We can, should we choose, send human beings to Mars. I don't mean the human beings whom we Americans find annoying or tiresome. This is not a suggestion for what to do about the Donald Trump problem.

The point is that, although the technological obstacles are hardly trivial, it should be possible in the next two decades to send astronauts to Mars and return them safely to Earth. The red planet may be tens of millions of miles away, but the simple truth is that you can get there from here.

A Mars mission is not merely a question of technology. It's also a matter of cultural will. Do we really want to do it? Why, exactly, would we go to the trouble of launching fragile human beings on so perilous a voyage? What urge would we be satisfying, and would that be one of our better urges or one of the urges we are supposed to have suppressed? Do we want to go to Mars because it is noble and brave to do so, or because we're incorrigible land-grabbers, obsessed with finding low-priced real estate?

A chance to renew the debate will pop up Friday, when NASA's unmanned Mars Polar Lander will, one hopes, make good on its name. (We should all put out of our minds that little problem a few months ago in which NASA engineers had a mix-up between metric and English units of measurement and flew their Mars Climate Orbiter to its doom.)

A successful landing is certain to be a media sensation. This is as it should be. To land on another planet isn't just a triumph of technology; it allows us, as a species, to share a very rare Galileo moment, so to speak. We have the chance to see something no human eyes have seen before, an immaculate little fragment of the Creation.

Then the big, expansive talk will begin. People will launch into their "destiny" speeches. I expect that while channel-surfing I'll see charismatic aerospace engineer Robert Zubrin, who wants not merely a manned mission but actual colonization of the planet. He favors, through an ambitious program of "terraforming," the creation of a new world that is hospitable to human beings. Zubrin, author of "The Case for Mars: The Plan to Settle the Red Planet and Why We Must," has argued that making Mars our own is hard-wired into our genes; after all, he says, we've been colonizers ever since our first primitive ancestor oozed its way out of the ocean (see Outlook, Sept. 26).

Unfortunately for Zubrin and his allies, American culture has a fundamental problem right now when it comes to ambitious space exploration: We're out of Soviets.

The Soviets were the best thing that ever happened to the U.S. space program. They invented it! The panic after Sputnik (October 1957) led to our incredibly rapid development of space technology, culminating 12 years later with Neil Armstrong's giant leap. But when we lost our anxiety about Soviet domination in space we lost much of the impetus to go to Mars. From a purely practical standpoint, it's hard to make the argument that we need to go winging off into space. In 1989, when President George Bush proposed a vastly expanded space program that included a Mars mission, the bean-counters figured out that the whole initiative might cost something like $450 billion, and Mars once again went on the back burner.

To fire up the American people for a manned Mars mission, a new motivator needs to emerge. Something or someone even more powerful than the godless communists. That entity, as we speak, is stepping forward. Yes, I'm talking about Hollywood.

This March, Disney's Touchstone Pictures will put out "Mission to Mars," a Brian De Palma film starring Gary Sinise. Zubrin and a number of NASA scientists were consultants. I hear that it involves not one but two manned spacecraft going to Mars, which ensures that at least one of them will get into serious trouble and require a pulse-pounding rescue. (Even highly futuristic events must adhere to formula.)

Meanwhile another Hollywood figure is thinking deeply about Mars--James Cameron, Mr. Titanic.

One day this summer I saw Cameron speak at a meeting of the Mars Society on the campus of Caltech, in Pasadena. The Mars Society is made up of people--like Zubrin--who need no convincing about our destiny in space. These are folks who have the surface of Mars memorized, who can sketch on a napkin the geological configuration of Gusev Crater, who have read all of Kim Stanley Robinson's massive novels on the terraforming of the planet from "Red Mars" to "Green Mars" to "Blue Mars."

Cameron may have sensed he was not in his natural Hollywood element, but he plunged ahead, outlining his reasons for making not one but two films about a manned mission to Mars. One will be a five-part miniseries, which is scheduled to air in February 2001, for Fox's TV network. The other is an IMAX film (with Zubrin as a co-producer).

"I believe exploration is ingrained in our soul," Cameron said. He invoked Columbus, and Magellan, and the Polynesians, and Amundsen and Byrd and Shackleton. Cultures that explored were always dominant cultures, he said. "To do this is to survive the next hurdle of evolution. To fail at this threshhold is to stagnate and die."

Mars . . . or death. This is a refrain of the Mars crowd. What a choice.

Cameron is precisely the kind of ambitious, intellectually rambunctious person who is attracted to the idea of colonizing the fourth rock from the sun. The uncharitable observer might think that when you have already made the most successful movie of all time--when you're the "king of the world"--you start looking for new worlds to conquer.

"The key to going to Mars," he said, "is to get the average person to want to do it."

Cameron isn't just trying to make a great film. For gosh sakes he's making this thing for Fox! He's going straight for the Al Bundy fans out there. His "event miniseries" will appear soon after a new president is inaugurated--perfect timing for inspiring a Kennedyesque announcement that we must send a human to Mars.

One person who wants us to go to Mars--and who thinks we will, eventually--is Daniel Goldin, the NASA administrator. Goldin is a fascinating character: brilliant, demanding and impatient to explore the galaxy. He'd like us to travel to Mars and far beyond, perhaps to planets orbiting distant stars. But he's also realistic about the cultural issue. He knows, for example, that the American people need to come to terms with the riskiness of space travel, and with the possibility (though he thinks it's unlikely) that astronauts on a Mars mission could perish.

"It would be irresponsible to say that we could make it bulletproof. There needs to be an open discussion in America about the value of doing it," Goldin told me recently.

And if we do go?

"It will be unbelievable," Goldin said. The two sentences that followed were classic Goldinisms: "It will give us a reason for living. It will touch not just our minds, but our souls."

Goldin is James Cameron-intense. He, Cameron and Zubrin are surely three of the most driven human beings currently occupying the surface of this planet. Goldin's worst-case scenario is that a Mars mission would be seen as a mere stunt, and wouldn't lead naturally to a long-term exploration of the galaxy. "We want to be very careful about not using retrograde technology, and have a brute-force feel-good mission to Mars. We want to have a constant pushing out of the boundary, a sustained presence beyond Earth orbit," he said.

It's true that expansion is a defining feature of life on Earth and, historically, human civilization. Life is hyperadaptable. Life can invade the most bizarre niches of the terrestrial environment, from boiling springs to subsurface muck to the pools of water under the icy lakes in the dry valleys of Antarctica. And humans have, in the past millennium, overrun the planet practically from pole to pole, and are now threatening to spill forth to other worlds.

But the great thing about human culture is that we actually get to choose what we do. We aren't paramecia anymore.

A different vision of the human future, competing with this expansionist, Space Age dream, may emphasize sustainability, the preservation of the environment, the defense of those things that we see as authentic and indigenous and real. An obsessively profit-driven, grasping, greedy civilization may not survive very long, even if it has a second planet to serve as additional turf.

If we go to Mars, we should go for the right reasons. Forget this talk of "manifest destiny." We should go for science, for knowledge, for the chance to find out more about Mars itself. The planet may have had life of some kind about three and a half billion years ago. In fact it could still have life, in aquifers beneath the surface. A trained exobiologist, someone like Chris McKay of NASA, would be far better than a robot at poking around the surface of Mars, extemporizing and figuring out which rock is worth looking under.

My guess is that we will go to Mars at some point. But we shouldn't go because Hollywood tells us we should, or because the true believers have ants in their pants. Human destiny is not a trivial issue, and the debate shouldn't be dominated by the technophiles, the empire builders and the space-crazed.

Mars has hurtled around the sun for billions of years, and will almost surely continue to do so for billions more. Someday, if the Mars-or-bust folks are correct and if our cultural will and technology deem it necessary, Mars could be reengineered into a blue world with a lovely climate and a teeming population of human descendants who call themselves Martians. But on Friday we'll have a chance to see the unreconstructed Mars, a pure, primitive, strange desert world--and perhaps some of us will decide we like it just the way it is.

Joel Achenbach, a Post reporter who writes the "Rough Draft" column for washingtonpost.com, is the author of the just-published "Captured by Aliens: The Search for Life and Truth in a Very Large Universe" (Simon & Schuster).