Five Billion Years of Solitude (27 page)

Kasting stopped walking, and stood silently twisting the grass to shreds between his fingers. “I would say this bears on at least one of the terms in the Drake equation, the fraction of planets that develop intelligent life,” he finally said, once again putting one foot in front of the other. “Whether through limitations of biology or in the geophysical evolution of the planetary environment, it took the first half of Earth’s lifetime to develop complex life. Intelligence has only now appeared at the halfway point in the Sun’s ten-billion-year lifetime, and it won’t be easy to hang around longer than another half-billion years. That’s a legitimate reason to think things like us are rare. People have called me an opponent of Lovelock’s Gaia hypothesis because I helped find an abiotic way to stabilize climates, but I’m more of a critic. It’s clear that life does alter its environment and can modulate climate to its benefit. It’s also clear that life can throw the climate out of equilibrium. It’s all a matter of perspective. Life caused the rise of oxygen, which probably caused runaway glaciation. That’s not Gaian. But then again, the rise of oxygen led to us. It’s probably a mistake to say there’s any kind of purpose in this, but if Gaia could be said to have a purpose, the evolution of higher forms of life, of humans, could be it. And that’s because humans in principle could postpone this planet’s demise and extend Gaia’s reach far beyond Earth. Intelligence and technology could prove to be more powerful than the cyanobacteria. You could call me a techno-Gaian. We probably can’t prevent the Sun from getting brighter, but we could still protect the Earth. The Sun will be a problem in hundreds of millions of years, but if we maintain our progress, within only a century or two we should be in a position to counteract a brighter Sun by making some type of solar shield, maybe orbital clouds of little mirrors to block a fraction of the sunlight from hitting the planet. If we don’t destroy ourselves or destroy the planet in other ways, we could protect the Earth for potentially billions of years. Why wouldn’t we? We don’t want to cook.”

“You don’t think we’re destroying ourselves or the planet right now?” I asked. We had reached the lake’s far shore without seeing
another human being. With a sudden heavy roar, a white Ford F-150 pickup truck crested over an adjacent sloping gravel road that ran through the lakeside hummocks, its spinning tires pinging pebbles like buckshot into the trees and underbrush. Three startled cottontail rabbits broke from cover and bounded deeper into the woods.

Kasting frowned and tossed the torn grass on the ground. “I lose sleep over what we’re doing as a species right now. It’s not just the climate, either. We’re squandering Earth’s resources. We’re doing terrible things to biodiversity. I have no doubt we’re living in the midst of another major mass extinction of our own making. I take what little comfort I can from knowing we probably can’t drive life itself to extinction or push the planet into a runaway greenhouse. The carbonate-silicate cycle will erase the fossil-fuel pulse in a timescale of a million years, and then the long decline of atmospheric CO
₂
will continue. If we knew better, we’d hoard all the oil and coal and gas for when the planet really needed it. There’s easily enough fossil fuel for us to raise the planet’s temperature by ten degrees Celsius and make the Earth as hot as it’s ever been in the past hundred million years, maybe longer. We could probably make the Earth the warmest it’s been since the Archean. That would melt the ice caps, and we might lose twenty percent of continental land area to rising seas. Equatorial regions could become essentially uninhabitable, because many agricultural crops there are already quite near their heat-tolerance limits. Half the world’s population could be displaced. Populations would shrink, and move poleward. Billions of human lives would be lost. . . . But technology keeps progressing. Maybe the global economy will recover in twenty, thirty years. Maybe we’ll figure out reasonable ways to reverse or counteract some of the worst effects of climate change. Maybe we will end up building and launching a TPF, and whatever it finds will make us better appreciate our own planet. I think there’s still time.”

Aberrations of the Light

T
he sky was hazy and overcast above Cape Canaveral, Florida, on the morning of July 8, 2011. A light breeze from offshore was the only respite against the sticky summer heat for the estimated 750,000 people who lined the beaches and coastal causeways surrounding Kennedy Space Center. They were there to say goodbye, awaiting the launch of NASA’s space shuttle
Atlantis
into low Earth orbit and into history as it embarked on the final flight of the thirty-year-old space shuttle program.

As the final countdown commenced, the shuttle’s last commander, Navy captain Chris Ferguson, contemplated the program’s end with the mission’s launch director, Mike Leinbach. “The shuttle is always
going to be a reflection of what a great nation can do when it dares to be bold and commits to follow-through,” Ferguson radioed from his seat astride the eighteen-story-tall, 4.5-million-pound shuttle stack—the orbiter, side-mounted to a hulking rust-colored external fuel tank and flanked by twin white rocket boosters. “We’re not ending the journey today, Mike, we’re completing a chapter in a journey that will never end.”

Ferguson, like many before him, was echoing the core sentiment of the reclusive philosopher Konstantin Tsiolkovsky, the father of modern rocket science, who, from a remote log cabin in fin de siècle
Russia, wrote passionately about space exploration and a human destiny amid the stars. Around the time that Orville and Wilbur Wright were pioneering powered flight at Kitty Hawk, on the other side of the planet Tsiolkovsky was theorizing about launching multistage rockets into orbit, living and working in outer space, and someday escaping the solar system. He famously devised what is now known as the “rocket equation,” a single mathematical formula that encapsulates all the key variables affecting a rocket’s maneuvers. Later luminaries like Germany’s Wernher von Braun and Russia’s Sergei Korolev cited Tsiolkovsky as influential in their pursuit of rocketry to explore and expand into space. In one of his early papers, Tsiolkovsky laid out the visionary impetus behind his work: “The bulk of mankind will probably never perish, but will just keep moving from sun to sun as each becomes extinguished. . . . There is thus no end to the life, evolution, and improvement of mankind. Man will progress forever. And if this be so, he must surely achieve immortality.” Often implied but rarely explicitly acknowledged today for fear of cynical ridicule, this vision of an unbounded future beyond Earth remains the purest and most noble purpose behind any human space program.

“I still have dreams in which I fly up to the stars in my machine . . . ,” Tsiolkovsky reminisced a decade before his death. “It should be possible to go into space with such devices, and perhaps to set up living facilities beyond the atmosphere of the Earth. It is likely to be hundreds of years before this is achieved and man spreads out not only over the face of the
Earth, but over the whole universe.” Because of the seeming remoteness of his visions from the world in which he lived, Tsiolkovsky considered himself almost a failure, writing when he was sixty-eight that “I have not accomplished much and have not had any notable success.” Tsiolkovsky died in 1935, still believing the conquest of space to be centuries in the future. Had it not been for World War II, he might have been right. But just over two decades after his death, Russian and American satellites were orbiting the Earth, the progeny of military spending on nuclear warheads and ballistic missiles.

Moments after Ferguson channeled Tsiolkovsky at Cape Canaveral, the shuttle’s engines and rocket boosters surged and crackled to life, pushing
Atlantis
and her crew skyward on a quivering cataract of golden flame and electric-blue shock diamonds. The thunderous roar of its ascent swept over the surrounding scrubby marsh flats for one last time, attenuating over distance so that the farthest onlookers saw the shuttle launch in ghostly silence.
Atlantis
rose above the launchpad, rolled into an arcing trajectory bound for the International Space Station (ISS), and slipped beyond sight through the low veil of clouds. As the shuttle soared on a final flight into the heavens, it left behind a space program fallen into quiet decay: NASA lacked a ready replacement for the shuttle fleet and was scaling back programs across the entire agency. For years to come it would possess no direct capability to launch humans into space, and its science missions would be in retrenchment.

The shuttles had been conceived in the technological ferment of the successful Apollo missions to the Moon. As part of a larger twenty-year plan to build lunar outposts and send humans to explore Mars, NASA’s top brass had pushed for funding to develop spacecraft that could launch like a rocket, rendezvous in orbit with robotic satellites and crewed space stations, then glide back to Earth through the fires of reentry to land like a plane at spaceports around the world. Unlike the gargantuan
Saturn V
rockets that were used once then discarded on the way to the Moon, such a system would in theory be fully reusable,
creating an economy of scale to reduce launch costs, which at the time were higher than $10,000 per kilogram. The space shuttle was sold as a revolutionary spacecraft that would fly again and again, perhaps once a week, making space travel cheap, frequent, and routine. The wide, wondrous expanse of the solar system would be thrown open to human curiosity and ingenuity. Lunar bases and human explorations of Mars would be only the beginning of an incredible journey to the stars.

Instead, President Richard Nixon balked at the projected expense of NASA’s grand plans. To ensure the agency would not pursue bases on the Moon and bootprints on Mars, he dramatically cut its funding and scrapped the Saturn rocket program. Perhaps because its focus was on making space travel more economical, the shuttle was the only piece of NASA’s plan to survive, albeit in diminished form. Its goal of full reusability was scaled down to a “semi-reusable” design that was cheaper to develop but more expensive to operate. Even so, the shuttle’s development required more money than a reduced NASA could provide, money that NASA found by appealing to the military’s need for launching and intercepting spy satellites. In exchange for its support, the Pentagon insisted on changes—a more spacious cargo bay, a heavier thermal protection system, and larger delta-shaped wings—all of which ramped up the shuttle’s complexity, cost, and risk.

The chimeric vehicles that finally emerged were elegant, versatile, and irreparably flawed. Instead of achieving 50 flights per year as originally projected, the entire shuttle fleet collectively flew 135 times during the program’s thirty-year lifetime. The shuttles lofted payloads to orbit at a cost estimated anywhere between $18,000 and $60,000 per kilogram—more expensive than the expendable launchers they were built to replace. The shuttle program’s failures came in part from the fact that many of its “reusable” components required extensive refurbishment by a small standing army of technicians after each flight. They also came from the shuttle’s inescapable operational risks, which led to the tragic losses of two orbiters and crews. Space shuttle
Challenger
exploded shortly after launch in 1986 due to a sealant failure in
one of its boosters, and the
Columbia
disintegrated during reentry in 2003 after a piece of foam insulation punctured a wing. Politically driven compromises made early in the shuttle design process proved to be major factors in both disasters.

The total cost of the program has been estimated at $150 billion, with a similar amount spent on its signature achievement, the ISS, a massive orbital laboratory that the vast majority of Earth’s scientists did not want and could not use. For a time, the shuttles and the ISS collectively consumed nearly half of NASA’s total budget, all while offering only the slimmest fraction of scientific returns in comparison to drastically less expensive robotic exploration. The most useful research to emerge directly from NASA’s shuttle-era human spaceflight program only involved astronauts as test subjects, in experiments measuring the effects of prolonged space flight on human beings. Of course, the value of such research vastly diminishes without a capability to visit new destinations and perform meaningful work once off-world. Saddled with the financial strain of operating the shuttles and building the ISS, NASA saw its once-bold vision for a human future in space become a literal path to nowhere, in which astronauts looped endlessly around low Earth orbit waiting for their bones and muscles to waste away in microgravity. In nearly every aspect, the shuttle program was a ruinous white elephant that failed to deliver on its most crucial promises.

The lone exception was arguably the shuttle program’s role in the Hubble Space Telescope, a school bus–size robotic observatory that was delivered into low Earth orbit by the space shuttle
Discovery
in 1990. After initially being proposed in the 1940s by the American astronomer Lyman Spitzer, the Hubble had been conceived and funded around the same time as the shuttles, and had taken decades and upwards of $2 billion to construct and launch. Its snug fit in a shuttle’s cargo bay was not coincidental, as the telescope’s design was derived from some of the same spy satellites the shuttle had been built to carry. It was not the first space telescope, but it was for its time by far the largest, with a 2.4-meter primary mirror of aluminized, precision-polished
ultra-low-expansion glass—an almost eight-foot-wide eye above the sky. Above the Earth’s atmosphere, Hubble’s big eye would not have to contend with shimmering layers of turbulent air that muddied and distorted celestial light. It promised to revolutionize all of astronomy with the unheralded clarity and sensitivity of its observations.