Machinery & Automation

Re-entry Vehicle Shape for Enhanced Performance

A convex structure is used with a continuous slope. A vehicle entering the atmosphere of a planet will do so at hypersonic speeds and will need to decelerate and maneuver through that atmosphere while protecting its payload from excessive heating. As a consequence, the vehicle shape must be designed to provide optimal aerodynamic lift and drag properties, while minimizing convective and radiative heating to the vehicle outer surfaces.

Posted in: Mechanical Components, Machinery & Automation, Briefs

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CubeSat Deployable Log Periodic Dipole Array

Any small satellite with a need for a VHF antenna might benefit from this design, in addition to communications and military applications. The antenna is composed of two main deployable structural components that help it achieve the large packing factor necessary to fit within the small volume of the CubeSat. The primary component of the antenna array is a tension stiffened truss, which is preloaded using a large tape spring. The truss bays are formed from solid discs connected by thin Kevlar thread. The Kevlar threads are set up in a hexapod configuration, and are fully tensioned and preloaded from the force of the tape spring, which runs through the center of the truss. The truss gets its overall stiffness from the properties and configuration of these Kevlar wires.

Posted in: Mechanical Components, Machinery & Automation, Briefs

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Protective Sleeve for a Pyrotechnic Reefing Line

The sleeve provides improved operation of a parachute reefing system. A metallic sleeve provides protection and guidance for the actuating lanyard pull of a parachute system reefing line cutter. This device ensures that the reefing line cutter is not damaged during packing or deployment. In addition, the device ensures that the actuating lanyard that initiates the cutter is pulled within the device’s specification cone angle. Combined, these features increase the durability of the reefing line cutter used in parachute reefing systems, and significantly increases the reliability of the underlying reefing cutter. Protecting such a critical element of the controlled deployment of parachutes significantly improves the operation of the parachute reefing system.

Posted in: Mechanical Components, Machinery & Automation, Briefs

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Metabolic Heat Regenerated Temperature Swing Adsorption

Liquid CO2 as a coolant will not contaminate the area as it is sublimated from the life support system for heat rejection. Two fundamental problems facing the development of a portable system to sustain life on extraterrestrial surfaces are (1) heat rejection and (2) rejection of metabolically produced CO2 to an environment with a ppCO2 of 0.4 to 0.9 kPa as is present on Mars. Portable life support systems typically use water for heat rejection via sublimation. Consequently, the water is removed from the life support system and into the surrounding environment after use. This wastes a valuable resource required for human life that is expensive to transport from Earth. Furthermore, rejecting the water vapor to the surrounding environment contaminates it, severely interfering with any search for life on extraterrestrial surfaces. A portable life support system should be able to use a variety of fluids for heat rejection, especially liquid CO2, as it can be easily acquired and cheaply stored on the surface of Mars. The use of liquid CO2 as a coolant has the advantage that it will not interfere with scientific investigations by contaminating the area as it is sublimated from the life support system for heat rejection.

Posted in: Mechanical Components, Machinery & Automation, Briefs

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Habitat Demonstration Unit (HDU) Vertical Cylinder Habitat

Modular habitats maximize floor area and are easy to join together. NASA’s Constellation Architecture Team defined an outpost scenario optimized for intensive mobility that uses small, highly mobile pressurized rovers supported by portable habitat modules that can be carried between locations of interest on the lunar surface. A compact vertical cylinder characterizes the habitat concept, where the large diameter maximizes usable flat floor area optimized for a gravity environment and allows for efficient internal layout. The module was sized to fit into payload fairings for the Constellation Ares V launch vehicle, and optimized for surface transport carried by the All-Terrain Hex-Limbed Extra- Terrestrial Explorer (ATHLETE) mobility system. Launch and other loads are carried through the barrel to a top and bottom truss that interfaces with a structural support unit (SSU). The SSU contains self-leveling feet and docking interfaces for Tri-ATHLETE grasping and heavy lift.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs, TSP

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Brushless Motors for In-Tank Fuel Pumps

The use of a brushless motor provides improvement in power usage and reduction of carbon dioxide emissions. Most automotive fuel systems use a Fuel Delivery Module (FDM) with components to filter and pump gasoline at a specified pressure and flow rate from the fuel tank to the engine. The FDM uses a reservoir assembly to maintain a fuel supply at the pump inlet and support components such as pressure regulators and/or limiters, filters, level sensor, and the electrical and hydraulic connections that pass through the tank. Current systems predominantly use passive electrical components such as brush pumps and resistive fuel level sensors that are independently connected to a voltage supply and body control module, respectively. The high flow levels of these systems require high-power pumps that may operate continuously at maximum speed conditions. Some newer systems may employ a voltage controller to modulate the pump supply voltage to discrete speeds depending on projected engine demand, and provide some improvement in power consumption.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs

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Origami-Inspired Folding of Thick, Rigid Panels

Hinges are used to achieve the necessary folding. To achieve power of 250 kW or greater, a large compression ratio of stowed-to-deployed area is needed. Origami folding patterns were used to inspire the folding of a solar array to achieve synchronous deployment; however, origami models are generally created for near-zero-thickness material. Panel thickness is one of the main challenges of origami-inspired design.

Posted in: Mechanics, Mechanical Components, Machinery & Automation, Briefs, TSP

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