Carl E. Sagan, the David Duncan Professor of Astronomy and Space Sciences and director of the Laboratory for Planetary Studies at Cornell University, died today, Dec. 20, 1996, in Seattle, Wash., after a two-year battle with a bone marrow disease. The cause of death was pneumonia.

A public memorial will be held Monday, Feb. 3, 1997, at 2 p.m. in Bailey Hall on the Cornell campus.

Sagan, 62, was at the Fred Hutchinson Cancer Research Center at the time of his death. He had received a bone marrow transplant from the center in April 1995 for the treatment of myelodysplasia, a pre-leukemic syndrome. Sagan continued to supervise undergraduate and graduate students and do research while recuperating from his illness, but returned unexpectedly to the Seattle hospital this month.

Astronomer, educator and author, Sagan was perhaps the world's greatest popularizer of science, reaching millions of people through newspapers, magazines and television broadcasts. He is well-known for his work on the PBS series Cosmos, the Emmy- and Peabody-award-winning show that became the most watched series in public-television history. It was seen by more than 500 million people in 60 countries. The accompanying book, Cosmos (1980), was on The New York Times bestseller list for 70 weeks and was the best-selling science book ever published in English.

"The entire Cornell community mourns the loss of our colleague Carl Sagan, the David Duncan Professor of Astronomy and Space Sciences," said Cornell President Hunter R. Rawlings III. "A gifted scholar and researcher, Carl Sagan inspired thousands of students here in Ithaca and across the world to open their minds to the wonders of science and the universe. Through his writings and television productions, he brought the excitement and challenges of scientific discovery into the homes of millions of families here and abroad. He used these talents effectively in the public sector, becoming a major force in support not only of planetary exploration but also in behalf of environmental protection here on Earth. We will sorely miss him, but his legacy at Cornell will last for generations to come. Our thoughts go out to his wife and collaborator, Ann Druyan, and the entire Sagan family."

Yervant Terzian, chairman of Cornell's astronomy department, said: "Carl was a candle in the dark. He was, quite simply, the best science educator in the world this century. He touched hundreds of millions of people and inspired young generations to pursue the sciences. He will be deeply missed by his colleagues and friends at Cornell and around the world."

Sagan has published more than 600 scientific papers and popular articles and is author, co-author or editor of more than 20 books, including "The Dragons of Eden" (1977), for which he won the Pulitzer Prize in 1978. The U.S. paperbound edition of his book "Pale Blue Dot: A Vision of the Human Future in Space" appeared on best-seller lists worldwide and was selected as one of the "notable books of 1995" by The New York Times. His reading of an abridged audiocassette version was nominated for a Grammy and was cited by Publisher's Weekly as one of the "two best audiobooks of the year."

This year, he published "The Demon-Haunted World: Science as a Candle in the Dark" (Random House), which became Sagan's eighth New York Times best-seller. With his wife, Ann Druyan, he was co-producing a major motion picture from Warner Brothers based on his novel "Contact." The movie is due to be released in 1997.

Carl Edward Sagan was born Nov. 9, 1934, in Brooklyn, N.Y. At Cornell since 1968, Sagan received a bachelor's degree in 1955 and a master's degree in 1956, both in physics, and a doctorate in astronomy and astrophysics in 1960, all from the University of Chicago. He taught at Harvard University in the early 1960s before coming to Cornell, where he became a full professor in 1971.

Sagan played a leading role in NASA's Mariner, Viking, Voyager and Galileo expeditions to other planets. He has received NASA Medals for Exceptional Scientific Achievement and twice for Distinguished Public Service and the NASA Apollo Achievement Award.

His research has focused on topics such as the greenhouse effect on Venus; windblown dust as an explanation for the seasonal changes on Mars; organic aerosols on Titan, Saturn's moon; the long-term environmental consequences of nuclear war; and the origin of life on Earth. A pioneer in the field of exobiology, he continued to teach graduate and undergraduate students in courses in astronomy and space sciences and in critical thinking at Cornell.

The breadth of his interests were made evident in October 1994, at a Cornell-sponsored symposium in honor of Sagan's 60th birthday. The two-day event featured speakers in areas of planetary exploration, life in the cosmos, science education, public policy and government regulation of science and the environment -- all fields in which Sagan had worked or had a strong interest.

Sagan was the recipient of numerous of awards in addition to his NASA recognition. He has received 22 honorary degrees from American colleges and universities for his contributions to science, literature, education and the preservation of the environment and many awards for his work on the long-term consequences of nuclear war and reversing the nuclear arms race.

Among his other awards have been: the John F. Kennedy Astronautics Award of the American Astronautical Society; the Explorers Club 75th Anniversary Award; the Konstantin Tsiolkovsky Medal of the Soviet Cosmonauts Federation and the Masursky Award of the American Astronomical Society. He also was the recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences, "for distinguished contributions in the application of science to the public welfare.

Sagan was elected chairman of the Division of Planetary Sciences of the American Astronomical Society, president of the Planetology Section of the American Geophysical Union and chairman of the Astronomy Section of the American Association for the Advancement of Science. For 12 years he was editor of Icarus, the leading professional journal devoted to planetary research.

He is co-founder of The Planetary Society, a 100,000-member organization and the largest space-interest group in the world. The society supports major research programs in the radio search for extraterrestrial intelligence, the investigation of near-Earth asteroids and, with the French and Russian space agencies, the development and testing of balloon and mobile robotic exploration of Mars. Sagan also was Distinguished Visiting Scientist at the Jet Propulsion Laboratory in California and was contributing editor of Parade magazine, where he published many articles about science and, most recently, about the disease that he has battled for the past two years.

Sagan is survived by his wife and collaborator, Ann Druyan; his sister, Cari Sagan Greene; five children, Dorion, Jeremy, Nicholas, Sasha and Sam; and a grandson, Tonio.

A graveside service will be held Monday, Dec. 23, at Lakeview Cemetery in Ithaca. Shuttle buses at the Ithaca High School parking lot will be available for transportation to and from the cemetery starting at 1 p.m. Friends, colleagues and relatives will pay tribute to Sagan at the Herbert F. Johnson Museum of Art on the Cornell campus at 3 p.m. Contributions in lieu of flowers may be sent to the Children's Health Fund of New York, 317 East 64th St., New York, NY 10021, or The Planetary Society, 65 North Catalina Ave., Pasadena, CA 91106.