History will note that the guy who discovered liquid water on Mars was an undergraduate at the University of Arizona, a 20-year-old who played guitar in a death-metal band and worked in a planetary science lab. One day, while comparing different satellite images of a single Martian crater taken at various times of year, he noticed something odd: a set of dark streaks in the soil that grew in the Martian summer and shrank in the winter. They seemed to flow down the craters slope, like a spill.
It took NASA a few years to gather more evidence after the student made his report, but finally, in September of 2015, the agency called a big press conference. It confirmed what the undergraduate had suspected almost right away: That was water in that crater.
Back in the 1970s, NASA scientists had informed everyone that the Red Planet was a dry, barren, dead place. Whoops. Now a new generation of NASA scientists were on a dais in Washington, DC, musing openly about what this new finding meant for the odds of discovering life on Mars. When you look at Earth, everywhere we go where theres liquid water, said Jim Green, the agencys director of planetary science, we find life. And the Martian water wasnt confined to that one crater wall. Once scientists knew what to look for, they found similar dark streaks at more than a dozen other sites. The agencys Curiosity rover was actually within striking distance of a few of these streaks. We might be able to visit, Green said. The announcement made headlines around the world. It also set off a bunch of quiet changes within the space agency itself.
About a month after the press conference, a NASA administrator named Cassie Conley was sitting in her office, staring into her computer screen at a crudely designed website called UFO Sightings Daily. Shed gotten a tip from someone at an astrobiology conference that she might want to check out a particular image posted there.
The site was a fairly typical UFO conspiracy operation, run by an amateur sleuth. There were posts that claimed to offer photographic evidence of miniature alien women, tiny star destroyers, and extraterrestrial squirrels. The item that Conley had come looking for was a photograph taken by the Curiosity rover and annotated by the websites author. As purported evidence of intelligent life on Mars, the UFO buff had circled a pile of rocks and labeled them building with a doorwaywhich was just silly. But that streak in the soil descending from a crook between two rocks? The guy had labeled it water. And it really did look like water.
The closest dark streaks to Curiosity that NASA had previously found were about 2 miles away, up the steep slopes of Mount Sharp. These new ones were a few feet from the roverConley could see its tire tracks imprinted on the sand nearby. She picked up the phone.
She and the Curiosity team needed to talk.
These Are Exciting times for anyone who loves the thought of going to Mars. In just the next five years, the worlds space agencies aim to send five missions to the Red Planet, which will more than double the number of active robots and landers on its surface. In late April, SpaceX announced that it will send an unmanned Red Dragon capsulethe vehicle it eventually plans to use for a human round tripto the planet as early as 2018. Between the star power of Elon Musk and the success of last years movie adaption of Andy Weirs The Martian, American pop culture has space on its mind again. The notion of colonizing the Red Planet has become respectable, as if it were no more far-fetched (and maybe less) than favoring Marxism.
Theres just one problem: Its looking more and more likely that Mars might already be inhabitedby Martians. Very tiny ones. Which concerns Cassie Conley.
Conleys full-time job at NASA is to make sure that we dont royally screw up our first encounter with aliens, however small. Her official title is US planetary protection officer. Shes a kind of interplanetary sheriff, whose main duty is to police the comings and goings of the tiniest Earthlings: microorganisms, which as it turns out are extraordinarily good at hitching rides on spacecraft. As NASAs increasingly large and sophisticated fleet of robot explorers has spread through space over the past decade and sent thrilling findings homewater on Mars, huge geysers erupting from Saturns moon Enceladus, churning seas beneath Europas iceConley has logged 14-hour days making sure those robots dont infect any heavenly bodies with germs from Earth. The more likely a destination is to support life, the more stringent she is.
The nurse pressed a phone to Conleys ear. Your worms survived the crash, the voice said.
Conleys tiny department at NASA, the Office of Planetary Protection (motto: All of the planets, all of the time), dates back to the Cold War, when the Soviets and Americans signed a treaty to prevent the contamination of space. One of the core rationales for the offices existence is purely scientific. If alien life exists, researchers will of course want to study how it originated and evolvedto glimpse what planetary scientist Chris McKay calls a second Genesis. And to prevent false leads, humans have to be careful not to muddy space with our own trail of bacteria.
Another less official rationale for todays planetary protection policy is ecologicalyou might even call it anticolonial. Essentially, Conleys office serves to prevent NASA from doing to Martians what European explorers did to Native Americans with smallpox. Because Mars lacks Earths history of abundant life, it has that much more raw material for Earths bacterial stowaways to devourshould any of them, say, come into contact with water, find a niche they can survive in, and start to reproduce. The whole planet is a dinner plate for these organisms, she says. They will eat Mars. Conley wants to make sure we at least know whether Martian life exists before we introduce an invasive species that will wipe it out.
And the third main rationale for Conleys office is, well, mildly apocalyptic. In the late 1960s, when the space age was brand-new, the specter of interplanetary contagion ran high in the public imagination. In 1969, Michael Crichton published The Andromeda Strain, his novel about an extraterrestrial microbe that drops to earth on a satellite and wipes out an Arizona town. Two months later, when the Apollo 11 crew returned from their triumphant moon landing, NASA spirited the astronauts from their ocean splashdown to a hermetically sealed facility in Houston, where they were isolated, poked, prodded, and scrubbed with bleach for two weeks before they could receive their full heros welcome. (A priceless photo shows Richard Nixon using a microphone to chat with the astronauts, who are locked, grinning, inside a sealed Airstream trailer.) In those days, planetary protection was primarily about usabout guarding this planet against potentially virulent alien life.
Those public fears gradually died down when the moon proved lifeless and the Viking rovers in the 1970s seemed to show Mars to be a barren place. But those findings turned out to be wrongso now, who knows?
In short, when Conley picked up the phone after her visit to UFO Sightings Daily, it wasnt to spur Curiositys team on toward that possible water. It was to keep the rover away from it.
Conley is a small person, slender and barely more than 5 feet tall. When we meet at NASAs Goddard Space Flight Center in suburban Maryland, she all but disappears inside her heavy coat. But if anyone was born to the job of planetary protection officer, she is probably it. Her father was a mathematician who did work for NASA. Her mother was a biologist who studied fruit fly genetics. The family hamster was actually named J. B. S. Haldane, after a famous 20th-century British geneticistwhose theories about the origins of life helped inspire the idea of planetary protection.
Conley started out working for NASA as a research biologist, specializing in experiments that used nematodes, or roundwormsorganisms the size of a speck of lintas animal specimens. In January 2003, she managed to get one of her experiments sent up on space shuttle Columbia. It was designed to test how nematodes muscle development and metabolism would stand up to prolonged time in zero gravity, the kind of exposure humans would need to endure on a journey to Mars.
But that February, during its return descent into Earths atmosphere, the shuttle disintegrated at an altitude of 227,000 feet while traveling at 22 times the speed of sound. Seven astronauts died.
For Conley, one wreck was followed by another. Eleven weeks later, she was riding down a California highway with two friends when another driver collided with their car, killing one of her companions and disabling the other. Conley awoke from three days of unconsciousness with five cracked vertebrae and a morphine drip. Soon after, a nurse pressed a phone to her ear. The New York Times was calling. The reporter said, Your worms survived the crash.
The debris field from the shuttle disaster had stretched over hundreds of miles of Texas and Louisiana. Workers spent months searching through the wreckage, and they had just recovered five small aluminum canisters. Inside, most of Conleys worms were still alivedormant from months without food but otherwise none the worse for wear.
The twin crashes imbued Conley with a visceral sense of how hardy simple organisms can be. Life seems fragile to people, because people can live only in a very small range of conditions. No air, food, or water: We die. Too hot or too cold: We die. If our vehicle explodes at 227,000 feetor just runs into another car on the roadwe die. Keeping a small number of humans alive on a voyage into space is a fantastically complicated, expensive problem. Complex life is delicate and rare. But most life is simple, abundant, and incredibly strong.
Setting out to kill all the bugs that would tag along on a space mission is, it turns out, a pretty elaborate and costly proposition in itself. But that became Conleys job in 2006, when she signed on as Americas planetary protector in chief. Day to day, her work involves calculating the odds that any given piece of equipment might encounter alien life (very low on a waterless body like our own moon; higher for spacecraft nearing Europa) and dialing in a regimen of cooking, sterilizing, and scouring in order to eradicate invasive Earth bugs accordingly. Every time scientists make new discoveries about Martian conditions, or even about the tolerances of extremophiles here on Earth, it alters the skein of probabilities that guide Conleys planetary protection protocols.
Because its impossible to eliminate all of the microbes from a Mars rover, even the most stringent decontamination protocols are defined in ratios and probabilities. The most Conley can do is make sure there are no more than 0.03 microbes per square meter of spacecraft surface area. That was the standard applied to the Viking mission in 1976. The job requires a research scientists openness to strange possibility and a Vegas oddsmakers statistical discipline.
To find out what it looks like to eradicate all those bugs, I take a trip to the Goddard Space Flight Center and find myself dressed from head to toe in a bunny suit inside a gleaming white clean room. To even enter the room I wrestle with a series of hoods, boots, gloves, and garments using an intricate choreography designed to prevent any contact with unclean surfaces.
Inside, a guy sits for hours a day in his own bunny suit, hand-assembling a mass spectrometer that will be sent to the Red Planet on the European Space Agencys ExoMars rover in 2020. A special hood constantly blows air and particles away from his work surface. Above it, mounted in the ceiling, is a device that emits microbe-killing ultraviolet-C light. Every day, a technician cleans the room with an alternating protocol of isopropyl alcohol and diluted hydrogen peroxide (to outflank microbes that grow resistant to one or the other), and then NASA microbiologist Erin Lalime swabs for microbial cultures and tests for levels of contamination. Once the mass spectrometer is assembled, it will get cooked for 60 hours at 110 degrees Celsius. And then, of course, it gets cast into space. But some microbes will still make it through.
To help me contemplate how this is even possible, Lalime describes how the strands of DNA inside a bacterial spore exposed to extreme conditions will huddle together into a small ball surrounded by a thick shell of protein. At that point, the spore is almost completely devoid of energy and water: metabolically, almost dead, she says. Dormant spores have been revived after thousands of years in airless isolation. To them, the harsh vacuum of spaceConley likes to put this phrase in air quotesis a Sunday stroll.
Conleys job is, by nature, a pretty lonely one. Shes a microbiologist in an agency dominated by physicists and engineers, a woman in a field dominated by men, and a sheriff (someone even gave her a joke badge) who stands a head shorter than many of her colleagues. Her work has made her an unpopular figure at times. To many engineers, geologists, and Mars enthusiasts, the whole project of planetary protection simply represents an expensive set of precautions taken in the name of extremely low-probability events. (To hear some critics talk, youd think that Conley is to NASA what the unctuous EPA agent Walter Peck was to the Ghostbusters.)
But Conley is undeterred. History, she says, is littered with stories of human carelessness and environmental devastation, born not from malice but from cognitive limitation, a failure to contend with the murkiness of unknown unknowns. We didnt think we were going to make parts of Central America uninhabitable for hundreds of years by bringing malaria from Europe. We didnt think we were going to cover the southern United States in kudzu. I never thought about whether nematodes could survive a shuttle crash. Then, Conley says, it crashed.
The curiosity rover wasnt supposed to be high on Conleys list of worries. NASA had deliberately sent it to Gale Crater, thought to be among the least likely places to harbor life, because the rover was largely built for geological research. Shed helped pick the landing site herself. When Curiosity left Earth in 2011, it was subjected to milder decontamination controls: It was allowed 300 organisms per square meter.
Now, trundling around a possibly somewhat damp Gale Crater millions of miles away, Curiosity was very likely infested with tens of thousands of hardy Earth microbes that had survived the violent blastoff and months-long journey through the harsh vacuum of space. All they needed to reanimate and reproduce was the right combination of food, water, and heat.
At the meeting that eventually got called, Ashwin Vasavada, lead scientist in charge of Curiosity, said he was skeptical that the newly discovered streaksthe ones from UFO Sightings Dailywere actually water. His own research suggested that conditions in Gale Crater do occasionally produce briny surface water, but that these particular streaks were probably just tiny avalanches. Still, probably wasnt really enough for Conley to go on. Vasavada agreed, because, as he later allowed, we cant be confident that we have a full understanding of these predictions. Together, they decided that the Curiosity team would have to scrutinize each days new batch of photos for signs of water before moving ahead.
Vasavada knew he had gotten off fairly easy. The people who are really having trouble with Planetary Protection, he said later, are the next mission.
There are huge battles going on inside NASA over planetary protection.
The mission he was referring to is called Mars 2020, which will land another robot rover much like Curiosity. In fact, the 2020 rover is being assembled partly with equipment left over from Curiositys build. The new rover will be designed to search for signs of ancient microbial life on Mars andeven more ambitiouslyto collect soil samples that can be retrieved by another spacecraft and sent back to Earth. The project is being developed at the Jet Propulsion Laboratory in Pasadena, California. And while the projects leaders declined to talk to me, observers inside and outside of NASA say theyre in a heated battle with the Office of Planetary Protection over where they can land and what measures they need to take to sterilize their craft before it leaves for Mars. Because much of their equipment was designed or built well before the discovery of water, it wouldnt withstand the strict protocols Conley would require today. And with the 2020 launch window rapidly approaching, the project has fallen behind schedule in getting its decontamination procedures approved by Conleys office.
There are huge, huge battles going on inside NASA, says The Martian author Weir, who has become close to several people at the agency. The planetary protection process is a huge burden to the design of these probes, he says. It makes every aspect more difficult.
In 2013, a pair of astrobiologists published an article in Nature Geoscience arguing that planetary protection should be all but abandoned on the Red Planet. If Earth microorganisms can thrive on Mars, they almost certainly do, they wrote, reasoning that large meteor strikes had probably already sent organism-infected chunks of Earth crashing into Mars. And if Earth life cant survive on Mars, they contend, we shouldnt worry about sending more.
Conley has a response to this argument. Even if a microbe on Mars shares the same deep origins as us, a few thousand years down a separate evolutionary pathway would still make them pretty alien indeed. But ultimately, the best case for caution, and for planetary protection, may be simply to point to all the ways in which our knowledge of Mars has changed just in the past few years. Curiosity ended up almost on top of possible liquid water because we didnt know what we didnt know. In a way, Conleys deepest arguments boil down to a quote from Haldane: The universe is not only queerer than we suppose, but queerer than we can suppose.
Sometimes, critics of Planetary Protection call the office a farce precisely because, well, we all know whats coming: When humans arrive on Marswith their coughs and sneezes and microbiomesmany of these sterilization protocols will go out the window. Conley understands that all too well. She knows that someday, probably before midcentury, men and women will walk on Mars. And to her, that means there is a small, precious window to learn as much as we canand just maybe discover life that is truly alien to usbefore they get there.
This article appears in the August 2016 issue.