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Committee and Staff Biographical Information

TIM LIEUWEN, Chair, is the executive vice president for research, a Regents’ Professor, and holder of the David S. Lewis, Jr. Chair at the Georgia Institute of Technology. He is also the founder and chief technology officer of TurbineLogic, an analytics firm working in the energy industry. Dr. Lieuwen is an international authority on clean energy and propulsion and his work has contributed to numerous commercialized innovations in the energy and aerospace sectors. He has authored 4 books and more than 400 other publications. Current and past board positions include governing/advisory boards for Oak Ridge National Laboratory, Pacific Northwest National Laboratory, National Renewable Energy Laboratory, Electric Power Research Institute, and appointment by the Department of Energy (DOE) Secretary to the National Petroleum Counsel. He is an elected member of the National Academy of Engineering (NAE), a fellow of the American Society of Mechanical Engineers (ASME), the American Physical Society, and the American Institute of Aeronautics and Astronautics (AIAA) and a foreign fellow of the Indian National Academy of Engineering. Major awards include the ASME R. Tom Sawyer Award, AIAA Pendray Award, and ASME’s George Westinghouse Gold Medal. Dr. Lieuwen has served on a variety of other National Academies of Sciences, Engineering, and Medicine studies, including Panel B: Propulsion and Power of the Decadal Survey on Civil Aeronautics; the Committee on Accelerating Decarbonization in the United States: Technology, Policy, and Societal Dimensions; the Committee on Advanced Technologies for Gas Turbines; and the Committee to Assess NASA’s Flight Research Capabilities.

STEVEN BARRETT is the Regius Professor of Engineering at the University of Cambridge (United Kingdom). Prior to this, he was the H.N. Slater Professor and head of the Department of Aeronautics and Astronautics at the Massachusetts Institute of Technology (MIT) and the director of the MIT Laboratory for Aviation and the Environment. His research expertise is on advancing scientific understanding of aviation’s environmental impacts and developing technical, operational, and fuel-based approaches to mitigating those impacts. One of his focus areas has been on modeling and observing contrails. This has included leading the development of advanced numerical models of contrail microphysical evolution and of machine learning approaches to detecting contrails in satellite imagery. He has also worked to develop and test operational contrail avoidance using near-real-time satellite observations. Other areas of research include characterizing aviation’s emissions, evaluating the atmospheric chemistry impacts of those emissions, and assessing policy options for mitigating the environmental impacts of aviation. Barrett received all of his degrees in engineering from the University of Cambridge.

SEAN BRADSHAW is the senior technical fellow for sustainable propulsion at Pratt & Whitney, where his primary focus is the development of advanced propulsion technologies that will power the future of flight. Dr. Bradshaw is also engaged in Pratt & Whitney–sponsored university research and the development of aerospace engineering workforce capability. He provides leadership to the aviation industry through service as the chair of the ASME Committee on Sustainability, an associate editor of the ASME Journal of Engineering for Gas Turbines and Power, a member of the ASME Heat Transfer Committee, a member of the National Academies’ Aeronautics and Space Engineering Board (ASEB) and Committee on Advanced Technologies for Gas Turbines, a former chair of the Gas Turbine Association, a former chair of the ASME Gas Turbine Technology Group, and an adjunct professor of mechanical engineering at Columbia University. Dr. Bradshaw earned a BS, an MS, and a PhD in aeronautics and astronautics from MIT.

LETICIA CUELLAR-HENGARTNER is a scientist at Los Alamos National Laboratory with more than 18 years of experience in stochastic and statistical modeling, risk assessment, and model validation of complex systems. She has served as the principal investigator (PI) on multiple high-profile initiatives, including an Ernst & Young–funded project developing forecasting models for audit risk, a study examining how human mobility affects disease propagation, and a co-led Probabilistic Effectiveness Methodology project assessing nuclear smuggling risks. Dr. Cuellar has authored or co-authored more than 100 technical reports and peer-reviewed journal articles, and she contributed to two National Academies’ reports on integrating unmanned aircraft systems into the National Airspace System and evaluating the Transport Airplane Risk Assessment Methodology. She is currently a member of the National Academies’ Community of Experts committee that advises the Federal Aviation Administration (FAA). Dr. Cuellar received a 2022 R&D 100 Award with special recognition as a Silver Medalist for Battling COVID-19 for her work on EpiGrid—an epidemiological software tool supporting decision making. She holds a master’s degree and a PhD in statistics from the University of California, Berkeley.

ERIC H. DUCHARME retired in 2020 as the chief engineer at GE Aviation. He is currently the founder of an aerospace consultancy, Martlet Engineering, LLC. Dr. Ducharme has been responsible for leading many efforts and teams at GE, including composite aeroelastic technology and several jet engine engineering programs over their complete product life cycle. There he also led Advanced Technology Operation responsible for delivering technologies and architectures for next-generation commercial and military flight propulsion. Dr. Ducharme is an active member of the NAE. He is a fellow of AIAA, ASME, and Royal Aeronautical Engineering Society. He serves on the NAE/NASA Aeronautics Research and Technology Roundtable and the Aeronautics and Space Engineering Board. He is formerly a member of the NASA Aeronautics Committee.

ANDREW GETTELMAN is a senior scientist at Pacific Northwest National Laboratory specializing in cloud physics and global climate. He was a senior scientist at the National Center for Atmospheric Research helping lead climate model development efforts. Dr. Gettelman is an expert on the atmospheric and climate effects of aviation, contrails, and the physics and simulation of ice clouds, with more than 20 years of experience. He has written many papers on contrails, developed a global climate model with contrails, and participated in assessments and reviews of the effects of aviation on climate. Dr. Gettelman is a fellow of the American Geophysical Union (AGU) and the American Meteorological Society (AMS). He has been a Clarivate Highly Cited Researcher for the past 10 years. Dr. Gettelman is the author or co-author on more than 200 peer-reviewed publications and a textbook on climate modeling. He has a PhD in atmospheric sciences as well as a certificate in environmental management from the University of Washington. He received a BS in civil engineering from Princeton University. Dr. Gettelman previously served on the National Academies’ Committee on Opportunities to Improve the Representation of Clouds and Aerosols in Climate Models with National Collection Systems.

ROBERT J. HANSMAN, JR., is the T. Wilson Professor of Aeronautics & Astronautics at MIT, where he is the director of the MIT International Center for Air Transportation. He conducts research in the application of information technology in operational aerospace systems. Dr. Hansman holds 7 patents and has authored more than 300 technical publications. He has more than 6,000 hours of pilot in-command time in airplanes, helicopters, and

sailplanes including meteorological, production, and engineering flight test experience and received the Wright Brothers Master Pilot Award. Professor Hansman chairs the FAA Research Engineering and Development Advisory Committee. He is the co-director of the national Center of Excellence in Aviation Sustainability Center. He is a member of the NAE, a fellow of AIAA, and has received numerous awards, including the AIAA Dryden Lectureship in Aeronautics Research, the ATCA Kriske Air Traffic Award, a Laurel from Aviation Week & Space Technology, and the FAA Excellence in Aviation Award.

RICHARD H. MOORE is an airborne research scientist at the NASA Langley Research Center. He joined NASA in 2012 after receiving his PhD in chemical and biomolecular engineering from the Georgia Institute of Technology and BS and MS in chemical engineering from Bucknell University. His research examines the role of atmospheric aerosols in influencing cloud formation, air quality, and climate. He has participated in more than 20 airborne field campaign deployments in both instrument and project scientist roles and most recently served as the PI for the NASA Aeronautics–funded Boeing ecoDemonstrator Emissions Flight and Ground Tests. He designs and executes airborne field campaigns to measure aircraft engine emissions and contrails at cruise altitudes. A particular research interest is to understand how sustainable aviation fuels, low-particle-emitting engine technologies, and hydrogen-burning engines might impact the formation of climate-altering contrail cirrus clouds. Dr. Moore has been the recipient of the Presidential Early Career Award for Scientists and Engineers, a NASA Early Career Achievement Medal, and a NASA Aeronautics Research Mission Directorate Associate Administrator Award for Technology and Innovation. He is a member of AGU and AIAA and a recent member of the board of directors of the American Association for Aerosol Research.

JOYCE E. PENNER is the Ralph J. Cicerone Distinguished University Professor of Atmospheric Science in the Department of Climate and Space Sciences and Engineering at the University of Michigan. Dr. Penner’s research focuses on improving climate models through the addition of interactive chemistry and the description of aerosols and their direct and indirect effects on the radiation balance in climate models. She is a fellow of AGU and AMS and was a winner of the Committee on Space Research William Nordberg Medal in 2022 and the AMS Syukuro Manabe Climate Research Award in 2021.

MICHAEL J. PRATHER, professor of Earth system science at the University of California, Irvine, retired but remains active in department governance and research. He was a Jefferson Science Fellow at the Department of State (2005) and a program manager at NASA Headquarters (prior to 1992). His studies of the chemistry and composition of the atmosphere focused on ozone depletion and climate change, authoring numerous World Meteorological Organization/United Nations Environment Programme and Intergovernmental Panel on Climate Change (IPCC) reports, including the 1999 IPCC Aviation Assessment. Dr. Prather’s core research addresses the mathematical underpinnings of atmospheric chemistry and global biogeochemical cycles. He earned a BS (mathematics, Yale University), BA (physics, Oxford University), and PhD (astrophysics, Yale University). Dr. Prather has worked on numerous National Academies’ studies that resulted in the following publications: Causes and Effects of Stratospheric Ozone Reduction: An Update, Rethinking the Ozone Problem in Urban and Regional Air Pollution, A Climate Services Vision: First Steps Toward the Future, Weather Forecasting for FAA Traffic Flow Management: A Workshop Report, Global Sources of Local Pollution: An Assessment of Long-Range Transport of Key Air Pollutants to and from the United States, Verifying Greenhouse Gas Emissions: Methods to Support International Climate Agreements, and The Future of Atmospheric Chemistry Research: Remembering Yesterday, Understanding Today, Anticipating Tomorrow.

STAFF

DWAYNE A. DAY is a senior program officer for the Aeronautics and Space Engineering Board (ASEB) of the National Academies. He has served as the study director for numerous studies for both ASEB and the Space Studies Board (SSB) on topics such as aeronautics research and technology, detecting and tracking potentially hazardous asteroids, planetary exploration, and astrophysics. Dr. Day has also published articles on space policy and history

on subjects ranging from Cold War intelligence space programs to Apollo and the Space Shuttle. He served as an investigator on the Columbia Accident Investigation Board and previously worked for the Congressional Budget Office and the George Washington University Space Policy Institute. He received a PhD in political science from George Washington University.

LINDA M. WALKER is a program coordinator with ASEB, the Board on Physics and Astronomy (BPA), and SSB. Ms. Walker has been with the National Academies since September 2007. She has more than 45 years of administrative experience. Ms. Walker attended the University of the District of Columbia and Strayer University, majoring in business administration with a minor in human services.

DIONNA WISE is a program coordinator with SSB, having previously worked for the National Academies’ Division of Behavioral and Social Sciences and Education. Recently, she was the lead study coordinator for the 2020 astronomy and astrophysics decadal survey. Wise has a long career in office administration, having worked as a supervisor in several capacities and fields. She attended the University of Colorado, Colorado Springs, majoring in psychology.

COLLEEN N. HARTMAN joined the National Academies in 2018, as the director for both SSB and ASEB, and became the director of the Board on Physics and Astronomy (BPA) in 2021. She is currently the senior director, aeronautics, astronomy, physics, and space science (SSB, BPA, ASEB). After beginning her government career as a presidential management intern under Ronald Reagan, Dr. Hartman worked on Capitol Hill for House Science and Technology Committee Chair Don Fuqua, as a senior engineer building spacecraft at NASA Goddard Space Flight Center, and as a senior policy analyst at the White House. She has served as the Planetary Division director, deputy associate administrator and acting associate administrator at NASA’s Science Mission Directorate, deputy assistant administrator at the National Oceanic and Atmospheric Administration, and deputy center director and director of science and exploration at the NASA Goddard Space Flight Center. Dr. Hartman has built and launched scientific balloon payloads, overseen the development of hardware for a variety of Earth-observing spacecraft, and served as the NASA program manager for dozens of missions, the most successful of which was the Cosmic Background Explorer (COBE). Data from the COBE spacecraft gained two NASA-sponsored scientists the Nobel Prize in physics in 2006. She also played a pivotal role in developing innovative approaches to powering space probes destined for the solar system’s farthest reaches. While at NASA Headquarters, she spearheaded the selection process for the New Horizons probe to Pluto. She helped gain administration and congressional approval for an entirely new class of funded missions that are competitively selected, called “New Frontiers,” to explore the planets, asteroids, and comets in the solar system. She has several master’s degrees and a PhD in physics. Dr. Hartman has received numerous awards, including two prestigious Presidential Rank Awards.