Tech Briefs

Non-Collinear Valve Actuator

This device separates the actions of the pneumatic actuator and the spring. Marshall Space Flight Center, Alabama Typical large aerospace valves use pneumatic actuators with large return springs to define a normal state. These springs are exclusively in line with the pneumatic actuator, and therefore are forced to have the same stroke and forces. These typical systems use either a large helical spring or a stack of Bellville springs. Each is long to ensure that the forces at the end of stroke are large enough to move the valve to the normal position with some margin. This invention reconfigures the actuator through the use of either a drag-link four-bar system or a cam to separate these two motions. The spring is allowed to have larger loads with significantly short spring stack length. This eliminates the need for long housings, heavy springs, and thus reduces the mass of the flight system. This configuration can be used for commercial valve actuators. Although commercial actuators generally do not have weight limitations, the reduction of the massive spring could reduce the cost of the product.

Posted in: Mechanics, Mechanical Components, Briefs

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Vibration and Thermal Cycling Apparatus for Cryogenic Tanks

Key design characteristics can be reliably and repeatedly tested together or separately as required by the design requirements. John F. Kennedy Space Center, Florida Understanding thermal and mechanical behaviors and their inter-dependencies of complex tank systems is crucial to making proper design decisions. Low-maintenance, high-performance systems are becoming more important as global energy demands and efficiency requirements increase.

Posted in: Physical Sciences, Briefs

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Integrated Rate Isolation Sensor

Sensor allows for fault detection and isolation using only two IMUs. Lyndon B. Johnson Space Center, Houston, Texas Some vehicles use an internal measurement unit (IMU) system to determine the speed, acceleration, orientation, position, and/or direction of movement of the vehicle. Vehicles used for high-availability or life-critical systems may employ a fault-tolerant IMU design. Typically, such vehicles use three or more IMUs to detect the failure of an IMU and isolate the failing IMU from the other functional IMUs. A fault-tolerant system having multiple IMUs pays an associated mass, power, and volume penalty for each additional IMU. The mass/power/volume (M/P/V) of a fault-tolerant IMU system is the M/P/V of an individual IMU multiplied by the number of IMUs employed to do fault tolerance. Furthermore, each additional IMU adds to the cost of a fault-tolerant system.

Posted in: Physical Sciences, Briefs

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Mercury-Cadmium-Telluride Focal Plane Array for Warm Alignment of Imaging Spectroscopy Systems

This array minimizes the need to cold-cycle instrumentation, reducing cost and time for integration and testing. NASA’s Jet Propulsion Laboratory, Pasadena, California A new technique allows a mercury-cadmium-telluride (MCT) focal plane array (FPA) to operate at room temperature. These results were obtained through experimentation by varying the integration time, frame rate, and bias levels to optimize the output when warm.

Posted in: Physical Sciences, Briefs

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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

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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

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Modeling Lunar Surface Systems Concepts of Operations

The plans that are generated can be optimized for a specific set of goals, such as maximizing science data or minimizing power consumption. NASA’s Jet Propulsion Laboratory, Pasadena, California The goal of this work was to model lunar surface systems using a declarative planning system (ASPEN — Activity Scheduling/Planning Environment), provide a parameterizable Excel document to aid in the model generation, and deliver both Mac and PC versions. An adaptation of Microsoft Excel and ASPEN for Lunar Surface System concepts of operations was used. The goal of the system is to enable searching through several concepts of operations. A concept of operations consists of a proposed schedule of high-level activities and parameterization of resources (e.g., power, communications, oxygen, water, etc.) where three distinct phases of development occurred: (1) initial system development for Lunar, (2) planning system development for Lunar, and (3) planning system development for NASA’s 13th Desert Research and Technology Studies (Desert RATS) live trial.

Posted in: Information Sciences, Electronics & Computers, Briefs

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