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Simplified Fabrication of Helical Copper Antennas

From concept to working prototype takes just a few hours. A simplified technique has been devised for fabricating helical antennas for use in experiments on radio-frequency generation and acceleration of plasmas. These antennas are typically made of copper (for electrical conductivity) and must have a specific helical shape and precise diameter.

Posted in: Briefs, TSP

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White Papers

Finite Element Implementation of Advanced Failure Criteria for Composites NASA recently developed LaRC02, a set of first-ply-failure criteria for composites that have been shown to be accurate and physically consistent. This white paper from Noran Engineering describes the LaRC02 criterion features and its implementation into NEiNastran.

Posted in: Blog

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Laser Measurement



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Repairing Chipped Silicide Coatings on Refractory Metal Substrates

Two methods have been demonstrated to be feasible. The space shuttle orbiter’s reaction control system (RCS) is a series of small thrusters that use hypergolic fuels to orient the orbiter in space. The RCS thrusters are constructed from a special niobium-based alloy — the C-103. This alloy retains excellent mechanical properties from cryogenic temperature all the way up to 2,500 °F (1,370 °C). Despite its excellent, high-temperature properties, C-103 is susceptible to rapid oxidation at elevated temperatures. Were the naked C-103 alloy exposed to the operational thruster environment, it would rapidly oxidize, at least losing all of its structural integrity, or, at worst, rapidly “burning.” Either failure would be catastrophic. To prevent this rapid oxidation during thruster firing, the RCS thrusters are coated with a silicide-based protective coating — the R512a. Over time, this protective coating becomes weathered and begins to develop chips. Launch Commit Criteria limit the diameter and depth of an acceptable pit; otherwise, the thruster must be removed from the orbiter — a very costly, time-consuming procedure. The authors have developed two methods to repair damaged R512a coatings on C-103.

Posted in: Briefs, TSP

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Momentum Measurement



Posted in: Blog

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Technologies of the Week

A fiber optic link noise measurement and optimization system is available. It includes an apparatus for measuring noise signals in each fiber optic link and apparatus for generating system performance data corresponding to the noise signals measured by the noise measurement apparatus. View this technology here.

Posted in: Blog

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Smell Test



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