A long time ago, in a galaxy far far away, George Lucas promised us some intimate movies … yeah, right

On either side of the Golden Gate Bridge in San Francisco he has constructed himself two temples where Star Wars is made and worshipped: at his Skywalker Ranch in Marin County and his newer office complex, the Letterman Digital Arts Centre at the Presidio, he has gathered all manner of relics honouring his six-film saga, from the imposing (life-size replicas of the villains Darth Vader and Boba Fett) to the self-congratulatory (a Yoda fountain) to the self-deprecating (a carbonite block encasing the much-loathed Jar Jar Binks).

Like religious shrines, these buildings both consecrate and confine the man for whom they were built.

Using the freedom and the fortune he has amassed largely on the astronomical success of Star Wars, Lucas has accumulated unparalleled creative resources; his next film could be anything from a sweeping epic to one of the intimate personal narratives he has often said he would like to make.

Instead, his next two ventures will be Star Wars projects, no less ambitious than his previous films yet potentially less commercial. And they come at a time when even the Star Wars faithful wonder if Lucas's continued mining of this fantasy world has anything more to yield.

Lucas, who is 64 with a full white beard, meets me at his Presidio offices somewhat reluctantly, on a layover between the European and Japanese premieres of Indiana Jones and the Kingdom of the Crystal Skull.

"I love making movies; I'm not the biggest fan of selling them," he says, seated in the library-like Lucasfilm boardroom, stocked with books about real-world military history and novels such as Quo Vadis. "But since I'm in the selling mood, that's what you're here for. I'm doing all my selling for two more weeks. Then I'm sold out."

He is pitching a computer-generated animated movie called Star Wars: The Clone Wars, which Warner Brothers will release in August and which will introduce an animated television series with the same title, to have its debut on the Cartoon Network this autumn.

Despite his vows to the contrary, Lucas did not conclude his Star Wars epic with his 2005 film Revenge of the Sith, the third in a trilogy of prequels that grossed about $850 million worldwide. As far back as 2002 he was contemplating an animated series that would take place between Episodes II and III, fleshing out the adventures of the Jedi knights Obi-Wan Kenobi and Anakin Skywalker (who is doomed to become the evil Darth Vader), and exploring heroes, villains and planets glossed over in the prequel films.

For Lucas this was an opportunity to revisit imaginary turf that gives him great personal satisfaction. Star Wars, he says, is "a sandbox I love to play in. It's not a matter of trying to prove anything to anybody – I don't have to."

But his enduring interest in Star Wars hints at a lesson that his filmmaking peers have already learned: it is sometimes easier to make big movies than small ones.

As his longtime friend and collaborator Steven Spielberg says: "All of us would like to make these little personal films that sneak into theatres under the radar. Sadly, for George and myself, and others who have enjoyed and endured great success – 'under the radar' has become a no-fly zone."

Lucas began pursuing his Clone Wars projects about three years ago when he summoned the technological might of his company's research and development division to start building Lucasfilm Animation, now a pair of studios at Big Rock Ranch – part of Skywalker – and in Singapore. (Lucasfilm declined to discuss budgets, but Lucas says that building a similar operation in the 1980s would have cost him $60-100 million.)

Next, he hired a team of young Star Wars-obsessed artists who revere Lucas as if he were Yoda. "He's the guy," says Dave Filoni, director of the Clone Wars show and movie. "Chewbacca exists because he named him, thought him up, put him in the cockpit."

The two men worked closely together (Filoni is a former director of Nickelodeon action cartoon Avatar: The Last Airbender) to hone the anime-inspired look of The Clone Wars and develop scripts, often drawing upon unused ideas Lucas had been stockpiling since the original Star Wars was released in 1977.

Lucas took the unusual step of waiting until the first 22-episode season of The Clone Wars was nearly finished before pitching it to television networks late last year.

There were no immediate takers. Fox Broadcasting, the sister company of 20th Century Fox, which released the live-action Star Wars movies, passed. And the Cartoon Network, which had broadcast a series of traditional 2D animated shorts called Star Wars: Clone Wars from 2003 to 2005, was lukewarm about the project.

That tepidness may have stemmed from some viewers' dissatisfaction with the Star Wars prequels, with their stilted dialogue and baffling politics. Or it may have indicated that Clone Wars wasn't compatible with a prime-time network schedule. "It didn't fit any of the moulds that everybody had," Lucas says. "It's not SpongeBob SquarePants, but at the same time it's also not Family Guy."

Lucas says Warner Brothers became interested only after he decided to produce a theatrical Clone Wars film (encouraged by the animation results he saw). The film studio then convinced its corporate siblings at the Cartoon Network to give the television series another look. (Executives at Warner Brothers and the Cartoon Network, both divisions of Time Warner, give slightly different chronologies but do not dispute this element of Lucas's account.)

For Time Warner, the Clone Wars collaboration is more than a one-time opportunity to share in the money-minting Star Wars franchise. "It's the relationship with Lucasfilm that we're very excited about," says Dan Fellman, president for domestic distribution of Warner Brothers Pictures. "Not just on the Cartoon Network but possibly for live-action television down the road."

Sure enough, Lucas is already developing a live-action Star Wars television series, and Time Warner would love to be able to demonstrate that one of its cable channels ( such as TNT or HBO) could give it a good home.

But the question remains: just because new Star Wars films can be made, should they be?

Some series aficionados – even those who have worked with Lucas on Star Wars projects – are ambivalent about his continued plundering of a science fiction property that has already spawned numerous comic books, video games and novels, not to mention six movies.

"I think it's the easiest thing to do, because he doesn't need to come up with a whole new thing; everything's established," says Genndy Tartakovsky, the animator who directed Lucas's previous Clone Wars shorts for the Cartoon Network. Speaking as a fan, he adds: "I appreciate that, but there's so much more that he could explore."

Lucas says he had no urgent or compelling reasons for returning to his most popular characters and mythologies, except that he can – and he enjoys doing so. To illustrate, he points to his work with Spielberg on the new Indiana Jones.

"I mean, why do we have to make another Indiana Jones movie? There was no point to it, other than, gee, this might be fun."

But to the extent that Star Wars has kept him from fulfilling his promise to return to making more personal, smaller-scale films, Lucas laments this distraction. "You get sidetracked easily," he says with a chuckle. "I do, anyway."

And he is deeply pessimistic about the marketplace he will face when he someday releases a movie that is not set in a galaxy far, far away. "Maybe it ends up in a festival somewhere," he says. "Maybe it ends up in half a dozen theatres around the country for a couple weeks."

As he so often does, Lucas takes a lesson from the experience of his friend and mentor Francis Ford Coppola, whose most recent film, Youth Without Youth, received a small independent release that was hardly on the scale of his Godfather movies. "Did you see it?" Lucas asks. "Uh, no. Did you even know it came out?"

Coppola agrees that the films he now makes, and that Lucas says he intends to make, have little chance of achieving blockbuster status. "We make films for ourselves," he tells me. "If no-one wants to see them, what can we do? Emotion does much better at the box office than philosophy."

Other former colleagues of Lucas argue that new Star Wars projects have provided technological boons for the entire film business, yielding Industrial Light and Magic, Lucas's pioneering special-effects company, and EditDroid, the digital film-editing hardware that was a forerunner to the Avid editing system.

"He does it in a way that might begin as self-serving and then, of course, is a bonanza for the whole industry," says Sid Ganis, the president of the Academy of Motion Picture Arts and Sciences, who was a Lucasfilm executive during the 1980s.

As Lucas would be the first to remind you, he has proved his detractors wrong many times in his career, from the film executives who thought American Graffiti would work better as a television movie to the industry colleagues who warned him not to finance The Empire Strikes Back with his profits from Star Wars.

When he works on the Star Wars properties he owns outright, Lucas has the freedom to ignore the input of others. In the case of The Clone Wars, he is financing the series himself and charging Time Warner licensing fees to distribute the film and broadcast the show.

"It's much easier for me to just do the show I want, say, 'Here it is, do you wish to license it or not?' " Lucas says. "That's it. There's no notes, no comments. I don't care what your opinion is. You either put it on the air or you don't."

But Lucas's independence cannot shield him from the realities of the film business. He is not planning, at least now, to go head to head with more established animation studios like DreamWorks, Disney and Pixar. The mid-August release of the Clone Wars movie – an unusually late date for a Star Wars film – was scheduled in part to avoid competition with recent offerings from these studios.

It is highly likely that The Clone Wars will be the lowest-grossing Star Wars movie ever; Lucas says he would be satisfied if it made $100 million in the US. Revenge of the Sith, by comparison, grossed $380 million domestically.

When he is not, say, testifying before a House subcommittee about classroom technology, or appearing at Cannes with his frequent companion, Mellody Hobson – president of investment firm Ariel Capital Management – Lucas has plenty of new projects to keep him busy.

He is already working on the second and third seasons of The Clone Wars and forging ahead on his live-action Star Wars television show. Then, he says, he will seek other films and television series for his animation studio and continue to develop Red Tails, a long-in-the-works feature film about the Tuskegee Airmen – America's first black military airmen – that he is producing.

After that, who knows?

Lucas points back to his very first feature film, THX 1138, a dystopian work of science fiction released in 1971, one that at the time he believed would be his one and only shot at directing a movie exactly as he envisioned it. (Its critical and commercial reception very nearly proved him right.)

All that his wealth has bought him, Lucas says, is the opportunity to make more films the way he wants to. "I've got more shots," he says. "I can go and make half a dozen THXes.' I'll lose everything I put into them, guaranteed. But I can have a lot of fun doing it."

• Star Wars: The Clone Wars is released on 15 August.