Tech Briefs

Low-Power-Consumption, Single-Mode Quantum Cascade Lasers Fabricated Without Epitaxial Regrowth

These low-power lasers can be used for spectroscopy instruments in health and safety monitoring, and industrial process monitoring.Quantum cascade (QC) lasers employ intersubband electronic transitions in semiconductor quantum well structures to generate emission at specific engineered wavelengths. QC devices have been particularly successful as mid-infrared emitters in the 4- to 12-μm wavelength range, a spectral regime that is difficult to access with interband diode lasers. As cascade devices, QC lasers can also be designed with many gain stages, which, combined with optimized doping and optical design, has enabled the development of lasers with remarkably high continuous output power (in excess of 1 W). One of the most important applications of mid-infrared QC lasers is quantitative gas detection using absorption spectroscopy, where a single-frequency laser is used to interrogate specific absorption lines of a target compound. While high output power is essential in certain applications, many in situ absorption spectrometers require only milliwatt-level output to effectively measure low levels of compounds of interest with strong absorption lines in the mid-infrared regime.

Posted in: Briefs, Manufacturing & Prototyping

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Common Workflow Service: A Standards-Based Process Management System

As mission operations grow in scale and complexity, there is a prevailing need for automating operational processes to increase efficiency, mitigate risks, and reduce operational costs. The need for automating operational processes has produced a few disparate automation systems within the Advanced Multi Mission Operations System (AMMOS). Without a common solution for process management and automation, each AMMOS subsystem that requires a workflow capability will need to develop its own expertise in the workflow domain as independent systems are developed. This can lead to many incompatible implementations that functionally do similar things. The Common Workflow Service (CWS) attempts to address this issue to avoid independent ad hoc workflow implementations.

Posted in: Briefs, Electronics & Computers, Information Sciences, Software

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Optimum Strategies for Selecting Descent Flight-Path Angles

Efficient and safe arrival operations under challenging traffic conditions are a key objective for air transportation modernization efforts taking place throughout the world. However, trajectory predictability issues often prevent Air Traffic Control (ATC) from allowing continuous descent approaches in congested airspace. An arrival procedure with a specific descent profile, such as a fixed-flight-path angle, provides high trajectory predictability for air-traffic management. Accordingly, it can enable ATC to increase the use of continuous descent approaches, thereby increasing the throughput of arrival operations and reducing fuel burn and other direct operating costs in the process. Moreover, such a procedure is already supported by current avionics in almost all small (regional, business, and light) jets and a fraction of large jets, including Boeing and Airbus.

Posted in: Briefs, Aeronautics, Aerospace

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Unmanned Aerial Systems Traffic Management

The traffic-management system supports UAS civilian applications that operate at lower altitudes.NASA has developed a traffic management system for Unmanned Aerial Systems (UASs) to maintain safe and efficient UAS operations. This novel technology enables the growth in civilian applications of UAS operations at lower altitudes by developing a UAS Traffic Management (UTM) system. There are a number of applications of UAS that includes goods and services delivery in urban, difficult terrain, and rural areas; imaging and surveillance for agriculture; and utility management. To enable significant commercial use of UASs within lower-altitude airspace and airspace that does not interfere with regular National Airspace System (NAS) operations, a UTM system is required. UTM is essential to enable accelerated applications of UASs. UTM will accommodate and support all types of UAS operations, ranging from disposable with minimalistic avionics capabilities, to highly capable UASs.

Posted in: Briefs, Aeronautics, Aerospace

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System and Method for Dynamic Aeroelastic Control

Innovators at NASA’s Armstrong Flight Research Center are developing a collection of algorithms that can accurately determine the structural state of an aircraft. This work is in response to new airframe designs that save weight — and thereby improve fuel efficiency — by removing stiffness in the wings and incorporating lighter materials such as composites.

Posted in: Briefs, Aeronautics, Aerospace

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Active Aircraft Pylon Noise Control System

This technology can be used in commercial aircraft, business jets, and UAVs.This technology is a new type of aircraft pylon design for noise control. A pylon connects the engine to the airframe of an aircraft. This design uses air passing through the pylon to actively disrupt the jet engine exhaust stream after it exits the engine, disrupting and redistributing the axial and azimuthal distributed sources of jet noise from the aircraft.

Posted in: Briefs, Aeronautics, Aerospace

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Supporting Test Aircraft with Lift Airbags

Aircraft lift equipment can be used for safer, more cost-effective wing strain gage load calibration.Innovators at NASA’s Armstrong Flight Research Center have developed a method of using aircraft lift airbags to support test aircraft during wing strain gage load calibration. In calibration testing, a set of known loads is applied to the wing, and the loads and strain gage responses are then recorded. Multigage shear, bending, and torque load equations can then be derived from linear regression analysis of the data. The method aims to address challenging strain measurement conditions present in certain aircraft with particular landing gear geometries. For example, the Gulfstream III test aircraft has main landing gear attached to the inboard wing at the rear spar. In aircraft with this type of landing gear geometry, the main gear load reaction into the wing changes as the applied test load changes, corrupting the test data and compromising the accuracy of the load equations.

Posted in: Briefs, Aeronautics, Aerospace

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