The pod-bay doors are about to open on the suite at the Waldorf, revealing Arthur C. Clarke, the legendary science-fiction seer, the Galactic Dreamer who wrote "2001: A Space Odyssey," the scientist who invented satellite communication in 1945. The man who has done for space travel what John Wayne did for the saddle. One imagines a daunting amalgam of Jules Verne, Alistair Cooke and Mr. Spock.

But this paunchy fellow at the door -- with the math-teacher glasses, discreet hearing aid and thin cirrus of hair, the red velvet slippers and unbelted pants--looks like some kind of GS-12 from the Bureau of Poultry Audits. And he wants you to see his Kermit the Frog doll.

Still, it's the G.D., all right. If you couldn't tell by his books on the mantelpiece, the messages and deliveries overflowing the small desk or the murmur of his assistant fielding calls in the next room, you'd know from the impish glint at the edge of the eyes, or the insouciant ease with which he lolls on the sofa next to the propped-up Kermit.

Back in the United States for the first time in five years, the 64-year-old British writer is on a promotional star trek for "2010: Odyssey Two," the sequel he once vowed he'd never write. "Well, I have a new definition of myself," he chuckles, "a failed recluse."

After "The Fountains of Paradise" (1979), "I thought it would be my last book. It tired me out, and I felt that I'd said everything I wanted to say." And why not, after 50 books of fiction and nonfiction -- 20 million copies of which have been translated into more than 30 languages. When Publisher's Weekly printed its list of the 50 essential science-fiction titles, four of them were Clarke's: "Childhood's End" (1953), "2001" (1968), "Rendezvous With Rama" (1973) and "Imperial Earth" (1976). He has won a half-dozen Hugos and Nebulas and the coveted Marconi Fellowship for his work on satellite communications. And when Commander Cronkite wanted a copilot for CBS' coverage of the Apollo missions, he tapped Clarke. No wonder "I eventually came to the point where I just wanted to enjoy myself and relax in Sri Lanka," where he has lived for the past two decades.

But four years ago, more in whimsy than earnest, he sent his agent, Scott Meredith, a 10-page movie treatment. To Clarke's surprise, it was printed in Omni magazine. Encouraged, he cranked up another 10-pager, outlining a possible sequel to "2001." "Well, Scott sent it straight back and said, 'You've got to write the book. I can get you a nice advance.' "

For sure: Back in 1968, millions of baffled moviegoers (many in the brain-bending grip of cannabis) had wobbled out of "2001" with a migraine's worth of questions: What went wrong with HAL, the talking computer who turned on his masters out by Jupiter? What were those lugubrious monoliths, anyway, and why did they need Keir Dullea? And what was all that Star Baby business at the end? Director Stanley Kubrick had been ambiguous, Clarke's novelization equally coy, and the unresolved themes, Clarke says, had "been burning a hole in my subconscious over the last 14 years." So when he set out to answer those questions in the new novel--aided by Voyager's recent revelations about Saturn and Jupiter -- "it was just like reporting."

Not quite: He got $1 million for the hardcover, paperback and Book-of-the-Month Club edition. That's not counting the Caedmon audio cassettes of Clarke reading from the book, or the likely consummation of one of 150 movie-rights inquiries so far. And in a brutally competitive market for science fiction, "2010" has rocketed to fifth place on The New York Times best-seller list--one slot above "Foundation's Edge" by Isaac Asimov, Clarke's friendly rival for 30 years. "Yeah, but he's got a movie going for him," says Asimov. "All I've got on my side is quality." Fortunately, there is the "Clarke-Asimov Treaty of Park Avenue," ratified when the two titans were sharing a cab. "We agreed," says Asimov, "that whenever someone asked Arthur who was the best science writer in the world, he would say Asimov. And whenever I was asked the best science-fiction writer, I'd say Clarke. . . . But neither one of us believes it." Clarke agrees. And as for the rest of the S-F fraternity, he says in ex cathedra deadpan, "I myself am rather above the smoke of battle."

He is similarly indifferent to the film possibilities. "I called Stanley [Kubrick] on the way over here and said, 'Your job is to stop anybody making it so I won't be bothered.' " He believes too many astro-flicks of the "Close Encounters" and "E.T." persuasion, by "over-glamorizing" space travel, make the real thing "disappointing when it happens." (He prefers "Blade Runner" and raves over "TRON.") And they may encourage "UFO cults--the idea that someone will come down and save our bacon for us. That's a dangerous notion, that we're rather helpless pawns. We can only save ourselves by our own exertions." As he once said, "If God does not exist, we may have to become Him."

Yet alien bacon-rescue is a staple of the Clarke canon. In fact, "2010" and "Childhood's End," though written 30 years apart, share an identical vision of human progress in which man (1) invents a technology, (2) threatens his future by warlike misuse of same and (3) is forced into a higher plane of evolution by Eerie Powers. In "Childhood's End," a saucer-load of devilish Overlords prevents mankind from nuking itself into briquettes until a race of superkids can evolve. In "2010," we learn that the monoliths are agents of a benignly ecological Cosmic Will that is trying to help man progress without endangering some emerging species out there by Jupiter. And Bowman, recruited by the Will and transmuted into pure energy, carries the message to man. Isn't that a pretty passive scenario? "Hmm. Maybe I am a passive character," he muses, twirling his velvet-clad foot. "After all, they say a masochist is merely a lazy sadist."

He is obviously bored sick with talking about his work. Even when alert, Clarke has the same expression as the guy who answers the parts-department buzzer at the appliance store; when uninterested, his face congeals into blankest apathy. He has a printed form warning journalists that after "several thousand" interviews, "I am now completely fed up with talking about myself, and all my ideas are better recorded in my writings. Moreover, I am now anxious to generate negative personal publicity." Unless the subject is of "major news importance," would-be inquisitors are admitted only "on the basis of one photo, one autograph, one question," with a bonus question for "anyone who can ask me one I've not heard before."

He is making a half-hearted exception for this global promotion, but it soon becomes clear he intends to do business on his own terms. Abruptly, he blasts off the sofa. "I have quite a few things to show you." This proves a monstrous understatement: Clarke is a one-man show-and-tell orgy. He wiggles his Kermit ("You like it? It's a gift. We get the Muppets in Sri Lanka and I adore them"). He sprints to the mantelpiece and points out the copies of his books. He offers old speeches, copies of his "Ego-grams" (lavishly detailed accounts of his doings that he periodically mass-mails to friends), samples of his "drop-dead" form letters squashing all entreaties. Each document is meticulously sheathed in plastic.

Mention any subject and Clarke will provide an exhibit. Is "2010" dedicated to "two great Russians," physicist Andrei Sakharov and cosmonaut Alexei Leonov? He produces a fiberglass attache' case and whips out snapshots of Leonov and himself being lionized at the Soviet space center. Want more? His assistant -- "I call him my memory module" -- arrives with another wad. (The Module is Steve Jongeward, a mild-voiced, cherubic 20-year-old who served as Clarke's amanuensis from 1979 until he had to return to the United States this year. A Clarke fan since age 8, Jongeward found the job "a dream come true," and is sheerly delighted to be helping again, although slightly resentful that "another guy took my place when I left.") Pretty soon, it's starting to feel like rush hour at Toys-R-Us. Is that a diving watch? Clarke gleefully unclasps the massive gold Rolex and hands it over for approval. "It's a real economy -- doubles as a weight belt, [but] I have a digital alarm which is infinitely more accurate and cost about $20." Did he win an Emmy in 1981 for his contributions to satellite broadcasting? Clarke rummages in the heap and then, with a flourish as if he were trumping a bridge trick, slaps down a Polaroid picture of the plaque!

A skeptic might infer an excess of self-esteem from this traveling archival tonnage. Asimov jokes that "I think he's the only science-fiction writer who's vainer than I am. At least I stop once in a while." But Roger Caras, an ABC-TV correspondent who has known Clarke for 25 years, says that's "absurd. He's not arrogant or conceited. Sure, he has pictures of himself with famous people in his attache' case and carries his reviews and everything with him," but it's "just his innocent celebration of being alive. He's a brilliant, brilliant child who loves toys, games, playing with his computers."

Such self-absorption may explain why character development plays such a minor part in Clarke's novels. His chief energies and best prose are reserved for elaborate solutions to creative physics problems (i.e. "Rendezvous With Rama"), served up with a perfunctory dollop of characterization and romance (recently tending toward jealous homo/heterosexual triangles in "Imperial Earth" and "2010").

But the Innocent Celebrant is no hermit. His bungalow in Colombo, the capital of Sri Lanka, houses a domestic staff of six and a protean menagerie of pets. "He's an extraordinarily sentimental man," says Caras, "who will stand at the grave of a dog and sob . . . gentle to a fault." Clarke says his livestock roster is now down to German shepherds and cats, although there were recently mongooses ("not very practical--we had to fight for our food") and two monkeys who "died and left us shattered."

Although still a British citizen, he has lived in Sri Lanka since the early '60s. At first, he would leave every six months to avoid the taxes; but in 1975 he persuaded the government to enact the Resident Guest Scheme (which everyone calls "The Arthur Clarke Law") permitting prominent foreigners who brought in hard currency to enjoy minimal taxes and pecuniary perks such as duty-free imports. Despite such discriminatory treatment, Clarke is one of the most popular men in the country.

"He lives in the most exclusive part of Colombo," says a former Sri Lankan official who knew Clarke there, "and the people are snobbish and very arrogant. But he was like an oasis in that neighborhood. He wore the sarong like everybody else and would go around barefoot. That made the people love him." He often wears the native dress abroad, and once shocked a staid IBM convention that had hired him to speak. "Want to see it? Steve!" The Module arrives with two varieties -- bright paisley and plain white. Clarke bustles out to change into the white ("I call this my Dr. No") and reappears complete with sandals.

The man is no introvert. When a friend once showed up with an antique Rolls-Royce safari car, Clarke, Caras and the friend took off into Colombo, generating an impromptu parade. When bystanders began throwing flowers, Clarke stood up in the back of the car, strewing petals to the crowd and crying, "I am Kipling! I am Kipling!" And no Scrooge. At one time he had the only TV set in Sri Lanka. He had been helpful in getting the United States to lend India a communications satellite, so in 1976 the Indian government got Clarke his own 15-foot dish antenna. Suddenly parties as large as 50 -- including the president of Sri Lanka -- were dropping over to ogle the tube. "You should have seen my liquor bill," says Clarke, still proud of "the first private satellite station on Earth."

For a "failed recluse," Clarke hardly goes idle. He has a diving business, Underwater Safaris. He's negotiating a sequel to "Arthur C. Clarke's Mysterious World," his 13-part British TV series. "And you know about my career as a film star, don't you?" Uh, no. A couple of years ago, Sri Lanka's only major director decided to film Leonard (Mr. Virginia) Woolf's only novel, "The Village in the Jungle" ("Beddegama"). Clarke immediately volunteered for the role of Woolf and got it. It won't hit Radio City this year, but Clarke says the BBC is interested. Which is more than he can say for his memoirs of the project, "Who's Afraid of Leonard Woolf?" "It's the only thing I've written that my agent simply hasn't been able to place. That's strange, in view of the Bloomsbury explosion."

His day begins with "bed tea" and the Voice of America at 6:30. He's at his desk by 7:30, and by 4 p.m. he's down at the club for "a couple of hours of table tennis. It's my only form of exercise" since a polio-like illness paralyzed him temporarily 20 years ago -- "I was a complete basket case." For intellectual exercise, "I read very little, I'm afraid. I spend more time looking at videotapes," but he tries to read the big S-F books.

He dates his obsession with the genre from the March 1930 issue of Astounding Stories. He was 12 when he saw it, the son of a Somerset farmer, and "I used to haunt Woolworth's in my youth to pick up issues I had missed." The interest continued through his first job as an auditor in the Exchequer, early membership in the British Interplanetary Society (regarded in the '30s as a group of pub-bleary crackpots), service as an R.A.F. lieutenant working in radar and a postwar physics and math degree from King's College, London. While editing a physics journal in the early '50s, he became a sudden success. "The Exploration of Space" (1951) became a Book-of-the-Month Club selection, and "Childhood's End" (1953) got rave reviews. Clarke was launched, financially able to pursue his other love, underwater exploration, the subject of a dozen of his books.

That brought him to Sri Lanka (then Ceylon) in the mid-'50s. By then he was married to an American, but they soon began living apart, the marriage "exploded," and they were divorced in 1964. Despite his obvious fictional and real-life affection for children, the marriage produced none. "I've had all of the fun and none of the responsibility," Clarke jokes, but his head hangs, his hand rises to his cheek and he is quiet for a moment.

He and his ex-wife are still friendly. "She sent him a Rubik's Cube last year," says The Module. "I wonder what it means," says Clarke. It seems just the widget for a gent with Clarke's silicon brain trust: A Hewlett-Packard computer ("I call it HAL Jr."), an Apple II ("for fun and games") and an Archives III word processor ("Archy"). He boasts that he sent the whole text of "2010" to New York on one five-inch magnetic disc and made corrections via satellite.

Unlike many of his S-F colleagues, Clarke is bullish on future tech ("Our technology, in the widest sense of the word, is what has made us human"). He believes science has its own momentum, that what can be imagined will probably be accomplished. And whatever his secret fears, his fictional prognoses are invariably benign: "There's something to be said for self-fulfilling prophecies. If enough people believe in it, it will happen."

Hence, his recent activism on behalf of arms reduction. In August, as a Sri Lankan representative to Unispace '82, he urged the U.N. Committee on Disarmament to endorse the creation of a "Peacesat" -- a multinational super-satellite to share scientific information and monitor arms buildups. He reiterated the plea to a New York group last week, and will carry the message to an informal meeting with congressmen when he visits Washington today. He says weapons "advertisements in aerospace journals are the real pornography," and "the time is right to do something." But "I will never sign manifestos," and he is wary of simplistic anti-nuclear rhetoric. "Unilateral disarmament was fine in the days of Gandhi."

Much of Clarke's clout comes from three decades of largely accurate predictions, but he insists that "I disclaim any identity as a prophet. I'm an extrapolator. I present people with alternatives and try to persuade them to select the better, if not the best." Still, in 1945 he published a paper describing, in astonishing detail, what decades later would become the satellite communications system, and later foreshadowed the Soviet's Sputnik coup, the moon landing, the space shuttle and more.

In "Profiles of the Future" (1963) he developed a time line forecasting colonization of other planets by the year 2000, human contact with extraterrestrials by 2030 and outright immortality by 2090. But because "the momentum of manned space travel has slackened," those bets are off. And he's still waiting for two "perfectly practical" pet schemes: a catapult to "shoot payloads off the moon using purely electrical energy," and the "space elevator" which would ascend a 50,000-kilometer cable stretching from Earth to a stationary space station.

The Galactic Dreamer. Have we seen his last vision? "No, I won't say that. But if I ever do write 'Odyssey III' -- allowing for the fact that my energies are declining -- it won't be before the year 2001."