Bruce C. Murray, a planetary geologist who won his spurs interpreting findings of early missions to Mars and who led NASA's Jet Propulsion Laboratory through a time of flagging support for new flights in the late 1970s, died Thursday at his home in Oceanside, Calif. He was 81.
The cause was Alzheimer's disease, said the Jet Propulsion Laboratory, which is operated for NASA by the California Institute of Technology in Pasadena. Mr. Murray was a professor emeritus at Caltech.
As director of the laboratory from 1976 to 1982, Mr. Murray faced shrinking budgets as the space agency shifted most of its resources to the emerging shuttle program. There were two Viking landings on Mars in his first year, and two Voyagers were launched to the outer planets. But prospects for any future missions were bleak.
On the brink of despair in 1981, Mr. Murray struck a defiant note in an interview with Discover magazine.
"We're sitting here watching the coffin being nailed shut, and what's inside is imagination and vision," he said. "I wasn't appointed director to preside over the dissolution of the U.S. space exploration program. I'm not going to be squeezed down to nothing."
Those were tough years, both for him and for the laboratory. In a New York Times Magazine article, science writer Timothy Ferris described Mr. Murray as a "square-jawed man more comfortable giving orders than listening to advice," adding that he "brought to the lab an aggressive -- some would say abrasive -- style of leadership under which its fortunes have sharply improved."
John Casani, a retired project manager at the laboratory, told The Associated Press: "People at JPL either loved or hated him. He was always shaking cages."
Through persistence, he kept the doors open. He managed to salvage a Jupiter orbital mission, later named Galileo, an imaging radar system for Earth mapping to be flown on space shuttles, an early Earth-observing satellite called Seasat and a joint project with Britain and the Netherlands called the Infrared Astronomy Satellite.
Out of concern for the future of planetary exploration, Mr. Murray joined with astronomer Carl Sagan and aerospace engineer Louis Friedman to found the Planetary Society, a public advocacy organization dedicated to exploring the solar system and searching for extraterrestrial intelligence. The society, based in Pasadena, has reported some 100,000 members. Mr. Murray was its retired chairman.
"We seem to have the idea that the Space Age started and ended with one generation," he said in an interview at the time. "We go to the planets and have a look and then walk away and do nothing."
Bruce Churchill Murray was born Nov. 30, 1931, in New York City. His family later moved to California, and he graduated from Santa Monica High School. He was educated at the Massachusetts Institute of Technology, where he earned a Ph.D. in geology in 1955.
After working as a geologist for Standard Oil, he spent two years in the Air Force as a geophysicist and then became a researcher at Caltech in 1960, at a time of growing excitement over space exploration.
He joined the faculty as an associate professor of planetary science in 1963 and became a member of the science team for Mariner 4, the first successful flyby of Mars, in 1965.
Those first pictures of a moonlike Mars of cratered plains were a disappointment to those who grew up imagining Martians. But further flyby exploration by Mariners 6 and 7, and especially Mariner 9's orbital survey in 1971-72 -- all with Mr. Murray on the science team -- began to reveal a more diverse Mars of mountains and canyons, with some evidence of water erosion in the distant past. He constructed a geologic history of Mars from these images.
From his Mars experience and as chief scientist for the Mariner 10 mission to Venus and Mercury, as well as his budget battles as the JPL director, Mr. Murray wrote a popular book, "Journey Into Space: The First Thirty Years of Space Exploration," in 1989. He also collaborated with Arthur C. Clarke, Ray Bradbury and Walter Sullivan on another book, "Mars and the Mind of Man," based on a symposium conducted at the time that Mariner 9 swept into an orbit of Mars.
He published more than 130 research papers and four other books as well, and was the associate director of an award-winning educational film, "Mars Minus Myth," first released in 1973 and revised in 1977.