A memorial service is scheduled for Thursday, May 3, from 3:00 to 4:00 p.m. in Stanford Memorial Church. A reception will follow at the Stanford Faculty Club.

Largely due to Walker's efforts, Stanford led the nation's major research universities in educating graduate students from underrepresented groups in physics. Astronaut Sally Ride, America's first woman in space, was among Walker's graduate students. The month before his death, he presided over the National Conference of Black Physics Students, hosted this year at Stanford.

Walker's recommendations to Congress were instrumental in creating a national solar observatory. In 1986, President Ronald Reagan appointed him to serve on the commission that investigated the space shuttle Challenger explosion and ultimately concluded that the disaster was preventable.

Walker was born in Cleveland on Aug. 24, 1936. He received a baccalaureate degree in physics with honors from Cleveland's Case Institute of Technology in 1957. He earned a master's degree in 1958 and doctorate in 1962 from the University of Illinois with a dissertation on the use of radiation to produce the particles that bind protons and neutrons together in the atomic nucleus.

Walker joined the U.S. Air Force in 1962 as a first lieutenant and was assigned to the Air Force Weapons Laboratory, where he developed instrumentation for an experiment that involved rocket launch of a satellite to measure Van Allen belt radiation in the Earth's magnetic field.

Upon completing his military duty in 1965, he joined the Space Physics Laboratory of the Aerospace Corporation, where for nine years he conducted pioneering physics experiments to study the sun and upper atmosphere of the Earth.

In the 1980s, senior research associate Troy Barbee at Stanford's Center for Materials Research created multi-layered thin films that could capture images produced by hot solar gas so energetic that it spewed radiation in the extreme ultraviolet end of the spectrum. In 1987, Walker used these materials to develop telescopes and complex instrumentation, which he mounted on rockets and launched into space to capture the first detailed pictures of the sun's outermost atmosphere, or corona. Images from the first flight of Walker's solar telescope appeared on the cover of Science magazine on Sept. 30, 1988.

Walker launched 14 telescopes in NASA's first Multi-Spectral Solar Telescope Array (MSSTA) flight in 1991 and 19 telescopes in the second flight. Since a telescope's flight filter only lets in one wavelength of light at a time - and each wavelength represents a different temperature - arrays of telescopes allow researchers to look at different temperatures throughout the sun and gain a greater understanding of solar activity. Walker's technique has since been used in NASA's Chandra X-ray Observatory, to study the nighttime sky, and in a worldwide chain of ground stations called the Global Oscillation Network Group (GONG), to study solar activity.

Walker is survived by his wife, Victoria T. Walker, of Stanford; daughter Heather M. M. Walker of Los Altos Hills; stepsons Nigel D. Gibbs of Los Angeles and Eric D. Gibbs of Temecula; and four grandchildren. He was also beloved by many cousins, other relatives and friends, and members of the Sigma Pi Phi fraternity (Gamma Chi Boule), of which he was a member of long standing.

In lieu of flowers, donations may be sent to the A.B.C. Walker II Memorial Fund for the greater inclusion of ethnic minorities and women in the sciences. Checks should be made payable to Stanford University and sent to:

Profile on Art Walker at: http://www.stanford.edu/dept/news/pr/00/walkerprofile1011.html