For Americans the rise of the machine had begun in the previous century, when steamboats, the telegraph, and the railroad turned a far-flung continental population into a networked society. By making the automobile affordable in the early 1900s, Henry Ford had turned that relationship into a love affair, especially for the tinkering, tool-mad American male. And yet like any love affair, the relationship was vexed: unlike steam engines and automobiles, whose parts and motions were visible, the new electronic machines were smooth, impassive. And with their power came a measure of fear. Consider HAL, the computer interface that was the artificial malevolence at work in “2001: A Space Odyssey” (which premiered in 1968). Director Stanley Kubrick may have understood the menace of the machine as a reflection of our own psyches, but to moviegoers in the Apollo era, the vision was that of a machine run amok.

America’s first manned space missions, the Mercury program, did not improve this image. Although its astronauts came from the test pilot world, mostly engineers, they were powerless strapped inside their capsules - “spam in a can,” as Chuck Yeager calls them in “The Right Stuff.” The Apollo astronauts, partly to avoid this fate, insisted on a capsule that would let them play an active role once they were launched. So NASA engineers devised ways to monitor systems, calculate variables, and navigate and steer from within the spacecraft. The resulting computer programs were something new - a set of tools “embedded” in the machine. Previously, computers were autonomous processing plants to which engineers paid visits when in need of calculating power. Apollo’s computer, by contrast, was linked directly to the spacecraft’s systems and inner workings - and through a new conception, the interface, it linked to the astronauts as well.

The craft the Apollo astronauts rode to the moon was a capsule of contradictions. It was both an engineering marvel and a jury-rigged bucket of bolts; its control systems were contrived to give its astronauts the familiar feel of flight in an environment whose importance was its unfamiliarity. It was a powerful symbol of existential enigma and loneliness that was also the most closely-monitored 200 cubic feet of space in the world. And in all those senses, it was a harbinger of the coming relation with technology.

That capsule brought men back from space for the last time on December 19, 1972. Since then, it is machines, not astronauts, that have fanned out across the solar system and beyond. The Voyager spacecraft, now traveling beyond the edge of our solar system, were launched with engraved images of human bodies to share with alien civilizations. Our first data from Mars came from the square, stolid Viking lander; while the recent Mars rovers Spirit and Opportunity have thrilled millions of people with their plucky, intrepid survival on the brutal planet. Earlier this year, the Japanese lunar orbiter Kayuga even offered a taste of tragedy by capturing HD video of its own demise as it descended toward the moon’s inscrutable surface en route to impact.

Machines can compute but cannot feel; they express our intentions but cannot share our passions. Such has been the understanding, and the dilemma, of modern times. But perhaps we’ve underestimated the machine - which is only another way of saying that we’ve underestimated ourselves. David Mindell, a technology historian at MIT who wrote Digital Apollo, a history of the lunar program’s engineering culture, thinks we’re catching up with the notion that our probes are our avatars, even ourselves, extending human experience to the farthest reaches of outer space. “We’re there!” he said in a recent phone conversation. “The difference is risk and experience{hellip} as we become more invested in virtual presence, the body doesn’t need to be present” for humans to explore the heavens.

Dimly, we’ve begun to realize that as we extend ourselves with tools, we animate those tools with our dreams and desires as well. Whether orbiting the outer planets or connecting us to far-flung fellow astronauts here on Earth, the technology that augments our senses and extends our powers springs from the same curious, tool-making human nature. Perhaps as we probe the reaches of interstellar space, we’ll feel more keenly the extension of our senses by even such abstract and remote tools as these. In the history of human technology, Apollo was a small step; but it was a great leap toward understanding how that technology makes us human. We’re coming to the point where machines may become not only extensions of our senses, but our heroes, too.