Jonathan Eberhart, 60, an award-winning aerospace writer who also was a folk singer and a founder in 1964 of the Folklore Society of Greater Washington, died of complications from multiple sclerosis Feb. 18 at Holy Cross Hospital. He lived in Washington.

By day, Mr. Eberhart was space sciences editor of the weekly newsmagazine Science News, covering space sciences and the development of the U.S. aerospace program. He worked there for more than 30 years before he retired in 1991.

For three decades, he also was a fixture of the Washington folk music scene, performing and recording on his own and with the group Boarding Party. He helped folk singer Pete Seeger sail the sloop Clearwater on its maiden voyage and sang at performances along the route and on the record of sea chanteys made by the crew.

He wrote songs -- including "Lament for a Red Planet," inspired by his coverage of NASA's Mars explorer mission for Science News -- and collected rare folk music and instruments from around the world. Among Mr. Eberhart's own records were "Life's Trolley Ride" on the Folk-Legacy label.

He helped stage the Folklore Society's popular free summer festivals, which drew thousands of music lovers to Glen Echo Park and other venues.

The gatherings started out as concerts at the Washington Ethical Society. They quickly grew into two-day, five-stage celebrations co-sponsored by the National Park Service. Hundreds of singers, dancers, musicians, storytellers and craftspeople came, along with thousands of visitors over a weekend.

Mr. Eberhart performed there, at the Smithsonian Institution and at festivals elsewhere. He also spent seven months in Osaka, Japan, as a musician-in-residence at the American Pavilion of the Expo 70 World's Fair, under the auspices of the U.S. Information Agency.

Friends described him as exhaustive in his research of the history and lore of songs and in finding performers from other countries for the festival. They said he was obsessive about uncovering unknown music, not hesitating to ask strangers, including waiters in ethnic restaurants, if they could teach him sea songs from their countries.

Mr. Eberhart was born in Evanston, Ill., and raised in Hastings-On-Hudson, N.Y. He attended Harvard University, working during the summer at Science News, and then joining the staff as a writer in 1964.

In 1976, he won the joint science writing award of the American Association for the Advancement of Science and Westinghouse Corp. for his coverage of the Viking landings on Mars. A few years later, astronomers named an asteroid "Joneberhart" in honor of his contributions to science journalism.

Mr. Eberhart's contributions to the local music scene included a radio program on international folk music for WGTB. His search for international talent reached to more than 30 countries as well as Washington's own international communities.

"It's easy to find a good banjo player," he said in an interview in The Washington Post, "but how do you find an Eritrean krar lyre player?" One of his investigative techniques was to ask cabdrivers speaking accented English where they were born and whether they knew someone who could play native instruments. The result would be festival or folklore society acts from Afghanistan or Iceland or Vietnam.

Mr. Eberhart said that, with performers and audiences "doing something together," a kind of mutual understanding was the result. "We're all raising sails on the same ship. That's not just what makes it fun. It's why it's a good thing."

"Washington is one of the most culturally diverse areas in the country, but many times, people never know about it," he said. "We wanted an event where, for free, people could come out and experience things they never thought existed. My hope was that every person who came would discover something so totally new, so different that they could leave feeling they had added something positive to themselves."

Mr. Eberhart's favorite songs were water-inspired celebrations of work and comradeship, and he collected them from seafaring nations around the world. The Boarding Party, which also included Tom McHenry, Bob Hitchcock, K.C. King and David Diamond, specialized in the songs and recorded several albums, including " 'Tis Our Sailing Time."

The record also featured closer-to-home music, including a song about the C&O Canal when it was traveled by 500 barges a day ("Otho's Song"); a look back at Baltimore ("Truxtun's Victory," about the frigate Constellation); and a view of turn-of-the-last-century oystering in the Chesapeake Bay ("The Shanghaied Dredger"). The group performed across the United States and in Canada, the British Isles and Europe.

Mr. Eberhart also wrote articles about music for publications that included Sing Out and liner notes for numerous recordings, notably the Nonesuch Explorer international series world music.

He leaves no immediate survivors.