I'm writing this just a couple of days after the Columbia shuttle disaster, which of course will be old news by the time this reaches print, the magazine production process being what it is. Before you get to read this, we will already have been through a long, dreary business of explanations, recriminations, Congressional inquiries, and demands for a rethinking of our entire space-exploration program. There will have been, I’m sure, a moratorium on further shuttle flights while all this work of inquiry is going on, and a general hold on all NASA projects will probably still be in effect when this piece is published.

The most profound short-range effect, surely, will be on the astronaut program. Even today, barely forty-eight hours after the shuttle exploded over Texas, the lead article in the Wall Street Journal bears the headline, "Shuttle Crash Raises Questions About Future of Manned Flights," and begins, "Why is America still sending men and women into space?"

I hope I’m simply preaching to the converted here when I reply that the answer to the Journal’s question, "Why?" is a simple "Why not?" A NASA flight controller quoted by the Journal gives a somewhat more elaborate answer: "The human race has been about exploration since it crawled out of the swamps on four legs. If you’re not exploring, you’re dying."

Makes sense to me, and probably to most of you, who wouldn’t be reading science fiction if you didn’t think the exploration of the cosmos was a worthwhile thing to do. But not to a substantial number of Americans who are asking, this morning, why we continue to risk precious human lives on something as remote from immediate everyday needs as trips into space, when robots and sensors could do the job just as well. (There are also, of course, plenty who are asking why we are bothering to spend money on space exploration at all, when there are so many dire problems still unsolved on Earth, etc., etc. A letter published today in the New York Times declares that the best possible outcome of the disaster would be the scrapping of the manned space program and the shifting of the billions of dollars thus saved to improving the science programs in our public schools. The best I can do in dealing with such remarks is to refer the anti-space people to the remarks of the NASA controller I quote above, and let them try to refute them. School science programs would not be well served by a curtailment of such a dramatic form of scientific research as the exploration of space.)

But this issue of risk–

We have become, it seems, a risk-averse nation. Last year’s controversy over smallpox vaccination is a good example: until a generation ago, everyone was routinely vaccinated against smallpox in childhood, and, since smallpox thereby was driven from the world, vaccination was universally regarded as a Good Thing. Suddenly it has been made to seem terribly risky, and people are shrinking back in horror from the thought of submitting to it. Likewise, the expenditure of human lives even in the name of national defense is a controversial issue now, which is why we used local troops instead of our own when we were hunting Osama bin Laden in the mountains of Afghanistan in 2001, and why our earlier attempts at striking out at terrorist camps were conducted by high-flying planes and guided missiles instead of actual battalions of troops. We had scarcely any casualties in those various remote-control military campaigns, but also we accomplished very little of what we had hoped to achieve. Sometimes risk is necessary; sometimes lives have to be lost in the process of attaining important ends.

I don’t like taking risks much, myself. I’m just a writer, not any kind of hero, and I wouldn’t volunteer to take a ride in a space shuttle, any more than I’d like to be fighting in Iraq just now. (Isaac Asimov, for whom this magazine was named, wasn’t much of a warrior either, and wouldn’t even travel in an airplane.)

Spaceships weren’t meant to be piloted by timid people like Isaac and me, nor are battles won by the likes of us. But there are plenty of braver people around–like the seven Columbia astronauts–who have a different attitude toward risk. And we should not bar their way.

It is necessary, naturally, to distinguish between sensible risks and stupid ones. One good reason why we don’t send manned expeditions to Jupiter is that an expedition that landed on Jupiter would have a non-debatable 0 percent chance of survival: Jupiter is a huge ball of nasty gases, with a massive hard core underneath that exerts a gravitational pull of enormous intensity. Any manned landing on Jupiter would be, in al-Qaeda’s fascinating phrase, "a martyrdom operation." Nor do we yet even contemplate sending a spaceship of human observers on an orbital voyage around Jupiter, because such information as we have gathered so far from three and a half decades of manned space exploration indicates that weightlessness for the period of several years such a voyage would require would have serious debilitating effects on the voyager’s skeletal structure.

We do know, though, that manned voyages to Mars, where gravity and a lethal atmospheric blanket would not be problems, would be possible using existing technology. Nobody’s talking about doing it, because NASA says the cost of such a mission would be upward of half a trillion dollars, but because we have kept astronauts aloft for periods of time approximating the length of a Mars voyage we know that humans could make the trip without suffering undue bodily harm. The astronauts who stayed up there for those long-term tests understood that risk was involved. But they stayed, and their bones did not turn to Jell-O during their months in space, and now we know. Their courage laid the foundation for the next phase–however far in the future it now lies–of manned space exploration.

Those astronauts saw what they were doing as a sensible risk, with much to gain from success and a reasonable probability of avoiding calamity. So did the ones who perished in our two shuttle disasters. Discovery is always a gamble. Columbus made it back alive from his journey to the West Indies, but Magellan didn’t survive his historic voyage of circumnavigation; Captain Cook also died at sea, but not before he, like Magellan, had ventured deep into unknown waters and vastly increased our understanding of our planet’s southern hemisphere. Many another explorer took similar gambles and lost–but it was the rest of us who gained from their sacrifices.

If we look at the early history of aviation–the dawn of manned flight–we see a horrendous record of human casualties. Orville and Wilbur Wright were the first to fly a mechanically powered heavier-than-air vehicle, traveling 852 feet in 59 seconds and landing safely. That was in 1903. It was not until five years later that the first airplane fatality occurred, when Lieutenant Thomas Selfridge of the U.S. Army Signal Corps, flying as Orville Wright’s passenger, was killed when a propeller malfunction caused the plane to crash. (Wright survived.) But then, as aviators began to attempt more elaborate exploits, the fatalities came thick and fast. In 1909 a French aviator, Eugene Lefebvre, was killed while flying a Wright plane. Edouard Nieuport, who designed the first workable single-wing plane, died in a plane crash in 1911; his brother Charles met the same fate in 1913. Charles Stewart Rolls, in 1910 the first aviator to make a round-trip flight across the English channel, died a month later while competing in an air race. George Chavez, who made the first flight over the Alps the same year, died as a result of injuries sustained while landing. John B. Moisant, who accomplished the first Paris-London flight in September, 1910, died a few months later while flying at New Orleans. Eugene Ely, who in 1910 took off from the deck of a cruiser anchored in the Atlantic and flew to land, and two months later set out from San Francisco and landed successfully on the deck of a battleship in the Pacific, thus making the first ship-to-shore and shore-to-ship flights, was killed in another flight soon after. Harriet Quimby, the first American woman pilot and the first woman to fly the English Channel, in 1912, died three months later while flying over Boston Harbor. And so on and so on–a lengthy tragic roster of pioneer mortality.

Since aviation was obviously so dangerous, it was banned by international treaty in 1913, right? Which is why American science fiction fans will have to make a five-day-long sea journey in 2005 if they want to get to the World Science Fiction Convention in Glasgow, Scotland, and why you will take the train from Atlanta to Phoenix to visit your parents next Thanksgiving.

Were the early aviators crazy to take the risks they did? No. Were they enormously brave? Absolutely. The brave shuttle astronauts weren’t crazy, either. They measured the risks against the rewards, and made a decision to go. (The odds were with them, too. We have had only two catastrophic failures in 113 shuttle flights. Going up in a rickety 1910 airplane was far riskier than that.)

The problem today is the national notion we have developed that Risk Is Bad, and, since space flight currently is a government monopoly and government officials don’t like to upset the voters, we must now go through a vast therapeutic process of inquiry and reassurance before the dreadful risks of manned space travel can be allowed again. The aviators of 1910 were free to put their own lives on the line without taking public-opinion polls.

I know there are many who think we can continue our space program using nothing but robots and computers. "Manned space flights are more about capturing the public’s imagination than science," one space historian has already said. "It’s circus, it’s just pure circus." Maybe so; but I don’t think capturing the public’s attention with romantic acts of bravery is always such a contemptible thing. Nor do I believe unmanned exploration is the right way to do the job. In the end, human perceptions, human decision-making, human descriptive abilities, are what will serve as the goads that get us out into the universe, not readouts from sensors, probes, and robot eyes.

Of course manned flight into space is going to get started again, sooner or later, once the current anguished debate dies down. (For one thing, the expensive international space station now up there can’t function without humans aboard. Do we just write it off? For that matter, who’s going to rescue the three astronauts currently living there?) Space flight will resume under NASA auspices after a time, or it will start up through private financing. (Or even that of some other country. What a nice public-relations coup for twenty-first-century China to put the first astronauts on Mars!) But how sad that the issue of continuing into space should arise at all, simply because seven brave explorers lost their lives. To shut down manned space flight because it is too risky would be to say that those seven died in vain. It’s the first step in a path of de-evolution that will take us back to those swamps.