Motion Control

Reactionless Drive Tube Sampling Device and Deployment Method

Springs and a counter-mass create a powerful and stable sampling device. NASA’s Jet Propulsion Laboratory, Pasadena, California A sampling device and a deployment method were developed that allow collection of a predefined sample volume from up to a predefined depth, precise sampling site selection, and low impact on the deploying spacecraft. This device is accelerated toward the sampled body, penetrates the surface, closes a door mechanism to retain the sample, and ejects a sampling tube with the sample inside. At the same time the drive tube is accelerated, a sacrificial reaction mass can be accelerated in the opposite direction and released in space to minimize the momentum impact on the spacecraft. The energy required to accelerate both objects is sourced locally, and can be a spring, cold gas, electric, or pyrotechnic. After the sample tube is ejected or extracted from the drive tube, it can be presented for analysis or placed in a sample return capsule.

Posted in: Briefs, TSP, Motors & Drives

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Developing Ceramic-Like Bulk Metallic Glass Gears

This technology has applications in gears, bearings, and gearboxes for automotive, spacecraft, and robotics. NASA’s Jet Propulsion Laboratory, Pasadena, California This invention describes systems and methods for implementing bulk metallic glass-based (BMG) macroscale gears with high wear resistance. This invention creates bulk metallic glasses (BMGs) with selected mechanical properties that are very similar to ceramics, such as high strength and resistance to wear, but without high melting temperatures. Ceramics are high-strength, hard materials that are typically used for their extremely high melting temperatures. Because of their extreme hardness, ceramics are optimal materials for making gears, due to their low wear loss. Unfortunately, ceramics suffer from low fracture toughness (typically <1 MPa·m1/2), and their high melting temperatures prevent them from being cast into net-shaped parts. Ceramic gears, for example, must be ground to a final shape at great expense.

Posted in: Briefs, Ceramics, Metals

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Products of Tomorrow: March 2015

The technologies NASA develops don’t just blast off into space. They also improve our lives here on Earth. Life-saving search-and-rescue tools, implantable medical devices, advances in commercial aircraft safety, increased accuracy in weather forecasting, and the miniature cameras in our cellphones are just some of the examples of NASA-developed technology used in products today.

Posted in: Articles, Products, Aviation, Electronics & Computers, Detectors, Sensors

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Evaluation of Rail Gun Technology for Launch Assist of Air-Breathing Rockets

John F. Kennedy Space Center, Florida A prototype horizontal electromagnetic rail launcher has been demonstrated along with a corresponding theory. This system builds out of published work in augmented rail guns, but modifies this technology so that the motor can operate for seconds rather than milliseconds, and provide low acceleration (such as might be needed to launch an aircraft) rather than the extreme accelerations seen in the guns. The final system operates off of relatively low voltages (tens of volts), but with substantial currents. A lab bench prototype has been constructed and operated, demonstrating 13 Gs acceleration of a small 230-gram sled.

Posted in: Briefs, Motors & Drives

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Using Harmonics to Control Flutter in Wings with Electrical Motors

This control system concept applies principles of forced aeroelasticity to distributed electric propulsion systems. Armstrong Flight Research Center, Edwards, California As aeronautics engineers develop innovative distributed electric propulsion systems, they face new challenges in ensuring that these innovative aircraft are safe as well as fuel efficient. In particular, these systems involve a large number of electrically driven fan motors mounted across a wing that induce vibrations that negatively affect the aircraft’s stability. These vibrations cause problems regardless of whether the motors are bottom-mounted, top-mounted, or wing-embedded.

Posted in: Briefs, Motors & Drives

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Micropulse Detonation Rocket Engine for Nano-Satellite Propulsion

Goddard Space Flight Center, Greenbelt, Maryland An efficient propulsion system would use a micropulse detonation rocket engine (–PDRE) for nano-satellite maneuverability in space. Technical objectives are to design, build, and conduct a small detonation tube experiment in order to explore the feasibility of using –PDRE for propelling a nano-satellite. The plan is to study the requirement and predict the performance of –PDRE using various candidate propellants, as well as to conduct ground experiments, demonstrate useful thrust, and measure the specific impulse in a two-year time frame, so that a follow-on project can be proposed in a future NRI Center Innovation Fund.

Posted in: Briefs, TSP

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Experimental Testbed for 1-MW Turboelectric Distributed Propulsion Aircraft

A low-cost glider design mitigates risk in conducting experiments for cutting-edge “green” aircraft concepts. Armstrong Flight Research Center, Edwards, California Researchers at NASA’s Armstrong Flight Research Center are developing a concept aircraft for testing turbo-electric distributed propulsion (TeDP) experiments. TeDP generally involves providing thrust to an aircraft via wing-mounted ducted electric fans, which consist of an electric motor, a fan, stators, and other components surrounded by cylindrical ducting within a fan case. The fan motors are powered by a combined battery and turboelectric generator system. To sufficiently power an aircraft approximately 50 ft (≈15 m) in length and with a gross weight of 25,000 lb (≈11,340 kg), this system must be capable of generating 1 MW of power.

Posted in: Briefs, Aviation, Motors & Drives

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