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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

An Overview of Research in Nondestructive Evaluation at the National Aeronautics and Space Administration’s Langley Research Center

The primary focus of the nondestructive evaluation (NDE) effort at Langley Research Center (LaRC) is to pioneer advances in NDE and structural health monitoring (SHM) through fundamental scientific research, technology development, and transferring these to the scientific and aerospace communities. This research supports a variety of NASA missions in space operations, exploration and aeronautics. The work presented will focus on the development of advanced inspection systems to detect critical flaws in both metallic and non-metallic materials and structures for aerospace applications. The emphasis is on increasing the performance of inspection systems to provide defect detection and quantitative characterization of the material state. LaRC NDE utilizes expertise in computational ultrasonic, thermal and eddy current simulations to reduce measured responses to size and locations of flaws, establish technique limitations and optimize performance. This presentation will highlight research into five strategic areas: (1) The development of novel solutions using state-of-the-art NDE technologies such as eddy current, ultrasound, thermography and x-ray computed tomography; (2) Research in the development of unique NDE technologies such as terahertz, wavefield imaging and nonlinear ultrasound; (3) The application of both computational and analytic models to NDE problems; (4) The development of advanced analytic methods to interpret large complex data sets; and (5) Advanced methods of applying and interrogating sensors for structural health monitoring.

NDE↗
NASA NTRS2001

InP MMIC chip set for power sources covering 86-170 GHz

We will present a Monolithic Millimeter-wave Integrated Circuit (MMIC) chip set which provides high output-power sources for driving diode frequency multipliers into the terahertz range. The chip set was fabricated at HRL Laboratories using a 0.l-μm gatelength InAI/InGaAs/InP high electron mobility transistor (HEMT) process, and features transistors with an fmax above 600 GHz. The HRL InP HEMT process has already demonstrated amplifiers in the 60-200 GHz range. In this paper, these high frequency HEMTs form the basis for power sources up to 170 GHz.

Ngo, Catherine↗
NASA NTRS2019

Broadband Continuous Single-mode Tuning of a Short-cavity Quantum-cascade VECSEL

Changing the length of a laser cavity is a simple technique for continuously tuning the wavelength of a laserbutis rarelyused for broad fractional tuning, with a notable exception of the diode laser VCSEL1,2. This is because, to avoid mode hopping, the cavity must be keptopticallyshort to ensure a large free-spectral-range (FSR) compared to the gain bandwidth of the amplifying material. Terahertz quantum-cascade (QC) lasers are ideal candidates for such a short cavity scheme as they demonstrate exceptional gain bandwidths (up to octave spanning) and can be integrated with broadband amplifying metasurfaces. We present such a QC-metasurface based vertical-external-cavity surface-emitting-laser (VECSEL) that exhibits over 20% continuous fractional tuning of a single laser mode. Such tuning is possible because the metasurface has sub-wavelength thickness which allows lasing on low-order Fabry-Pérot cavity modes. Good beam quality and high output power are simultaneously obtained.

Christopher A Curwen↗
NASA NTRS2022

Phosphine in the Venusian Atmosphere: A Strict Upper Limit from SOFIA GREAT Observations

The presence of phosphine (PH3) in the atmosphere of Venus was reported by Greaves et al. based on observations of the J = 1–0 transition at 267 GHz using ground-based, millimeter-wave spectroscopy. This unexpected discovery presents a challenge for our understanding of Venus's atmosphere, and has led to a reappraisal of the possible sources and sinks of atmospheric phosphorous-bearing gases. Here we present results from a search for PH3 on Venus using the German REceiver for Astronomy at Terahertz Frequencies instrument aboard the Stratospheric Observatory for Infrared Astronomy aircraft, over three flights conducted in November 2021. Multiple PH3 transitions were targeted at frequencies centered on 533 and 1,067 GHz, but no evidence for atmospheric PH3 was detected. Through radiative transfer modeling, we derived a disk-averaged upper limit on the PH3 abundance of 0.8 ppb in the altitude range 75–110 km, which is more stringent than previous ground-based studies.

M. A. Cordiner↗
NASA NTRSDate not supplied

NASA Balloon Program Overview (2021-2023)

The United States National Aeronautics and Space Administration's (NASA) Balloon Program offers low-cost access to a near-space environment. As the science community's needs continue to evolve, the NASA Balloon Program adjusts to support the scientific community, providing enhanced capabilities across a spectrum of balloon-related disciplines. The disciplines supported by the NASA Balloon Program include astrophysics, heliophysics, planetary science, earth science, technology development, and education. A broad overview of the NASA Balloon Program that touches on critical highlights, including launch locations, standard systems, and development efforts will be presented. In addition, the specific campaigns supported from 2021 through 2023 will be discussed. The period under review witnessed significant strides in balloon technology, payload instrumentation, and mission design, all aimed at enhancing the Program's scientific capabilities—the integration of cutting-edge technologies allowed for executing ambitious missions, and fostering collaboration with domestic and international partners. Specific information on commercial satellite communications with off-the-shelf hardware will be provided. The Program's strategic goals, emphasizing its commitment to advancing atmospheric and astrophysical research, are highlighted via the GUSTO mission. The Galactic/Extragalactic ULDB Spectroscopic Terahertz Observatory or GUSTO mission was the first NASA Explorer-class mission to utilize the balloon platform. The Program is vital in supporting educational and outreach activities, fostering the next generation of scientists and engineers. Collaborative efforts with educational institutions and outreach programs have expanded public engagement and inspired students to pursue careers in STEM fields. The Program's versatility and success in facilitating groundbreaking research underscore its continued significance in advancing our understanding of the Earth and the universe.

GUSTO↗
NASA NTRS2004

A THz heterodyne instrument for biomedical imaging applications

An ultra-wide-dynamic-range heterodyne imaging system operating at 2.5 THz is described. The instrument employs room temperature Schottky barrier diode mixers and far infrared gas laser sources developed for NASA space applications. A dynamic range of over 100dB at fixed intermediate frequencies has been realized. Amplitude/phase tracking circuitry results in stability of 0.02 dB and +-2 degrees of phase. The system is being employed to characterize biological (human and animal derived tissues) and a variety of materials of interest to NASA. This talk will describe the instrument and some of the early imaging experiments on everything from mouse tail to aerogel.

biomedical applications↗