Between exploration, science, commerce, warfare and even recreation, there are numerous ways to measure progress in spaceflight since Oct. 4, 1957, when the Soviet Union launched the first man-made satellite. That fact alone is a good indicator of how far things have come in 50 years: Space today is a means to many different ends; not an end in itself.

It’s not that people didn’t recognize this would become the case: More than a decade before Sputnik, the visionary science fiction writer Arthur C. Clarke saw the potential for using satellites in geostationary orbit as radio relays, and long-distance communication became one of the early space applications. Military planners, meanwhile, immediately recognized the strategic implications of the Soviet Union’s historic achievement: Then-U.S. President Dwight D. Eisenhower authorized the Corona spy satellite program just a few months later.

But as much as anything, spaceflight in the early days was about conquering frontiers, if for no other reason than winning Cold War bragging rights. The Soviets were the first to launch a satellite and the first to send a person into space, while America eventually could boast that it won the race to the Moon.

Today space-related capabilities are ingrained into everyday life and becoming more so. Whether they know it or not, people rely on satellites for their daily weather reports, television services and credit card transactions. Meanwhile, GPS-based navigation systems and satellite radios are becoming standard equipment on new automobiles.

Space also is an integral component of modern warfare. The U.S. military, in fact, has become so dependent on space capabilities that some see a vulnerability – take away the Pentagon’s satellites and you take away its eyes and ears, not to mention its ability to communicate.

It was a mere 12 years after Sputnik that the United States landed the first astronauts on the Moon. Since then, however, human spaceflight has languished in low Earth orbit; only recently did the United States chart a course for getting back to the Moon – by 2020. This is in part testimony to just what a monumental achievement the Apollo lunar landings were. But it is also true that the triumph of conquering new frontiers – the old flags and footprints argument – has lost the urgency it had during the heat of a superpower competition.

In the last year or so, some U.S. space exploration advocates

have raised the specter of a space race with China in an attempt to rally a largely indifferent American public to the cause. But the reality is that space exploration is increasingly becoming an international endeavor, America’s current go-it-alone strategy for getting back to the Moon notwithstanding. Sending humans out beyond the Moon, to asteroids or to Mars, almost certainly will be done internationally – barring some unforeseen technological breakthrough, no one country has the resources to undertake such missions.

The conquering of new frontiers is now the domain of unmanned satellites that visit other planetary systems and observe distant galaxies as they were eons ago. Science is the primary driver of robotic space exploration, and the more scientists learn about the universe, the more there is to know.

In the meantime, and in the same manner that satellites, television and the Internet have made the world smaller, entrepreneurs have brought space figuratively closer to Earth. For the first 45 years of the space age, space travel was reserved for an elite, government-selected and highly trained few; today, it is available to private citizens with reasonably good health and the ability to write a very large check. Space tourism is a frontier of a different kind, one that is only beginning to be tamed.

In reciting the past accomplishments and future promise of spaceflight, however, one must also take note of the challenges and dangers that lie ahead. Much like Earth, space is becoming increasingly polluted with civilization’s debris. Even more frightening is the possibility that space could one day become a theater – perhaps even a trigger – of global warfare.

China’s destructive test of an anti-satellite weapon Jan. 11 served to highlight the urgency of mitigating the twin perils of orbital debris and space warfare, a task that will only get more complicated as the ranks of spacefaring nations continue to grow. The seriousness with which these countries take this challenge – and by extension their success in meeting it – will in large part determine whether the 75th anniversary of Sputnik is recognized with celebration or regret.