Suddenly talk of space exploration is back in the headlines–more or less. But rather less than more, I’m afraid.

It’s been pretty slow slogging out on the space frontier these past five years. We did send the space shuttle up pretty regularly for a while, but those missions, which never were intended to get very far from Earth in the first place, seemed merely to be going through repetitive activities, and then the whole enterprise came to an ugly halt when the shuttle Columbia exploded in flight last year as it was making its landing approach. As of now no resumption of shuttle flights has been announced. And the sixty billion dollars International Space Station, understaffed and with no visible scientific program in pro-gress, seems to be, well, just spinning its wheel.

As for lunar exploration, no one in NASA seems to be even thinking about doing that any more. Who could have imagined, back there in 1969 when Neil Armstrong was coming down the ladder of Apollo XI to take that first small step for a man on the surface of the Moon, that manned lunar exploration would stop in its tracks a couple of expeditions later? Here we are, thirty-five years later, and the excitement of following a spaceship from Earth on its way to the Moon is something that only us older folks remember. For the rest of you–including, I suspect, about half the readers of this magazine–the landings on the Moon are something out of ancient history, the way the assassination of President McKinley was for me when I was a high-school student fifty-odd years ago. I’ve just been looking at an article by a NASA official in the 1970 almanac that predicts the imminent "establishment of a semipermanent lunar base, housing six to twelve men who would rotate home at six-month intervals. . . . By the 1980s a lunar base might be established that could support eighteen to twenty-four men for as long as a few years. By the turn of the century, a fifty- to a hundred-man lunar colony is possible." Well, the century has turned, and that colony on the moon remains something out of a Heinlein novel. We don’t seem to hear anything from NASA about lunar colonies any more.

Such space exploration as has taken place has involved unmanned vehicles that go off somewhere and either do or don’t succeed in sending back anything valuable. Most of them arouse no public interest whatever, or at best just a little, and not for very long. Pretty pictures of the moons of Jupiter and Saturn may give a thrill to the likes of Larry Niven and Joe Hal-deman and thee and me, but for the general public they’re just a one-night wonder on the evening news, with none of the impact that a manned expedition used to create. We don’t even know the names of the vehicles that go forth these days. Do you remember, you oldsters, how well we knew the names of all the early space probes and satellites? There was Sputnik, of course–no one who heard the news of Russian space success that day in October 1957 will ever forget it. Vanguard, Explorer, Discoverer; Pioneer III, which discovered the Van Allen layer in 1958, and Pioneer IV, which went zooming past the Moon the following year and took up a solar orbit, and Mariner II, which got within twenty-one thousand miles of Venus in 1962, and Ranger and Surveyor and all the rest. But we take space for granted nowadays. Like many of you, I subscribe to a satellite-based television service. HBO and Showtime and PBS and CNN come to me from an orbiting gizmo somewhere beyond the stratosphere, just as the writers for Astounding Science Fiction said they would back in 1942. Do I know the name of the satellite that beams the pictures my way? Do I know who launched it, or when? No and no and no.

Only the biggest of space spectaculars get our attention, now, and those have been few and far between of late. Recently, though, there have been stirrings of renewed interest in space exploration, with much of the talk involving our red neighbor Mars. Mars has been the center of fascinating speculations since the nineteenth century, when the Italian astronomer Giovanni Schiaparelli discovered long grooves that he called canali–"channels"–on the Martian surface; canali can also mean "canals," though, and the widespread assumption grew that Mars, even then known to be a desert planet, was crisscrossed with the irrigation canals of an intelligent alien race. One of the most vocal proponents of this theory was the New England astronomer Percival Lowell, who argued that Mars not only was inhabited, but that the Martian civilization was older and more advanced than our own. By the turn of the last century H.G. Wells had given us The War of the Worlds, the prototypical invaders-from-Mars novel, and from 1912 onward Edgar Rice Burroughs, who would become famous later as the creator of Tarzan, spawned about a dozen swashbuckling adventure novels involving an Earthman, John Carter, among the desert tribesmen of Barsoom, as the Martians call their own world –a fantastic place of ferocious swordsmen of various races with green, black, or yellow skins and lovely princesses who, although they reproduced by laying eggs, were mysteriously interfertile with Homo sapiens of Earth. And as recently as 1938 Orson Welles’s radio adaptation of the H.G. Wells novel convinced millions of Americans that invaders from Mars had actually landed near Trenton, New Jersey.

Well, no one today expects Martians to invade us. But the planet is full of mysteries. There seems to be ice there; is there any liquid water? Are there any algae or bacteria? Was there once enough water on Mars to support higher forms of life? We do wonder. Mars can offer vital information about the origin of life and, perhaps, about how a world’s life comes to its end. But most recent attempts to get answers to these problems have ended in failure. The Mars Climate Orbiter vanished in September 1999 as it was about to land. The Mars Polar Lander and its two probes likewise made inexplicable disappearances three months later. We did get the plucky twenty-four-pound Pathfinder Rover down safely in 1997, and millions of us delightedly watched it scuttle around some forbidding desert landscape, but that was the only such success of recent times, and the Pathfinder’s path took it over only 328 feet of the Martian surface. As I write this in the opening days of 2004 a new three-pronged attempt to land robot explorers on Mars is approaching its culmination. One of the three prongs, Europe’s Beagle II, is already bent, but Spirit, the first of two American roving landers, did make a safe landing in Gusev Crater near what looks like an ancient lakebed and is sending back color photos already. The fate of the other, Opportunity, will be known a couple of weeks after I turn this column in.

And just yesterday–though it will be months in the past when you read this–President Bush lit a firecracker under the sleepy NASA bureaucracy with a stirring call for dramatic new American space ventures in the decades ahead. He proposes relegating the shuttle program to history within the next six years and designing a new vehicle capable of ferrying astronauts to a permanent lunar base that will serve, eventually, as the takeoff point for manned expeditions to Mars. In the past thirty years, he said, no human has ventured more than 386 miles into space, roughly the distance from Washington to Boston. "It is time for America to take the next step," he said.

This should come as no surprise. The first President Bush, after all, called for a manned landing on Mars in 1989, to mark the twentieth anniversary of the first Apollo lunar landing. That notion never got anywhere, mainly because of budgetary concerns; but, as we have seen in other contexts, the second President Bush sometimes has a way of finishing the work that his father left undone.

Can we send a manned expedition to Mars? Should we?

The issue of expense arises, and also that of the impact of such a long mission on the physiology of the explorers. They will absorb punishing radiation during the long trip unless properly shielded, and a prolonged stay in space of that sort will jeopardize their bone mass as well. But Dr. Robert Zubrin, founder of the space-advocacy group called the Mars Society, thinks we need to attempt it rather than settle for being confined to our home planet for all the rest of eternity; that we can do it at a cost of no more than forty billion dollars or so–chicken feed, in current Federal budgetary terms; and that a way can be found around the physiological issues and other technical problems. His idea involves a series of stages, beginning with unpiloted vehicles. The first to set down on Mars would be parked there to be used as the return vehicle for the explorers; later vehicles would bring supplies, tools, prefabricated habitats, and fuel for the eventual trip home; finally the explorers themselves would arrive for a prolonged stay in which they would experiment with developing ways to live off the land on an indefinite basis. Cute little robotic Rovers can discover a great deal, but only actual ambulatory human scientists can exercise the sort of on-site judgment that we need here. And, of course, consider the tremendous worldwide interest that the sight of human spacefarers walking around on the surface of the red planet would engender.

Timothy Ferris, another space advocate, also looks favorably on the idea of a Mars expedition, but thinks we should return to the Moon first, setting up a station there where our astronauts can master the techniques of living for months or years on another world before making the longer jump to Mars. Fuel for a future Mars expedition, and perhaps metal to be used in the construction of a Mars habitat as well, could be mined on the Moon and stored in orbit, a much cheaper proposition than lifting it all the way from our high-gravity planet. And the whole thing could be paid for by setting up solar-power collectors that would ship electricity via tightly focused microwave beams to consumers on Earth.

But will we go back to the Moon before long? Will we dare to venture onward to Mars? Or will we continue to limp along with a token space program of shuttle flights to a space station that is quite literally going nowhere and the occasional launching of underfinanced and undersized unmanned probes that often fail to reach their destinations? Already the political objections to a Mars mission are being raised–"We need the money for social programs right here"–and a long, grinding battle lies ahead as space advocates try to convince their opponents that it is possible for a government to spend money on other things than Medicare and social programs. (In the 2004 Federal budget, 34 percent of the cash goes for Social Security, Health and Human Services, the Labor Department, etc., and just 1 percent for NASA. This may be wholesome and heartwarming but it is also terribly unimaginative: a society that spends its money only on its own comfort is one that is turning in on itself in a dangerously self-centered way.)

Meanwhile, next month, I want to look beyond the basic idea of once more sending astronauts to the Moon, or even to Mars, and talk about some very much farther-out proposals for the renewed exploration of space.