List of people in systems and control

This is an alphabetical list of people who have made significant contributions in the fields of system analysis and control theory.

Eminent researchers

The eminent researchers (born after 1920) include the winners of at least one award of the IEEE Control Systems Award, the Giorgio Quazza Medal, the Hendrik W. Bode Lecture Prize, the Richard E. Bellman Control Heritage Award, the Rufus Oldenburger Medal, or higher awards such as the IEEE Medal of Honor and the National Medal of Science. The earlier pioneers such as Nicolas Minorsky (1885–1970), Harry Nyquist (1889–1976), Harold Locke Hazen (1901–1980), Charles Stark Draper (1901–1987), Hendrik Wade Bode (1905–1982), Gordon S. Brown (1907–1996), John F. Coales (1907–1999), Rufus Oldenburger (1908–1969), John R. Ragazzini (1912–1988), Nathaniel B. Nichols (1914–1997), John Zaborszky (1914–2008) and Harold Chestnut (1917–2001) are not included.

Name Institution Nationality Contributions Age Awards
Brian D. O. Anderson Australian National University Australian 1941 Hendrik W. Bode Lecture Prize (1992),
IEEE Control Systems Award (1997),
Giorgio Quazza Medal (1999)
Karl Johan Åström Lund University Swedish [1] Author of five books, including Introduction to Stochastic Control Theory (1970 and Dover, 2006) and (with Wittenmark) of Adaptive Control (Addison-Wesley, 1995). 1934 Rufus Oldenburger Medal (1985),
Giorgio Quazza Medal (1988),
IEEE Control Systems Award (1990)
Michael Athans
(Μιχαήλ Αθανασιάδης)
Massachusetts Institute of Technology Greek-American 1937 Hendrik W. Bode Lecture Prize (1993),
Richard E. Bellman Control Heritage Award (1995)
John Baillieul Boston University American [2] Works on robotics, mechanical system control and non-holonomic constraints. 1945 Hendrik W. Bode Lecture Prize (2011)
B. Ross Barmish University of Wisconsin–Madison Canadian-American [3] Author of New Tools for Robustness of Linear Systems (Macmillan, 1994). For fundamental contributions to the analysis of systems with parametric uncertainty and to probabilistic robustness, and for contributions to the design of stock-trading algorithms that are robust to market variability. IEEE fellow and IFAC fellow. 1949 Hendrik W. Bode Lecture Prize (2013)
Tamer Başar University of Illinois at Urbana–Champaign Turkish-American [4] Works on dynamic games, control and communication theory, etc. 1946 Hendrik W. Bode Lecture Prize (2004),
Giorgio Quazza Medal (2005),
Richard E. Bellman Control Heritage Award (2006),
IEEE Control Systems Award (2014)
Richard E. Bellman University of Southern California American 1920–1984 John von Neumann Theory Prize (1976),
IEEE Medal of Honor (1979),
Richard E. Bellman Control Heritage Award (1984)
Dimitri P. Bertsekas
(Δημήτρης Παντελής Μπερτσεκάς)
Massachusetts Institute of Technology Greek-American 1942 Richard E. Bellman Control Heritage Award (2014),
John von Neumann Theory Prize (2018),
IEEE Control Systems Award (2022)
Stephen P. Boyd Stanford University American [5] Works on engineering applications of convex optimization. Winner of John R. Ragazzini Award in control systems. 1958 IEEE Control Systems Award (2013)
Roger W. Brockett Harvard University American [6] Works on dynamics and control of smart structures. 1938 Richard E. Bellman Control Heritage Award (1989),
IEEE Control Systems Award (1991),
Rufus Oldenburger Medal (2005),
Giorgio Quazza Medal (2017)
Arthur E. Bryson, Jr. Stanford University American 1925 Rufus Oldenburger Medal (1980),
IEEE Control Systems Award (1984),
Richard E. Bellman Control Heritage Award (1990)
Peter E. Caines McGill University Canadian [7] Works in the areas of stochastic, adaptive, large scale and hybrid systems, Mean Field Games (or Nash Certainty Equivalence). Fellow of the IEEE, SIAM, the Institute of Mathematics and its Applications, the Canadian Institute for Advanced Research and Royal Society of Canada. Recipient of the Bode Lecture Prize in 2009. 1945 Hendrik W. Bode Lecture Prize (2009)
Edward J. Davison University of Toronto Canadian 1928 Giorgio Quazza Medal (1993),
Hendrik W. Bode Lecture Prize (1997)
John C. Doyle California Institute of Technology American [8] Co-author of (with Zhou and Glover) Robust and Optimal Control (Prentice Hall, 1996), Essentials of Robust Control (1997), and Feedback Control Theory (Macmillan, 1992). 1954 IEEE Control Systems Award (2004)
Walter R. Evans General Electric; Rockwell International; Ford Aeronautic Company American 1920–1999 Rufus Oldenburger Medal (1987),
Richard E. Bellman Control Heritage Award (1988)
Bruce Francis University of Toronto Canadian 1947–2018 Hendrik W. Bode Lecture Prize (2014),
IEEE Control Systems Award (2015)
Gene F. Franklin Stanford University American 1927–2012 Hendrik W. Bode Lecture Prize (1994),
Richard E. Bellman Control Heritage Award (2005)
Elmer G. Gilbert University of Michigan American 1930–2019 IEEE Control Systems Award (1994),
Richard E. Bellman Control Heritage Award (1996)
Keith Glover University of Cambridge British 1946 IEEE Control Systems Award (2001)
Graham Goodwin University of Newcastle, Australia Australian 1945 Hendrik W. Bode Lecture Prize (1999),
Giorgio Quazza Medal (2008),
IEEE Control Systems Award (2010),
Rufus Oldenburger Medal (2013)
J. Karl Hedrick University of California, Berkeley American [9] Total Domination of Etcheverry Hall. Seminal contributions in nonlinear control and estimation. 1944–2017 Rufus Oldenburger Medal (2006)
Yu-Chi "Larry" Ho
(何毓琦)
Harvard University Chinese-American [10] Co-author of Applied Optimal Control (1969, 1975), the most cited book on the subject. Since 1983 he has been working on discrete event system theory. 1934 IEEE Control Systems Award (1989),
Richard E. Bellman Control Heritage Award (1999),
Rufus Oldenburger Medal (1999)
Alberto Isidori Sapienza University of Rome; Washington University in St. Louis Italian 1942 Giorgio Quazza Medal (1996),
Hendrik W. Bode Lecture Prize (2001),
IEEE Control Systems Award (2012)
Eliahu I. Jury
(إلياهو جوري)
University of California, Berkeley; University of Miami Iraqi-American 1923 Rufus Oldenburger Medal (1986),
Richard E. Bellman Control Heritage Award (1993)
Thomas Kailath Stanford University Indian-American [11] Author of Linear Systems (Prentice Hall, 1980) and co-author of Linear Estimation (Prentice Hall, 2000). 1935 IEEE Medal of Honor (2007),
National Medal of Science (2012)
Rudolf E. Kalman
(Kálmán Rudolf Emil)
University of Florida; ETH Zurich Hungarian-American 1930–2016 IEEE Medal of Honor (1974),
Rufus Oldenburger Medal (1976),
Richard E. Bellman Control Heritage Award (1997),
Charles Stark Draper Prize (2008),
National Medal of Science (2009)
Hidenori Kimura
(木村英紀)
Riken Japanese 1941 Giorgio Quazza Medal (2011)

IEEE Control Systems Award (2021)

Petar V. Kokotovic
(Петар В. Кокотовић)
University of California, Santa Barbara Serbian-American [12] Works on nonlinear control, both adaptive and robust. He initiated the development of back-stepping (a popular, recursive, design technique). Industry consultant on control of car and jet engines. 1934 Giorgio Quazza Medal (1990),
Hendrik W. Bode Lecture Prize (1991),
IEEE Control Systems Award (1995),
Richard E. Bellman Control Heritage Award (2002)
Arthur J. Krener Naval Postgraduate School American 1942 Hendrik W. Bode Lecture Prize (2006),
Richard E. Bellman Control Heritage Award (2012),
IEEE Control Systems Award (2016)
Miroslav Krstic University of California, San Diego Serbian-American PDE backstepping control, nonlinear delay systems, extremum seeking, adaptive control, stochastic nonlinear stabilization, and their industrial applications 1964 Rufus Oldenburger Medal (2017),
W. T. and Idalia Reid Prize (2019),
Richard E. Bellman Control Heritage Award (2021),
Hendrik W. Bode Lecture Prize (2023)
Harold J. Kushner Brown University American 1933 IEEE Control Systems Award (1992),
Richard E. Bellman Control Heritage Award (2004)
George Leitmann University of California, Berkeley American 1925 Rufus Oldenburger Medal (1995),
Richard E. Bellman Control Heritage Award (2009)
Lennart Ljung Linköping University Swedish [13] Author of System identification - Theory for the user (Prentice Hall, 1999) and 12 other books. Fellow IEEE. 1946 Giorgio Quazza Medal (2002),
Hendrik W. Bode Lecture Prize (2003),
IEEE Control Systems Award (2007)
David Luenberger Stanford University American 1937 Hendrik W. Bode Lecture Prize (1990),
Rufus Oldenburger Medal (1998)
David Q. Mayne Imperial College London British [14] Works on differential dynamic programming, adaptive control and model predictive control. 1930 IEEE Control Systems Award (2009),
Giorgio Quazza Medal (2014)
Sanjoy K. Mitter Massachusetts Institute of Technology Indian-American 1933 IEEE Control Systems Award (2000),
Richard E. Bellman Control Heritage Award (2007)
Manfred Morari ETH Zurich; University of Pennsylvania; United Technologies Austrian-American [15] Works on model predictive control, optimization for control system, Youla-Parametrization, and internal model control (IMC). Co-author of Predictive Control of Linear and Hybrid Systems and the author of Robust Process Control. 1951 IEEE Control Systems Award (2005),
Hendrik W. Bode Lecture Prize (2010),
Richard E. Bellman Control Heritage Award (2011),
Rufus Oldenburger Medal (2015)
A. Stephen Morse Yale University American 1939 IEEE Control Systems Award (1999),
Richard E. Bellman Control Heritage Award (2013)
Richard M. Murray California Institute of Technology American 1963 Hendrik W. Bode Lecture Prize (2016),
IEEE Control Systems Award (2017)
Kumpati S. Narendra Yale University Indian-American 1933 Hendrik W. Bode Lecture Prize (1995),
Richard E. Bellman Control Heritage Award (2003)
Howard H. Rosenbrock University of Manchester Institute of Science and Technology British 1920–2010 IEEE Control Systems Award (1982),
Rufus Oldenburger Medal (1994)
Shankar Sastry University of California, Berkeley Indian Rufus Oldenburger Medal (2021)
Eduardo D. Sontag Northeastern University Argentine-American 1951 Hendrik W. Bode Lecture Prize (2002),
IEEE Control Systems Award (2011)
Masayoshi Tomizuka
(富塚诚义)
University of California, Berkeley Japanese 1946 Rufus Oldenburger Medal (2002),
Richard E. Bellman Control Heritage Award (2018)
John G. Truxal State University of New York at Stony Brook American 1924–2007 Richard E. Bellman Control Heritage Award (1991),
Rufus Oldenburger Medal (1991)
John N. Tsitsiklis
(Ιωάννης Νικόλαος Τσιτσικλής)
Massachusetts Institute of Technology Greek-American 1958 IEEE Control Systems Award (2018),
John von Neumann Theory Prize (2018)
Pravin Varaiya University of California, Berkeley Indian-American 1940 IEEE Control Systems Award (2002),
Hendrik W. Bode Lecture Prize (2005),
Richard E. Bellman Control Heritage Award (2008)
Mathukumalli Vidyasagar University of Texas at Dallas Indian [16] Professor of Systems Biology Science at the University of Texas at Dallas. Author of Nonlinear systems analysis (Prentice Hall, 1993 and SIAM, 2002). 1947 IEEE Control Systems Award (2008),
Rufus Oldenburger Medal (2012)
Jan C. Willems University of Groningen Belgian [17] Author of The analysis of feedback systems (1971). Worked on LQ control, dissipative systems and linear matrix inequalities. Co-author of Introduction to mathematical system theory – a behavioral approach (Wiley, 1998), where the behavioral approach is a representation free way to discuss system dynamics. 1939–2013 IEEE Control Systems Award (1998)
W. Murray Wonham University of Toronto Canadian 1934 IEEE Control Systems Award (1987),
Giorgio Quazza Medal (2020)
Dante C. Youla Polytechnic Institute of New York University American 1925 IEEE Control Systems Award (1988)
Lotfi A. Zadeh
(Persian: لطفی علی‌عسگرزاده
Azerbaijani: Lütfi Rəhim oğlu Ələsgərzadə)
University of California, Berkeley Iranian-Azerbaijani-American 1921–2017 Eringen Medal (1976),
Rufus Oldenburger Medal (1993),
IEEE Medal of Honor (1995),
Richard E. Bellman Control Heritage Award (1998),
Golden Goose Award (2017)
Moshe Zakai
(משה זכאי)
Technion Israeli 1926–2015 IEEE Control Systems Award (1993)
George D. Zames McGill University Polish-Canadian 1934–1997 IEEE Control Systems Award (1985),
Rufus Oldenburger Medal (1996)

Eminent researchers of USSR (including Russian SFSR, Ukrainian SSR, Byelorussian SSR, etc. from 1922 to 1991)

Name Institution Place of birth Contributions Age Awards
Nikolay Bogolyubov
(Никола́й Никола́евич Боголю́бов)
National Academy of Sciences of Ukraine Nizhny Novgorod Together with Nikolay Krylov developed the describing function method as an approximate procedure for analyzing nonlinear control problems. 1909–1992 Stalin Prize (1947, 1953),
Lenin Prize (1958),
USSR State Prize (1984),
Lomonosov Gold Medal (1985)
Yakov Z. Tsypkin
(Яков За́лманович Цы́пкин)
Moscow Institute of Physics and Technology; Moscow Power Engineering Institute Dnipropetrovsk 1919–1997 Lenin Prize (1960),
Giorgio Quazza Medal (1984),
Rufus Oldenburger Medal (1989)
N. N. Krasovski
(Никола́й Никола́евич Красо́вский)
Ural State University Yekaterinburg 1923 Lenin Prize (1976),
USSR State Prize (1984),
IEEE Control Systems Award (2003)
Vladimir Yakubovich
(Влади́мир Андре́евич Якубо́вич)
Saint Petersburg State University Novosibirsk Pioneered the usage of linear matrix inequalities in control theory.[18] Considered as the father of the field. 1926–2012 IEEE Control Systems Award (1996)
Faina Mihajlovna Kirillova
(Фаина Михайловна Кириллова)
National Academy of Sciences of Belarus Zuyevka Developed a constructive theory of extremal problems, proved the quasi-maximum principle for discrete systems, and developed algorithms for adaptive optimization. 1931 USSR Council of Ministers Prize (1986)
Vadim Utkin
(Вадим Иванович Уткин)
Ohio State University Moscow 1937 Lenin Prize (1972),
Rufus Oldenburger Medal (2003)

Other active researchers

Name Institution Nationality Contributions Field Awards
Damiano Brigo Imperial College [19] Works on nonlinear filtering (jointly introduced with Bernard Hanzon and François Le Gland the projection filters).
William L. Brogan University of Nevada, Las Vegas Author of book Modern Control Theory. ISBN 0-13-589763-7
Munther A. Dahleh Massachusetts Institute of Technology [20] Co-author of Control of Uncertain Systems: A Linear Programing Approach (Prentice Hall, 1995).
Moonyong Lee Yeungnam University [21] Adviser of Process Systems Design and Control Laboratory. Working on IMC based Optimal Design of Industrial Three Term Controllers, Robust Analytical Design of Multi-loop PID Controllers, Optimization Based Controller Design for Constrained Optimal Control, Advanced Control for Thermally Coupled Distillation Process, Real-time Monitoring and Control Software Package, Optimal Design of Thermally Coupled Distillation Process Including Divided Wall Column.
Karl Henrik Johansson KTH Royal Institute of Technology Sweden [22] Works in many areas, including application of hybrid systems and networked control system, security of cyber-physical systems, and model reduction. IEEE Fellow 2013, Fellow of Royal Swedish Academy of Engineering Science 2017
Mehran Mesbahi University of Washington [23] Works on networks, distributed robotics, aerospace GN&C, and optimization. Co-author of the book "Graph Theoretic Methods in Multiagent Networks" (Princeton, 2010).
Jan H. van Schuppen Free University of Amsterdam and CWI [24] is author of more than one hundred publications in control theory, system identification, realization theory and filtering.
Arjan van der Schaft University of Groningen [25] He is notable for his contributions to network modeling and control of complex systems as Port-Hamiltonian systems, Passivity-based Control,[26] Nonlinear H_infty control and Hybrid systems. He is a Fellow of the (IEEE).
S. S. Sritharan Naval Postgraduate School [27] ( Developed Deterministic and Stochastic Control Theory and nonlinear filtering for Fluid Dynamics and MHD using Navier–Stokes equations and magnetohydrodynamic equations as state space models).
Peter Stoica Uppsala University [28] Works on System Identification and Modeling.
Jakob Stoustrup Aalborg University [29] Works on loop-transfer recovery, gain scheduled control, fault tolerant control and several other areas.
Roberto Tempo CNR-IEIIT, Politecnico di Torino [30] Author of the book titled Randomized Algorithms for Analysis and Control of Uncertain Systems, with Applications (Springer-Verlag, 2013).
Kevin Warwick University of Reading [31] Developed the first state-space based self-tuning controller, now involved more in application studies of feedback control, particularly where a human is part of the system.
Stephen Yurkovich University of Texas at Dallas [32] Fellow of the IEEE, and holds the Louis Beecherl, Jr. Distinguished Chair in Engineering at the University of Texas at Dallas, where he is also Program Head of Systems Engineering.
Yutaka Yamamoto Kyoto University Japan [33] Author of the book Repetitive Control (in Japanese) and a large number of research, survey and tutorial articles. Fellow of the IEEE. Former Chair of the IEEE Control System (CSS) Society.
Masayuki Fujita Tokyo Institute of Technology Japan [34] works on passivity-based control in robotics, multi-agent robotics, and robust control. co-author of Passivity-Based Control and Estimation in Networked Robotics. IEEE Fellow 2016

Historical figures in systems and control

These people have made outstanding historical contributions to systems and control.

Given Names Last Name Institution Year Contributions
George Biddell Airy 1840 Early investigations into the instability phenomenon in Watt governors.
William Ross Ashby University of Illinois at Urbana–Champaign Made many early contributions to cybernetics and complex systems, such as the concept of variety (cybernetics).
Robert H. Park 1929 Published last century's 2nd-ranked power engineering paper for developing Park Transform of AC machines with time-invariant-coefficient LDEs, widely used for vector control in AC drive & other power electronics applications.
Richard Bellman 1953 Developed dynamic programming
Harold Stephen Black Worcester Polytechnic Institute 1927 Invented the negative-feedback amplifier
Hendrik Bode 1945 Published Network Analysis and Feedback Amplifier Design (Van Nostrand), invented the Bode plot and introduced the Bode integral formula.
Nikolay Bogolyubov Together with Nikolay Krylov developed the describing function method as an approximate procedure for analyzing nonlinear control problems.
Leonhard Euler Developed the Laplace transform, the main tool for analyzing LTI systems. His Euler–Lagrange equation is the basis for model predictive control.
Rudolf Kalman 1960 Pioneered the state-space approach to systems and control. Introduced the notions of controllability and observability. Developed the Kalman filter for linear estimation.
Walter R. Evans Developed the root locus method for feedback design.
Gene F. Franklin His 1958 text "Sampled-Data Control Systems" introduced digital control to a discipline which had previously operated almost exclusively in the analog domain.
Joseph Fourier Introduced the Fourier series, allowing analysis in the frequency domain.
Ernst A. Guillemin Developed techniques for analysis and synthesis of networks of RLC components.
Harold Hazen 1934 Author of Theory of Servomechanisms.
Faina Kirillova National Academy of Sciences of Belarus Developed a constructive theory of extremal problems, proved the quasi-maximum principle for discrete systems, and developed algorithms for adaptive optimization.
Andrey Kolmogorov Co-developer of the Wiener–Kolmogorov filter. Formulated the Kolmogorov forward and backward equations in the theory of stochastic processes.
Nikolay Krylov together with Nikolay Bogolyubov developed the describing function method as an approximate procedure for analyzing nonlinear control problems.
Irmgard Flügge-Lotz Stanford University Developed discontinuous automatic control, which laid the foundation for automatic on-off aircraft control in jets.
Alexander Lyapunov 1892 His paper Sur le problème général de la stabilité du mouvement (in French) marks the beginning of stability theory.
James Clerk Maxwell 1868 Paper "On governors" investigated the stability of governors in a systematic way and discovered the necessary conditions for stability.
Nicolas Minorsky 1922 Ship designer, was the first to provide an analysis of the three term (or PID) controller and to suggest its use for ship steering.
Nathaniel B. Nichols 1947 Developed the Nichols plot. Published Theory of Servomechanisms with H. M. James and R. S. Phillips.
Harry Nyquist 1927 Developed the Nyquist stability criterion for feedback systems (1932) and co-developed Nyquist–Shannon sampling theorem.
Lev Pontryagin Main author of Pontryagin's minimum principle for optimal control problems.
Vasile Popov Developed the Kalman–Yakubovich–Popov lemma and the Popov criterion for stability.
John R. Ragazzini 1954 His book Sampled-data control systems introduced digital control and the z-transform.
Edward John Routh Early theorist, developed Routh–Hurwitz theorem and Routh–Hurwitz stability criterion.
Claude E. Shannon Developed information theory and pioneered switching theory.
John Tukey Developed the Fast Fourier transform algorithm, which made frequency analysis easy to implement.
Norbert Wiener Co-developer of the Wiener-Kolmogorov filter. Coined the term Cybernetics. Studied the stochastic process known as the Wiener process.
W. Murray Wonham 1974 Linear Multivariable Control.[35] Supervisory control theory. Internal Model Principle. Pole Assignment Theorem.[36]
Vladimir Andreevich Yakubovich Saint Petersburg State University 1996 Pioneered the usage of linear matrix inequalities in control theory.[18]
George Zames McGill University Developed robust control theory, including the small-gain theorem and H-infinity control.

See also

References

  1. "Karl Johan Åström". Archived from the original on March 5, 2010.
  2. "John Baillieul". people.bu.edu.
  3. "B. Ross Barmish".
  4. [decision.csl.uiuc.edu/~tbasar/ Tammer Basar]
  5. "Stephen Boyd | Stanford Institute for Computational & Mathematical Engineering". profiles.stanford.edu. Archived from the original on October 28, 2006.
  6. "Professor Roger W. Brockett". people.seas.harvard.edu.
  7. "CAINES, Peter".
  8. John C. Doyle
  9. "J. Karl Hedrick". Archived from the original on December 12, 2012.
  10. Y.C. Ho
  11. "Thomas Kailath". web.stanford.edu.
  12. "Petar V. Kokotovic". Archived from the original on August 31, 2005.
  13. Ljung, Lennart. "Lennart Ljung, Linköping University". people.isy.liu.se.
  14. "The Sargent Centre for Process Systems Engineering | Research groups | Imperial College London". www.imperial.ac.uk.
  15. "Morari, Manfred, Prof. Em. Dr. | ETH Zurich".
  16. "Mathukumalli Vidyasagar - University of Texas at Dallas". personal.utdallas.edu.
  17. "Jan C. Willems".
  18. History of LMIs in Control Theory
  19. "Damiano Brigo". Archived from the original on 2012-02-22. Retrieved 2008-12-15.
  20. "Munther Dahleh Research Group". Retrieved 2023-03-31.
  21. "PSDC". psdc.yu.ac.kr.
  22. "Karl Henrik Johansson's Webpage".
  23. "Mehran Mesbahi". Archived from the original on April 1, 2011.
  24. "Jan van Schuppen". Archived from the original on December 28, 2008.
  25. "Arjan van der Schaft".
  26. "EOLSS" (PDF).
  27. "S. S. Sritharan". Archived from the original on 2009-09-03. Retrieved 2009-10-09.
  28. Peter Stoica
  29. "Jakob Stoustrup". Archived from the original on 2002-10-05. Retrieved 2002-10-07.
  30. "Roberto Tempo".
  31. "Kevin Warwick". Archived from the original on 2007-08-10. Retrieved 2007-08-31.
  32. "Steve Yurkovich - Systems Engineering and Management at the University of Texas at Dallas". Archived from the original on 2011-07-12. Retrieved 2012-03-25.
  33. Yutaka Yamamoto Archived 2002-09-27 at the Wayback Machine
  34. "Home". hatanaka_lab.
  35. Linear Multivariable Control.
  36. Wonham, W. M. (February 1, 1967). "On pole assignment in multi-input controllable linear systems" (PDF) via ntrs.nasa.gov. {{cite journal}}: Cite journal requires |journal= (help)
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