nasa langley research paper

LANGLEY RESEARCH CENTER

• 2022 Annual Report
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• Space Exploration
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• Inspire Through Discovery

THE YEAR IN REVIEW

TOGETHER, WE DISCOVER.

NASA explores the unknown in air and space, innovates for the benefit of humanity, and inspires the world through discovery. Each day, Langley’s diverse workforce drives mission success.

EXPLORE WITH US.

Many hands, many minds contribute to every groundbreaking NASA mission. Innovation requires energy, talent, and fresh perspectives, so Langley expands opportunity and spreads inspiration far and wide.

A BETTER WAY TO WORK.

At Langley, we forge partnerships with businesses and groups that are aligned with our values and vision. Our collaborators share our diversity, equity, inclusion, and accessibility goals.

LANGLEY LEADERSHIP

From the Director

NASA's astounding success in 2022 shows what's possible when we work together. When we link our talents, energy, and goodwill, there's no obstacle we can't overcome, no frontier we can't explore. This year at Langley, people connected and discovered solutions with potential to improve lives around the globe. We're finding new ways to partner and use our expertise for even greater impact. Together, we will create a bright future.

Clayton P. Turner, Center Director

Langley Leadership

"NASA's astounding success in 2022 shows what's possible when we work together. When we link our talents, energy, and goodwill, there's no obstacle we can't overcome, no frontier we can't explore."

Clayton P. Turner

Center Director

From the Deputy Director

"The people of NASA Langley dug deep and delivered sky-high success in 2022. Once again, the team's determination brought benefits to all." Dave Young, Deputy Director

Deputy Director

From the Associate Director

"At Langley, we're building a welcoming culture where people of all backgrounds and walks of life converge to help NASA achieve great things." Lisa Ziehmann, Associate Director

Lisa Ziehmann

Associate Director

From the Associate Director, Technical

"The center's role in the world of aerospace has grown into something more connected and collaborative. We believe this new mode will yield amazing advances for the American people and the world." Kevin Rivers, Associate Director, Technical

Kevin Rivers

Associate Director, Technical

Our Missions

Reach to Deep Space

As NASA prepares to send astronauts to the Moon and beyond, Langley's expert engineers create tools to energize human and robotic exploration.

Fly Everywhere

NASA's aeronautics researchers find ways to fly that are faster, cheaper, safer, and cleaner. They also build systems that will help drones take on jobs from package delivery to search and rescue. Photo credit: Joby Aviation -->

Understand Earth and Beyond

Langley scientists and their partners expand knowledge of Earth's atmosphere and how our planet absorbs and reflects sunlight — drivers of weather and our changing climate. Scientists also unlock the secrets of deep space.

Explore With Us

At Langley, enthusiasm for Science, Technology, Engineering, and Math is sky high. The team finds ways to inspire young people in underserved communities, sharing a sense of possibility and wonder.

Fiscal 2022

Budget (billion), patents & inventions, internships.

Expanding Excellence NASA invents new technologies that make historic human exploration of Mars possible. Inflatable heat shields — tested successfully in 2022 — may be key to landing large payloads on the red planet. Learn More

NASA's Next Wind Tunnel New aircraft will take shape faster thanks to NASA's first new wind tunnel in decades. The Flight Dynamics Research Facility will cut costs and expand test capabilities. Learn More

Construction

A New Kind of Airport With more helicopter-style aircraft poised to buzz through American skies, NASA maps out a new vision for urban flight. Learn More

Advanced Air Mobility

Accuracy Matters Powerful sensing systems will enable space exploration as well as autonomous aircraft of tomorrow. Together, NASA and industry build new possibilities. Learn More

Sensor Tests

Eye on Air Quality TEMPO will be the first space-based tool monitoring major air pollutants across North America hourly during daytime. It will revolutionize air quality forecasts and help people with lung disease breathe easier. Learn More

Prepare for Launch

Million Match Moment Citizen scientists who record and share weather data get to explore STEM and help protect our home planet. Learn More

Hands-On Science

A Cleaner Way to Fly NASA helps the nation address climate change by making flight sustainable. An experimental design for airliners aims to trim fuel consumption by 10 percent. Learn More

Aviation Innovation

Taming of the Boom Routine supersonic passenger flight over land would transform the aviation industry — and lives around the globe. The Quesst mission attacks one major hurdle: the disruptive sonic boom. Learn More

Walking on Air The whole idea of flight to me has always been fascinating … It just really excites the child in me." --Walt Silva, X-59 Structures Lead Learn More

Langley People

Bridging the Gap "NASA has shown me that you need both humanities —communication, journalism, writing — and STEM to solve some of the problems of the world." — Karen Yang, Langley summer intern Learn More

Elevate to Innovate A second round of funding from NASA helps minority college students explore ways to improve aerospace manufacturing while also learning entrepreneurship. Learn More

Benefits To You

A Home for Discovery, Collaboration A new five-story, 175,000-square-foot laboratory helps researchers and their partners create sensors to investigate climate change, improve autonomous vehicles, and expand knowledge of our solar system. Learn More

Measurement Systems Laboratory

The Search for Reliable Energy Weather and solar data collected by NASA scientists helps communities find renewable energy, design sustainable buildings, and improve farming. Learn More

Learning, Growing "My career path at NASA has been steady. I like to think that my motto is 'to work on cool things and learn something new every day.'" — Daniel Mangosing, web developer and software release administrator for DEVELOP program Learn More

Seeing the Future College students imagine airports of tomorrow through a NASA competition focused on more accessible, sustainable flight. Learn More

Students Compete

Volcano Brings Burst of Data Eruptions like the one near the South Pacific Island of Tonga give scientists a window into atmospheric systems and a chance to improve climate predictions. Learn More

Understand Earth

Hello from Headquarters Members of a local youth chapter of the National Society of Black Engineers get a behind-the-gates tour of Langley and meet dignitaries including NASA Administrator Bill Nelson. Learn More

Engineering Progress

Langley Lifts Artemis Ideas shaped at Langley will help NASA put the first woman and first person of color on the Moon and establish a permanent human presence there as a stepping stone to Mars. Learn More

Moon to Mars

Feeling the Heat With a deeper understanding of how heat shields react when zooming through a planet's atmosphere, NASA builds better landers for human exploration. Learn More

Safe Landings

Explore Safely "Being here now, part of the team that’s going to ensure that astronauts are safe on this next step as we go beyond low Earth orbit is the most exciting thing I’ve done." Dr. Martha Clowdsley, deputy project manager for Exploration Capabilities RadWorks Project Learn More

Learning to Fly on a Moon of Saturn A component of a drone-like vehicle designed to fly on Titan was tested in a Langley wind tunnel. Called Dragonfly, it begins its journey before the end of the decade. Learn More

Our Solar System

NASA Looks at Safety of Future Flight Before new types of aircraft carrying people and cargo take to the skies, engineers need to know what would happen if they crash. Learn More

From Space, NASA Observes a Warming Earth An orbiting instrument measures how much of the sun’s energy is absorbed by Earth and how much is emitted to space. An imbalance means Earth is warming. Learn More

Virginia Teachers Show Impact of Math A teacher ambassador program helps instructors give students an inspiring taste of computer modeling and simulation. Learn More

Tomorrow's Workforce

Our POWER applied science project — now in its 25th year — has played a part in hundreds of thousands of energy-saving and crop-modeling projects worldwide. This year we are averaging 4.5 million data orders per month and still growing!” Learn More Paul Stackhouse Senior Research Scientist at Langley and leader of the Prediction of Worldwide Energy Resources, or POWER, project

The longer I work in climate science and learn from the data about how humans have impacted our planet, the more I appreciate the fragility of our one and only home, and the more I want to take care of it. Learn More Yolanda Shea Project Scientist for the CLARREO Pathfinder mission

What motivates me most is that our research and observations will benefit society. Learn More Ali Omar Langley’s Deputy Director of Science (Acting)

I hope everyone can find that kind of passion thread where they get to do something that they really love and enjoy and get paid for it. And NASA is a really great place for that. Learn More Tim Lewis Acting Deputy Manager for Science and Technology Utilization in Langley’s Systems Analysis and Concepts Directorate

My experience as a NASA intern has helped me strengthen valuable skills such as accountability, strong work ethic, time and project management skills, and effective decision making. Learn More Lucy Somervill Langley fall intern who worked with the SABERS team

The Measurement Systems Laboratory was designed as a place where researchers and engineers from different technical disciplines would cross paths. Those connections can lead to exciting discoveries and solutions. Learn More Chris Edwards Associate Director for Science, Langley Engineering Directorate

The NESC (NASA Engineering & Safety Center) does great work—I appreciate the integrity of the teams and the focus on safety, and the value they add to the programs. Learn More Jonathan Austin Commercial Crew Program Loads Subsystem Manager in the Loads, Induced and Dynamic Environments group

This is a culmination of a 30-year career for me. The day that I heard that we had been approved to move forward with the X-59, I think was probably the most emotional day I've ever had at NASA. Learn More Lori Ozoroski Aerospace Engineer working on the Quesst mission's X-59 aircraft

Much of what we’re doing is taking composites production to the next level. We’re using materials that can be formed into parts faster and using machines to automate assembly and inspection. Learn More Rick Young Project Manager for the Hi-Rate Composite Aircraft Manufacturing, or HiCAM, project

LOOKING TO THE FUTURE

Exploration.

IN MEMORIAM

Jeremiah F. Creedon

November 15, 1939 — October 29, 2022

“Studying the problems of flight with a view to their practical solution wasn’t just a motto. It was part of the way of life.”

Creedon served as Langley’s Center Director 1996-2002.

NASA Official: Joyce Ortiz

www.nasa.gov/langley

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Future Strategic Issues/Future Warfare [Circa 2025]

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• Graphic Violence
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Dennis M. Bushnell, "Future Strategic Issues/Future Warfare [Circa 2025]" ( sic ), NASA Langley Research Center (National Aeronautics and Space Administration), July 2001, 113 pp.; PDF, 1400357 bytes, MD5: c833f3fbc55d07fe891f5f4df5fb2f57. The aforesaid PDF was found on the US Department of Defense's Defense Technical Information Center (DTIC) website, as archived by the following Internet Archive URL: http://wayback.archive.org/web/20031224161719/http://www.dtic.mil/ndia/2001testing/bushnell.pdf

Dennis M. Bushnell is the Chief Scientist at NASA's Langley Research Center. The following is a biography page for him:

Joe Atkinson, "Dennis Bushnell", NASA Langley Research Center (National Aeronautics and Space Administration), Mar. 21, 2013. http://www.nasa.gov/centers/langley/news/researchernews/snapshot_DBushnell.html

Bushnell's above presentation was given on August 14, 2001 at the 4th Annual Testing and Training for Readiness Symposium and Exhibition organized by the National Defense Industrial Association (NDIA) and held at the Rosen Centre Hotel (formerly the Omni Rosen Hotel) in Orlando, Florida. For information on that, see the following page in which the above presentation is available:

"The 4th Annual Testing and Training for Readiness Symposium & Exhibition: Emerging Challenges, Opportunities and Requirements, 13-16 August 2001", Defense Technical Information Center (DTIC). http://wayback.archive.org/web/20020409151859/http://www.dtic.mil/ndia/2001testing/index.html , http://wayback.archive.org/web/20040825220041/http://www.dtic.mil/ndia/2001testing/2001testing.html

See also the following announcement page for this conference:

"4th Annual Testing and Training Symposium and Exhibition: A National Partnership, on August 14-16, 2001 in Orlando, FL at the Omni Centre Hotel", National Defense Industrial Association (NDIA). http://wayback.archive.org/web/20010410031320/http://register.ndia.org/interview/register.ndia?~Brochure~1070

The following is the conference proceedings:

Testing and Training for Readiness Symposium and Exhibition (4th Annual): Emerging Challenges, Opportunities and Requirements Held on 13-16 August 2001 (on CD-ROM) , National Defense Industrial Association (NDIA), Aug. 2001; National Technical Information Service (NTIS) Issue Number: 1014. http://www.ntis.gov/search/product.aspx?ABBR=ADM002244 , http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADM002244

The text on each page stating "Future Strategic Issues, 7/01" within the above PDF refers to the document's finalization date of July 2001. The creation date of the above PDF is given as Thu 13 Dec 2001 08:48:04 AM EST, which possibly refers to when the PDF was created from a Microsoft PowerPoint file (.ppt), as it looks like the document was perhaps originally a PowerPoint file.

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Papers & Reports 2021

Improvements in simulating a mach 0.80 transonic truss-braced wing configuration using the spalart-allmaras and k-ω sst turbulence models.

D. Maldonado, C. Hunter, J. Housman, S. Viken, M. Piotrowski, S. McMillin, C. Kiris, and E. Milholen Published online January 4, 2021

Teams from the NASA Ames Research Centers (ARC) and Langley Research Center (LaRC) have been working on validating their computational fluid dynamics (CFD) results for the Boeing Mach 0.80 Transonic Truss-Braced Wing (TTBW) configuration. Experimental data used for the validation were gathered from a test conducted of a 4.5% scale Mach 0.80 TTBW model in the NASA Ames Research Center 11- by 11-Foot Transonic Wind Tunnel. Improvements in Simulating a Mach 0.80 Transonic Truss-Braced Wing Configuration using the Spalart-Allmaras and k-ω SST Turbulence Models, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Structured Overset and Unstructured Grid Simulations for the Third AIAA Sonic Boom Prediction Workshop

J. Duensing, J. Jensen, J. Housman, M. Piotrowski, G. Kenway, D. Maldonado, E. Sozer, and C. Kiris Published online January 4, 2021

Predictions using the Launch Ascent and Vehicle Aerodynamics (LAVA) Unstructured and Structured Curvilinear solvers for the Biconvex and C608 geometries are compared in support of the 3rd AIAA Sonic Boom Prediction workshop. Description of the mesh generation techniques and numerical methods are provided along with a comparison of nearfield and far-field predictions with available experimental data as well as other workshop submissions. Structured Overset and Unstructured Grid Simulations for the Third AIAA Sonic Boom Prediction Workshop, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

An Adjoint Elasticity Solver for High-Order Mesh Deformation

J. Macron, A. Garari, M. Denison, and S. Murman Published online January 4, 2021

We propose a new method to optimally deform high-order meshes using an adjoint elasticity solver. Mesh quality measures based on the norm of the Jacobian matrix and the metric tensor are compared against the determinant of the scaled Jacobian, as quantities of interest (QoI) for the optimization problem. We optimize the spatially varying material properties used in the elasticity equations, namely Young's modulus and Poisson's ratio, with a particular emphasis on the most deformed elements. An Adjoint Elasticity Solver for High-Order Mesh Deformation, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Transonic Lift and Drag Predictions using Wall-Modelled Large Eddy Simulations

A. Ghate, G. Kenway, G.-D. Stich, O. Browne, J. Housman, C. Kiris Published online January 4, 2021

Wall-modelled Large Eddy Simulations (WMLES) of the NASA Common Research Model (CRM) at transonic conditions and various angles of attacks leading up to and including shock-induced flow separation are performed using the LAVA computational framework. The simulations are shown to accurately predict the lift curve slope and the onset of separation characterized by the break in the pitching moment. Transonic lift and drag predictions using Wall-Modelled Large Eddy Simulations 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

High-Fidelity Simulations of HyMETS Arc-Jet Flows for PICA-N Modeling

P. Ventura Diaz, J. Meurisse, A. Brandis, B. Bessire, M. Barnhardt, and S. Yoon Published online January 4, 2021

A joint effort between the NASA Ames and Langley Research Centers was undertaken to analyze the Mach 0.745 variant of the Boeing Transonic Truss-Braced Wing (TTBW) Design. Two different flow solvers, LAVA and USM3D, were used to predict the TTBW flight performance. Sensitivity studies related to mesh resolution and numerical schemes were conducted to define best practices for this type of geometry and flow regime. Validation efforts compared the numerical simulation results of various modeling methods against experimental data taken from the NASA Ames 11-foot Unitary Wind Tunnel experimental data. High-Fidelity Simulations of HyMETS Arc-Jet Flows for PICA-N Modeling, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Surface-Normal Active Flow Control for Lift Enhancement and Separation Mitigation for High-Lift Common Research Model

S. Hosseini, C. Van Dam, and S. Pandya Published online January 4, 2021

This study explores the feasibility of using small surface-normal jets near the flap trailing edge as active aerodynamic load control on the high-lift Common Research Model wing/body configuration. Chimera Grid Tools are utilized to generate structured curvilinear overset grids, and the Reynolds-averaged Navier-Stokes solver OVERFLOW is employed to solve for the flow-field around the geometry. The so-called microjet is initially employed across both the inboard and the outboard flaps on the pressure-side near the trailing edge. Surface-Normal Active Flow Control for Lift Enhancement and Separation Mitigation for High-Lift Common Research Model, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Jet Noise Prediction with Large-Eddy Simulation for Chevron Nozzle Flows

G.-D. Stich, J. Housman, A. Ghate, and C. Kiris Published online January 4, 2021

Arc-jets are essential facilities used in the research, development and evaluation of thermal protection systems for hypersonic vehicles since they can reproduce the high-enthalpy environments seen during planetary entry. A test campaign is underway in the Hypersonic Materials Environmental Test System arc-jet, in support of the oncoming Mars 2020 mission to screen the response of the PICA-NuSil system. High-fidelity thermochemical non-equilibrium computational fluid dynamics simulations have been carried out to assist the test campaign by simulating the complete test matrix for the facility. Jet Noise Prediction with Large-Eddy Simulation for Chevron Nozzle Flows, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Cartesian Mesh Simulations for the Third AIAA Sonic Boom Prediction Workshop

W. Spurlock, M. Aftosmis, and M. Nemec Published online January 4, 2021

Simulation results are presented for all cases from the Third AIAA Sonic Boom Prediction Workshop. An inviscid, embedded-boundary Cartesian-mesh flow solver is used in conjunction with adjoint-based mesh adaptation to compute nearfield pressure signatures. Specialized techniques are applied to maximize accuracy and minimize cost on Cartesian meshes. Cartesian Mesh Simulations for the Third AIAA Sonic Boom Prediction Workshop, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

3D Realistic Modeling of Main-Sequence Stars with Shallow Outer Convection Zone

I. Kitiashvili, A. Wray, A. Kosovichev Published online January 11, 2021

Our current state-of-the-art computer simulations allow us to build 3D dynamical and radiation models of F-type stars from physical first principles. Using the stellar interior’s structure from the MESA stellar evolution code as initial conditions, we generate models of main-sequence stars with the mass from 1.4 Msun to 2 Msun for various metallicity composition, in the range of [Fe/H] from -0.3 to 0.2. 3D Realistic Modeling of Main-Sequence Stars with Shallow Outer Convection Zone Bulletin of the American Astronomical Society, vol. 53, issue 1, January 11, 2021

Upping the Ante: The TESS Mission Shortens Full Frame Images to 10 Minutes and Introduces a Twenty-Second Data Collection Mode

J. Jenkins, J. Twicken, P. Tenenbaum, et al. Published online January 11, 2021

The Transiting Exoplanet Survey Satellite (TESS) recently completed its initial two-year, near all-sky survey, identifying over 79 exoplanets and over 2000 exoplanet candidates. We discuss the performance and behavior of the data products generated by the TESS Science Processing Operations Center (SPOC) at NASA Ames Research Center and highlight the new 20-sec data mode and the 10-min FFIs. Upping the Ante: The TESS Mission Shortens Full Frame Images to 10 Minutes and Introduces a Twenty-Second Data Collection Mode Bulletin of the American Astronomical Society, vol. 53, issue 1, January 11, 2021

Primary Mission Threshold Crossing Events in the TESS SPOC Transit Search

J. Twicken, J. Jenkins, D. Caldwell, et al. Published online January 11, 2021

We present an overview of the single- and multiple-sector results of the Science Processing Operations Center (SPOC) transit search in the primary Transiting Exoplanet Survey Satellite (TESS) mission. TESS was designed to survey bright stars in the greater Solar neighborhood in search of transiting exoplanets. Data were acquired at a 2-minute cadence for 16,000-20,000 pre-selected target stars in each 28-day observation sector and processed in the SPOC pipeline at NASA Ames Research Center. Primary Mission Threshold Crossing Events in the TESS SPOC Transit Search Bulletin of the American Astronomical Society, vol. 53, issue 1, January 11, 2021

Stabilization of the Adjoint for Turbulent Flows

A. Garai and S. Murman Published online February 24, 2021

Traditional adjoint variables grow exponentially for turbulent chaotic flows. Most proposed methods (for example. ensemble adjoint, shadow-based, and unstable-subspace-based approaches, etc.) are computationally prohibitive for practical problems. In the current paper, we evaluate a stabilization approach for the adjoints of turbulent flows, which is computationally cheap compared to the previously mentioned methods. Stabilization of the Adjoint for Turbulent Flows, 2021 AIAA SciTech Forum, Virtual Event, January 11-21, 2021

Connecting Atmospheric Properties and Synthetic Emission of Shock Waves Using 3D RMHD Simulations of the Quiet Sun

V. Sadykov, I. Kitiashvili, A. Kosovichev, A. Wray Published online March 3, 2021

We analyze the evolution of shock waves in high-resolution 3D radiative MHD simulations of the quiet Sun and their synthetic emission characteristics. The simulations model the dynamics of a 12.8 × 12.8 × 15.2 Mm quiet-Sun region (including a 5.2 Mm layer of the upper convection zone and a 10 Mm atmosphere from the photosphere to corona) with an initially uniform vertical magnetic field of 10 G, naturally driven by convective flows. Connecting Atmospheric Properties and Synthetic Emission of Shock Waves Using 3D RMHD Simulations of the Quiet Sun The Astrophysical Journal, vol. 909, no. 1, March 3, 2022

Fine Pointing of Laser Beams by Using Laser Arrays for Applications to CubeSats

P. Goorjian Published online March 5, 2021

A method of fine pointing of laser beams by using laser arrays has been developed. The telescope system combines a lens system and a VCSEL/Photodetector Array. In computer simulations, it is applied to CubeSats that use body pointing. Computer simulations of this fine pointing capability have been applied previously to CubeSats in the OCSD program. In this paper, computer simulations of laser pointing using this telescope design are applied to CubeSats in LLO, at 100 km. Fine Pointing of Laser Beams by Using Laser Arrays for Applications to CubeSats Proceedings of the 2021 SPIE LASE, Volume 11678, Free-Space Laser Communications XXXIII, March 6-12, 2021

Planetary Defense Preparedness: Identifying the Potential for Post-asteroid Impact Time Delayed and Geographically Displaced Hazards

T. Titus, D. Robertson, J. Sankey Published online March 5, 2021

A considerable amount of effort has been done to quantify the initial effects of an asteroid impact on Earth. However, delayed downstream and downwind effects will propagate, and disturb areas not immediately affected by the initial impact. This white paper addresses the need for models to anticipate and predict delayed effects on regional areas. Planetary Defense Preparedness: Identifying the Potential for Post-asteroid Impact Time Delayed and Geographically Displaced Hazards Bulletin of the American Astronomical Society, vol. 53, issue 4, March 18, 2021

Viscous Vortex Layers Subject to More General Strain and Comparison to Isotropic Turbulence

K. Shariff, G. Elsinga Published online March 26, 2021

Viscous vortex layers subject to a more general uniform strain are considered. They include Townsend's steady solution for plane strain (corresponding to a parameter a = 1), in which all the strain in the plane of the layer goes toward vorticity stretching, as well as Migdal's recent steady asymmetric solution for axisymmetric strain (a = 1/2), in which half of the strain goes into vorticity stretching. Viscous Vortex Layers Subject to More General Strain and Comparison to Isotropic Turbulence Physics of Fluids, vol. 33, issue 3, March 26, 2021

Microjet Configuration Sensitivities for Active Flow Control on Multi-Element High-Lift Systems

S. S. Hosseini, A. Cooperman, C. P. van Dam, S. Pandya Published online April 21, 2021

Various characteristics of small surface-normal jets (microjets) located on a flap’s pressure-side near the trailing edge are investigated as an active aerodynamic load control technology for multi-element high-lift systems. Two-dimensional computational studies are carried out to investigate the sensitivity of microjet aerodynamic effectiveness to configuration. Initially, the effects of microjet location and width are explored. Microjet Configuration Sensitivities for Active Flow Control on Multi-Element High-Lift Systems AIAA Journal of Aircraft, vol. 58, no. 4, July 2021

The Impact and Recovery of Asteroid 2018 LA

P. Jenniskens, M. Gabadirwe, Q.-Z. Yin, D. Roberson, et al. Published online April 23, 2021

The June 2, 2018 impact of asteroid 2018 LA over Botswana is only the second asteroid detected in space prior to impacting over land. Here, we report on the successful recovery of meteorites. Additional astrometric data refine the approach orbit and define the spin period and shape of the asteroid. Video observations of the fireball constrain the asteroid's position in its orbit and were used to triangulate the location of the fireball's main flare over the Central Kalahari Game Reserve. The Impact and Recovery of Asteroid 2018 LA Meteoritics & Planetary Science, vol. 56, issue 4, April 2021

Comparison of Thermal Radiation Damage Models and Parameters for Impact Risk Assessment

A. Coates, E. Stern, C. Johnston, L. Wheeler, D. Mathias Published online April 26, 2021

Asteroid risk assessments, such as those produced using NASA's probabilistic asteroid impact risk (PAIR) model, have typically estimated radiation using nuclear-based engineering-level models. However, large uncertainties have remained in how well such models represent asteroid airburst radiation and in the luminous efficiency parameter that is used to represent how much of the asteroid entry energy contributes to thermal damage. To investigate these thermal damage modeling assumptions and sensitivities, this study compares results of a 2005 model, which has been used in impact risk assessments, with results of a new higher-fidelity asteroid entry radiation model. Comparison of Thermal Radiation Damage Models and Parameters for Impact Risk Assessment 7th IAA Planetary Defense Conference, Vienna, Austria, April 26-30, 2021

Probabilistic Blast Damage Modeling Uncertainties and Sensitivities

L. Wheeler, M. Aftosmis, J. Dotson, D. Mathias Published online April 26, 2021

This presentation expands upon the probabilistic asteroid impact risk assessments being performed as part of the 2021 PDC hypothetical impact exercise, focusing on key aspects of blast damage modeling uncertainties and sensitivities. We review the current modeling and simulation approaches employed in the current assessment, compare the relative levels of uncertainty stemming from each main element of the problem, and highlight any notable trends and sensitivities for the current scenario case. Probabilistic Blast Damage Modeling Uncertainties and Sensitivities 7th IAA Planetary Defense Conference, Vienna, Austria, April 26-30, 2021

Asteroid Impacts - Downwind and Downstream Effects

T. Titus, D. Robertson, J. Sankey, L. Mastin Published online April 26, 2021

Most of the research on the effects of an intermediate-sized asteroid impact or air burst have focused on immediate damage caused by the shock wave and the thermal radiation. Our focus is to quantify additional effects that could disrupt a larger geographical area than the initial blast. We classify these effects as either downwind or downstream. Some of these effects may occur within hours while others may extend to months, adding to the economic and social cost of the impact event. Asteroid Impacts - Downwind and Downstream Effects 7th IAA Planetary Defense Conference, Vienna, Austria, April 26-30, 2021

High-Fidelity Blast Modeling of Impact from Hypothetical Asteroid 2021 Pdc

M. Aftosmis, W. Spurlock, L. Wheeler, J. Dotson Published online April 26, 2021

The PDC 2021 hypothetical impact exercise poses an interesting challenge to traditional threat assessment methods since it combines a potentially large impactor with minimal warning time. With large uncertainty in the early observational data, this case presents a particular problem for high-fidelity simulation techniques since many of the key input parameters are simply unknown. In this work, we show how recent advances in Bayesian inference and probabilistic risk assessment can be used to develop specific impactors that facilitate high-fidelity simulation in spite of the early uncertainty. High-Fidelity Blast Modeling of Impact from Hypothetical Asteroid 2021 Pdc 7th IAA Planetary Defense Conference, Vienna, Austria, April 26-30, 2021

Dutch-Roll Stability Analysis of an Air Mobility Vehicle Using Navier-Stokes Equations

G. Guruswamy Published online April 30, 2021

Dutch-roll motions caused by sudden gusts are studied for a typical advanced air mobility vehicle. The selected lift+cruise configuration consists of a fuselage with high wing powered by lifting and pushing propellers. Flow is modeled using the Navier–Stokes equations. A procedure is developed to embed the Dutch-roll motion equations in an overset grid topology along with rotating blades. (Full paper requires login.) Dutch-Roll Stability Analysis of an Air Mobility Vehicle Using Navier-Stokes Equations AIAA Journal of Aeronautics and Astronautics, vol. 59, no. 10, October 2021

Resolving Pitching Airfoil Transonic Aerodynamics by Computational Fluid Dynamics Data Modeling

U. Kaul Published online May 27, 2021

A detailed numerical study of harmonically pitching airfoils of NACA00 series is presented here. Based on the analysis of the computational fluid dynamics (CFD) results, a hypothesis is made that a simple data model can capture the dynamics of the airfoils in pitch. The data model is based on the c l −α (lift coefficient–angle of attack) hysteresis loops that retain generic geometrical characteristics for a wide range of reduced frequency, k, encountered in flutter in transonic flows for all the NACA00 airfoils considered. Resolving Pitching Airfoil Transonic Aerodynamics by Computational Fluid Dynamics Data Modeling Journal of Fluids Engineering, vol. 143, issue 9, September 2021

Influence of Center-to-Limb Effects on Observations of the Solar Atmosphere

I. Kitiashvili, V. Sadykov, A. Wray Published online June 18, 2021

The complexity of the highly dynamical atmospheric layers of the Sun in the presence of inhomogeneous magnetic fields makes it challenging to correctly interpret observations from space and ground-based instruments. In particular, the center-to-limb variations of spectro-polarimetric properties may lead to significant misinterpretations of helioseismic and magnetic observables. To address these challenges and study the physical processes behind observations of various types, we use 3D MHD radiative models, which reproduce the dynamics and observational properties with high-degree realism. Influence of Center-to-Limb Effects on Observations of the Solar Atmosphere Bulletin of the American Astronomical Society, vol. 53, issue 6, June 18, 2021

Compression of Solar Spectroscopic Observations: a Case Study of Mg II k Spectral Line Profiles Observed by NASA's IRIS Satellite

V. Sadykov, I. Kitiashvili, A. Sainz Dalda, V. Oria, A. Kosovichev, E. Illarionov Published online June 24, 2021

In this study, we extract the deep features and investigate the compression of the Mg II k spectral line profiles observed in quiet Sun regions by NASA's IRIS satellite. The data set of line profiles used for the analysis was obtained on April 20th, 2020, at the center of the solar disc, and contains almost 300,000 individual Mg II k line profiles after data cleaning. Compression of Solar Spectroscopic Observations: a Case Study of Mg II k Spectral Line Profiles Observed by NASA's IRIS Satellite International Conference on Content-Based Multimedia Indexing, Lille, France, June 28-30, 2021

Prediction of Solar Proton Events with Machine Learning: Comparison with Operational Forecasts and "All-Clear" Perspectives

V. Sadykov, A. Kosovichev, I. Kitiashvili, V. Oria, G. Nita, E. Illarionov, P. Keefe, Y. Jiang, S. Fereira, A. Ali Published online July 8, 2021

Solar Energetic Particle events (SEPs) are among the most dangerous transient phenomena of solar activity. As hazardous radiation, SEPs may affect the health of astronauts in outer space and adversely impact current and future space exploration. In this paper, we consider the problem of daily prediction of Solar Proton Events (SPEs) based on the characteristics of the magnetic fields in solar Active Regions (ARs), preceding soft X-ray and proton fluxes, and statistics of solar radio bursts. Prediction of Solar Proton Events with Machine Learning: Comparison with Operational Forecasts and "All-Clear" Perspectives arXiv:2107.03911 [astro-ph.SR], July 8, 2021

3D Modeling of Solar-Type Stars to Characterize Stellar Jitter

I. Kitiashvili, A. Wray, S. Granovsky Published online July 23, 2021

Detection of Earth-mass planets requires measurements of radial velocity with extreme precision. To capture the tiny disturbances caused by a planet's motion, it is necessary to understand and characterize the host star’s turbulent dynamics in order to apply proper filtering to the observational data. We take advantage of current computational and technological capabilities to develop 3D realistic models of the stellar subsurface convection and atmospheres and thereby estimate the photospheric jitter. 3D Modeling of Solar-Type Stars to Characterize Stellar Jitter Presented at the TESS Science Conference II, August 2-6, 2021

Probing Stellar Cores by Asteroseismic Inversions

A. Kosovichev, I. Kitiashvili Published online July 23, 2021

Precision asteroseismology data from Kepler and TESS provide a unique opportunity to investigate the interior structure of stars at various stages of stellar evolution. Detection of mixed acoustic-gravity oscillation modes has opened perspectives for probing the properties of energy-generating cores. We present direct asteroseismic inversions using the method of optimally localized averages, which effectively eliminates the surface effects and attempts to resolve the stellar core structure. Probing Stellar Cores by Asteroseismic Inversions Presented at the TESS Science Conference II, August 2-6, 2021

Detectability of Transiting Terrestrial Planets in the Habitable Zone with TESS

J. Twicken, J. Jenkins, L. Kaltenegger, D. Caldwell Published online July 23, 2021

The Revised TESS Habitable Zone Catalog identified the 2-min TESS target stars that were observed for sufficient duration over consecutive primary mission sectors to unambiguously capture a transit signature of planets orbiting in the Habitable Zone (HZ). We employ the Combined Differential Photometric Precision computed at 15 pulse durations in the Science Processing Operations Centertransit searches of the primary mission light curves to estimate the signal-to-noise ratio associated with transiting terrestrial planets in the HZ of the Catalog stars. Detectability of Transiting Terrestrial Planets in the Habitable Zone with TESS Presented at the TESS Science Conference II, August 2-6, 2021

Dynamics and Structure of Main-Sequence Stars with Shallow Convection Zones

I. Kitiashvili, A. Wray Published online July 23, 2021

A dramatic increase in observational data from NASA's Kepler, K2, and TESS missions and supporting ground-based observatories have opened new opportunities to investigate the internal structure, dynamics, and evolution of stars and their atmospheres. We present 3D radiative MHD simulations for several main-sequence stars with masses from 1.4 to 1.5 Msun. The simulations are performed using the "StellarBox" code developed for modeling stellar turbulent convection and atmospheres with a high degree of realism. Dynamics and Structure of Main-Sequence Stars with Shallow Convection Zones Presented at the TESS Science Conference II, August 2-6, 2021

TESS Science Processing Operations Center Pipeline Status and Updates

J. Jenkins, J. Twicken, D. Caldwell, et al. Published online July 25, 2021

The past eighteen months have seen a number of important changes for the TESS Science Processing Operations Center (SPOC) and our archival data products as TESS embarked upon its first extended mission. First, the SPOC developed and deployed a new 20-sec cadence pipeline, promising to unveil exciting new astrophysics at these short timescales for up to 1000 targets per observing sector. We also developed an FFI light curve pipeline that creates light curves and associated data products for up to 160,000 targets in each sector and archive these as High-Level Science Products at the Mikulski Archive for Space Telescopes. TESS Science Processing Operations Center Pipeline Status and Updates Presented at the TESS Science Conference II, August 2-6, 2021

Aerodynamic Optimization of a Transonic Strut-Braced-Wing Regional Aircraft Based on the Reynolds-Averaged Navier-Stokes Equations

T. Chau, D. Zingg Published online July 28, 2021

The aerodynamic design and fuel burn performance of a Mach 0.78 strut-braced-wing regional jet is investigated through aerodynamic shape optimization based on the Reynolds-averaged Navier-Stokes equations. Conceptual-level multidisciplinary design optimization is first performed to size the strut-braced-wing aircraft for a design mission similar to the Embraer E190-E2, with a design range of 3,100 nmi at a maximum capacity of 104 passengers, and a maximum payload of 30,200 lb. Aerodynamic Optimization of a Transonic Strut-Braced-Wing Regional Aircraft Based on the Reynolds-Averaged Navier-Stokes Equations AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Integral Velocity Sampling for Unsteady Rotor Models on Cartesian Meshes

J. Chiew, M. Aftosmis Published online July 28, 2021

An unsteady body-force rotor model utilizing integral velocity sampling is developed for Cartesian meshes with a focus on accurate performance predictions. In this approach, the rotors are modeled as body-force source terms, and integral sampling is used to define the local freestream velocity vector. (Full paper requires login.) Integral Velocity Sampling for Unsteady Rotor Models on Cartesian Meshes AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Uncertainty Estimates for Sonic-Boom Pressure Signatures and Loudness Carpets

M. Nemec, M. Aftosmis, L. Smith Published online July 28, 2021

A non-intrusive uncertainty quantification method is applied to computational analysis of supersonic, low-boom aircraft. The mean and standard deviation statistics of the pressure waveforms and loudness metrics are evaluated through use of numerical quadrature. (Full paper requires login.) Uncertainty Estimates for Sonic-Boom Pressure Signatures and Loudness Carpets AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Adjoint-Based Minimization of X-59 Sonic Boom Noise Via Control Surfaces

D. Rodriguez, M. Aftosmis, M. Nemec, W. Spurlock Published online July 28, 2021

A multidisciplinary design optimization methodology to directly minimize the ground-level noise generated by a supersonic aircraft's sonic boom is presented. A gradient-based optimizer is coupled with a Cartesian Euler flow solver and an atmospheric propagation tool to forge a unique design capability. (Full paper requires login.) Adjoint-Based Minimization of X-59 Sonic Boom Noise Via Control Surfaces AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Evaluation of CFD Predictions of Cobra-MRV Control Surface Effectiveness at the NASA Langley Unitary Plan Wind Tunnel

M. Denison, J. Garcia, B. Nikaido, S. Murman, J. Ross, R. Childs, P. Stremel, B. Kleb, S. Alter, T. West, P. Robinson Published online July 28, 2021

The ability of CFD simulations to serve as a surrogate for wind tunnel testing at high supersonic speeds has been evaluated for a sub-scale model of the Co-Optimization Blunt-body Re-entry Analysis-Mid-lift-to-drag Rigid Vehicle (CobraMRV) human Mars entry vehicle concept. The vehicle was tested at the Unitary Plan Wind Tunnel (UPWT) at the NASA Langley Research Center under flow conditions and surface control configurations relevant to the entry stage of a flight mission. (Full paper requires login.) Evaluation of CFD Predictions of Cobra-MRV Control Surface Effectiveness at the NASA Langley Unitary Plan Wind Tunnel AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

CFD Analysis of Space Launch System Solid Rocket Booster Separation within the Langley Unitary Plan Wind Tunnel

J. Koch, E. Dumlupinar, J. Housman, C. Kiris, M. Patel, B. Kleb, G. Brauckmann, S. Alter Published online July 28, 2021

This paper is a joint effort between the National Aeronautics and Space Administration (NASA) Ames and Langley research centers to assess the capability of modern Computational Fluid Dynamic (CFD) codes to accurately simulate experimental force and moment loads on the core stage rocket and Solid Rocket Boosters (SRBs) during the SRBs' separation from a Block 1B configuration Space Launch System (SLS) exploration-class launch vehicle test article within a supersonic wind tunnel. CFD Analysis of Space Launch System Solid Rocket Booster Separation within the Langley Unitary Plan Wind Tunnel AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Efficient Preconditioning of a High-Order Solver for Multiple Physics

M. Franciolini, A. Garai, S. Murman Published online July 28, 2021

This work addresses preconditioning approaches for an implicit high-order solver framework applied to multiple physics. The solver is based on a space-time spectral element method and matrix-free Newton-Krylov solver developed at NASA over the recent years. Within this context, most preconditioning methods are impractical, as the computational time and memory requirements scale poorly with increasing polynomial orders. Efficient preconditioning of a high-order solver for multiple physics AIAA Aviation 2021 Forum, Virtual Event, August 2-6, 2021

Perspective on CFD/CSD-Based Computational Aeroelasticity during 1977–2020

G. Guruswamy Published online July 26, 2021

A perspective on CFD/CSD-based time accurate computational aeroelasticity (CCA) is presented by a researcher who has been actively pursuing this research area since its beginning in late 70s. Discusses the use of terminology focusing on differences between the time accurate coupling and loose coupling methods in CCA. Highlights the misplaced interpretation of tight coupling. Need for time accurate CCA is illustrated with an example that compares CCA results with wind tunnel data that could not be computed using the linear aerodynamic theory. The paper provides a guideline for newcomers to the ever growing CCA research field. Perspective on CFD/CSD-Based Computational Aeroelasticity during 1977–2020 Journal of Aerospace Engineering, vol. 34, issue 6, November 2021

An Immersed Boundary Fluid–Structure Interaction Method for Thin, Highly Compliant Shell Structures

J. Boustani, M. Barad, C. Kiris, C. Brehm Published online August 1, 2021

A parallel computational method for simulating fluid–structure interaction problems involving large, geometrically nonlinear deformations of thin shell structures is presented and validated. A compressible Navier-Stokes solver utilizing a higher-order finite difference immersed boundary method is coupled with a geometrically nonlinear computational structural dynamics solver employing the mixed interpolation of tensorial components formulation for thin triangular shell elements. An Immersed Boundary Fluid–Structure Interaction Method for Thin, Highly Compliant Shell Structures Journal of Computational Physics, vol. 438, August 1, 2021

Construction of Conservative Numerical Fluxes for the Entropy Split Method

B. Sjögreen, H. Lee Published online August 24, 2021

The entropy split method is based on the physical entropies of the thermally perfect gas Euler equations. The Euler flux derivatives are approximated as a sum of a conservative portion and a non-conservative portion in conjunction with summation-by-parts (SBP) difference boundary closure recently proved that the entropy split method is entropy conservative and stable. The current work is our first attempt to derive a high order conservative numerical flux for the non-conservative portion of the entropy splitting of the Euler flux derivatives. Construction of Conservative Numerical Fluxes for the Entropy Split Method Communications on Applied Mathematics and Computation, August 24, 2021

Inlet Flow Distortion in an Advanced Civil Transport Boundary Layer Ingesting Engine Installation

D. Hall, E. Greitzer, A. Uranga, M. Drela, S. Pandya Published online September 16, 2021

This paper presents first-of-a-kind measurements, and complementary computations, of the flow through the propulsion system of a boundary layer ingesting, twin-engine advanced civil transport aircraft configuration. The experiments were carried out in the NASA Langley 14- by 22-foot Subsonic Tunnel, using a 1:11 scale model of the D8 “double-bubble” aircraft with electric ducted fans providing propulsive power. Inlet Flow Distortion in an Advanced Civil Transport Boundary Layer Ingesting Engine Installation ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition, vol. 1, June 7-11, 2021

Bridging Reinforcement Learning and Online Learning for Spacecraft Attitude Control

J. Elkins, R. Sood, C. Rumpf Published online September 28, 2021

Artificial intelligence is expected to revolutionize all areas of space operations in the coming years. The most advanced space systems will possess the ability to adapt and improve performance over time, or online learning. This work presents a novel framework that uses the highly researched artificial intelligence paradigm, reinforcement learning, to perform online learning. Bridging Reinforcement Learning and Online Learning for Spacecraft Attitude Control Journal of Aerospace Information Systems, vol. 19, no. 1, January 2022

Structured and Unstructured Simulations for the Third AIAA Sonic Boom Prediction Workshop

J. Duensing, J. Jensen, J. Housman, M. Piotrowski, D. Maldonado, E. Sozer, C. Kiris, G. Kenway Published online October 29, 2021

Artificial intelligence is expected to revolutionize all areas of space operations in the coming years. The most advanced space systems will possess the ability to adapt and improve performance over time, or online learning. This work presents a novel framework that uses the highly researched artificial intelligence paradigm, reinforcement learning, to perform online learning. Structured and Unstructured Simulations for the Third AIAA Sonic Boom Prediction Workshop Journal of Aircraft, vol. 58, no. 3, May 2022

A Positivity-Preserving High-Order Weighted Compact Nonlinear Scheme for Compressible Gas-Liquid Flows

M. L. Wong, J. Angel, M. Barad, C. Kiris Published online November 1, 2021

We present a robust, highly accurate, and efficient positivity- and boundedness-preserving diffuse interface method for the simulations of compressible gas-liquid two-phase flows with the five-equation model by Allaire et al. using high-order finite difference weighted compact nonlinear scheme (WCNS) in the explicit form. The equation of states of gas and liquid are given by the ideal gas and stiffened gas laws respectively. A Positivity-Preserving High-Order Weighted Compact Nonlinear Scheme for Compressible Gas-Liquid Flows Journal of Computational Physics, vol. 444, November 1, 2021

An Automated Bolide Detection Pipeline for GOES GLM

J. Smith, R. Morris, C. Rumpf, R. Longenbaugh, N. McCurdy, C. Henze, J. Dotson Published online November 1, 2021

The Geostationary Lightning Mapper (GLM) instrument onboard the GOES 16 and 17 satellites has been shown to be capable of detecting bolides (bright meteors) in Earth’s atmosphere. Due to its large, continuous field of view and immediate public data availability, GLM provides a unique opportunity to detect a large variety of bolides, including those in the 0.1 to 3 m diameter range and complements current ground-based bolide detection systems, which are typically sensitive to smaller events. We present a machine learning-based bolide detection and light curve generation pipeline being developed at NASA Ames Research Center as part of NASA’s Asteroid Threat Assessment Project (ATAP). An Automated Bolide Detection Pipeline for GOES GLM Icarus, vol. 368, November 1, 2021

Modeling Stellar Jitter and its Effects on the Stellar Spectrum for More Precise Radial Velocity Measurements

S. Granovsky, I. Kitiashvili, A. Wray Published online November 5, 2021

Detection of Earth-size exoplanets is a technological and data analysis challenge. Future progress in Earth-mass exoplanet detection is expected from the development of extreme precision radial velocity (EPRV) measurements. The required precision of these measurements necessitates developing a new physics-based data analysis methodology to discriminate planetary signals from host-star-related effects, taking stellar variability and instrumental uncertainties into account. In this work, we investigate and quantify stellar disturbances of the planet-hosting solar-type star HD121504 from 3D radiative modeling obtained with the StellarBox code. Modeling Stellar Jitter and its Effects on the Stellar Spectrum for More Precise Radial Velocity Measurements Presented at the International Astronomical Union Symposia, France, November 8-12, 2021

Feasibility of Running Singularity Containers with Hybrid MPI on NASA High-End Computing Resources

S. Chang, S. Heistand, R. Hood, H. Jin Published online November 17, 2021

Detection of Earth-size exoplanets is a technological and data analysis challenge. Future progress in Earth-mass exoplanet detection is expected from the development of extreme precision radial velocity (EPRV) measurements. The required precision of these measurements necessitates developing a new physics-based data analysis methodology to discriminate planetary signals from host-star-related effects, taking stellar variability and instrumental uncertainties into account. In this work, we investigate and quantify stellar disturbances of the planet-hosting solar-type star HD121504 from 3D radiative modeling obtained with the StellarBox code. Feasibility of Running Singularity Containers with Hybrid MPI on NASA High-End Computing Resources 3rd International Workshop on Containers and New Orchestration Paradigms for Isolated Environments in HPC, November 2021

Computational Aerodynamics Analysis in Support of the CRM Tail Cone Thruster Configuration Wind Tunnel Test

L. Santos Fernandes, L. Machado, J. Duensing, C. Kiris Published online December 29, 2021

NASA's Advanced Air Transport Technology (AATT) project is breaching the boundaries of aircraft design in pursuit of eco-friendly solutions that are compatible with urban noise comfort levels. Boundary layer ingesting (BLI) propulsion systems promise to reduce fuel burn with additional potential benefits in noise reduction. Type-II BLI systems of the STARC-ABL type are the subject of a test campaign planned for fiscal year 2022 in the National Transonic Facility (NTF), for which a CRM-based model with a retrofitted tail cone thruster (TCT) has been designed. The present work is a precursor to the NTF test, where the 240 cases planned for the experiment were simulated using the Launch, Ascent, and Vehicle Aerodynamics (LAVA) computational framework. Computational Aerodynamics Analysis in Support of the CRM Tail Cone Thruster Configuration Wind Tunnel Test AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

High-Fidelity Aerodynamic Analysis and Optimization of the SUSAN Electrofan Concept

L. Machado, T. Chau, G. Kenway, J. Duensing, C. Kiris Published online December 29, 2021

The Subsonic Single Aft Engine (SUSAN) Electrofan is a new single-aisle regional jet class transport aircraft being studied by NASA, which benefits from reduced fuel consumption through a reduction in the number of hydrocarbon fuel-burning engines from two to one. This is achieved through a hybrid-electric system architecture, where a series of generators are used to extract power from a fuel-consuming tail cone thruster to drive electric propulsors mounted on the wings. To support the development of these propulsion systems, which involve high levels of propulsion-airframe integration, this paper presents high-fidelity analyses through computational fluid dynamics (CFD) simulations provided by the Launch, Ascent, and Vehicle Aerodynamics (LAVA) framework, which also includes capabilities for modeling the effect of active propulsors. High-Fidelity Aerodynamic Analysis and Optimization of the SUSAN Electrofan Concept AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

High-Fidelity Simulations of a Quadrotor Vehicle for Urban Air Mobility

P. Ventura Diaz, S. Yoon Published online December 29, 2021

High-fidelity computational fluid dynamics simulations have been carried out to analyze NASA's quadrotor air taxi concept for urban air mobility. High-order accurate schemes, dual-time stepping, and the delayed detached-eddy simulation model have been employed. The flow solver has been loosely coupled with the rotorcraft comprehensive analysis code. The vehicle simulated is a six-passenger quadrotor for air taxi operations. High-Fidelity Simulations of a Quadrotor Vehicle for Urban Air Mobility AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Wall Modeled Large Eddy Simulations for NASA's Jet Noise Consensus Database of Single-Stream, Round, Convergent Jets

G.-D. Stich, A. Ghate, J. Housman, C. Kiris Published online December 29, 2021

A campaign of wall-modeled large-eddy simulations (WMLES) using structured curvilinear overlapping grids has been performed with the Launch Ascent and Vehicle Aerodynamics (LAVA) computational fluid dynamics (CFD) software to predict jet noise for single-stream axisymmetric round jets. The simulations address the new Prediction Uncertainty Reduction (PUR) technical challenge within the context of NASA's Commercial Supersonic Technology (CST) project. Wall Modeled Large Eddy Simulations for NASA's Jet Noise Consensus Database of Single-Stream, Round, Convergent Jets AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

1st AIAA CFD Transition Modeling and Prediction Workshop: OVERFLOW Results for the SST and Langtry-Menter Models

M. Denison Published online December 29, 2021

This paper reports the results of CFD simulations of the test cases for the AIAA 1st CFD Transition Modeling and Prediction Workshop held at the AIAA Scitech Forum on 21-22 January, 2021 using the NASA solver OVERFLOW. The Langtry-Menter transition model was used in combination with the Shear Stress Transport (SST) turbulence model. 1st AIAA CFD Transition Modeling and Prediction Workshop: OVERFLOW Results for the SST and Langtry-Menter Models AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Conceptual Exploration of Aircraft Configurations for the SUSAN Electrofan

T. Chau, G. Kenway, C. Kiris Published online December 29, 2021

This paper presents an aircraft configuration trade space exploration for NASA’s SUbsonic Single Aft eNgine (SUSAN) Electrofan, which is a 180 passenger regional class transport aircraft that utilizes electrified aircraft propulsion and advanced propulsion airframe integration technologies to enable reduced fuel consumption and emissions. Conceptual Exploration of Aircraft Configurations for the SUSAN Electrofan AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Fluid-Structure Interaction Simulations of the ASPIRE SR01 Supersonic Parachute

J. Boustani, G. Kenway, F. Cadieux, M. Barad, C. Brehm, C. Kiris Published online December 29, 2021

High-fidelity computational fluid dynamics (CFD) simulations have so far only played exploratory and supporting roles in the study and qualification of parachutes for planetary entry. The last few years have seen the maturation of coupled computational methods that are capable of modeling the complex fluid-structure interactions between a parachute canopy and the supersonic flow in the wake of an entry vehicle in flight conditions. Fluid-Structure Interaction Simulations of the ASPIRE SR01 Supersonic Parachute AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

High-Lift Common Research Model: RANS, HRLES, and WMLES perspectives for CLmax prediction using LAVA

C. Kiris, A. Ghate, J. Duensing, O. Browne, J. Housman, G.-D. Stich, G. Kenway, L. Fernandes, L. Machado Published online December 29, 2021

A unified assessment of three turbulence treatments: Reynolds Averaged Navier-Stokes (RANS), Hybrid RANS/LES (HRLES) and Equilibrium Wall-Modelled Large Eddy Simulation (WMLES) is presented for the High-Lift Common Research Model (CRM-HL). For the free-air configuration, steady-state RANS simulations show very accurate drag polar predictions in the low-AoA linear regime. High-Lift Common Research Model: RANS, HRLES, and WMLES perspectives for CLmax prediction using LAVA AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Investigation of a Smooth Local Correlation-based Transition Model in a Discrete-Adjoint Aerodynamic Shape Optimization Algorithm

M. Piortrowski, D. Zingg Published online December 29, 2021

A smooth local correlation-based transition model is fully coupled to a RANS-based Newton-Krylov flow solver and discrete-adjoint gradient-based optimization algorithm. The free-transition optimization framework is evaluated using lift-constrained drag minimizations of airfoils at design conditions ranging from light to single-aisle aircraft and an infinite swept wing at design conditions representative of a transonic strut-braced wing aircraft. Investigation of a Smooth Local Correlation-based Transition Model in a Discrete-Adjoint Aerodynamic Shape Optimization Algorithm AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Numerical Behaviour of a Smooth Local Correlation-based Transition Model in a Newton-Krylov Flow Solver

M. Piotrowski, D. Zingg Published online December 29, 2021

The numerical behaviour of transport-equation-based transition models, including both iterative and grid convergence, is influenced by the source terms. Transition models contain source terms that are large and highly nonlinear, and can be destabilizing in a strong implicit solver. Linearization strategies with varying levels of coupling are evaluated in conjunction with a source-term time step restriction to determine best-practices for solving the SA-sLM2015 smooth local correlation-based transition model in an implicit Newton-Krylov flow solver. Numerical Behaviour of a Smooth Local Correlation-based Transition Model in a Newton-Krylov Flow Solver AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Overlap Preservation Using Loosely-Coupled Boundary Conditions for Body-Fitted Structured Overset Grids

A. Chuen, W. Chan Published online December 29, 2021

Several improvements are made to overlap preservation in the automated approach to generating overset structured meshes. A loosely-coupled boundary condition (LCBC) is introduced to maintain optimal overlap for surface meshes generated from overlapping initial curves. Extension of the LCBC scheme to three-dimensional volume meshing is also presented. Overlap Preservation Using Loosely-Coupled Boundary Conditions for Body-Fitted Structured Overset Grids AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Scale-Resolving Simulations of Supersonic Retro-Propulsion Concept For Mars Entry, Descent, and Landing

F. Cadieux, S. Neuhoff, M. Barad, C. Kiris Published online December 29, 2021

Supersonic retro-propulsion (SRP) is a deceleration technology that could enable larger payloads and potentially humans to be brought from space to the surface of Mars safely. Accurate and reliable CFD predictions are needed to help design future Mars entry, descent, and landing (EDL) vehicles due to the cost and limitations of wind tunnel tests. This work demonstrates how high-order scale-resolving simulations on Cartesian adaptive mesh refinement (AMR) grids can provide accurate and reliable time-averaged aerodynamic loads on the vehicle for this challenging flow regime. Scale-Resolving Simulations of Supersonic Retro-Propulsion Concept For Mars Entry, Descent, and Landing AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Subsonic Single Aft Engine (SUSAN) Transport Aircraft Concept and Trade Space Exploration

R. Jensen, C. Kiris, T. Chau, L. Machado, J. Duensing, et al. Published online December 29, 2021

A trade space exploration of a new NASA regional transport aircraft concept called the SUbsonic Single Aft eNgine (SUSAN) Electrofan is presented. The SUSAN concept uses a 20MW Electrified Aircraft Propulsion (EAP) system to enable advance Propulsion Airframe Integration (PAI) in transport category aircraft. This paper presents the status of the trade space exploration; however the concept definition is not finished. Subsonic Single Aft Engine (SUSAN) Transport Aircraft Concept and Trade Space Exploration AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Wind Tunnel Experiment of Microjet-based Flow Control on a Multi-Element High-Lift Airfoil

C. Van Dam, S. Mothukuri, S. Hosseini, E. White, L. Brown, D. Kutz, E. Justiniano Published online December 29, 2021

A wind tunnel model was designed, manufactured, and tested to evaluate the potential of active aerodynamic flow control for multi-element airfoils. The configuration selected for this test is the NLR7301 two-element airfoil and it was tested in the Oran W. Nicks Low-Speed Wind Tunnel at Texas A&M University at a chord Reynolds number of 2.0 million and Mach number of 0.10. This paper presents wind tunnel results for the NLR7301 in the Flap 20 and Flap 30 configurations. Wind Tunnel Experiment of Microjet-based Flow Control on a Multi-Element High-Lift Airfoil AIAA SciTech 2022 Forum, San Diego, CA, January 3-7, 2022

Progress in Developing a Prototype Science Pipeline and Full-Volume, Global Hyperspectral Synthetic Data Sets for NASA’s Earth System Observatory’s Upcoming Surface, Biology and Geology Mission

J. Jenkins, P. Tenenbaum, Y. Shinozuka, B. Wohler, A. Michaelis, et al. Published online January 2022

The Surface Biology and Geology (SBG) mission is one of the core missions of NASA’s Earth System Observatory (ESO). SBG will acquire high resolution solar-reflected spectroscopy and thermal infrared observations at a data rate of ~10 TB/day and generate products at ~75 TB/day. As the per-day volume is greater than NASA’s total extant airborne hyperspectral data collection, collecting, processing/re- processing, disseminating, and exploiting the SBG data presents new challenges. To address these challenges, we are developing a prototype science pipeline and a full-volume global hyperspectral synthetic data set to help prepare for SBG’s flight. Progress in Developing a Prototype Science Pipeline and Full-Volume, Global Hyperspectral Synthetic Data Sets for NASA’s Earth System Observatory’s Upcoming Surface, Biology and Geology Mission Presented at the AGU 2021 Fall Meeting, New Orleans, LA, December 13-17, 2021

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NASA Langley Space Radiation Group (SRG)

The Space Radiation Group (SRG) at NASA Langley Research Center is concerned with protecting humans and electronics from the harmful effects of space radiation. This web site contains links to publications, including journal articles and NASA technical papers, that have been produced by the group (and some collaborators) since the year 2000. There are also links to two important radiation analysis software tools called OLTARIS (On-Line Tool for the Assessment of Radiation in Space) and NAIRAS (Nowcast of Atmospheric Ionizing Radiation System), which predict radiation environments for spacecraft and aircraft respectively.

To the right is a near-real-time (updated every 15 minutes) image of the sun from the Solar Dynamics Observatory.

Norman G. Loeb (NASA)

Dr. Norman Loeb is the NASA Senior Technologist for Radiation Sciences. He also serves as the NASA Principal Investigator for Clouds and the Earth’s Radiant Energy System (CERES) and is a Commissioner of the International Radiation Commission (Co-Leader of the Earth Radiation Budget Working Group). He is a panel member on the World Climate Research Programme CLIVAR (CLImate and ocean – VARiability, predicability, and change) research focus team on Planetary heat balance & ocean heat storage. Dr. Loeb is a fellow of the American Meteorological Society.

Publication Bibliography:

• https://ceres.larc.nasa.gov/people/dr-norman-loeb/

Select Publications:

• Loeb, N. G., M. M. Mayer, S. Kato, J. T. Fasullo, H. Zuo, R. Senan, J. M. Lyman, G. C. Johnson, and M. Balmaseda, 2022: Evaluating twenty-year trends in Earth’s energy flows from observations. J. Geophys. Res., 127, e2022JD036686, https://doi.org/10.1029/2022JD036686
• Loeb, N. G., G. C. Johnson, T. J. Thorsen, J. M. Lyman, F. G. Rose, and S. Kato, 2021: Satellite and ocean data reveal marked increase in Earth’s heating rate. Geophys. Res. Lett., 48, e2021GL093047. https://doi.org/10.1029/2021GL093047 .
• Loeb, N. G., W. Su, N. Bellouin, Y. Ming, 2021: Changes in Clear-Sky Shortwave Aerosol Direct Radiative Effects Since 2002. J. Geophys. Res., 126(5), e2020JD034090. doi: https://doi.org/10.1029/2020JD034090 .
• Loeb, N. G., and D. R. Doelling, 2020: CERES Energy Balanced and Filled (EBAF) from afternoon-only satellite orbits. MDPI Remote Sensing, 12, 1280; doi: 1280; doi:10.3390/rs12081280.
• Loeb, N. G., H. Wang, R. P. Allan, T. Andrews, K. Armour, J.N.S. Cole, et al., 2020: New generation of climate models track recent unprecedented changes in earth’s radiation budget observed by CERES. Geophys. Res. Lett., 47, doi:10.1029/2019GL086705.
• Loeb, N.G., F.G. Rose, S. Kato, D.A. Rutan, W. Su, H. Wang, D.R. Doelling, W.L. Smith, Jr., and A. Gettelman, 2020: Towards a consistent definition between satellite and model clear-sky radiative fluxes. J. Climate, 33, 61-75. doi: 10.1175/JCLI-D-19-0381.1.
• Loeb, N.G., H. Wang, F.G. Rose, S. Kato, W.L. Smith, Jr., S. Sun-Mack, 2019: Decomposing shortwave top-of-atmosphere and surface radiative flux variations in terms of surface and atmospheric contributions. J. Climate, https://doi.org/10.1175/JCLI-D-18-0826.1 .
• Loeb, N.G., T.J. Thorsen, J.R. Norris, H. Wang, and W. Su, 2018: Changes in Earth’s energy budget during and after the “Pause” in Global Warming: An observational perspective. MDPI Climate, 6, 62; doi:10.3390/cli6030062.
• Loeb, N.G., P. Yang, F.G. Rose, G. Hong, S. Sun-Mack, P. Minnis, S. Kato, S.-H. Ham, W.L. Smith, Jr., S. Hioki, and G. Tang, 2018: Impact of ice cloud microphysics on satellite cloud retrievals and broadband flux radiative transfer model calculations. J. Climate, 31,1851-1864.
• Loeb, N. G., D. R. Doelling, H. Wang, W. Su, C. Nguyen, J. G. Corbett, L. Liang, C. Mitrescu, F. G. Rose, and S. Kato, 2018: Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) Top-of-Atmosphere (TOA) Edition 4.0 data product, J. Climate, 31, 895-918. doi: 10.1175/JCLI-D-17-0208.1.

Virtual Presentation:

First Light on NASA’s Newest Clouds and the Earth’s Radiant Energy System by Norman Loeb [YouTube]

• 2007 Performance Award, NASA Langley Research Center

Professional Memberships:

• American Meteorological Society
• American Geophysical Union
• B.Sc. and Ph.D. degrees in Atmospheric Sciences, McGill University
• M.Sc. degree in Atmospheric Sciences, York University

National/International Leadership:

Commissioner of the International Radiation Commission (Co-Leader of the Earth Radiation Budget Working Group)

January 24, 2022

Four joint flights were conducted this past Tuesday and Wednesday (Jan 18-19) to capitalize on another cold air outbreak event, similar to the previous week. We observed significant temperature variations in the various vertical profiles conducted by the low-flying Falcon, with evidence of significant precipitation near the transition from overcast to open-cell cloud conditions. A significant decreasing gradient in cloud drop number concentrations was observed with distance offshore especially during the January 18 flights.

June 20, 2022

ACTIVATE’s final flight deployment ended this past week with Research Flight 179 (Saturday June 18) transiting back from Bermuda to Virginia. A number of flights in the past week continued to build on the dataset for aerosol-cloud-meteorology interactions surrounding the Bermuda area, including on Tuesday June 14 a “process study flight” where the coordinated aircraft characterized a building cumulus cloud system. The Falcon conducted its traditional “wall” pattern used during process study flights with ~20 stacked legs going from below to above the cloud. Meanwhile the UC-12 flew overhead conducting remote sensing measurements of the same system while launching numerous dropsondes. A day earlier (June 13), the joint research flight conducted was synchronized with a CALIPSO overpass in conditions that are ideal for intercomparison of data including cloud-free air with significant aerosol concentrations and a diversity of aerosol types including in particular African dust. Now the ACTIVATE team focuses on processing and data archival of the 2022 flight deployments.

June 14, 2021

This past week included two double-flight days on Monday-Tuesday (June 7-8). June 7 was notable in that the second flight (RF 80) was a “process study” flight, which accounts for approximately 10% of ACTIVATE flights. We targeted an area with a cluster of clouds and conducted a total of 10 Falcon legs in cloud at different altitudes ranging from ~2 to ~13 kft. These legs and a subsequent downward spiral resulted in 10 cloud water samples for a single cloud system. Simultaneously, the King Air conducted a ‘wheel and spoke” pattern far above to allow the remote sensors to characterize the environment and cloud that the Falcon was directly sampling. A total of 14 dropsondes were launched by the King Air in the ~3 hr flight. This flight and the other “process study” flight in this summer campaign (RF77 on June 2) will provide a remarkable dataset to investigate aerosol-cloud-meteorology interactions with very detailed measurements for single evolving cloud systems.

March 15, 2021

ACTIVATE conducted four more successful joint flights (Research Flights 51-54) this past week. We characterized a variety of cloud conditions including post-frontal clouds associated with another cold air outbreak on Monday (March 8) in contrast to the following day (Tuesday March 9) where there was a sharp inversion with uniform cloud top heights and generally thin clouds. Flights this past week were marked by influence from local and regional burning emissions. The second of two flights on Friday (March 12) was coordinated with a CALIPSO overpass.

Febraury 5, 2021

ACTIVATE’s had its first joint flight of the winter 2021 campaign on February 3. We were successful to sample a transition from overcast stratocumulus clouds to broken cumulus clouds near our farthest southeast point of the flight track. There was extensive mixed-phase precipitation in areas closer to shore but pure liquid clouds farther offshore coinciding with the open cell cloud field. Although at low optical depth, an interesting aerosol layer was observed above 6 km that most likely was dust due to its depolarizing nature.

January 30, 2020

This past week ACTIVATE took to the skies again to begin our 2021 winter campaign. In contrast to last year, we started a bit earlier in the month of January to capitalize on a higher frequency of cold air outbreak events. Friday’s flights (January 29) were particularly ideal with both aircraft sampling along cloud streets aligned with the predominant wind direction coming from the north/northwest. We observed a transition from supercooled droplets to mixed phase precipitation with distance away from shore.

June 13, 2022

The past week coincided with a string of excellent weather conditions leading to eight joint flights between June 7-11 (RF166-173). There was evidence of African dust in the region that the aircraft sampled, in addition to coordinated efforts with glider platforms operated by the Bermuda Institute of Ocean Sciences to study the upper parts of the ocean surface that may affect the ACTIVATE measurements via sea-air interactive processes. Research flight 166 on 7 June was somewhat unique in that we sampled distinct cloud streets that we more commonly flew in during the winter season associated with cold air outbreaks. The ACTIVATE team also hosted a successful outreach event at the Longtail Aviation hangar featuring 40 students from three local grade schools.

June 6, 2022

On 31 May, the ACTIVATE team conducted a joint plane transit flight from Langley Research Center to Bermuda to base operations there until June 18. A series of flights (Research Flights 161-165) up through Sunday 5 June helped obtain statistics of atmospheric conditions around Bermuda. Many of the local Bermuda flights ended with a spiral sounding just offshore the Tudor Hill facility to obtain important vertical data for trace gases, aerosol, and weather parameters that will complement extensive surface monitoring work going on in coordination with the NSF-funded BLEACH project going on focused on halogen chemistry. Flights have already gathered important statistics associated with shallow “popcorn” cumulus cloud fields.

May 23, 2022

Four graduate students from the University of Arizona visited Langley Research Center to learn about and participate in the operational side of ACTIVATE. They took part in a very active flight week, with a total of eight joint flights deployed (Flights 153 - 160). Flights 156 and 157 on Wednesday, May 18th were special because these were the first flights to and from Bermuda that included a CALIPSO underflight. The CALIPSO track was clear of clouds and various aerosol layers such as smoke and dust were present. Another set of joint flights to and from Bermuda was conducted on Saturday, marking a successful end to the May flights. The next update will be in a couple weeks as the coming week will be used to prepare to fly out to Bermuda to base operations there from 1-18 June.

May 16, 2022

The previous week was marked by a persistent low pressure system positioned off the mid-Atlantic coast that impacted flight operations. Only one joint flight was conducted as a result on Tuesday (10 May; Research Flight 152), which featured strong northeasterly winds and warm air advection over the coastal cold waters created stratiform clouds near the surface. During parts of the flight there were several layers of decoupled stratiform cloud in the lower (free) troposphere.  There was evidence of strong sea salt influence on this day with a high volume of cloud water samples collected that will be helpful for continued characterization of the cloud chemistry in the study region. This week was marked by some visitors to Langley Research Center from the science team including Hailong Wang (PNNL) and Minnie Park (BNL), along with Simon Kirschler who is visiting from DLR in Germany.

May 09, 2022

ACTIVATE’s sixth and final deployment began this past week with three successful joint flights (Flights 149-151). In contrast to the winter deployment, aerosol optical depths increased this past week with dust and smoke signatures, with the latter possibly stemming from plumes advected from the western United States. These data will be helpful to learn more about the impacts of these aerosol types on clouds even if they reside above cloud tops. On Thursday (5 May 2022) we conducted a successful refueling trip to Providence, Rhode Island marked by extensive cloud characterization and upwards of 20 cloud water samples helpful for cloud composition studies.

March 30, 2022

We wrapped up Deployment 5 on Tuesday after finishing a couple joint flights (Research Flights 146-148). Monday’s flight was intriguing owing to the diversity of aerosol types sampled ranging from the usual marine aerosol types such as sea salt to also smoke, dust, and pollen. Tuesday’s flights were excellent for cold air outbreak characterization including upwind clear air sampling and then also the transition from overcast cloud conditions to an open cloud field. We will begin Deployment 6 in the first week of May and conduct flights through the end of June.

March 28, 2022

After considerable effort and patience due to pandemic-related barriers, ACTIVATE was able to successfully execute its first flight to Bermuda this past week. Research flights 142-143 on Tuesday March 22 nd involved out-and-back flights from Hampton, Virginia to Bermuda. Flights to Bermuda are important for a number of reasons including the ability to extend the spatial range of data off the U.S. East Coast to be farther removed from continental and Gulf Stream influence and closer to more “background marine” conditions. Flights 144-145 on Saturday March 26 th were special in that a wide range of aerosol types were sampled including dust, smoke, sea salt, and biological particles especially in the form of pollen near the coast.

March 21, 2022

ACTIVATE had a golden flight day on 13 March 2022 (Sunday) with a cold air outbreak and two joint flights in morning and afternoon. In the morning flight we sampled an overcast cloud field that began to transition into a more broken field. We conducted 3 “walls” with the low flyer (Falcon) involving level legs below and in cloud stacked vertically on top of each other for better vertical characterization of the ‘aerosol-cloud system’. We launched 11 dropsondes with the high flyer (King Air). Data suggest significant new particle formation above cloud tops offshore during the cold air outbreak event. The two flights that day provide excellent data for model intercomparison to understand boundary layer cloud evolution. Later in the week (Monday March 14) was marked by smoke conditions offshore that the Falcon was able to characterize with its suite of instruments. Two graduate students and a research scientist from the University of Arizona visited NASA Langley Research Center this past week to learn about and participate in the operational side of ACTIVATE.

March 14, 2022

This week was dominated by a stalled cold front over the ACTIVATE flight domain, which prevented the team from executing flights most of the week owing to complex conditions that would affect data quality (e.g., mid and high level clouds impacting remote sensors on the King Air) and sampling of well-defined boundary layer clouds. We were successful though with flights at the beginning of the week (Research flights 135-136) on Monday March 7 th , including both clear air and cloud characterization to the southern part of our usual sampling domain. The following week appears to be very promising with cold air outbreak conditions setting up as soon as this Sunday March 13 th .

March 7, 2022

The past week of ACTIVATE flights (research flights 130-134) including more clear air characterization than past weeks, with both dust and smoke influence over the northwest Atlantic. Two of the flights consisted of a vertical spiral sounding in cloud-free and polluted conditions with the HU-25 Falcon with the King Air flying overhead, which will be helpful for a number of types of analyses, including intercomparison between aerosol remote sensing products from the HSRL-2/RSP (on the King Air) and in situ aerosol observations from the Falcon. The two flights on Friday March 4 th in particular were excellent as there was high cloud fraction across most of our sampling region which afforded a chance to sample clouds impacted by potential dust and smoke plumes.

March 1, 2022

After standing down for a week to swap the B200 with the UC-12 King Air, flights resumed this past week (research flights 120-125) with three days of double-flights (Feb. 15, 16, 19). The statistical database representative of typical wintertime conditions continued to expand with these flights that all included cloud sampling and similar characteristics as recent weeks. For instance, gradients of decreasing cloud drop concentration with distance east of the shore continued to be observed, along with both warm and mixed-phase precipitation, and situations where cumulus clouds connected to overlying stratiform clouds.

February 22, 2022

February 7, 2022

Research flights 115-119 in the past week continued the extensive characterization of the northwest Atlantic in during typical wintertime conditions. Notable features this week included gradients offshore such as how in flight 115 (Tuesday, Feb 1) clouds were initially scattered by the coast and then rapidly started to deepen and fill in forming an overcast deck on the outbound leg. Towards the northeast part of the flight path, clouds took on a distinctly decoupled appearance with cumulus clouds feeding an upper stratiform deck. Aerosol gradients were evident too with regard to number concentration and composition. These distinct differences in the study region on individual flights present a critical opportunity for data analysis to better understand the aerosol-cloud-meteorology system.

January 31, 2022

Six joint flights were conducted this past week, including three double-flight days between January 24 and 27. The two flights on January 24 th included more sampling towards the southern part of our operation domain to get more diversity in conditions with regard to weather and aerosol conditions. The two flights on Thursday (Jan 27) included a refueling stop at Providence, Rhode Island to allow us to extend our spatial range of sampling. That day included complex cloud structure with wave characteristics (i.e., variable base and top heights) and decoupling of cloud layers. There was an abundance of ice nuclei during the two flights on this day.

January 18, 2022

ACTIVATE returned with flights this past week by executing Research Flights 100-104, including consecutive double-flight days on Tuesday and Wednesday (January 11-12, 2022). The two flights on January 11 th were used to sampled upwind and into a region of clouds during a cold air outbreak event; the second flight was used to keep tracking the evolution of the cold air outbreak farther downwind to the southeast of where the first flight left off. Intriguing features were observed on the two flights on Tuesday including steam fog, funnel clouds, and waterspouts. Both warm and mixed-phase precipitation were observed, along with new particle formation above cloud tops.

December 13, 2021

Four joint flights were conducted this past week in ACTIVATE’s final week of science flights for December before resuming flights in January 2022. Notable was the back-to-back flight day on Thursday (9 Dec 2021) when the two aircraft flew north for a refueling stop at Quonset State Airport (Rhode Island). This marks the first refueling stop at a secondary base in the ACTIVATE project. Extending our typical spatial range was helpful for a more extensive characterization of the complex cloud scene  including solid and broken boundary layer cloud structure with distinctly different cloud types including both warm and mixed-phase precipitation. ACTIVATE measurements during these two flights will be very helpful to understand gradients in the aerosol-cloud system during the transitions between cloud types (e.g., stratocumulus, fair weather cumulus) and the solid versus broken cloud fields.

December 6, 2021

The 5th ACTIVATE deployment started this past week with two joint flights having similar headings going southeast from the base of operations at NASA Langley Research Center. These flights allowed for unique sampling of trace gases, aerosols, and marine boundary layer clouds in the month of December, which has yet to be done during ACTIVATE’s first 93 flights leading up to these two flights. More flights are planned in the coming week before a break and then resumption of flights in January.

July 1, 2021

We finished our summer campaign this past week with four more ACTIVATE flights (Research Flights 90-93) between June 28 and 30. These flights focused on extensive data collection in typical summertime shallow cumulus clouds. A notable feature in these flights was sampling behind ship vessels near the coast that yielded especially large enhancements in particle concentration parameters.

June 28, 2021

Four flights were conducted last week, with two single flight days on June 22 and 24, and a double flight day on June 26. Saturday’s conditions (June 26) were in particular very good for ACTIVATE with a scattered shallow cumulus cloud scene throughout the day that both planes were able to jointly characterize. The past week also was linked to high variability in aerosol conditions with the northward advancement of African dust into our study region.

June 21, 2021

This past week included three single-flight days on Tuesday-Thursday (June 15-17). The first flight of this week (June 15) was a statistical cloud survey but proved to be a challenging flight to execute as the King Air encountered pervasive cirrus along the track and the Falcon dealt with low clouds at varying altitude ranges. The June 16 flight targeted mostly clear skies with observations of moderate aerosol loading. This flight also included an overflight of Langley Research Center at the end to intercompare with the AERONET site and the High Altitude Lidar Observatory (HALO) HSRL/water vapor lidar that was conducting upward looking ground tests. The last flight of the week (June 17) included a coordinated run along the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) satellite overpass and then two reverse headings to capture in cloud data in vicinity of the ASTER overpass for additional contextual data. The flights on June 16-17 both saw non-spherical particles near the coast and drizzle over the ocean was observed on June 17.

June 7, 2021

Four successful joint flights occurred last week. The double flight day on Wednesday June 2 was particularly noteworthy. Our morning flight conducted our typical statistical survey flight plan to an area south of the Virginia coast where there was a cumulus cloud field, with some regions evolving into deeper, more organized, convection. Based on that flight and satellite imagery, we set up the second flight to execute a “process study” pattern where the Falcon conducted a series of transects through a selected cloud cluster to characterize the vertical microphysical properties of the developing cluster immediately followed by an environmental profile in the surrounding cloud-free region. Simultaneously, the King Air conducted a “wheel and spoke” pattern centered around the cloud system, with multiple dropsondes launched above, and on the periphery of the cloud cluster alongside remote sensing transects to characterize the cloud and aerosol system underneath. Data from both planes will be used to characterize the range of cloud types observed on that day, with a focus on understanding the processes that drive shallow cumulus organization.

June 1, 2021

The last two weeks were busy with 9 joint flights, including three separate double-sortie days. The May 21 morning flight in particular was intriguing with a mixture of different conditions offshore with the two aircraft flying mostly straight to the east and then returning on the same track to NASA LaRC. Closer to shore, the aircraft observed a stratus deck with a prominent aerosol layer just above cloud as observed by the HSRL-2. These clouds then transitioned progressively into a more scattered cumulus cloud field to the east. At the far eastern end of the track there was a cold pool that we sampled within and just outside. Throughout this and the other flights this past week, there was evidence both either (or both) smoke and dust in the free troposphere. Measurement data will help unravel how these various aerosol types interact with the different types of clouds such as in the May 21 flights. On May 19, we also coordinated the flight along the CALIPSO satellite track where both aircraft and the satellite had successful made measurements.

May 17, 2021

After a short break after the Winter 2021 campaign, ACTIVATE took back to the skies this past week to start the Summer 2021 campaign. We conducted 4 successful joint flights between May 13-15 with interesting cloud conditions in each flight. The lower-flying Falcon characterized multiple layers of clouds and observed both warm and mixed-phase precipitation. Remote sensing observations on the higher-flying King Air detected aerosol layers aloft in the free troposphere potentially from dust and smoke on separate flights.

April 5, 2021

ACTIVATE wrapped up its winter 2021 flight campaign with five joint research flights this past week (RF 57-61) capped off by a double-flight day on Friday (4/2) to capitalize on another cold air outbreak event. Those two flights included an increased number of dropsondes (~10 per flight) to get extensive temporal and spatial characterization of the vertical atmospheric structure as the cold air outbreak cloud field evolved during the day. Notable in the other flights last week was successful coordination with ASTER and CALIPSO overpasses in our flight region.

March 29, 2021

We executed a joint flight (RF 56) on Tuesday March 23rd on a day marked by fairly ‘clean’ conditions in terms of very low aerosol and cloud drop number concentrations in the marine boundary layer. Cloud fraction on this day was markedly lower than a typical cold air outbreak type of day, which is helpful for ACTIVATE which is aiming to generate statistics in a wide range of conditions associated with aerosols, clouds, and meteorology.

March 22, 2021

The previous week posed significant weather challenges but Saturday (March 20, 2020) did finally provide low clouds evolving in a cold air outbreak. Interesting features in that joint flight (Research Flight 55) were Asian dust residing aloft above the boundary layer clouds, in addition to an interesting layer of depolarizing aerosol right above clouds near the end of flight as observed by the HSRL-2; it is unclear what the source of that layer was, but data analysis with the Falcon data will help unravel those details.

March 8, 2021

ACTIVATE executed three successful joint flights (Research Flights 48-50) this past week. On Thursday March 4th we coordinated our flight with a NASA A-Train overpass over an area with some scattered marine boundary layer clouds. The back-to-back flights on Friday March 5th served two objectives to capitalize on an excellent cold air outbreak event: (i) characterize the aerosol and meteorological characteristics upwind of the cloud field farther downwind; and (ii) characterize the evolution of the cloud field with the desire to capture the transition from overcast cloudy conditions to open cell structure. Noteworthy features in these flights were dust layers from long-range transport and significant new particle formation.