Physical Sciences

Enhanced Auditory Alert Systems

Spatial modulation is used to improve the detectability of an alert signal. Ames Research Center, Moffett Field, California Auditory warning systems for human interfaces are often designed around criteria that depend primarily upon signal loudness. It is well understood from the auditory literature that, by making an alert signal substantially louder than the measured background noise level, one can insure that an alert signal will be detectable. Such auditory alert systems have been used in the aviation industry for a number of years in order to raise the awareness of the crew for terrain proximity, for example. However, if an alert signal amplitude is too loud, the alert signal may produce a “startle effect” that hinders performance in some high-stress situations.

Posted in: Physical Sciences, Briefs, TSP

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Carbon Monoxide Silicate Reduction System

This system generates high oxygen yields from lunar soil and can be used for the production of ferrosilicon and high-grade silicon metal. Lyndon B. Johnson Space Center, Houston, Texas Oxygen produced from lunar resources is a very desirable product to greatly reduce the mass lifted from the Earth’s surface in support of exploration activities. The ability to obtain high yields of oxygen from undifferentiated lunar soils enables planning for near-term piloted missions to the Moon. One technology tested for the production of lunar oxygen has been hydrogen reduction of lunar soils. Oxygen yields from hydrogen reduction are generally between one and four percent of un-beneficiated lunar soil.

Posted in: Physical Sciences, Briefs, TSP

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Real-Time Minimization of Tracking Error for Aircraft Systems

Direct adaptive control looks at errors and decides if and when corrections are needed. Ames Research Center, Moffett Field, California In many cases when an aircraft/spacecraft vehicle encounters a failure (such as a jammed control or loss of a part), there are still enough redundant actuation mechanisms to safely maneuver the vehicle. However, most pilots/autonomous systems are unable to adapt to the altered configuration and learn to control the damaged aircraft in the very short time available for safe operation. Fortunately, the flight computer may have the necessary information as well as bandwidth available to learn the new dynamics and determine mechanisms to control the vehicle quickly. The flight computer needs an intelligent controller that flies the vehicle with the baseline controller during normal conditions, and adapts the design when the vehicle suffers damage. Using information about the vehicle from all the available sensors, the system determines whether the vehicle is damaged. Direct adaptive control (DAC) looks directly at the errors, and updates the control law accordingly. This technology looks not just at the tracking error, but rather its characteristics over time to determine whether the controller needs to be adapted or left alone. This is typically fast and meets the timing considerations for aircraft/spacecraft system implementation.

Posted in: Physical Sciences, Data Acquisition, Briefs, TSP

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Lunar Organic Waste Reformer

Possible applications also include conversion of terrestrial organic wastes into fuel for power generation or into feedstock for chemical manufacture. John H. Glenn Research Center, Cleveland, Ohio The Lunar Organic Waste Reformer (LOWR) is a novel technology to convert organic wastes from human space exploration outposts into useful propellant constituents. The LOWR meets NASA’s Trash to Supply Gas (TtSG) objective under the Advanced Exploration Systems Logistics Reduction and Repurposing project by integrating steam reformation, methanation, and electrolysis to convert organic waste into methane and oxygen products. At reformer temperatures above 700 °C, oxygenated steam reacts with organic matter to produce a gas mixture largely composed of hydrogen, carbon monoxide, and carbon dioxide. After condensing and removing excess water, the reformer exhaust gases are fed to a catalytic Sabatier reactor where they are combined with supplemental hydrogen at 350 to 500 °C to produce methane and water. The methane product can be liquefied for storage.

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Digital Laser Frequency Stabilization via Cavity Locking Employing Low-Frequency Direct Modulation

Direct modulation reduces complexity, volume, and mass. NASA’s Jet Propulsion Laboratory, Pasadena, California This project’s goal was to simplify laser frequency stabilization. A simpler system will have many benefits, including reduction of power consumption, complexity, volume, mass, and risk of failure. To implement the Pound-Drever-Hall (PDH) technique requires both RF modulation and demodulation electronics, including an electro-optic modulator, a photoreceiver of sufficient bandwidth to detect the RF modulation fields, demodulation electronics of sufficient bandwidth, and an RF function generator. For a space mission, this equipment can be costly and power-hungry, in addition to the difficulty of being rated to operate in the harsh space environment.

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Deep UV Discharge Lamps in Capillary Quartz Tubes with Light Output Coupled to an Optical Fiber

NASA’s Jet Propulsion Laboratory, Pasadena, California Researchers at Jet Propulsion Laboratory have come up with a novel approach to the simplification of the 194-nm light source and optical guidance in mercury trapped ion spectroscopy research. Mercury plasma is generated in a capillary tube with a diameter of a few hundred microns (in contrast to current lamp bulbs with a diameter of 13 mm). The deep ultraviolet (DUV) light from the plasma can be guided directly to the ions held in an ion trap in a vacuum system via a piece of DUV fiber that is fused at the end of the capillary tube.

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Speech Acquisition and Automatic Speech Recognition for Integrated Spacesuit Audio Systems, Version II

System offers superior performance from prior version, and a number of commercial applications. John H. Glenn Research Center, Cleveland, Ohio Astronauts suffer from poor dexterity of their hands due to the clumsy spacesuit gloves during Extravehicular Activity (EVA) operations, and NASA has had a widely recognized but unmet need for novel human-machine interface technologies to facilitate data entry, communications, and robots or intelligent systems control. A speech interface driven by an astronaut’s own voice is ideal for EVA operations, since speech is the most natural, flexible, efficient, and economical form of human communication and information exchange.

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