Leon van Speybroeck, widely recognized as the premier X-ray telescope
mirror designer, died on December 25, 2002 in Newton, Massachusetts at
the age of 67.

Van Speybroeck was the Telescope Scientist for NASA’s Chandra X-ray
Observatory and led the team that designed the mirrors for the
observatory. Chandra’s mirrors are the most precise mirrors ever made,
smooth with tolerances of a few atoms. If the state of Colorado had the
same relative smoothness as the surface of these mirrors, Pike’s Peak
would be less than an inch tall.

Since its launch aboard the space shuttle Columbia in July of 1999,
Chandra has made spectacular X-ray images of nearby and remote celestial
objects including comets, exploding stars, jets of gas expelled from the
vicinity of black holes, and powerful quasars more than 10 billion light
years from Earth. The data from the observatory have led to new
discoveries about the evolution of stars and galaxies, the nature of the
black holes, dark matter, and the topography of the universe.

“Leon was one of the master mirror designers of our time,” said Harvey
Tananbaum, director of the Chandra X-ray Center at the
Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. “His
contributions were essential to the tremendous success of the Chandra
mission.”

“Leon was one of the best instrumentalists I ever knew and a dear
colleague and friend,” said Nobel Physics laureate Riccardo Giacconi of
Associated Universities, Inc. in Washington, DC, who established and led
the team that built the first X-ray telescopes. “Together with Giuseppe
Vaiana he perfected the X-ray telescopes which were used for solar
research in the late 60’s and early 70’s. He was directly responsible
for the development of the Einstein and Chandra X-ray telescopes.
Leon’s contributions were essential to the achievement of Chandra
angular X-ray resolution, the highest yet obtained in X-ray astronomy.
Many of the outstanding scientific results from Chandra could not have
been obtained without it. He brought to his work complete intellectual
integrity and a search for excellence. We all feel his loss as a
colleague and a friend.”

“A giant of X-ray astronomy has passed from our midst,” said Irwin
Shapiro, director of the Center for Astrophysics, where van Speybroeck
spent most of his career. “Leon was also a wonderful person, always
modest, unfailingly helpful to anyone in need, and ever precise and
accurate in his statements.”

Van Speybroeck, a native of Wichita, Kansas, received a Ph. D. in
nuclear physics from the Massachusetts Institute of Technology in
Cambridge. After graduating, he joined Giacconi’s X-ray astronomy group
at American Science & Engineering where he became involved in the design
of the X-ray mirrors on Skylab. After moving to the Center for
Astrophysics in 1973, he had primary responsibility for designing and
developing the mirrors for the Einstein X-ray Observatory, the
predecessor to Chandra.

The construction of X-ray mirrors is extremely challenging because the
high energies of the X-rays require ultra-smooth mirrors. Furthermore,
X-rays reflect only at glancing angles, like skipping pebbles across a
pond, so the mirrors must be shaped like cylinders rather than the
familiar dish shape of mirrors on optical telescopes. The Chandra X-ray
Observatory contains four co-aligned pairs of mirrors.

These technical obstacles made many experts skeptical that an X-ray
mirror with resolution comparable to the finest optical telescopes could
be constructed, but van Speybroeck and colleagues proved them wrong.
Chandra’s X-ray mirrors resulted from more than two decades of
collaboration between van Speybroeck and colleagues at the Center for
Astrophysics, NASA’s Marshall Space Flight Center, TRW, Inc.,
Hughes-Danbury (now BF Goodrich Aerospace), Optical Coating
Laboratories, Inc. and Eastman-Kodak.

In recognition of his contributions to X-ray optics, van Speybroeck was
awarded the 2002 Bruno Rossi Prize of the High Energy Astrophysics
Division of the American Astronomical Society. On learning of this
honor, van Speybroeck commented, “Many, many other people made essential
contributions to the Chandra program, and hopefully some of them will
receive proper recognition. I am thoroughly enjoying my days in the sun,
but am quite humbled by the list of past recipients.”

“Leon truly loved his family, his friends and colleagues, and his work.”
said Tananbaum. “We will miss him dearly and will think of him often as
exciting new Chandra results appear.”

A Remembrance Service is planned by his friends and family for February
8, 2003. The family welcomes gifts made to MIT for the Leon P. van
Speybroeck Memorial Fund managed by the Office of Memorial Gifts,
E19-439, MIT, 77 Massachusetts Avenue, Cambridge, MA, 02139-4307.

More on Leon van Speybroeck:

http://chandra.harvard.edu/press/02_releases/press_012302.html

More on the Telescope System:
http://chandra.harvard.edu/about/telescope_system.html