Propulsion

Magnetically Conformed, Variable-Area Discharge Chamber for Hall Thruster, and Method

NASA's Jet Propulsion Laboratory has developed a Hall thruster with a variable-area discharge chamber that improves the performance and lifetime of the thruster. Conventional Hall thrusters have poor ionization efficiency, which limits the thrust-to-power ratio that can be achieved with the thruster. JPL's novel Hall thruster has a variable-area discharge chamber that conforms to the curvature of the local magnetic field and optimizes the ionization efficiency of the thruster and, therefore, significantly improves the power-to-thrust ratio that can be achieved. This innovative device decreases spacecraft costs and enables fast, efficient orbit transfers.

Posted in: Briefs, Propulsion, Engine efficiency, Spacecraft
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Multi-Thruster Propulsion Apparatus

This device switches between ion- or Hall-thruster mode, depending on whether the principal need is efficiency or thrust power.

Two different types of electrostatic thrusters are used to propel spacecraft: ion thrusters and Hall-effect thrusters. Ion thrusters have the benefit of relatively high exhaust velocities with higher overall thrust efficiencies. Hall-effect thrusters typically offer higher thrust-to-power ratios, but they operate somewhat less efficiently than ion thrusters. To take advantage of both thrusters’ strengths, innovators at NASA's Glenn Research Center have developed what is essentially a dual-thruster propulsion system. This patented electric propulsion device offers the ability to switch a spacecraft's propulsion system to ion-thruster mode or Hall-thruster mode, depending on whether the principal need is efficiency or thrust power. In addition, Glenn's novel technology allows the dual thruster to operate in burst mode, with one thruster acting as an ion thruster and one as a Hall thruster. This capability can be valuable to facilitate smooth transitions between operating modes or to raise total thrust level (for short periods) beyond what either mode can achieve on its own.

Posted in: Briefs, Propulsion, Electro-thermal engines, Engine efficiency, Spacecraft
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Propellant Distributor for a Thruster

Innovators at NASA's Glenn Research Center have developed several new technological innovations to improve the capability of Hall-effect thrusters, which are used primarily on Earth-orbiting satellites and can also be used for deep-space robotic vehicles. Hall thrusters are susceptible to discharge channel erosion from high-energy ion impingement, which can reduce operational thruster lifetimes. Glenn researchers have developed several approaches to mitigate this problem. One is a magnetic circuit design that minimizes discharge chamber ion impingement. Another successful improvement developed by Glenn is a means of replacing eroded discharge channel material via a channel wall replacement mechanism. A third innovation is a propellant distributor that provides both a high degree of flow uniformity, and shielding from back-sputtered contamination and other potential contaminants. All of these advances work toward increasing the operational lifetime and efficiency of Hall thrusters.

Posted in: Briefs, Propulsion, Propellants, Performance upgrades, Engine efficiency, Satellites
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Technical Webinar Series from the Editors of SAE: Hybrid & EV Propulsion

In Conjunction with SAE

Greater use of vehicle electrification is essential for OEMs to meet the far more stringent global CO2 emission standards coming early in the next decade, and the technologies related to batteries, power control, and e-motors are progressing steadily. New vehicle electrical architectures, including 48-V hybrid systems and lower-cost EV drives, are poised to play a major role. In this 60-minute Webinar, experts discuss what’s over the technology horizon and what challenges engineers face as the plug-in future approaches.

Posted in: On-Demand Webinars, Propulsion
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Is Pluto a Planet? Scientists Seek New Definition

In 2006, the International Astronomical Union demoted Pluto to "non-planet" status. Johns Hopkins University scientist Kirby Runyon led a group of six researchers to draft a new definition of "planet" — one that includes more than 100 other celestial bodies, including Pluto. The proposal was presented at the Lunar and Planetary Science Conference, hosted in Houston, Texas on March 21.

Posted in: News, Cameras, Imaging, Physical Sciences, Propulsion
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High Speed Idle Engine Control Mode

Innovators at NASA's Glenn Research Center have developed an engine control mode that improves an engine's responsiveness to throttle commands during emergency landing conditions. The high speed idle (HSI) control mode increases the speed of the engine's fan and core shafts, allowing faster response and increased maneuverability during landing conditions when engines are in a low-power state. The innovation uses existing engine actuators to change the engine operating point to allow for faster engine response. Use of HSI increases fuel consumption, but it is anticipated to be used only in emergencies where the additional engine performance will help improve aircraft survivability.

Posted in: Briefs, Aeronautics, Aerospace, Propulsion, Sensors and actuators, Sensors and actuators, Engine control systems, Hazards and emergency management, Hazards and emergency operations, Entry, descent, and landing
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Servo Couplings for High-Tech Systems

Proper coupling ensures a design will meet performance requirements and have a long, trouble-free life.

Couplings are a critical part of system performance in high-tech applications, yet they are often one of the last components to be specified. Selecting the proper coupling ensures the equipment will meet performance requirements and have a long, trouble-free life. Poor coupling selection can lead to high maintenance costs, frequent downtime, and imprecise positioning.

Posted in: Articles, Joining & Assembly, Motion Control, Power Transmission, Sensors and actuators, Sensors and actuators, Materials properties, Fittings, Parts
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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: News, 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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