Propulsion

Metallic Glass Shatters Gear Limitations

Gears play an essential role in precision robotics, and they can become a limiting factor when the robots must perform in space missions. In particular, the extreme temperatures of deep space pose numerous problems for successful gear operation. At NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, CA, technologist Douglas Hofmann and his collaborators aim to bypass the limitations of existing steel gears by creating gears from bulk metallic glass (BMG).

Posted in: Articles, Aerospace, Manufacturing & Prototyping, Metals, Mechanical Components, Motion Control, Motors & Drives, Power Transmission, Robotics, Robotics, Alloys, Glass, Gears, Durability, Durability, Spacecraft
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Dike Inspection Robot is Energy-Autonomous

Inspecting the condition of dikes and other sea defense structures is typically a task for robots, working in a team and in a highly autonomous way. But if they move around across the dikes, perform tests, and communicate the results for six hours a day, they use a lot of energy.

Posted in: INSIDER, Motion Control, Motors & Drives, Power Transmission
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Rocket Motor Design Could Boost Small Satellite Missions

Researchers at Los Alamos National Laboratory have developed a rocket motor concept that could be used to power CubeSat low-cost satellites. The Los Alamos team recently tested a six-motor CubeSat-compatible propulsion array with tremendous success.

Posted in: News, Motors & Drives, Power Transmission
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Film Cooled Surface

Turbine film cooling flows typically are subject to jet detachment and reduced cooling effectiveness for high blowing rates. Current concepts to improve jet attachment involve impractical or overly complex hole designs due to manufacturing or durability constraints. Novel film cooling concepts from NASA’s Glenn Research Center involve creating a V-shaped recess on the flow surface of a turbine blade to induce fluid, temperature, or shedding effects; threading turbine film cooling holes with helical channels or grooves (much like the threads of a screw) for the purpose of producing a swirling flow of cooling fluid exiting the film cooling hole; and pairing the threaded holes with holes that have an opposite direction of swirl.

Posted in: Briefs, Aeronautics, Aerospace, Propulsion, Computational fluid dynamics, Cooling, Machining processes, Gas turbines
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NASA’s Pursuit of Power

Advances in Capacitor Materials

Electrochemical capacitors, or supercapacitors, have gained intense interest as an alternative to traditional energy storage devices. Applications for supercapacitors range from plug-in hybrid electric vehicles (PHEVs) to backup power sources. While the power density of supercapacitors surpasses that of batteries, commercially available batteries have a significantly higher specific energy density.

Posted in: Articles, Aerospace, Power Management, Propulsion, Batteries, Energy storage systems, Ultracapacitors and supercapacitors, Batteries, Energy storage systems, Ultracapacitors and supercapacitors, Nanomaterials, Spacecraft
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Generation-2 Lean Direction Injection System

John H. Glenn Research Center, Cleveland, Ohio

An advanced Lean-Direct-Injection (LDI) turbine engine combustor was developed. Named LDI-II, which stands for second-generation LDI, this technology has vastly improved and expanded the performance characteristics of the initial LDI design by not only exceeding NASA’s N+2 emissions goal, but also meeting the operability requirements of full engine power range. The key enabling feature of the technology is the coherence combination of fuel staging and positioning/sizing of swirler-venturi fuel/air mixer elements.

Posted in: Briefs, Propulsion, Exhaust emissions, Fuel injection, Gas turbines
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Testing Aircraft Electric Propulsion Systems on NASA’s Modular Stand

As powered flight expands to include electric propulsion technologies, aeronautics designers need to understand the electrical, aerodynamic, and structural characteristics of these systems. Therefore, researchers at NASA’s Armstrong Flight Research Center have developed a modular test stand to conduct extensive measurements for efficiency and performance of electric propulsion systems up to 100 kW in scale.

Posted in: Briefs, Propulsion, Electric motors, Engine efficiency, Jet engines, Performance tests, Test facilities
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Iodine-Compatible Hall Effect Thruster

The Hall effect thruster (HET) was designed for long-duration operation with gaseous iodine as the propellant. Iodine is an alternative to the state-of-the-art propellant xenon. Compared to xenon, iodine stores as a solid at much higher density and at a much lower pressure. Because iodine is a halogen, it is reactive with some of the materials with which a Hall thruster is typically constructed. Through research and testing, the new method allows for the HET to be used with iodine propellant for long periods of time.

Posted in: Briefs, Physical Sciences, Propulsion, Propellants, Spacecraft fuel, Storage, Rocket engines
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Burnable-Poison-Operated Reactor Using Gadolinium Loaded Alloy

The problem to be resolved in this work was the use of radial control drums as the sole active reactivity control system for nuclear thermal propulsion, which results in significant rocket performance changes during full-power operation. This can result in large inefficiencies in propellant usage, inaccurate estimations in Isp and thrust, and can be a dangerous operation requiring continuous active control of the reactor given the unstable nature of current nuclear thermal rocket reactor designs.

Posted in: Briefs, Propulsion, Nuclear energy, Alloys, Electro-thermal engines, Engine efficiency
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An On-Demand Gas Generator for CubeSat or Low-Mass Propulsion Systems

NASA’s Jet Propulsion Laboratory, Pasadena, California

There are difficulties related to storing enough gas to propel a CubeSat within an onboard tank. Currently, a CubeSat requiring a large volume of gas for extended propulsion (outside Earth orbit) would need to store liquefied gases that require heavy-bodied tanks that add significant weight to the spacecraft. Safe storage of gases is difficult and not suited well to the CubeSat platform.

Posted in: Briefs, Propulsion, On-board energy sources, Spacecraft fuel, Gases, Fuel tanks, Satellites
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