The dance of the moon, Venus, and Mars in the western sky after sunset last week had me taking the long view – and not just across the ecliptic plane. For three nights in a row I watched the crescent moon, fat with earthshine, climb past brilliant Venus and fainter, more distant Mars. In my lifetime, human beings and human machines have been to all three places. Little robotic rovers are rambling around on Mars right now.
I wonder now if I’ll live long enough to witness the next giant leap for mankind: a human landing on Mars. It’s a massive undertaking, and it would have to be an international effort. But perhaps it could also be a unifying one.
Mars is an order of magnitude farther away than the moon, and that much harder to get to. It’s also cold, airless, and exposed to harmful radiation from space. But these obstacles could all be overcome in time. The important thing is getting there.
The Earth is now home to more than seven billion people. Collectively, they own and operate some 1.2 billion motor vehicles. Sixty million new cars are built each year, with metals pulled from the planet’s crust and rubber wrenched from its rainforests. Most of them run on fossil fuels, which are probably, at least in the solar system, unique to Earth. There won’t be any fossil fuels on Mars, because there probably weren’t any plants, let alone plant-eating dinosaurs.
The machines we’ve sent to Mars and the other planets come from the same place all those cars do. They are made of Earth-stuff. To go into space, humanity had to first invent heavy industry. Two centuries of heavy industry have begun to change the planetary climate in ways that we are just beginning to see.
But the inner solar system is abundant with materials. And, because of our ability to extract stuff from the earth and turn it into spaceships, we can now get there. Mars is closer to the main body of the asteroid belt, and asteroids are rich in metals. Even the surface of the moon contains usable stuff. The sun provides the energy, which small nuclear reactors could augment. In the future, much of the building material for space missions will come from space itself.
On Mars, if we don’t find any indigenous life, a little man-made global warming might be a good thing. Mars does have an atmosphere, though it’s tenuous and mostly made up of carbon dioxide. But if we could somehow make more air, a small greenhouse effect would take hold and the planet would begin to warm. Subsurface ice would thaw. Lichens and other hardy plants could be introduced alongside industrial sites. Eventually, through a process called terraforming, the air could become breathable – in a thousand or so years.
But what if the process could be sped up by the introduction of cars? From what I’ve seen, a lot of Mars looks like New Mexico, minus the cactus. New Mexico isn’t at all unpleasant to drive through, though it is kind of eerie in its emptiness.
Those places are disappearing on Earth. Seven billion people in more than a billion vehicles can get just about anywhere. But Mars remains largely unexplored. Most of what we know about the place comes from a few friends with wheels: Opportunity, Spirit, and Curiosity.
The car has beaten humankind to Mars. Perhaps the rovers should bear plaques that read: “We came in peace for vehicles everywhere.”
The last man to drive on a world other than Earth, Eugene Cernan, died in January at the age of 82. He and geologist Harrison Schmidt explored their lunar landing site in a rover that looked like a dune buggy. Cernan had piloted the lunar module to within ten miles of the surface in the dress rehearsal Apollo 10 mission, and returned as commander of Apollo 17. When he stepped into the lunar module for the final time on December 19, 1972, it marked the end of an era. Human beings have not been back to the moon since.
But we sure have manufactured a lot of cars. Imagine if we diverted a quarter of that mass and energy to space. We could build space stations and mining ships. We could ensure our long-term future by inhabiting multiple worlds. We could have walkable cities here on Earth, and introduce industry and motor vehicles to Mars, releasing greenhouse gases on a planet where climate change would be welcome.