Alan Burdick

The (New) Web of Life
: All the known creatures on Earth may soon be a click away

Interview with Will Wright: The master of the computer ‘god game’ tackles alien life and dreams up a world that would make Darwin drool

Will Wright followed a typically eccentric path into computer-game design: some college classes in computer science and architecture, a few homemade robots, no university degree. A deep interest in science, however, infuses all his creations. SimAnt, in which players try to corral an ant colony into conquering a suburban home, was modeled on the insights of ant expert Edward O. Wilson. For SimEarth, a global-ecosystem game, Wright consulted with biologist James Lovelock, originator of the Gaia “Earth as organism” hypothesis. SimCity was inspired by urban-dynamics models developed by MIT scientist Jay Forrester. The Sims games, beneath their animated-dollhouse exteriors, are time-management experiments, based in part on a trove of data gathered by sociologist John Robinson on how Americans spend their hours.

Wright’s next game, Spore, due out next year, simulates the entire cosmos; he refers to it jokingly as SimEverything. The player starts as a microbe in a cell-eat-cell world and gradually advances onto land, evolves sentience, develops culture, forms tribes, cities, and civilizations, and finally acquires the ability to move freely through a breathtakingly vast universe of planets, stars, and galaxies. Everything is malleable: A player can create a creature with, say, 3 legs and 15 eyes and stretch it like clay. The animating software then figures out how best to make it walk, run, and stalk prey. A player can create ringed planets and watch the moons orbit leisurely for hours. Meanwhile, the many worlds in your Spore cosmos are pollinated automatically from an online database of plants and animals created by other players.

“As you play, you create the elements of the universe, which are used to populate other players’ worlds,” Wright says. “In a sense, you’re creating the universe for other players. We’re making the player the game designer.”

Through your games, you come across as a guy who’s trying to decipher the natural world bit by bit, through computer simulations.

That’s not far off. When I was a kid, I liked taking things apart to see how they worked. Computer simulation is similar, it’s reductionist; you’ve got these parts, you want to see how they interact, so you build a model and compare it to the real world. When you formulate a model, you quickly see your misperceptions. That’s the value of simulation in science, to spotlight our ignorance.

Modeling is one of the things that led to an understanding of chaos theory. Back in the 1960s, Dennis and Donella Meadows, a husband and wife team, tried to model the world in terms of things like population, food production, standard of living, and so on to get some sense of where the world was going. When they ran their model, it basically showed the whole world population crashing–quickly, by 1985, according to them. Of course, that didn’t come true. Looking back, it became clear that just a couple of variables were off by a few percent and got very amplified. The scientists didn’t foresee the green revolution in agriculture–the use of fertilizers and pesticides. So their food production numbers were just a bit low, but it compounded year after year. One little thing off a little bit can have a huge impact on the eventual destination.

What were you doing at age 10 that steered you toward game design?

Building a lot of models–plastic, wood, whatever. That evolved into making things with motors, and that evolved into robots. Robots got me into computers. One of my favorite robots was one called Mr. Rogers. I built it when I was about 20. It had three wheels and an ultrasonic sensor for mapping the room and was attached to an Apple II. I still love robots; it’s kind of a background hobby. My daughter, Cassidy–she’s 19, she’s in art school–was doing Robot Wars and BattleBots with me for many years.

Spore takes its cue from astrobiology, both in its spatial sweep–from microbiology to galaxies–and in the interplanetary spread of life. What turned you on to the subject?

Well, I’ve always had an interest in the SETI program, which led me to astrobiology and to Drake’s equation. Drake’s equation is simple. Basically, you take the average number of stars in the galaxy and you ask what percentage have habitable planets. Then you ask what percentage of those couple of planets does life arise on? And on what percentage of those is the life intelligent? What’s the average life span of that civilization? You crunch all those numbers together and get one that tells you how many intelligent species are out there asking themselves the same question. For some reason, most of these models leave out panspermia [the theory that life may have originated elsewhere in the cosmos]; I love to think panspermia’s gotten short shrift. Anyway, all the factors lead back to how unique we are. Stars and galaxies are complex and interesting, but they’re still nowhere near as complex as life.

One thing that interests me is that all the factors in Drake’s equation map to different size scales. It’s almost like an index into science at different scales: chemistry, biology, sociology. As humans we’re stuck at the scale of our bodies, but there are all these different levels above and below us; each one has its own dynamics, its own processes, its own timescale. I’ve always been intrigued by Charles and Ray Eames’s Powers of Ten book and movie. They really tried to give an overall sense of where we are in the universe, to give some perspective on the history of life. That awareness can make you feel insignificant. But in some sense, it’s also the reverse. If we’re the only life around, what an incredible responsibility! It’s humbling and deeply empowering at the same time.

So Spore is an existential game?

One of my original goals was to give players the equivalent of a drug-induced epiphany. I’ve been surprised, given Spore’s epic scale, that it has such broad appeal–that the average person finds some meaning in it. Of course, every player finds a different meaning: how big the universe is, or the existence of different timescales, or how precious life is. The important thing is getting people to step back and enjoy the view.

The Spore universe plays like a planetarium show; you’ve clearly worked hard to model orbital and galactic motions accurately.

You should see all the stuff that’s not in the game! We did a huge number of prototypes, modeling almost anything you can imagine, from autocatalytic chemistry to the dynamics of interstellar gases. For a brief while, we considered making gas giants playable, but not having a solid surface makes game play difficult.

I’m told you collect artifacts from the Russian space program.

I’ve always had a fascination with it. I’m impressed by their approach and the success they’ve had compared to NASA. And they’ve done it at one-fifth the cost. These days you have to hire the Russians to get you into space, not NASA. I like to collect their stuff, take it apart, see how it works. It’s incredibly durable, and cheap. I’ve got control panels from the Mir space station and the complete interior of a Soyuz spacecraft. I’m going to Russia next week, actually, to Star City and some other places. A lot of the coolest stuff is down in the basements of these aerospace corporations. I’m going with several friends; it’s sort of a space junket.

Would you ever go up in space?

Oh, sure, I’d do it under the right circumstances. But not $20 million to fly in the Soyuz.

Do you play computer games besides the ones you design?

Oh, yeah. I spend maybe five hours a week playing games. On the PC, I still play Battlefield 2 and Advance War on my old Game Boy. Lately I’ve been into Guitar Hero. It’s a game for PlayStation 2 that comes with a guitar controller, which has buttons on its frets instead of strings. You try to play along to real rock songs, and there’s this whole little audience on-screen that’ll boo you off the stage if you stink. When you get it right, it’s really satisfying.

What makes a game compelling to you?

In the kinds of games I focus on, I’m interested in amplifying the players’ natural abilities. I want a player to feel surprised: “Wow, I made this thing!” Then, because you feel ownership over it, you start feeling things like pride–or even guilt if you run the situation badly. People talk about how games don’t have the emotional impact of movies. I think they do–they just have a different palette. I never felt pride, or guilt, watching a movie.

A lot of what makes things fun generally is people challenging themselves, learning new patterns. You’re building a model in your head that will help you predict what the system’s going to do and enable you to perform in that system more accurately. That’s why kids play, I think. From a very early age, that’s how we relate to the world. We look for patterns, we poke and prod: If I do this, what happens? That’s how we learn causality.

So games are fun because they allow us to play with time?

Partly. You can think of games almost as time machines. They allow us to explore the possibility space around a given starting point. You can hit Start Over and do the Groundhog Day thing: Relive the same day and try doing this, replay the same day and try doing that. You can control time in a way that you can never do in real life and get some sense of how chaotic a system can be.

Storytelling is the same way. Say I’m a caveman and I almost get killed by a tiger. I can come tell you that I left my cave and a tiger almost got me. I’m sharing an experience and can now influence your behavior. Next time you leave the cave, you’ll look out for the tiger. That’s a time machine for experience–lessons that we might learn.

You’ve collected and analyzed thousands of hours of data gathered from people who play The Sims online. To what extent is playing The Sims a behavioral experiment?

It’s an interesting kind of Rorschach test. The way in which people play the game says a lot about their personal interests and creativity. Some focus on giving their Sims skills, climbing the career ladder, building McMansions. Others focus on romance or building a family. Others are into creating a cast of characters and saving it on the Web; for them The Sims is more like a set of actors and sets with which to tell stories. It’s up to you to decide how you want to make your Sim happy. SimCity is like that as well. We don’t tell you that you have to build a big city, or a happy city, or a clean city; people come up with their own goal state that has a lot to do with their own value system. The game almost asks them,OK, what do you think a good city is? Or a good life?

You’ve modeled planetary dynamics, ant colonies, even the way players play your games. What’s left?

Do you know about fitness landscapes? It’s this idea that you can map evolutionary fitness. If you were this genetic combination, you’d be this fit. If you were that genetic combination, you’d be that fit. Any given population is basically climbing a fitness landscape. It’s cross-correlated: The shape of the landscape is dependent on what all the organisms are doing, so even as an organism evolves, the landscape is always changing.

I did some modeling of this–fairly long-term models of creatures evolving on different landscapes. Interestingly, the results I got were very similar to punctuated equilibrium [an evolutionary theory championed by Niles Eldridge and Stephen Jay Gould]. You’d see regions of stability for long periods of time, then diversity would go up, then suddenly the whole system would go into chaos, you’d have this mass die-off, and then it would go back up pretty rapidly.

You’re doing this for fun? That’s what you do on the weekend?

Yeah, pretty much just for fun. I get really into biology. I find it more and more fascinating, especially macroevolutionary stuff. Actually, I think the idea of evolution is one that a lot of people have a hard time wrapping their minds around. They think, oh, you’ve got this one mutation and then the creature is a little bit better at seeing, therefore it survives. But, in fact, it’s much more of a numbers game: You have thousands of creatures that have a slightly better chance of seeing, and statistically they survive 1 percent better. People aren’t used to dealing with the numbers and the timescales involved. But once you look at it from that point of view, evolution just seems so much more plausible. It makes perfect sense.

In Wikipedia, Spore is described as a “teleological evolution” game. Do you think the game will bring natural selection to the masses?

You can look at it in a number of ways. What’s ironic, really, is it’s intelligent design. As a player, you go through an arc of being this lowly little cell, being attacked by pond scum, to eventually becoming a god. At the godlike level, you can almost do the whole creationist thing if you want: “I will create a planet; I will create species; I will put them on the planet.” But you’re a god without a whole lot of foresight. You put all this stuff on a planet, and it might go kerflooey. You might make a really badly balanced ecosystem. You’re not necessarily an omnipotent god. That’s even more fun. You have these godlike powers, yet the repercussions of them become totally unpredictable to you.

If you could rebuild Earth in any way–add or subtract any creature or process, for instance–what would you do?
What’s my starting point? The Paleolithic?

Now, whenever, any time you want. The world is your oyster.

Hmmm. Well, the development of life was amazing and maybe incredibly improbable, so I wouldn’t want to mess that up. The development of intelligence was possibly even more improbable; I wouldn’t want to modify anything until that happens either. Even then . . . I wouldn’t want to touch it, actually. If I started now, maybe I’d do something to increase the odds of humans surviving on Earth. But maybe not! Can I give you James Lovelock’s answer? I’d probably eliminate cattle entirely. They’re the Earth’s second-largest producers of methane, which is a serious greenhouse gas. The clearing of rain forests is done mainly to accommodate livestock, so getting rid of cattle would help protect biodiversity.

The Future of TimeCan we increase productivity by revving up the neural pacemakers in the brain?

Seeding the Universe
The search for life on Mars could be a bit complicated by the hitchhikers on our rovers"

THE search for extraterrestrial life begins, and perhaps ends, in a white gymnasium-size room in the smoggy foothills of Pasadena, California, on the sprawling campus of NASA’s Jet Propulsion Laboratory. This is the Spacecraft Assembly Facility (SAF), where interplanetary probes are assembled and tested before being launched toward their various cosmic destinations. The Mars Pathfinder rover, which in 1997 captured stunning photographic vistas of the Martian surface, was built here. Spirit and Opportunity, the two rovers that continue to roam and prod Mars for evidence of water, were built here. Cassini, now orbiting Saturn, and Huygens, a small probe that in December will drop into the atmosphere of Saturn’s moon Titan, were built here too. The Spacecraft Assembly Facility is a gateway, truly a portal to the rest of the universe. What passes through it promises to reveal a great deal about the origins, and possible fate, of life in the cosmos.

Come on in. First, however, you must be decontaminated. A visitor places one foot, then the other, into an automatic shoe scrubber, a box on the floor with spinning bristles that flagellate the soles for a minute or so. A guide provides blue paper booties to slip over shoes, a blue shower cap to cover hair, and a white gown, made of paper with a shiny cling-free coating, to wear over your clothing. Finally, an air shower— a glass booth with several nozzles blowing furiously. Then and only then, ruffled but purified, may you enter. Inside the facility, a company of blue-bootied, shower-capped, paper-gowned technicians fuss over the skeletons of spacecraft-to-be. The room is arid as a desert, the humidity a drastically low 42 percent. The floors are regularly scrubbed to remove dander and bacteria. NASA’s intent is to create an environment hostile to any microbes that might hitch a ride aboard the outbound spacecraft yet benign to the human engineers who must assemble these delicate vehicles. If that sounds like an impossibility, it is. Welcome to the paradox of planetary protection.

In 1967, inspired by a new international outer-space treaty, the space-racing nations of the world agreed to spare no effort in preventing the potential spread of organisms from one moon or planet to another. At NASA, this mandate evolved into an official planetary protection policy, a Sisyphean effort to shield the universe from the people exploring it.

Traditionally, the assumed beneficiary of planetary protection has been the planet Earth. We’ve all seen the movies, we know the disaster scenarios: Extraterrestrial spores return from outer space, and in no time the citizens of Earth are heaps of dust or brain-dead zombies. Accordingly, NASA has developed an elaborate quarantine protocol to handle soil samples retrieved from other planets—comforting, perhaps, but statistically of marginal value. Contagion spreads from the haves to the have-nots, and so far as scientists have yet determined, Earth is the only planet with life to give. Besides, virtually all the spacecraft that leave Earth depart on one-way missions: They drift eternally through interstellar space, or they burn up in foreign atmospheres, or they sit on Mars, never rusting, transmitting data until their batteries fade away. Among all the lawns in the cosmos, ours is the one with dandelions, and the wind is blowing outward.

No, if anybody should be worried about biocontamination, it’s our planetary neighbors. In the coming decade, NASA has scheduled no less than four major missions to Mars to grope for hints of water or life. Down the road is a robot that will drill below the icy surface of the Jovian moon Europa to probe a briny ocean believed to exist there, and the Titan Biological Explorer, which will plumb the atmosphere of the Saturnian moon Titan for the chemical precursors of life. Interplanetary traffic is picking up, and NASA would like to avoid going down in history as the agency that accidentally turned the Red Planet green with life.

But the true worry isn’t ecological; it’s epistemological. Any earthly contamination—of the Martian soil or of the instruments sent to study it—would seriously muddy the multibillion-dollar hunt for extraterrestrial life. As Kenneth Nealson, a University of Southern California geobiologist and Jet Propulsion Laboratory visiting scientist, recently told the journal Nature: “The field is haunted by thinking you’ve detected life on Mars and finding that it’s Escherichia coli from Pasadena.” As it turns out, that fear is well founded. Not only does microbial life survive in the Spacecraft Assembly Facility; in some cases it thrives there. There is no question whether we’re exporting life into the cosmos—we absolutely are. What’s left to determine is exactly what kind of life is emigrating and how far it is spreading.

* * *

“BUGS are very clever,” Kasthuri Venkateswaran says with affection. “They started out on Earth 3.8 billion years ago, when nothing else was here!”

Venkateswaran—bow tie, oxford shirt, smart round glasses—occupies a bunker-like office a couple hundred yards up the hill from the Spacecraft Assembly Facility. Unofficially, he is an astrobiologist, a job description recently coined at NASA to describe the cadre of scientists involved in the agency’s accelerating search for life beyond Earth. Officially, he is the senior staff scientist of the biotechnology and planetary protection group. While his celebrated colleagues design ever more inventive spaceships and robots to scour the surface of Mars for some signature of life, Venkateswaran quietly examines the machinery itself, searching for any clever microbes—”bugs,” he calls them—that might try to tag along. Neat and kindly as country doctor, he is in fact the biological protector of the universe. To colleagues and, at his insistence, visitors, he is simply “Venkat.”

“The life-detection techniques we have today are incredibly sensitive,” Venkat says. “A few molecules could jeopardize the sample you’re bringing back.” He pulls out an official pamphlet: Biological Contamination of Mars, Issues and Recommendations. The surfaces of outbound NASA spacecraft and instruments, it declares, should be rid of living stuff, dead stuff, parts of dead stuff, and any stuff that might be mistaken for any of these. And everything in this effort is always being rethought. Recently, NASA stopped using cotton swabs in the cleaning process: To a life-detection instrument, the atomic bonds in a stray filament of cotton could be mistaken for the signature of proteins. The last thing Mars scientists want to discover is that Martians are the evolutionary descendants of Q-Tips.

In the old days, ridding the average spacecraft of bugs was a simple matter: Place it in an oven, heat it up to a jillion degrees or so, and bake it for a couple of days. Today, spacecraft are far more sophisticated and fragile, made of lightweight polysyllabic polymers and stuffed with microcircuits and light-years-beyond-Microsoft software.

“Nowadays, most electronics can’t take that kind of heat,” Venkat says. Instead, the individual components of the spacecraft are swabbed down with alcohol during construction; the components that can take it also undergo some sort of heat treatment. (The swab approach is by no means bugproof. Venkat has found that the alcohol sometimes breaks apart microbes and glues their innards to the spacecraft; this kills the microbe but leaves the prospect of life-detection even muddier than before.) The various parts of a given spacecraft are built, and decontaminated, by subcontractors around the globe. NASA readily concedes that it is physically—or at least financially—impossible to remove every speck. Instead, the agency issues guidelines intended to minimize the risk of contamination: no more than 300 specks per square meter, say, for a landing pod actively involved in the life-detection process. The components are then sent to the Jet Propulsion Laboratory or another NASA campus for inspection and final assembly. This is where Venkat’s research begins in earnest.

I toured the Spacecraft Assembly Facility with Victor Mora and Jesse Gomez, two of the space-age custodians responsible for keeping the place tidy. Spacecraft parts that come into the room are relatively free of microbes to begin with, they said. All that’s required is to keep the density of free-floating particles to a minimum. Dust, hair, the sloughed-off skin cells of NASA workers—all are contaminants in their own right and, more important, nutritious meals for whatever microbes might be around. “We’re shedding all the time,” Mora said. “Even our eyes shed.” Giant fans in the ceiling, several dozen feet overhead, suck particulates upward and outward into exile. The antistatic robes worn by technicians funnel personal particles down toward the floor, which is swabbed regularly.

“Microbes need particles to attach to,” Venkat says. “Without particles, without nutrients, the environment is essentially extreme.”

If astrobiologists have learned anything, however, it’s that almost no environment is too extreme for life. In the past few years, scads of extremophile organisms have been discovered thriving under conditions once considered inhospitable. Clams have turned up in the sunless, high-pressure depths surrounding seafloor vents. Algae in the Antarctic, where conditions resemble the dry valleys of Mars, spend much of their lives desiccated and drifting in the wind, waiting for their situation to improve. Microbes have been found miles underground in hot geysers, in gold mines, in solid volcanic rock, deriving their nourishment from sulfur, manganese, iron, petroleum. In recent years, a whole new field called geo-microbiology has sprung up precisely to study tiny creatures that are otherwise indistinguishable from rocks. Astrobiologists agree that if there is life to be found beyond Earth, it almost certainly will be very small and equally hard to discern.

Trained as a microbiologist, Venkat brings to his task an impressive history of sleuthing out wily tiny critters. In 1998 he discovered a bacterium that survives the high salinity of Mono Lake in California by living inside the lake’s rocks. After prominent newscasters and government officials were mailed anthrax spores in the autumn of 2001, Venkat published a paper later used by the Department of Homeland Security on how to distinguish anthrax from other microbes. None of his encounters in the microworld, however, quite prepared him for the discoveries he has made in Pasadena. Using a sophisticated array of life-detection methods—the same methods being refined for the hunt for extraterrestrial life—Venkat has discovered a plethora of bizarre microbes thriving in the Spacecraft Assembly Facility, microbes that would have escaped detection by older technologies. He held up a red-capped vial for me to see. Inside, invisible in a thimble-size sea of clear liquid, were the newly found inhabitants of Planet NASA. Venkat’s lab encompasses a true microcosm: a new world, hitherto unexplored, as enlightening as any that his stargazing colleagues will ever hope to find.

* * *

THUS far, Venkat has identified 22 species of microbes in the Spacecraft Assembly Facility, in other, similar NASA environments, even on actual spacecraft. Many are microorganisms common to arid environments, such as B. mojavensis, a bacterium that probably drifted in from the Mojave Desert. A handful are entirely new species. One, which Venkat has named B. nealsonii (in honor of Kenneth Nealson, who was his supervisor at the Jet Propulsion Laboratory), possesses two protective coats, making it a tough spore capable of surviving in the ultradry environment of the assembly facility. As Venkat discovered, the second spore coating also offers a secondary benefit: It makes the organism unusually resistant to gamma rays, a form of cosmic radiation that, in large doses, is fatal to men and microbes alike. (Earth’s atmosphere screens out most gamma radiation; Mars, in contrast, is a gamma-ray frying pan.) Tough as it is, the bacterium is probably not unique to NASA. The world of undiscovered microbes is vast, and Venkat suspects that B. nealsonii also resides outside the assembly facility.

Venkat has found bugs in the spacecraft-assembly facility at the Kennedy Space Center in Florida; on hardware and in drinking water from the International Space Station; in circuit boards destined for an upcoming mission to Europa; and on the metal surface of the Mars Odyssey spacecraft, which has been orbiting Mars since October 2001. While Odyssey was being assembled at the Kennedy Space Center, Venkat isolated a new species of bacterium—Bacillus odysseyi, officially—that carries an extra spore layer, or exosporium, that makes it several times more resistant to radiation than other spore-forming microbes found in the facility. “It carries novel proteins as a sunscreen,” Venkat says. Like B. nealsonii, B. odysseyi may turn out to live elsewhere besides its assembly facility. But What’s notable, Venkat says, is that the very traits that render these bugs impervious to decontamination also grant them a decent chance of surviving the radiation shower they would encounter en route to and on the surface of a place like Mars.

One discovery, a bacterium named Bacillus pumilis, has given Venkat particular cause to marvel. He found the microbe thriving directly on spacecraft surfaces, presumably drawing its energy from ions of trace metals like aluminum and titanium. “Aluminum is toxic,” Venkat exclaims, baffled. “There are no nutrients. There is no water.” In addition, the species exhibits a remarkable defense against desiccation. The individual cells form protective spores, which then band together to create what Venkat calls an igloo. In microphotographs, this spore house looks rather like a macaroon. Moreover, when Venkat cuts open the igloo, he finds no visible trace of the individual spores; they’ve all dissolved into the collective matrix. High-tech methods of life-detection reveal no evidence of life. Yet when Venkat warms up the igloo and adds a little moisture, B. pumilis again springs into being. If the microbe is any indication of the sort of life that awaits discovery on Mars or elsewhere, he says, good luck to the robot sent to detect it.

B. pumilis itself isn’t a new species. It has been studied throughout the world for years, but its igloo-forming habits were not well known. For instance, its attachment to aluminum is novel. Last month, Venkat published a paper claiming that the SAF version of B. pumilis is in fact a new species after all—a substrain that has adapted and evolved to the conditions imposed on it by NASA, like an herbicide-resistant dandelion or the supertough microbes that sometimes spring up in hospitals. He has named it Bacillus safensis, and it represents precisely the kind of organism that his fellow astrobiologists are looking for in outer space. it’s not a Martian, but in form and function it may turn out to closely resemble one.

It is, in any event, one step closer than any other earthly creature to becoming the first organism to survive on another planet. Venkat has found the bacterium in every other NASA assembly facility he’s studied. Three years ago he found it on the Mars rovers Spirit and Opportunity, then under assembly at the Jet Propulsion Laboratory. At this very moment, the rovers are actively poking around in the Martian dirt, as they have been for the past nine months. B. safensis is almost certainly aboard them, alive and well, Venkat says. “They could be there for millions of years because they are spores. Whether they will become active and begin terraforming—that research is still ongoing.”

The Space Assembly Facility is a standing paradox. Through its assiduous effort to avoid spreading life throughout the cosmos, NASA has created an environment that inadvertently fosters the very kind of life it is traveling so far beyond Earth to find. As Venkat says, “We have a kind of survival of fitness.” What began as a means to an end is now an end in itself; the doorstep has become a laboratory, a nursery even, a small-town study in life’s cosmic persistence. It is a study, too, in the impossibly high cost of perfect hygiene. Venkat found that, in at least one instance, some of the microbes appeared to have been introduced during the cleaning process devised to eliminate them. Wherever humans go, it seems, we go with company. Looking around the assembly facility with Mora and Gomez, I saw a man-made cosmos, every surface a habitable planet, its ethers traversed by micronauts riding spacecraft named Human Hair and Eyeball Cell.

“People are the dirtiest things around,” Gomez said.

“Yeah,” said Mora. “We’re the contaminants.”

Seeding the Universe The search for life on Mars could be a bit complicated by the hitchhikers on our rovers

THE search for extraterrestrial life begins, and perhaps ends, in a white gymnasium-size room in the smoggy foothills of Pasadena, California, on the sprawling campus of NASA’s Jet Propulsion Laboratory. This is the Spacecraft Assembly Facility (SAF), where interplanetary probes are assembled and tested before being launched toward their various cosmic destinations. The Mars Pathfinder rover, which in 1997 captured stunning photographic vistas of the Martian surface, was built here. Spirit and Opportunity, the two rovers that continue to roam and prod Mars for evidence of water, were built here. Cassini, now orbiting Saturn, and Huygens, a small probe that in December will drop into the atmosphere of Saturn’s moon Titan, were built here too. The Spacecraft Assembly Facility is a gateway, truly a portal to the rest of the universe. What passes through it promises to reveal a great deal about the origins, and possible fate, of life in the cosmos.

Come on in. First, however, you must be decontaminated. A visitor places one foot, then the other, into an automatic shoe scrubber, a box on the floor with spinning bristles that flagellate the soles for a minute or so. A guide provides blue paper booties to slip over shoes, a blue shower cap to cover hair, and a white gown, made of paper with a shiny cling-free coating, to wear over your clothing. Finally, an air shower— a glass booth with several nozzles blowing furiously. Then and only then, ruffled but purified, may you enter. Inside the facility, a company of blue-bootied, shower-capped, paper-gowned technicians fuss over the skeletons of spacecraft-to-be. The room is arid as a desert, the humidity a drastically low 42 percent. The floors are regularly scrubbed to remove dander and bacteria. NASA’s intent is to create an environment hostile to any microbes that might hitch a ride aboard the outbound spacecraft yet benign to the human engineers who must assemble these delicate vehicles. If that sounds like an impossibility, it is. Welcome to the paradox of planetary protection.

In 1967, inspired by a new international outer-space treaty, the space-racing nations of the world agreed to spare no effort in preventing the potential spread of organisms from one moon or planet to another. At NASA, this mandate evolved into an official planetary protection policy, a Sisyphean effort to shield the universe from the people exploring it.

Traditionally, the assumed beneficiary of planetary protection has been the planet Earth. We’ve all seen the movies, we know the disaster scenarios: Extraterrestrial spores return from outer space, and in no time the citizens of Earth are heaps of dust or brain-dead zombies. Accordingly, NASA has developed an elaborate quarantine protocol to handle soil samples retrieved from other planets—comforting, perhaps, but statistically of marginal value. Contagion spreads from the haves to the have-nots, and so far as scientists have yet determined, Earth is the only planet with life to give. Besides, virtually all the spacecraft that leave Earth depart on one-way missions: They drift eternally through interstellar space, or they burn up in foreign atmospheres, or they sit on Mars, never rusting, transmitting data until their batteries fade away. Among all the lawns in the cosmos, ours is the one with dandelions, and the wind is blowing outward.

No, if anybody should be worried about biocontamination, it’s our planetary neighbors. In the coming decade, NASA has scheduled no less than four major missions to Mars to grope for hints of water or life. Down the road is a robot that will drill below the icy surface of the Jovian moon Europa to probe a briny ocean believed to exist there, and the Titan Biological Explorer, which will plumb the atmosphere of the Saturnian moon Titan for the chemical precursors of life. Interplanetary traffic is picking up, and NASA would like to avoid going down in history as the agency that accidentally turned the Red Planet green with life.

But the true worry isn’t ecological; it’s epistemological. Any earthly contamination—of the Martian soil or of the instruments sent to study it—would seriously muddy the multibillion-dollar hunt for extraterrestrial life. As Kenneth Nealson, a University of Southern California geobiologist and Jet Propulsion Laboratory visiting scientist, recently told the journal Nature: “The field is haunted by thinking you’ve detected life on Mars and finding that it’s Escherichia coli from Pasadena.” As it turns out, that fear is well founded. Not only does microbial life survive in the Spacecraft Assembly Facility; in some cases it thrives there. There is no question whether we’re exporting life into the cosmos—we absolutely are. What’s left to determine is exactly what kind of life is emigrating and how far it is spreading.

* * *

“BUGS are very clever,” Kasthuri Venkateswaran says with affection. “They started out on Earth 3.8 billion years ago, when nothing else was here!”

Venkateswaran—bow tie, oxford shirt, smart round glasses—occupies a bunker-like office a couple hundred yards up the hill from the Spacecraft Assembly Facility. Unofficially, he is an astrobiologist, a job description recently coined at NASA to describe the cadre of scientists involved in the agency’s accelerating search for life beyond Earth. Officially, he is the senior staff scientist of the biotechnology and planetary protection group. While his celebrated colleagues design ever more inventive spaceships and robots to scour the surface of Mars for some signature of life, Venkateswaran quietly examines the machinery itself, searching for any clever microbes—”bugs,” he calls them—that might try to tag along. Neat and kindly as country doctor, he is in fact the biological protector of the universe. To colleagues and, at his insistence, visitors, he is simply “Venkat.”

“The life-detection techniques we have today are incredibly sensitive,” Venkat says. “A few molecules could jeopardize the sample you’re bringing back.” He pulls out an official pamphlet: Biological Contamination of Mars, Issues and Recommendations. The surfaces of outbound NASA spacecraft and instruments, it declares, should be rid of living stuff, dead stuff, parts of dead stuff, and any stuff that might be mistaken for any of these. And everything in this effort is always being rethought. Recently, NASA stopped using cotton swabs in the cleaning process: To a life-detection instrument, the atomic bonds in a stray filament of cotton could be mistaken for the signature of proteins. The last thing Mars scientists want to discover is that Martians are the evolutionary descendants of Q-Tips.

In the old days, ridding the average spacecraft of bugs was a simple matter: Place it in an oven, heat it up to a jillion degrees or so, and bake it for a couple of days. Today, spacecraft are far more sophisticated and fragile, made of lightweight polysyllabic polymers and stuffed with microcircuits and light-years-beyond-Microsoft software.

“Nowadays, most electronics can’t take that kind of heat,” Venkat says. Instead, the individual components of the spacecraft are swabbed down with alcohol during construction; the components that can take it also undergo some sort of heat treatment. (The swab approach is by no means bugproof. Venkat has found that the alcohol sometimes breaks apart microbes and glues their innards to the spacecraft; this kills the microbe but leaves the prospect of life-detection even muddier than before.) The various parts of a given spacecraft are built, and decontaminated, by subcontractors around the globe. NASA readily concedes that it is physically—or at least financially—impossible to remove every speck. Instead, the agency issues guidelines intended to minimize the risk of contamination: no more than 300 specks per square meter, say, for a landing pod actively involved in the life-detection process. The components are then sent to the Jet Propulsion Laboratory or another NASA campus for inspection and final assembly. This is where Venkat’s research begins in earnest.

I toured the Spacecraft Assembly Facility with Victor Mora and Jesse Gomez, two of the space-age custodians responsible for keeping the place tidy. Spacecraft parts that come into the room are relatively free of microbes to begin with, they said. All that’s required is to keep the density of free-floating particles to a minimum. Dust, hair, the sloughed-off skin cells of NASA workers—all are contaminants in their own right and, more important, nutritious meals for whatever microbes might be around. “We’re shedding all the time,” Mora said. “Even our eyes shed.” Giant fans in the ceiling, several dozen feet overhead, suck particulates upward and outward into exile. The antistatic robes worn by technicians funnel personal particles down toward the floor, which is swabbed regularly.

“Microbes need particles to attach to,” Venkat says. “Without particles, without nutrients, the environment is essentially extreme.”

If astrobiologists have learned anything, however, it’s that almost no environment is too extreme for life. In the past few years, scads of extremophile organisms have been discovered thriving under conditions once considered inhospitable. Clams have turned up in the sunless, high-pressure depths surrounding seafloor vents. Algae in the Antarctic, where conditions resemble the dry valleys of Mars, spend much of their lives desiccated and drifting in the wind, waiting for their situation to improve. Microbes have been found miles underground in hot geysers, in gold mines, in solid volcanic rock, deriving their nourishment from sulfur, manganese, iron, petroleum. In recent years, a whole new field called geo-microbiology has sprung up precisely to study tiny creatures that are otherwise indistinguishable from rocks. Astrobiologists agree that if there is life to be found beyond Earth, it almost certainly will be very small and equally hard to discern.

Trained as a microbiologist, Venkat brings to his task an impressive history of sleuthing out wily tiny critters. In 1998 he discovered a bacterium that survives the high salinity of Mono Lake in California by living inside the lake’s rocks. After prominent newscasters and government officials were mailed anthrax spores in the autumn of 2001, Venkat published a paper later used by the Department of Homeland Security on how to distinguish anthrax from other microbes. None of his encounters in the microworld, however, quite prepared him for the discoveries he has made in Pasadena. Using a sophisticated array of life-detection methods—the same methods being refined for the hunt for extraterrestrial life—Venkat has discovered a plethora of bizarre microbes thriving in the Spacecraft Assembly Facility, microbes that would have escaped detection by older technologies. He held up a red-capped vial for me to see. Inside, invisible in a thimble-size sea of clear liquid, were the newly found inhabitants of Planet NASA. Venkat’s lab encompasses a true microcosm: a new world, hitherto unexplored, as enlightening as any that his stargazing colleagues will ever hope to find.

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THUS far, Venkat has identified 22 species of microbes in the Spacecraft Assembly Facility, in other, similar NASA environments, even on actual spacecraft. Many are microorganisms common to arid environments, such as B. mojavensis, a bacterium that probably drifted in from the Mojave Desert. A handful are entirely new species. One, which Venkat has named B. nealsonii (in honor of Kenneth Nealson, who was his supervisor at the Jet Propulsion Laboratory), possesses two protective coats, making it a tough spore capable of surviving in the ultradry environment of the assembly facility. As Venkat discovered, the second spore coating also offers a secondary benefit: It makes the organism unusually resistant to gamma rays, a form of cosmic radiation that, in large doses, is fatal to men and microbes alike. (Earth’s atmosphere screens out most gamma radiation; Mars, in contrast, is a gamma-ray frying pan.) Tough as it is, the bacterium is probably not unique to NASA. The world of undiscovered microbes is vast, and Venkat suspects that B. nealsonii also resides outside the assembly facility.

Venkat has found bugs in the spacecraft-assembly facility at the Kennedy Space Center in Florida; on hardware and in drinking water from the International Space Station; in circuit boards destined for an upcoming mission to Europa; and on the metal surface of the Mars Odyssey spacecraft, which has been orbiting Mars since October 2001. While Odyssey was being assembled at the Kennedy Space Center, Venkat isolated a new species of bacterium—Bacillus odysseyi, officially—that carries an extra spore layer, or exosporium, that makes it several times more resistant to radiation than other spore-forming microbes found in the facility. “It carries novel proteins as a sunscreen,” Venkat says. Like B. nealsonii, B. odysseyi may turn out to live elsewhere besides its assembly facility. But What’s notable, Venkat says, is that the very traits that render these bugs impervious to decontamination also grant them a decent chance of surviving the radiation shower they would encounter en route to and on the surface of a place like Mars.

One discovery, a bacterium named Bacillus pumilis, has given Venkat particular cause to marvel. He found the microbe thriving directly on spacecraft surfaces, presumably drawing its energy from ions of trace metals like aluminum and titanium. “Aluminum is toxic,” Venkat exclaims, baffled. “There are no nutrients. There is no water.” In addition, the species exhibits a remarkable defense against desiccation. The individual cells form protective spores, which then band together to create what Venkat calls an igloo. In microphotographs, this spore house looks rather like a macaroon. Moreover, when Venkat cuts open the igloo, he finds no visible trace of the individual spores; they’ve all dissolved into the collective matrix. High-tech methods of life-detection reveal no evidence of life. Yet when Venkat warms up the igloo and adds a little moisture, B. pumilis again springs into being. If the microbe is any indication of the sort of life that awaits discovery on Mars or elsewhere, he says, good luck to the robot sent to detect it.

B. pumilis itself isn’t a new species. It has been studied throughout the world for years, but its igloo-forming habits were not well known. For instance, its attachment to aluminum is novel. Last month, Venkat published a paper claiming that the SAF version of B. pumilis is in fact a new species after all—a substrain that has adapted and evolved to the conditions imposed on it by NASA, like an herbicide-resistant dandelion or the supertough microbes that sometimes spring up in hospitals. He has named it Bacillus safensis, and it represents precisely the kind of organism that his fellow astrobiologists are looking for in outer space. it’s not a Martian, but in form and function it may turn out to closely resemble one.

It is, in any event, one step closer than any other earthly creature to becoming the first organism to survive on another planet. Venkat has found the bacterium in every other NASA assembly facility he’s studied. Three years ago he found it on the Mars rovers Spirit and Opportunity, then under assembly at the Jet Propulsion Laboratory. At this very moment, the rovers are actively poking around in the Martian dirt, as they have been for the past nine months. B. safensis is almost certainly aboard them, alive and well, Venkat says. “They could be there for millions of years because they are spores. Whether they will become active and begin terraforming—that research is still ongoing.”

The Space Assembly Facility is a standing paradox. Through its assiduous effort to avoid spreading life throughout the cosmos, NASA has created an environment that inadvertently fosters the very kind of life it is traveling so far beyond Earth to find. As Venkat says, “We have a kind of survival of fitness.” What began as a means to an end is now an end in itself; the doorstep has become a laboratory, a nursery even, a small-town study in life’s cosmic persistence. It is a study, too, in the impossibly high cost of perfect hygiene. Venkat found that, in at least one instance, some of the microbes appeared to have been introduced during the cleaning process devised to eliminate them. Wherever humans go, it seems, we go with company. Looking around the assembly facility with Mora and Gomez, I saw a man-made cosmos, every surface a habitable planet, its ethers traversed by micronauts riding spacecraft named Human Hair and Eyeball Cell.

“People are the dirtiest things around,” Gomez said.

“Yeah,” said Mora. “We’re the contaminants.”