Let's Stop Wasting Money Sterilizing Our Spacecraft

Each year, NASA spends lots of money making sure its spacecraft are properly sterilized so that our Mars landers and probes don't bring any bacterial life from Earth to mix it up with whatever may or may not be living there. The same goes for any theoretical spaceships coming back to Earth from Mars, in hopes of saving mankind from alien diseases.

It's time to stop doing that.

There's lots of reasons sterilization became the norm, but the more we learn about the nature of space and of life in general, the dumber it becomes for us to continue wasting money on clean rooms, disinfectants, and so-called "planetary protection." Two scientists said as much, in kinder terms, in a paper called "The Overprotection of Mars," published Thursday in Nature. Others say that sterilization is a "farce" that's been impeding Mars science for nearly four decades.

It's unclear how much money NASA spends on its clean rooms, developing microbial-resistant materials, and ultimately launching sterile spacecraft, but the agency has an "Office of Planetary Protection" whose mission is to "assist and promote the responsible exploration of the solar system by minimizing the biological contamination of explored environments" and to "preserve our ability to study other worlds as they exist in their natural states."

The official budget lumps "planetary protection" in with its Mars Program Management line item, which also includes "advanced mission studies and program architecture, program science, and telecommunications coordination and integration." In 2012, NASA spent $23.4 million on Mars Program Management, and $341.4 million on its overall Mars program, with much of that coming on the Curiosity Rover and the Mars Science Lab.

The money dedicated to planetary protection is wasted, argue a Cornell astronomer and a Washington State University environmentalist in the Nature paper. That's because either all microbes are killed by the trip to Mars (or soon after landing on the surface), making sterilization unnecessary, or Mars is already so riddled with Earth's microbes that it doesn't matter if we send a little more on future rovers or probes.

From a logical standpoint, it makes sense. Each year, roughly 500 kilograms of Martian soil makes its way to Earth, launched from its atmosphere by asteroid impacts. We can assume, then, that similar amounts of Earth's crust land on Mars each year. Here's what the paper has to say about it:

"If life on Mars originated independently and has not yet died out, life indigenous to Mars and life imported from Earth by interplanetary transport are already coexisting and have coexisted for eons. Possible microorganisms onboard our spacecraft would not interact with the indigenous Mars life in a different way than previous Earth life transported to Mars. Any competition between Mars life and Earth life would have played out long before the arrival of human spacecraft. Future missions would simply find the survivors of this natural selection process, and these survivors would be expected to be better adapted to martian conditions than new arrivals from Earth."

That's what scientist Robert Zubrin, head of the Mars Society, has been screaming for years. In his book The Case for Mars, he has a whole chapter dedicated to picking apart NASA's argument that we must preserve the ecological integrity of Mars.

But NASA is still abiding by protocols developed in the 1960s, when the United Nations' Treaty on the Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies stated that all countries "shall pursue studies of outer space, including the moon and other celestial bodies, and conduct exploration of them so as to avoid their harmful contamination."

Back then, sterilization made sense, says Alberto Fairen, one of the authors of the Nature paper.

"I can't put myself in the minds of the scientists in the 70s, but I absolutely understand the concerns and the reasons why the [sterilization] programs were implemented," he said. "What we say now is that maybe it's a good time to to reevaluate the situation."

Here, according to NASA, is what all of its rovers undergo prior to launch:

Each Mars Exploration Rover complied with requirements to carry a total of no more than 300,000 bacterial spores on any surface from which the spores could get into the martian environment. Technicians assembling the spacecraft and preparing them for launch frequently cleaned surfaces by wiping them with an alcohol solution. The planetary protection team carefully sampled the surfaces and performed microbiology tests to demonstrate that each spacecraft meets requirements for biological cleanliness. Components tolerant of high temperature, such as the parachute and thermal blanketing, were heated to 110 degrees Celsius (230 Fahrenheit) or hotter to kill microbes.

Despite all that, we're not even terribly good at keeping spacecraft sterile. Roughly 250,000 bacterial spores are believed to have survived the transit aboard Curiosity, and tests before launch showed that the Martian atmosphere does most of the work for us. In a paper published in 2011, researchers contaminated a Curiosity stand-in with more than 100,000 times the amount of expected bacteria that could survive. More than 97 percent of that was killed within hours of being exposed to UV light designed to mimic Mars' atmosphere.

Two major events have made sterilization programs almost entirely unnecessary, Zubrin says.

In 1976, Viking determined the makeup of the Martian atmosphere, and a meteorite that landed on Earth from Mars in 2001 had gas bubbles in it that confirmed "we were being bombarded with Martian rocks, and we were able to tell many of these rocks were not sterilized" by the trip through space.

"This makes the entire protocol a very costly farce, and it's one of the primary impediments for a Mars sample return," Zubrin said. "And there's unquestionably been terrestrial contamination on Mars. We go to heroic lengths to sterilize our own spacecraft, when Mother Nature has already sent Mars millions of her own contaminants."

That makes it possible, even likely, that any life on Mars initially came from Earth. Does that make those hypothetical microbes "alien?" Probably, Fairen says.

"If Earth life was transferred to Mars say 3 billion years ago, when Mars was wetter and more Earth-like, and life actually endured, and it has evolved to adapt to the particular changing environmental conditions on Mars, then i think the descendants of those early voyagers are by all means Martians," he said.

Last year, Catharine Conley, head of NASA's Planetary Protection Office, defended her position, saying that invasive species often decimate environments on Earth--and that the same goes for bringing back samples from Mars.

"If you bring [Martian] soil back to Earth, we have to contain it at the same level of security we use to contain things like the Ebola virus," she said. "We also have to make sure Earth life doesn't get into the samples."

That's nonsense for several reasons, Zubrin says, most notably because there are no macro-life forms on Mars, which would be necessary for microbes to evolve to be dangerous to humans.

"The life cycle of a Martian pathogen is impossible to hypothesize," he said. "Earth pathogens have particularly adapted for millions of years ever since we've evolved. Only those can infect us."

And, like I mentioned earlier, soil from Earth and soil from Mars have been getting blasted back and forth between each other for billions of years. When a rock from Mars enters our atmosphere, it doesn't stop for a Lysol bath on the way. The most damage a Mars rock has ever done, according to at least some tall tales, is kill a dog in Egypt 100 years ago when it hit the poor guy in the head.

The idea that any sample returned from Mars would first have to be sterilized, Zubrin says, is like "finding a viable dinosaur egg and then sterilizing it. This hysteria is an insult to the science."

The other major NASA argument for sterilization, and one that Fairen sort of agrees with, is to prevent "false positives" like the one Viking found in the 70s--that is, finding life on Mars that came on the spaceship from Earth. Fairen says that sterilization should be used "only in life-searching missions, and only to avoid false positives."

That, on its face, makes more sense, but in the case of any sort of sample return mission, it'd likely be wholly unnecessary. Analyzing soil samples from millions of miles away is tough, but analyzing them on Earth, where DNA can be sequenced and we can use high-powered microscopes, separating out that which is "Martian" from Earth microbes would be cake.

Zubrin points to the fact that researchers were able to trace microbes used in the 2001 anthrax terrorist attacks to a specific lab in Iowa to point out how easy it'd be to separate alien from familiar microbes.

"They were able to trace that anthrax to a certain strain developed in Ames, Iowa, and furthermore, the degree of genetic drift apparent in that sample allowed them to tell it had been removed from the lab in 1987," Zubrin said. "That's how specific they could be. Microorganisms are not generic, they're specific."

All this talk of sterilization, by the way, goes out the window the second you send a human to Mars.

"You can't sterilize humans," Zubrin said. "As soon as a human goes outside on Mars, there will be bacteria that escape."