Abstract: Stacked satellite dispensing systems are described herein. The disclosed systems have diagonal struts that stabilize satellite stacks horizontally and vertically without adding performance-reducing mass. The diagonal struts increase the number of bracing points and improve stability. The improved stability can allow for the satellite stack to be made heavier and taller, such as by having more satellites than a dispensing system with vertical struts. The diagonal struts, which provide the improved stability, can also allow for sub-stacks to be used. The sub-stacks include batches of satellites retained by the stacked satellite dispensing system. Therefore, the stacked satellite dispending system can release single satellites batches at once, rather than all the satellites at once.

Abstract: Methods for a reusable space vehicle to land at substantially the same location as its launching site. The vehicle traveling in a particular orbit, which is a repeating ground track orbit, allows for launching and landing at the same location once per day. The repeating ground track orbits that allow for launching and landing at the same location once per day overfly the launch and landing site once per day. Launching and landing at the same site provides a number of direct advantages. For example, the just-landed vehicle may be transported a relatively short distance to the launch site, reconditioned relatively quickly, and be ready for a quick turn-around launch.

Abstract: Systems and methods for nuclear reactor direct drive of a cryocooler turbine. A nuclear thermal propulsion (NTP) system may have a nuclear reactor that heats a thermal working fluid for directly driving the turbine to power a cryogenic fluid management (CFM) system for keeping propellant at cryogenic temperatures. The features may be used on NTP rockets. The propellant may be liquid hydrogen.

Abstract: Transpiration-cooled systems having permeable and non-permeable portions are provided. In one aspect, a nozzle for a rocket engine includes a non-permeable outer layer, a plurality of walls, a permeable layer, and a plurality of cooling channels. The non-permeable outer layer forms a predetermined shape of the nozzle and defines an interior space. The plurality of walls extend generally orthogonal to the non-permeable outer layer and into the interior space. The permeable layer is disposed between each set of adjacent walls of the plurality of walls. The permeable layer is spaced a distance from the non-permeable outer layer. The plurality of cooling channels are formed between the permeable layer, the non-permeable outer layer, and a set of adjacent walls of the plurality of walls. The plurality of cooling channels are configured to transport a fluid.

Abstract: Systems and methods are provided for wirelessly transferring power to a multi junction photovoltaic cell of a space apparatus via a light emission system. The light emission system uses multiple lasers emitting different wavelengths and/or photon energies to produce electron-hole pairs in each layer of the multi junction photovoltaic cell to prompt power generation by the multi junction photovoltaic cell. The light emission system may be located on Earth or on another space apparatus. The multi junction photovoltaic cell can convert sunlight and the light emitted by the light emission system into electrical energy.

Abstract: A method of joining a first work-piece to a second work-piece is provided. Each of the first work-piece and the second work-piece include a top surface, an opposed bottom surface, and a side surface connecting the top surface and the opposed bottom surface. In one aspect, the method includes positioning the side surface of the first work-piece adjacent to the side surface of the second work-piece, and advancing a friction stir additive manufacturing tool across the top surface of the first work-piece and the top surface of the second work-piece along a weld line between the first work-piece and the second work-piece. As the friction stir additive manufacturing tool advances along the weld line, a filler material is deposited along the weld line and into a plurality of through holes formed in either or both of the first work-piece and the second work-piece.

Abstract: A representative phase-shift based method for using a transformer system to detect movement of an object, and associated systems and methods are disclosed. A representative transformer system detects movement of an object and includes an excitation coil configured to receive an excitation coil input signal that results from an input sinusoidal signal. The transformer further includes first and second sensing coils, and a core configured to be operatively coupled to the object. The core moves relative to the first and second sensing coils when the object moves. First and second impedance loads are connected to the first and second sensing coils, respectively. The two impedance loads have different phase-shifting characteristics. A phase-shift sensing circuit determines a phase-shift between the excitation coil input signal and the input sinusoidal signal that is correlated with a position of the core relative to the first and second sensing coils.

Abstract: Systems and methods for pointing photovoltaic arrays for optimal power generation. One or more methods among a plurality of methods for pointing an array may be used by a spacecraft control system to point the array. Example methods to use to point the photovoltaic array relate to analyzing current output, analyzing image data, and analyzing computational knowledge of reflective bodies or light sources. The spacecraft may be further controlled to reduce shadow by re-orienting, receiving light reflected off spacecraft, and orienting a photovoltaic array relative to incoming light sources based on topographic properties of the array such as cell grooves.

Abstract: A modular damper plug forming a multi-volume acoustic resonator in an acoustic liner of a rocket engine is provided. In one aspect, the damper plug includes a main body including a top surface spaced from a bottom surface by a first height, a left surface spaced from a right surface by a width, and an exterior surface spaced from an interior surface by a length. A chamber within the main body extends along a part of the height, a part of the width, and a part of the length, and communicates with the top surface through an opening. The chamber also communicates with the interior surface through one or more ducts. The main body is sized and shaped to be received in any one of a plurality of cavities in the acoustic liner. The chamber includes an upstream volume of the acoustic resonator, and the one or more ducts communicate with a downstream volume of the acoustic resonator when the damper plug is received in any one of the plurality of cavities.

Abstract: Transpiration-cooled systems having permeable and non-permeable portions are provided. In one aspect, a nozzle for a rocket engine includes a non-permeable outer layer, a plurality of walls, a permeable layer, and a plurality of cooling channels. The non-permeable outer layer forms a predetermined shape of the nozzle and defines an interior space. The plurality of walls extend generally orthogonal to the non-permeable outer layer and into the interior space. The permeable layer is disposed between each set of adjacent walls of the plurality of walls. The permeable layer is spaced a distance from the non-permeable outer layer. The plurality of cooling channels are formed between the permeable layer, the non-permeable outer layer, and a set of adjacent walls of the plurality of walls. The plurality of cooling channels are configured to transport a fluid.

Abstract: Systems and methods for receiving a descending rocket, which may be at sea. The rocket may descend vertically with the nose higher than the nozzle. The rocket body may be angled as it descends. A boom arm with hooks may extend at an angle to the rocket body to engage a cable suspended by a semisubmersible platform at sea. The platform may include a dampened cable and lateral straps for securing and rotating the rocket into a horizontal orientation. The platform may receive a ship and purge water to elevate the platform for placing the horizontal rocket onto the ship.

Abstract: Systems and methods for achieving pristine microgravity in low earth orbit (LEO) using electric propulsion. Long-duration, low thrust, electric thrusters provide a constant thrust force for a pristine microgravity environment within a given volume of a space vehicle experiencing drag forces in LEO. Large space vehicles in LEO configured to be pressurized for human habitation, for instance having a mass of at least 40,000 kg and an internal volume of at least 400 m3, can use the electric propulsion systems and methods to achieve a quasi-steady acceleration less than or equal to 1.0 ?g for durations of 180 consecutive days or longer.

Abstract: Systems and methods for securing an upright rocket. The rocket may be on a moveable platform, such as a landing area of a ship. The rocket may land on the deck, and the system may include cables that surround the landing area. The cables may be tightened about the rocket after the rocket has landed in an upright position. The system may include poles that telescope upward, such that the cables may tighten about the upright rocket at various heights along the body of the rocket.

Abstract: A representative seal system (such as a seal system for a turbopump of a rocket engine) automatically adjusts a balance ratio of a seal. The system can include a ring element encircling an axis. A front side of the ring element contacts a revolving surface to form a seal with the revolving surface. The front side can include a stepped surface having two or more steps. Each step includes a sealing surface configured to contact the revolving surface to form a sealing area that is different from a sealing area of each other sealing surface. Each step is positioned and configured to wear away during operation of the machine to expose an underlying surface to the revolving surface, to change the sealing area and the balance ratio of the seal. A representative method of operating a turbomachinery system includes changing the balance ratio of a seal while rotating a rotor.

Abstract: A representative system includes an alignment tool for aligning attachment interfaces of horizontally-oriented launch vehicle portions. The tool can include a receiver assembly for connecting to a first launch vehicle portion and an actuation assembly for connecting to a second launch vehicle portion. When a first connecting element of the receiver assembly is engaged with a second connecting element of the actuation assembly, the second connecting element can apply force to the receiver assembly, and the actuator assembly applies an opposite force to the second launch vehicle portion, to align fastening features in the launch vehicle portions and/or to reshape the launch vehicle portions. A representative method includes connecting the alignment tool to the launch vehicle portions and operating the tool to apply oppositely-directed forces to align the launch vehicle portions for installing fasteners to connect the launch vehicle portions. One or more bracing beams can connect two tools together.

Abstract: A high temperature thermal protection systems for rockets, and associated methods, is disclosed. A representative system includes a launch vehicle having a first end and a second end generally opposite the first end. The launch vehicle is elongated along a vehicle axis extending between the first and second ends and carries a propulsion system having at least one nozzle positioned at the second end of the launch vehicle. A thermal protection apparatus positioned around the nozzle is used to provide cooling and/or insulation to the nozzle during the flight of the launch vehicle. The thermal protection apparatus can include multiple fabric layers and an insulation layer stacked and stitched together. The fabric layers can include metal alloy fibers. In representative systems, the thermal protection apparatus can further include provisions for water that saturates the insulation layer to provide further insulating and/or cooling effects.

Abstract: A representative spacecraft system includes a connecting device, which in turn includes a housing having a common port opening, a first connecting element carried by the housing and positioned to connect with a corresponding first spacecraft connecting structure having a first configuration, and a second connecting element carried by the housing and positioned to connect with a corresponding second spacecraft connecting structure having a second configuration different than the first configuration. At least one of the first and second connecting elements is moveable relative to the other between an operational position and a non-operational position, and each of the first and second connecting elements, when connected to the corresponding first or second spacecraft connecting structure, is positioned to allow transport through the common port opening.

Abstract: A variable flow area injector for a liquid rocket engine. The injector has a poppet with a variable outer width portion and a housing with a variable inner width portion. An annular flow path is defined between the variable width portions. Increased throttling of the engine passively increases the annular flow area of the injector by forcing the poppet in a distal direction. Decreased throttling allows a restoring spring to move the poppet in a proximal direction to decrease the annular flow area. A bellows can be included to dampen movement of the poppet. The bellows may be in a propellant-filled cavity separate from the main propellant flow path and have a series of openings through which the separate propellant flows.

Abstract: Rocket components having internal heat fins are described herein. The disclosed components have internal heat fins that mitigate buckling and uneven force application by adding thermal capacity to the component without adding component stiffness. This reduces a thermal force fight (i.e., tension versus compression between cold and hot areas, respectively), which inhibits the buckling loads on the propellant tank. The internal heats fins also provide for a reduced mass of the propellant tank wall relative to a propellant tank wall without internal heat fins. By reducing the thermal force fight, as discussed above, less material can be used which further allows for thinner welds to be used (i.e., less welding material).

Abstract: The present technology is directed to thrusting rails for launch vehicles, and associated systems and methods. Certain embodiments of the thrusting rails can include a first rail housing portion having a cavity and a second rail housing portion having a projection positioned at least partially within the cavity. The rails can include a bellows positioned within the cavity and an elongated tube positioned within the bellows. The elongated tube can include a vent opening in a lateral wall of the elongated tube. A shield can be positioned between the vent opening at the bellows and a sleeve can be positioned within the elongated tube. The sleeve can be constructed from a fibrous material and positioned to retain an ordnance within the elongated tube.