Space / Extraterrestrial Life

“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.

BACILLUS SAFENSIS Highly resistant to gamma and UV radiation, B. safensis is named for the Jet Propulsion Laboratory’s Spacecraft Assembly Facility (SAF), in which it lives. It can also be found on the current Mars rovers, Spirit and Opportunity.