Articles

Electromagnetic Waves Transformed from a Coherent to a Quasi-Coherent Nature

NASA’s Jet Propulsion Laboratory, Pasadena, California The transformation of naturally occurring electromagnetic waves called “chorus” from a coherent nature to a quasi-coherent nature when propagating a distance from its source was demonstrated. The aim of the mission was to study the energizing of electrons by the waves and also the loss of these particles by interaction with the waves. Both of these processes will be affected by the quasi-coherent nature of chorus. This work indicates that if coherent waves are not propagated in enhanced ionization ducting, the waves will become only quasi-coherent, and their effect of scattering trapped particles will be substantially diminished.

Posted in: Articles, Briefs

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An Earth-Observing, Frequency-Agile Radar Receiver for RFI Mitigation

Applications include automotive collision-avoidance radar, cellular phone networks, and radar surveillance sensors for unmanned vehicles. NASA’s Jet Propulsion Laboratory, Pasadena, California The Soil Moisture Active Passive (SMAP) mission will have the first L-band radar/radiometer sensor suite dedicated to global measurements of soil moisture. For the radar sensor, the requirements for achieving high backscatter measurement accuracy from low-Earth orbit present a unique design challenge in the presence of terrestrial radio frequency interference (RFI). The SMAP radar shares the same 1,215 to 1,300 MHz spectrum used by high-power ground-based transmitters like air-route and defense surveillance radars, which can generate strong interference in a conventional fixed-frequency spaceborne radar. The noisy ground environment motivated the development of a frequency-hopping (self-tuning) feature in the radar design. As the SMAP spacecraft orbits across various regions of the Earth, the radar continually adjusts its RF operating frequency to quieter areas of the spectrum for improved fidelity in soil-moisture science data observations.

Posted in: Articles, Briefs, TSP

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Wireless Electrical Devices Using Floating Electrodes

Langley Research Center, Hampton, Virginia A wireless, connection-free, open circuit technology can be used for developing electrical devices like sensors that need no physical contact with the properties being measured. At the core of the technology is the SansEC (Sans Electrical Connections) circuit that is damage-resilient and environmentally friendly to manufacture and use.

Posted in: Articles, Briefs, TSP, Sensors

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Web-Enabled and Automatic Ground Processing Infrastructure Servicing the UAVSAR Airborne Missions

NASA’s Jet Propulsion Laboratory, Pasadena, California The UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) ground data processing infrastructure facilitates a wide range of mission operational processes through a centralized database, Web-enabled interfaces, and background automation. By tracking flight request submissions and flight planning activities, the database provides the most up-to-date historical records on how and when flight missions took place, as well as what radar data were collected. As data-collection missions wrap up, post-mission reports are uploaded to the database via a Web interface, while raw data are scanned into the database enabling the operator to perform polarimetric/interferometric processing on the radar data.

Posted in: Articles, Briefs, Aviation, Data Acquisition

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Variable-Sweep-Wing Aircraft Configuration

There are significant improvements in structural, aerodynamic, and energy efficiency. Ames Research Center, Moffett Field, California Efficient aircraft designs are increasingly desired in order to support the continued growth of the air transportation industry. Continued expansion of this vital mode of transportation is threatened due to concerns over ever-increasing emissions, noise, and the demand for fuel. Current airport runway, ramp, and terminal facilities are increasingly constrained by encroaching growth and neighborhood environmental issues. The challenges associated with ever-increasing demand for air travel will require the development of aircraft that can fly efficiently over wide speed ranges, minimize their environmental impacts, offer the potential for sizing and growth relative to market demand, and make efficient use of constrained airport and airspace resources.

Posted in: Articles, Briefs, Aviation, Energy Efficiency

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Automated Table Lookup Solution Algorithm of the Optimal Powered Descent Guidance for Planetary Landing

NASA’s Jet Propulsion Laboratory, Pasadena, California A novel automated table lookup method is developed to compute the near-fuel-optimal powered descent guidance trajectories, in real-time, for planetary soft landing. The main advantage of this algorithm is that it can be executed autonomously in milliseconds without performing iterative numerical computations to obtain the solution of the optimization problem. The key enabling idea behind this approach is to store, in a lookup table, a number of optimal trajectories that have been computed on the ground for a systematically chosen set of initial conditions. In flight, a near-fuel-optimal trajectory is computed for the actual initial condition by interpolating between these pre-computed trajectories. The lookup method requires only a small, predetermined number of basic algebraic operations. Moreover, this method guarantees that the interpolated solutions are in a prescribed neighborhood of the true optimal solutions.

Posted in: Articles, Briefs, Aviation

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Head-Worn Display Concepts for Ground Operations for Commercial Aircraft

This display enables a higher level of safety during ground operations, including taxiway navigation and situational awareness. Langley Research Center, Hampton, Virginia The Integrated Intelligent Flight Deck (IIFD) project, part of NASA’s Aviation Safety Program (AvSP), comprises a multi-disciplinary research effort to develop flight deck technologies that mitigate operator-, automation-, and environment-induced hazards. Toward this objective, the IIFD project is developing crew/vehicle interface technologies that reduce the propensity for pilot error, minimize the risks associated with pilot error, and proactively overcome aircraft safety barriers that would otherwise constrain the next full realization of the Next Generation Air Transportation System (NextGen). Part of this research effort involves the use of synthetic and enhanced vision systems and advanced display media as enabling crew-vehicle interface technologies to meet these safety challenges.

Posted in: Articles, Briefs, TSP, Aviation, Displays/Monitors/HMIs

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