Roger A. Broucke (March 25, 1932 – June 21, 2005) was an

aerospace engineer Aerospace engineering is the primary field of engineering concerned with the development of aircraft and spacecraft. It has two major and overlapping branches: aeronautical engineering and astronautical engineering. Avionics engineering is si ...

known for his solutions to the

three-body problem In physics and classical mechanics, the three-body problem is the problem of taking the initial positions and velocities (or momenta) of three point masses and solving for their subsequent motion according to Newton's laws of motion and Newton's ...

. After working on practical orbital mechanics at the

Jet Propulsion Laboratory The Jet Propulsion Laboratory (JPL) is a federally funded research and development center and NASA field center in the City of La Cañada Flintridge, California, United States. Founded in the 1930s by Caltech researchers, JPL is owned by NASA an ...

, he became a professor at the

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...

Life

Broucke was born on a farm in

Veurne Veurne (; french: Furnes, italic=no, ) is a city and municipality in the Belgian province of West Flanders. The municipality comprises the town of Veurne proper and the settlements of , , , , , Houtem, , , Wulveringem, and . History Origins up ...

. He studied at the

Catholic University of Leuven University of Leuven or University of Louvain (french: Université de Louvain, link=no; nl, Universiteit Leuven, link=no) may refer to: * Old University of Leuven (1425–1797) * State University of Leuven (1817–1835) * Catholic University of ...

, earning bachelor's and master's degrees in mathematics in 1955 and 1957 respectively, under the mentorship of

Georges Lemaître Georges Henri Joseph Édouard Lemaître ( ; ; 17 July 1894 – 20 June 1966) was a Belgian Catholic priest, theoretical physicist, mathematician, astronomer, and professor of physics at the Catholic University of Louvain. He was the first to th ...

. After completing his military service he worked for the oil industry while earning a second master's degree, in

operations research Operations research ( en-GB, operational research) (U.S. Air Force Specialty Code: Operations Analysis), often shortened to the initialism OR, is a discipline that deals with the development and application of analytical methods to improve deci ...

, from the University of Brussels in 1960. He returned to

Leuven Leuven (, ) or Louvain (, , ; german: link=no, Löwen ) is the capital and largest city of the province of Flemish Brabant in the Flemish Region of Belgium. It is located about east of Brussels. The municipality itself comprises the historic ...

for his doctoral work, on the three-body problem, which he completed in 1962. At this time he moved to California to work at the

; while there, he also took adjunct positions at

West Coast University West Coast University (WCU) is a private, for-profit university focused on healthcare degrees with campus locations in Los Angeles, Anaheim, and Ontario, California; Richardson, Texas; and Miami, Florida. David Pyle founded American Career Colle ...

, the

University of Southern California The University of Southern California (USC, SC, or Southern Cal) is a Private university, private research university in Los Angeles, California, United States. Founded in 1880 by Robert M. Widney, it is the oldest private research university in C ...

, and the

University of California, Los Angeles The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

(UCLA). His position at UCLA became a regular-rank associate professorship in 1969. In 1975, Broucke moved to the

as an associate professor of aerospace engineering and engineering mechanics. At Austin, he helped found the Texas Institute for Computational Mechanics in 1976.

Contributions

In the three-body problem, Broucke's doctoral research involved pioneering use of computer simulations to classify stable and unstable orbits. He investigated what happens to this classification for earth–moon–satellite systems in the limit as the ratio of earth to moon mass approaches zero; his conjecture about this limiting behavior, "Broucke's principle", was finally proven correct in 1981 by Lawrence Perko. As part of this work, he also developed

symbolic computation In mathematics and computer science, computer algebra, also called symbolic computation or algebraic computation, is a scientific area that refers to the study and development of algorithms and software for manipulating mathematical expressions ...

methods for handling Poisson series. Later, he studied the anisotropic Kepler problem, a mathematical model of the motion of an electron trapped in a potential well. As he showed, this system is not purely chaotic: it has periodic orbits as well. He also studied the use of

gravity assist In orbital mechanics and aerospace engineering, a gravitational slingshot, gravity assist maneuver, or swing-by is the use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the p ...

in finding efficient flight plans for space probes.

Recognition

In 1973, Broucke became executive editor of the journal ''

Celestial Mechanics Celestial mechanics is the branch of astronomy that deals with the motions of objects in outer space. Historically, celestial mechanics applies principles of physics (classical mechanics) to astronomical objects, such as stars and planets, to ...

''. The

American Astronautical Society Formed in 1954, the American Astronautical Society (AAS) is an independent scientific and technical group in the United States dedicated to the advancement of space science and space exploration. AAS supports NASA's Vision for Space Exploration ...

gave him their Dirk Brouwer Award in 2002.

Personal

Broucke's daughter,

Mireille Broucke Mireille Esther Broucke is a professor of electrical and computer engineering at the University of Toronto, interested in control theory, mathematical systems theory, and swarm robotics. Broucke did her undergraduate studies at the University of ...

, is a noted

control theorist Control may refer to: Basic meanings Economics and business * Control (management), an element of management * Control, an element of management accounting * Comptroller (or controller), a senior financial officer in an organization * Controlling ...

at the

University of Toronto The University of Toronto (UToronto or U of T) is a public research university in Toronto, Ontario, Canada, located on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution ...

Selected publications

* * * * *

References

{{DEFAULTSORT:Broucke, Roger A. 1932 births 2005 deaths American aerospace engineers Belgian aerospace engineers Belgian emigrants to the United States Catholic University of Leuven (1834–1968) alumni University of Southern California faculty UCLA Henry Samueli School of Engineering and Applied Science faculty 20th-century American engineers