By Samantha Miller
Updated September 10, 2001 12:00 PM

It had been a good summer. In July, a few weeks after wrapping K-19: The Widowmaker—a submarine thriller for which he made a whopping $25 million—action actor Harrison Ford, 59, flew his helicopter to help find Cody Clawson, a 13-year-old Boy Scout lost overnight in the forest near Ford’s Jackson Hole, Wyo., ranch. It was the second time in two years the avid pilot had pitched in to aid a rescue team. Ford’s greeting to the stranded Scout: ” ‘Well, you should get a merit badge for this.’ ”

Rescuing his marriage, unfortunately, has proved more difficult. On Aug. 23 Ford’s wife of 18 years, screenwriter Melissa Mathison, filed for legal separation in Los Angeles. The move dashed friends’ hopes that the long-admired couple—who began living apart last October but reconciled in the spring—could work out their problems. Citing irreconcilable differences for the split, Mathison, 51, requested joint custody of their children, Malcolm, 14, and Georgia, 11. Says Ford’s longtime manager Patricia McQueeney: “The separation is amicable, and the couple remain very friendly.”

The news saddened those close to the couple, many of whom hoped that their split last fall had just been “a temporary thing,” as a relative put it to PEOPLE. “It’s a damn shame,” says novelist Warren Adler, whose book Random Hearts was made into a 1999 movie starring Ford. “Obviously they’ve been having their problems, but such is life. They are very devoted family people, so a split comes as a shock.”

The separation—a move that allows Mathison to follow with a divorce petition after six months as a California resident—could lead to high-stakes negotiations rivaling any in Hollywood history, including Tom Cruise and Nicole Kidman‘s ongoing battle. (In fact, Mathison has hired Cruise’s divorce lawyer Dennis Wasser.) The Star Wars and Indiana Jones star’s vast fortune includes his 700-plus-acre Wyoming ranch, a Connecticut estate worth at least $6 million, an apartment in New York City estimated at $3.5 million, a collection of 19th-century paintings and drawings, and five planes, including a Gulfstream jet worth at least $6 million.

For a while, it seemed Ford and Mathison had survived their rough patch, which one family friend described in May as “a midlife crisis” on Ford’s part. In the weeks after their separation last fall, Ford—who moved into a hotel near his family’s Manhattan apartment—appeared to be savoring the solo life, drinking and socializing at New York City nightspots. A club-hopping encounter with actress Lara Flynn Boyle led to reports of a romantic liaison, which both Ford and Boyle denied. Now, as then, there are “absolutely not” any third parties involved in the split, McQueeney says.

By last Christmas Ford and Mathison were talking about getting back together, and a few months later Ford began staying at their three-bedroom apartment near Central Park on weekends off from K-19. “They were going to try to work things out because of the kids,” the family friend says. Recently, though, Ford had been turning up in his Manhattan neighborhood solo or with his kids—walking his Labrador retriever, buying black coffees at Starbucks, treating the kids to chocolates—but rarely with Mathison.

Perhaps, says one longtime Jackson Hole resident, Mathison had finally had enough of Ford’s foibles. 5 “Harrison’s moodiness and reclusiveness are well-known,” says the neighbor. “Melissa is even-tempered enough to handle it—to a point. Frankly, I think many women who aren’t as sweet as she is might have left him a long time ago.”

When the two met on the set of Apocalypse Now in 1976, “I found her very attractive,” Ford has said. “But it wasn’t just the look of her. It was the way she behaved, the intellectual connection we made.” His first marriage, to Mary Marquardt, with whom he has two adult children, was crumbling (they divorced in 1979). Mathison—who went on to write E.T. and 1997’s Kundun—and Ford wed in a 15-minute ceremony at the Santa Monica courthouse in 1983.

For now, says McQueeney, the pair are both headed back to the New York City area, where Malcolm and Georgia are both starting a new school year. Meanwhile, neighbors in Jackson Hole find it hard to imagine not having the couple around. “Everybody liked them,” says Warren Adler. “It seems very sad, because it looks to me like they had a wonderful life together.”

Samantha Miller

Keith Raether in Jackson Hole, Julie Jordan in Los Angeles and K.C. Baker and Marianne V. Stochmal in New York City