To 21st-century humanity, space exploration feels like a forgone conclusion. We have always looked heavenward, organizing stars into constellations and constellations into elaborate mythologies to explain the natural world and our human condition. Once we slipped the surly bonds of Earth’s gravity, the race was on—to go higher, travel farther, explore ever more distant worlds.
We began with the moon, an obvious first destination that looms large over our psyches and our backyards. It illuminates our nights with its reflected light, pinning our shadows to the ground like specimens on a vast terrestrial display.
Next came Mars, lure of Bezos and Musk, tantalizing in its challenge and its proximity. Then, look! Venus slid into our orbit to pull focus toward her come-hither, brilliant glow.
But Europa? Why Europa? Invisible to the naked eye and all the way out there in Jupiter’s deadly radiation belt? Why, given the cost, distance, and time involved, would humans choose to go to the smallest of the four Galilean moons orbiting Jupiter, especially when Mars and Venus shine bright with such promise?
Invisible to the naked eye and all the way out there in Jupiter’s deadly radiation belt.
For a small group of scientists working to justify a mission to Europa, the answer is simple: water. Fifteen miles under Europa’s outer crust of ice there is believed to be a vast, liquid-water ocean, complete with hydrothermal vents and plate tectonics much like those found on the floor of Earth’s oceans. Europa hints at a potential habitability triad: water, energy, and chemistry. We must explore Europa’s oceans, scientists argue, because maybe, just maybe, hic sunt dracones.
For David W. Brown, author of The Mission: A True Story—How a Disciple of Carl Sagan, an Ex-Motocross Racer, a Texas Tea Party Congressman, the World’s Worst Typewriter Saleswoman, California Mountain People, and an Anonymous NASA Functionary Went to War with Mars, Survived an Insurgency at Saturn, Traded Blows with Washington, and Stole a Ride on an Alabama Moon Rocket to Send a Space Robot to Jupiter in Search of the Second Garden of Eden at the Bottom of an Alien Ocean Inside of an Ice World Called Europa, the romance of a mission to Europa in search of hypothetical dragons (or fish, or single-celled organisms) looms nearly as large as his book’s subtitle.
At nearly 400 pages dense with historical, biographical, and scientific detail, The Mission is not a quick read. That said, Brown is a nimble, gifted writer, downright Dickensian in his pointed descriptions and irreverent humor. His affection for the science and personalities that populate his tale is clear from the first page, where he introduces us to Robert Pappalardo, who would grow up to become a senior scientist on the Europa-mission project.
For a small group of scientists working to justify a mission to Europa, the answer is simple: water.
Pappalardo and his Europa-loving colleagues play a multi-year-long game of chess with Mars fanatics, NASA naysayers, and tightfisted budgetary bean counters. The Europa mission-game is nearly won, then lost, then nearly won, then lost again, until a key discovery is published in Science magazine: Hubble Space Telescope images reveal clear evidence of Europa’s plumes—columns of water vapor that shoot up and out hundreds of miles into space from the depths of its icy seas—providing the Europa team’s check and mate, and the answer to the question “Why Europa?”
In the coming decade, Europa Clipper will launch, journey to Jupiter’s orbit, and make 45 flybys past Europa in order to photograph its surface and sample the chemical composition of the plumes. This isn’t just NASA’s mission, either. It’s our mission, our chance to find evidence of life somewhere else in the universe—hell, next door, in our own solar system.
When planetary scientist Jonathan Lunine read his first real-world scientific paper about the Mariner 9 mission to Mars—sent to him by Carl Sagan, no less—“He was now a part of something. He was connected to this thing: astronomy, space exploration. He lived on a spinning ball of rock ninety-three million miles from the sun, and he had this. This thing. These pages. This was his. He was part of it.”
This is precisely how I felt as I read The Mission, as Brown’s language drew me in to the world of interplanetary science and made me a part of it. The Europa Clipper mission is scheduled to launch in 2024 and, thanks to The Mission, I will be looking up, dreaming of Europa’s oceans, and those plumes, and waiting for news of what we find there.