“He applied to several schools where he thought he had a good chance of admission, and then found himself with one extra stamp, so on a whim, he applied to the University of Pennsylvania,” his daughter said. “Much to his surprise, he was accepted as a probationary student and studied under Dr. Frank B. Wood.” He earned a doctorate in 1961.
On a summer break, he worked at the Naval Observatory in Washington, D.C. He also was a summer translator at the1964-1965 New York World’s Fair.
“He met the emperor of Japan,” his daughter said. “The emperor did not talk directly with people in those days, so my father spoke in Japanese, and then the emperor’s translator would say the same thing to the emperor, and so they spoke back and forth, in Japanese.”
Dr. Kondo completed his doctoral studies in four years, and his mentor, Dr. Wood, a noted astronomer, later said that Dr. Kondo had been his brightest student.
He met his future wife, Ursula Tutermann while at the University of Pennsylvania. They married in September 1965.
He received a National Academy of Sciences postdoctoral fellowship and did research for three years at NASA Goddard Space Flight Center. He and his family then lived in Greenbelt.
He joined a fellow astronomer, Karl Henize, at a talk at NASA’s Johnson Space Center in Texas. Dr. Henize, who was also an astronaut, asked his colleague to design and manage a moon-based observatory.
In 1968, Dr. Kondo and his family moved to Nassau Bay, Texas, where Dr. Kondo was the head of the astrophysics lab at the Johnson Space Center for the Apollo and Skylab missions. “Sadly, the use of Saturn V rockets was discontinued, and no lunar observatory was ever built.” his daughter said. He was director of the geosynchronous satellite observatory for 15 years.
He served as president of the International Astronomical Union’s commissions on astronomy from space, close binary stars, and variable stars.
He moved to Columbia in 1978 when he was named NASA project scientist for the International Ultraviolet Explorer and later the Extreme Ultraviolet Explorer.
He also founded the Columbia Aikido & Judo Club at the Columbia Athletic Club. He advanced to a sixth-degree black belt in judo and a seventh-degree black belt in aikido.
Dr. Kondo had a second career as a science-fiction writer. Because of his role in astrophysics, he received questions from the science-fiction writer Robert Heinlein about astronomy.
They became friends, and that led to a meeting with another author, John Maddox Roberts. Dr. Kondo, who wrote under the name Eric Kotani, collaborated with Mr. Roberts on a series of popular books, including “Island Worlds,” “Delta Pavonis” and “Legacy of Prometheus.” He also wrote his own novel, “Death of a Neutron Star,” which was published by Simon & Schuster as No. 17 in its Star Trek series.
Dr. Kondo also helped established an annual Robert Heinlein Award at the annual Balticon science-fiction convention.
Dr. Kondo published more than 220 scientific articles and edited 11 scientific books. He was also a special adviser to Dan Goldin, the former NASA administrator.
He received a NASA Medal for Exceptional Scientific Achievement, the Federal Design Achievement Award and the National Space Club’s Science Award.
In 2003, the Lunarians, the New York Science Fiction Society, awarded him its Isaac Asimov Memorial Award.
Over the years, he also taught at the University of Houston, the University of Pennsylvania, George Mason University, the Institute of Space & Astronautical Research in Japan, University of La Plata in Argentina and Catholic University of America.
A private memorial service is being planned for Nov. 4.
In addition to his daughter and his wife of 52 years, an instructor of Japanese flower arranging, survivors include two other daughters, Cynthia Kondo of Pasadena and Angela Kondo of Dublin, Ireland; a brother, Akira Kondo of Japan; and three grandchildren.