At the helm is Mimi Leder, who won an Emmy for the famous “Love’s Labor Lost” episode of ER. Here, she attempts to blend action and apocalyptic sequences with small stories of people in desperate circumstances. Most of the time, it works.

Unlike other recent end-of-the-world pictures such as Independence Day, Deep Impact addresses the issue seriously, without winking at the audience. The premise on which it is based is not science fiction at all; just a few months ago – until astronomers hastily refigured their calculations – we thought our planet was facing this exact situation. And though we dodged the bullet that time, a comet will collide with Earth at some point in the future. So Deep Impact tries to enact a plausible scenario for how we’ll deal with this crisis, with science that holds together if you don’t examine it too closely.

In the United States, the government’s response is to hope for the best and prepare for the worst. As President Tom Beck, Morgan Freeman inspires confidence. He’s grave yet kindly and he lays out the facts without raising false expectations. He makes it clear that there will be no doomsday profiteering or looting. “Work will go on,” he tells the American people. “You will pay your bills.”

In secret, the feds have been building a spacecraft called Messiah that will try to detonate warheads on the comet to deflect its course away from Earth. But if that doesn’t work, vast underground bunkers are being dug into the caves of Missouri, enough to hold 2 million people. Those with special expertise and knowledge vital to the country’s survival are selected, and the rest are chosen at random from the population. The catch: Only those under 50 will be drawn for the lottery, presumably because adults of child-bearing age will be needed. This government-playing-God maneuver is accepted with remarkable passivity by the public; you’d think there would be more social unrest, which the movie doesn’t show enough of.

Panicked citizens brace for cataclysm in Deep Impact.

Instead, in typical ER fashion, it dwells on several individual stories, some less interesting than others. When the action drags, the film is rescued by an amazing cast of actors. Robert Duvall has a humanizing role as an old astronaut – the last guy to walk on the moon – who is brought back to command the Messiah mission. Among the younger crewmembers, Mary McCormack is a standout as the shuttle pilot. Elijah Wood, one of the best child actors of the Nineties, has matured into a teenage heartthrob and is still doing fine work. James Cromwell makes the most of his cameo. Vanessa Redgrave, on the other hand, is wasted in a depressing role.

The single worst mistake in Deep Impact is the gross miscasting of Tea Leoni as a TV reporter. No network exec in his right mind would ever hire this colorless girl as an anchorwoman. Leoni is utterly lacking in warmth, humor, or charisma. She has all the effervescence of a schizophrenic doped up on Thorazine. Her voice is an inflectionless drone, her personality a cipher, and her hair looks like she cuts it herself with a kitchen knife. She’s not someone you’d look to for reassurance as the apocalypse approaches. Indeed, she’d have you reaching frantically for the remote to erase her from your TV screen.

But aside from this one misstep, Deep Impact is fairly well done. Though it’s not a special-effects-heavy film, there are two notable sequences. The landing on the comet’s surface is unusual, something that’s never really been depicted in movies before. And the tidal wave that inundates the Eastern seaboard is way cool – worth the price of admission.

Like Titanic, this film tries to balance out the disaster-epic thrills with intimate moments. Sometimes it descends almost to soap-opera level (especially in any scene involving Leoni and her boring family), but there are some instances of courage and sacrifice – particularly among characters whom we’ve come to know well enough that we’re saddened by their loss – that are genuinely moving.