Charles Sheffield, 67, a physicist and science fiction writer who was a recipient of the prestigious Nebula and Hugo awards for his 1993 novelette "Georgia on My Mind," died of brain cancer Nov. 2 at Casey House Hospice in Rockville.

Dr. Sheffield, former chief scientist of Earth Satellite Corp., a Bethesda-based raw data analysis company, also won the 1991 Japanese Sei-un Award for science fiction for "The McAndrew Chronicles" and the 1992 John W. Campbell Memorial Award for best science fiction novel for "Brother to Dragons."

Martin Morse Wooster, an associate editor of American Enterprise magazine, described Dr. Sheffield as a "subtle and gifted novelist" in a review of science fiction writers published in The Washington Post in 2000.

Dr. Sheffield was a prolific writer, with nonfiction books, short stories, collections and anthologies to his credit. He also wrote more than 100 technical papers on astronomy, large-scale computer systems, image processing, space travel, earth resources, gravitational field analysis, nuclear physics and general relativity.

His popular nonfiction books include "Earthwatch," a compilation of digitally enhanced images of Earth from observation satellites, and its sequel, "Man on Earth," both of which were published in several languages. He co-authored "Space Careers" and published "Borderlands of Science," which was based on his weekly science column of the same name, distributed by Paradigm TSA.

According to autobiographical sketches posted on his Web site, he began to explore creative writing at age 40 after discovering a dearth of well-written, scientifically accurate science fiction novels. Writing also proved a therapeutic distraction as his first wife battled colon cancer.

His early manuscripts of 10,000 words or less generated a stack of rejection slips from publishers until 1977, when "What Song the Sirens Sang" was published in Galaxy magazine.

As a scientist, he was an adviser to the congressional Office of Technology Assessment and principal investigator and consultant for the National Aeronautics and Space Administration, for which he analyzed the moon's gravitational field on the motion of a spacecraft in the 1960s.

He then served as chief scientist and board member of Earth Satellite Corp. before he turned to writing full time in the late 1980s. He reviewed science books and novels for New Scientist, the World & I and The Washington Post.

He attended science fiction conventions, where he was known as an erudite, witty speaker who provided encouraging words to new writers.

Dr. Sheffield, a Silver Spring resident, was born in England and graduated from Cambridge University's St. John's College with double first-class honors in mathematics and physics. He received a doctorate in theoretical physics from American University in Washington.

He was past president of Science Fiction and Fantasy Writers of America as well as the American Astronomical Society. He was a fellow of both the American Association for the Advancement of Science and the British Interplanetary Society.

His first wife, Sarah Sanderson, died in 1977. His second marriage, to Linda Zall, ended in divorce.

Survivors include his wife of five years, science fiction author Nancy Kress of Silver Spring; two children from his first marriage, Ann Sheffield of Cochranton, Pa., and Charles Christopher "Kit" Sheffield of Vienna; two children from his second marriage, Elizabeth Rose Sheffield and Victoria Jane Sheffield, both of Silver Spring; his mother, Emma Sheffield of England; and a sister, Ann G. Hunt of England.