Billy Bob Thornton was on the cusp of turning 14 when Neil Armstrong took one small step for man, one giant leap for mankind.

Billy Bob Thornton says "The Astronaut Farmer" has appeal for children and is edgy enough for adults. Click photo for larger image. Listen In: Hear excerpts from Billy Bob Thornton's conversation with the PG's Barbara Vancheri: Who Thornton used as the model for his character, Charles Farmer. On whether the South lends itself to movies about big dreams. On his first viewings of the movie and early audience reaction. On whether children should see the film, rated PG.

"When I was a kid, we all thought those guys were big heroes. The first one that we remembered was John Glenn. I was a little kid then, but it was a big deal. He had that sort of stoic American cowboy thing about him. It was easy to make a hero out of him," Thornton, 51, said in a recent phone call from Philadelphia while promoting "The Astronaut Farmer."

To play the title character, he borrowed a little bit from Chuck Yeager, the daring test pilot who broke the sound barrier in 1947, and even more from the family ranchers he knew in his home state of Arkansas.

In the movie opening today, Thornton plays a Texan named Charles Farmer who once dreamed of becoming an astronaut but instead finds himself grounded, running a ranch and married with three children. But he never gave up his desire to rumble into the skies, even building a rocket in his barn which he hopes to launch.

The movie, filmed in New Mexico, is set among the wide open spaces of Texas.

"The South lends itself to these stories about big dreams. Those sort of vast open spaces out there, it's easy to imagine the sort of folklore and dreaming big and everything else out there. In a way, it's funny because it has a landscape that would make you think of the moon or something like that."

Writers Mark Polish and Michael Polish (who also directed) based Charles Farmer on their father, a pilot who could do and build anything, they claim. "I actually met him, but they didn't tell me they modeled him after their father till well into shooting," Thornton said.

The Polish brothers are identical twins, and Thornton says, "That's a whole different world. They finish each others' sentences a lot. They were similar to working with the Coen brothers," not twins but collaborators who typically split the directing and producing duties.

To further cement the family connection, the little girls who play Thornton's daughters are the children of the filmmakers. Michael Polish's 7-year-old daughter, Jasper, plays Stanley (named for Stanley Kubrick) and Mark's 4-year-old girl, Logan, is Sunshine. Max Thieriot plays the eldest, a son named Shepard in a tribute to the late astronaut Alan Shepard.

By the time Thornton arrived on the set, the rocket that stands in Farmer's barn was already in place. "It was pretty impressive. I almost behaved the way Bruce Willis did in the scene when he comes in and sees it for the first time. Pretty spectacular."

Thornton and Willis had appeared in the 1998 blockbuster "Armageddon," about an asteroid the size of Texas headed for Earth, along with Barry Levinson's 2001 comedy "Bandits." Asked if he approached Willis about the role, Thornton said, "Yes, I did. I sure did, and Bruce is real good about that ... he really loved the script."

Thornton believes "Astronaut Farmer" can have the same broad appeal as other triumphant movies, such as "Hoosiers" and "Field of Dreams." In talking to preview audiences, he realized he had to quit referencing "Mr. Smith Goes to Washington," since some of the younger moviegoers drew a blank on Frank Capra's 1939 film.

"Astronaut Farmer" is rated PG, and Thornton suggests, "I would say that anybody can see it. ... There's not anything that's too bad for little kids to see, but they just may not be interested or understand it if they're under 10. I would say 10 or 11 on up, they would be fine with it.

"A 12- or 13-year-old would really love it, because of the rocket aspect, but the good thing is, a lot of times when adults take their kids to the movies, the adult is bored because it's too kid-like for them. But this one is edgy enough and has a story behind it that's good enough for adults to watch it."

Thornton finds himself promoting "Astronaut Farmer" during Hollywood's awards season, which this year swept up Penelope Cruz, whom he directed in "All the Pretty Horses."

She stopped to visit him while in town and talk about a possible project. Thornton said she is tremendously proud of "Volver," the movie which earned her a Best Actress nomination. "I'm going to make an effort to see that, and I wish her the best because she's just such a great person."

So, what advice would Thornton, an Oscar winner for writing "Sling Blade" and two-time acting contender, have for Cruz this awards season? "Every minute during the whole dog-and-pony show during the awards ceremonies and everything, just imagine everybody has their pants down."

Apparently worked for him.