The first model of the U.S.S. Enterprise, the starship that appeared in the opening credits of the original “Star Trek” television series, has been returned to Eugene Roddenberry, the son of the creator of the series, decades after it went missing.

“After a long journey, she’s home,” Mr. Roddenberry wrote on social media on Thursday.

For die-hard Trekkies, the model’s disappearance had become the subject of folklore, so an eBay listing last fall, with a starting bid of $1,000, didn’t go unnoticed.

“Red alert,” someone in an online costume and prop-making forum wrote, linking to the listing.

Mr. Roddenberry’s father, Gene Roddenberry, created the television series, which first aired in 1966 and ran for three seasons. It spawned numerous spinoffs, several films and a franchise that has included conventions and legions of devoted fans with an avid interest in memorabilia.

The sellers of the model were bombarded with inquiries and quickly took the listing down.

The sellers contacted Heritage Auctions to authenticate it, the auction house’s executive vice president, Joe Maddalena, said on Saturday. As soon as the sellers, who said they had found it in a storage unit, brought it to the auction house’s office in Beverly Hills, Calif., Mr. Maddalena said he knew it was real.

“That’s when I reached out to Rod to say, ‘We’ve got this. This is it,’” he said, adding that the model was being transferred to Mr. Roddenberry.

It was not clear what Mr. Roddenberry, who was traveling and could not immediately be reached on Saturday, would do with the reclaimed model. It was also unclear how it got to the storage unit in the first place and who had it before its discovery.

The original U.S.S. Enterprise, a 33-inch model, was mostly made of solid wood by Richard C. Datin, a model maker for the Howard Anderson Company, a special-effects company that created the opening credits for some of the 20th century’s biggest TV shows.

An enlarged 11-foot model was used in subsequent “Star Trek” television episodes, and is now part of the permanent collection of the Smithsonian National Air and Space Museum, where it was donated by Paramount Studios in 1974.

Mr. Maddalena said that Gene Roddenberry, who died in 1991, kept the original model, which appeared in the show’s opening credits and pilot episode, on his desk.

The model went missing after Mr. Roddenberry lent it to the makers of “Star Trek: The Motion Picture,” which was released in 1979, Mr. Maddalena said.

“This is a major discovery,” he said, likening the model to the ruby slippers from the “The Wizard of Oz,” a prop that was stolen in 2005 and recovered by the F.B.I. in 2018, and that Heritage Auctions is selling.

While the slippers represent hope, he said, the starship Enterprise model “represents dreams.”

“It’s a portal to what could be,” he said.