In Outland," writer-director Peter Hyam has adapted the plot of" "High Noon" to an intriguing sci-fi environment -- a huge titanium mine located on Io, a volcanic moon of Jupiter.

But the conventions that worked for "High Noon" break down in the high-tech atmosphere of "Outland" and the story seems trite and dinky.

Sean Connery inherits the Gary Cooper role, playing a grizzled, solitary marshal who uncovers a murder conspiracy soon after arriving for a year's tour of duty. The evidence points immediately and exclusively to the mine's general manager, played by Peter Boyle. Failing to buy off the the incorruptible new lawman, Boyle puts out an emergency call for two gunmen, who arrive 70 hours later on the weekly shuttle and proceed to stalk Connery around the rooms, corridors and superstructure of the mine.

Hyams miscalculates in several respects. The compact setting of the frontier town in "High Noon" is lost in the serpentine depths of the Io mining town. It looks as if the antagonists could walk for months without crossing paths. Futhermore, watching a big digital clock tick off the microseconds from 70 hours isn't quite the same as sweating out the minutes in "High Noon."

Instead of being amusing, the anachronistic elements are merely stale. Like Cooper, Connery is portrayed as a lawman abandoned by his deputies and the community he's sworn to protect. Like Cooper, he is given a runaway wife. However, Cooper's domestic tribulations always seemed superfluous once he strode out to confront the bad guys. The same action-movie imperative applies here, so Connery's unhappy, sniffly spouse (Kika Markham) is excess baggage.

Moreover, the marshal in "Outland" has access to an electronic security system that appears to give him decisive advantages over the opposition. For example, he calls up a tape of the very transmission in which Boyle ordered assassins from a company rep at the nearest space station. You wonder what prevents Connery from isolating the gunmen the moment he sees them stop in a corridor to put their weapons together. His deputies turn out to be cowardly or treacherous. This issue is even more peripheral in "Outland" than it was in "High Noon," where the portrayal of the townspeople as craven cowards always seemed expedient anyway. "Outland" might have been more fun if Hyams had given the hero robot deputies who could be trusted.

The functionaries you really begin to feel for are the unsung janitors who must have to clean up the blood and gore left by all those exploding bodies. An entire greenhouse is obliterated before the marshal gets his men.

It's peculiarly self-defeating to take the attitude that Io is such a godforsaken outpost that only sheer desperation or greed would attract anyone there. The very idea of this mining operation still belongs to the realm of fantastic speculation, and the strongest pictorial aspects of the movie enhance one's curiosity about the way things might look and work on a space station. "Outland" is sustained by entertaining decor and props, like the diagnostic computer operated by Frances Sternhagen as a crusty medic who takes a shine to Connery, or the back-projection golf game that preoccupies Boyle, an otherwise phlegmatic villain.

Hyams seems to think that his recycled plot counts for more than his novel setting, but he's got things backwards. The inescapable fact is that he lacks the right stuff for the outlands.