Mechanical & Fluid Systems

Six-Degree-of-Freedom Control With Only Eight Thrusters

Even as few as eight thrusters can provide six-degree-of-freedom control of a spacecraft and do so without undesired coupling between torque and translational force generation functions.

NASA’s Jet Propulsion Laboratory, Pasadena, California

Typical spacecraft thruster configurations are often unable to provide full six-degree-of-freedom control and may have unwanted interaction between their attitude control and trajectory control functions, have undesirably high instantaneous electrical power demands, and use more thrusters than desirable. These last two potential problems gain increased significance if a spacecraft is required to have especially small size and mass, and have very low cost.

Posted in: Briefs, TSP, Mechanical Components, Attitude control, Attitude control, Spacecraft
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Irreversible Entropy Production Rate in High-Pressure Turbulent Reactive Flows

NASA’s Jet Propulsion Laboratory, Pasadena, California

To model high-pressure reactive flows, the most promising methodology is large eddy simulation (LES) in which one solves the large scales of the problem and models the small scales. There is currently no guidance as to the relative importance of small scales originating from different phenomena.

Posted in: Briefs, Mechanical Components, Simulation and modeling
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Piezoelectric Actuator for a 2-inch Isolation Cryogenic Valve

Lyndon B. Johnson Space Center, Houston, Texas

This project is focused on the development of a high-force, high-speed piezoelectric actuator for control of a 2-inch (≈5-cm) isolation valve application in a cryogenic vacuum environment. The piezo motor actuators on the two cryogenic isolation valves were successfully tested at NASA MSFC at 300 to 400 psi (≈2.07 to 2.76 MPa) flow pressure. The testing did not expose the piezo elements to temperatures below 0 °C. Iceramic piezo material has not failed under cryogenic testing to the date of this reporting.

Posted in: Briefs, TSP, Mechanical Components, Sensors and actuators, Sensors and actuators, Ceramics, Parts
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Torque Plug Actuator Design for Sample Return Sample Tubes

NASA’s Jet Propulsion Laboratory, Pasadena, California

During the transportation of any sample material, it is important to ensure that no damage or contamination of the sample occurs while in transit. This concept is extremely important within the sample caching rover sample return architecture. Adequately sealing the sample tubes is important because inorganic contamination of sample material will affect any potential science experiment upon return.

Posted in: Briefs, Mechanical Components, Seals and gaskets
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Habitat Water Wall for Water, Solids, and Atmosphere Recycle and Reuse

This technology can be used in wastewater treatment plants.

A method was developed that allows water recycling, air treatment, thermal control, and solid residuals treatment and recycle to be removed from the usable habitat volume and placed in the walls of a radiation-shielding water wall. This design also provides a mechanism to recover and reuse water treatment (solid) residuals to strengthen the habitat shell.

Posted in: Briefs, Green Design & Manufacturing, Recycling Technologies, Mechanical Components, Waste management, Water reclamation, Passenger compartments, Thermal management, Passenger compartments, Thermal management, Spacecraft
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Novel Feedthrough for Instrumentation Lead Wires

John F. Kennedy Space Center, Florida

This invention is a method and design for the conveyance of instrumentation lead wires from one pressure boundary to another pressure boundary in cryogenic process systems. Such a device or article is commonly referred to as a feedthrough. The novelty of the present invention is the extreme low-temperature conditions commensurate with extreme leak-tightness requirements that are managed by a relatively simple and economical approach. The design is directly applicable to any process system or instrumentation device operating below approximately 300°F. The novel feedthrough design is very cost-effective and easy to produce, yet provides solutions to sealing problems under severe conditions or for extremely demanding requirements.

Posted in: Briefs, Mechanical Components, Wiring, Wiring, Seals and gaskets, Test equipment and instrumentation
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Pneumatic Conveying of Lunar Regolith Simulant

Closed-loop conveying may be desirable in terrestrial applications where the motive gas is scarce or expensive, such as helium.

John F. Kennedy Space Center, Florida

Planetary regolith (dust) is an aggregation of various minerals and different particle sizes. Collection, storage, processing, and disposal of this material are very challenging in the harsh planetary environment. Extraterrestrial operations involving In-Situ Resource Utilization (ISRU) require conveying of regolith. The regolith needs to be transported from the planetary surface to chemical/thermal reaction vessels, and spent (processed) regolith needs to be conveyed to a disposal area.

Posted in: Briefs, Mechanical Components, Particulate matter (PM), Waste disposal, Pneumatic systems, Test equipment and instrumentation
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Low-Cost, Portable Platform for Mounting Multiple Antennas for Automatic UAV Tracking

This continuous-rotation platform holds ~60 pounds of antennas to track any line-of-sight object carrying multiple radio frequency sources.

Armstrong Flight Research Center, Edwards, California

Researchers at NASA’s Armstrong Flight Research Center have developed an innovative antenna-mounting platform that addresses an unmet need in the unmanned aerial vehicle (UAV) market.

Posted in: Briefs, Mechanical Components, Antennas, Antennas, Mountings, Unmanned aerial vehicles
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'Snap' Design Mimics Venus Flytrap

A team led by physicist Christian Santangelo at the University of Massachusetts Amherst uses curved creases to give thin shells a fast, programmable snapping motion. The technique – inspired by the natural "snapping systems" like Venus flytrap leaves and hummingbird beaks – avoids the need for complicated materials and fabrication methods when creating structures with fast dynamics.

Posted in: News, Materials, Joining & Assembly, Mechanical Components
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Wallops Flight Facility 6U Advanced CubeSat Ejector (ACE)

Six-unit (6U) CubeSats are recognized as the next nanosatellite to be considered for standardization. The CubeSat standard established by California Polytechnic University (Cal Poly), which applies to 1U–3U sizes, has proven to be a valuable asset to the community. It has both provided design guidelines to CubeSat developers and a consistent, low-risk interface to launch service providers. This has ultimately led to more flight opportunities for CubeSats. A similar path is desired for the 6U CubeSat. Through this process of standardization, a consistent, low-risk interface for the 6U needs to be established.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Satellites
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