When F. Scott Fitzgerald wrote, "There are no second acts in American lives," he was ruefully noting the early rise and fall of celebrated people. Last century, success was a young man's game, and so was failure. But today's Americans might take Fitzgerald's jeremiad as a compliment: there are no second acts because they prolong the first act forever; they work and play hard to extend adolescence for another 40, 50 years. It's hard work, consuming all that wheat germ and Viagra, but it's worth it to stay tan, teen and terrific. Besides, the alternative is so unattractive. To be old in America is almost as uncool as being poor.

That makes the recent films of Clint Eastwood a bracing, useful social corrective. "I don't know how to break this to you, Frank," a longtime adversary tells Eastwood in Space Cowboys, "but you're an old man." No need to tell Eastwood; he knows. As a sleuth in True Crime and In the Line of Fire, and as a career criminal in Unforgiven and Absolute Power, the actor-director has dramatized the perils and grace of something we all do (if we're lucky): age. His breath is short, his trigger finger is arthritic, and the young women in his life are more likely to be his daughters or his bosses than a hot amour. Yet even at 70, he's still Clint, which means he's about the best any of us can hope to be in our reclining years.

Once upon a time (in the West), Eastwood was the grizzled loner, using the Old Testament playbook to clean up Tombstone or San Francisco. Here he's surrounded by other gents of a certain age: hotdogging fly-boys of the '50s named Hawk (Tommy Lee Jones), Jerry (Donald Sutherland) and Tank (James Garner) who were pioneers in Air Force research but got passed over for the first U.S. astronaut program. An old Soviet satellite is about to crash to earth, threatening humanity; since Frank built the technology the Russkies swiped, his expertise is needed. He insists on going up to fix the damn thing and taking his pals along for a senior-citizen road trip to outer space. The Over the Moon Gang rides again, in an alter-kocker Armageddon.

Four guys doing something kooky-that sounds like a teen-hormone romp. But the Space Cowboys quartet has been alive for a cumulative 261 years, and in films for 156. They're too mature to fiddle with bra straps or play with pastry. Besides, Eastwood is a gentleman of sorts, so-except for displaying the four men's naked behinds, which is quite an archaeological sight-he will embarrass neither them nor us. Directing from a script by Ken Kaufman and Howard Klausner, he finds fresh breezes in familiar vectors: the residual rivalry of Frank and Hawk, the tensions between the ancient astronauts and the modern ones, the impact of decay and disease on minds that are still bright, wills that are still strong.

For its first hour, this is an engaging rite-of-passage comedy for the Grumpy Old Men set. When the men go into orbit, so does the film. It blends tension and emotion, computer wizardry and dramatic skill in a vigorous climax-and the most impressive, haunting final shot of the movie year.