least one controller is configured to determine a tip-path-plane angle of the aircraft based on the first position and the first configuration, and determine at least one of a current wind speed or current wind direction based on the tip-path-plane angle.

Abstract: An electrical conductor assembly for a rotor blade includes a substrate and at least one electrical conductor. The substrate includes an inboard end portion and an outboard end portion. The at least one electrical conductor is attached to the substrate and extends between the inboard end portion and the outboard end portion. The at least one electrical conductor is configured to transmit electricity along a length of the rotor blade. The inboard end portion and the outboard end portion are structured such that when the electrical conductor assembly is installed within the rotor blade, the inboard end portion is securable relative to the rotor blade and the outboard end portion is movable relative to the rotor blade.

Abstract: In one embodiment, a method for reducing drag includes forming a smooth surface on a first portion of a physical object. The method also includes forming periodic riblets on a second portion of the physical object. The method further includes generating a flow over the periodic riblets of the second portion of the physical object and over the smooth surface of the first portion of the physical object. The second portion of the physical object is adjacent to the first portion of the physical object. Each peak of each riblet of the periodic riblets of the second portion of the physical object is located above a plane of the smooth surface of the first portion of the physical object. Each valley between adjacent riblets of the periodic riblets of the second portion of the physical object is located below the plane of the smooth surface of the first portion of the physical object. A length of each riblet of the periodic riblets runs parallel to a direction of the flow.