Mars Rocks: Interplanetary Contamination Risk?
Air Date: Week of February 27, 1998
As evidence mounts that there may be life elsewhere in the solar system, the national space agency gears up to protect Earth from possible extraterrestrial contamination. For the first time, Apollo scientists are admitting publicly that efforts to protect Earth from extraterrestrial microbes were a failure. And they are warning that (the) NASA must do a better job with samples they plan to bring back from the planet Mars in the year 2003. Living on Earth's Daniel Grossman reports.
CURWOOD: It's Living on Earth. I'm Steve Curwood.
[Children's yells, "You guys, there's dinosaur eggs over there!"]
CURWOOD: In a corner of Boston's Museum of Science, is a glass cabinet containing three specks of black rock. They're samples, scooped up from the surface of the Moon, during the first human expedition by astronauts Neil Armstrong and Buzz Aldrin in 1969. Few visitors stop to view the lunar display today, but there was a time when the rocks were considered fascinating, even dangerous. There were fears that lunar material could contain extraterrestrial microbes, and elaborate systems were designed to protect the Earth from potential infection. As NASA prepares to send a probe to bring back samples from Mars in the year 2008, concerns about contamination are resurfacing. Apollo scientists now admit that the safety systems for their missions were inadequate, and there are warnings that the space agency must do a better job with any material it brings back from the Red Planet. Living on Earth's Daniel Grossman has an update.
(An audience applauds)
MCKAY: I'm going to talk about how Mars compares to Earth, how it represents a second example, possibly, of life, and our understanding of it as a planet, and how we might investigate that, in particular where we would go.
GROSSMAN: A crowd of scientists packed into a lecture hall listening intently to Chris McKay.
GROSSMAN: He's a NASA researcher and champion of the idea that the planet Mars may have once harbored life, and possibly may still.
MCKAY: On Earth, life is essentially little bags of water. And so, seeing that on Mars, in its past, it had liquid water, is the fundamental motivation to consider the question of life there.
GROSSMAN: Although there's no liquid water on the planet today, Mars does have polar ice caps. And space probes orbiting Earth's neighbor have beamed back photos showing what appear to be ancient river beds cut into the Martian surface. Last summer, the Pathfinder robot discovered rounded pebbles, erosion patterns, and other evidence that water once flowed over the Red Planet. If life took root, some researchers say fossil remains may be there. It's even possible tenacious microbes still inhabit underground rock deposits or undiscovered hot springs.
MCKAY: Let me answer a related question, which is, Earth and Mars started off so similar, why did they take such different trajectories? Why did Mars go bad? Is it, bad schools, bad neighborhoods--
GROSSMAN: Chris McKay says finding conclusive evidence of life on Mars would turn biology upside down.
MCKAY: All of life on Earth is a single phenomenon, is a single related system. It's all the same DNA, the same protein structure. The question is, is that unique? Is that a freak? Or is life wide-spread in the universe? Going to Mars and searching for even fossil evidence of life, will be, I think, a concrete way where we can actually get data to address the question.
GROSSMAN: The search for life elsewhere in the solar system is not just the pipe dream of a few scientists. It's captured the imagination of the nation. President Clinton endorsed the idea in a ceremony at the White House.
CLINTON: I am determined that the American space program will put its full intellectual power and technological prowess behind the search for further evidence of life on Mars.
GROSSMAN: The space agency NASA is planning no fewer than 7 missions to Mars in the coming decade.
GROSSMAN: The first conclusive proof of extraterrestrial life could come as early as 2008, with a probe designed to bring Martian soil back to Earth. But what if the sample contains more than just live evidence of life? What if it harbors live or dormant organisms? Could they pose an ecological threat? Or even infect humans with a deadly disease, like in the science fiction thriller, "The Andromeda Strain?"
[Weird space music]
"ANDROMEDA STRAIN" ACTOR 1: No proteins, no enzymes, no nucleic acid? Impossible! No organism can maintain life without them!
"ANDROMEDA STRAIN" ACTOR 2: You mean no Earth organism. It must have evolved in a totally different way.
"ANDROMEDA STRAIN" ACTOR 3: You got it. It doesn't come from here.
GROSSMAN: Researchers say such threats are highly unlikely. The Martian surface is probably too inhospitable to harbor life today. It's drier than Earth's most barren desert, fried by intense ultraviolet radiation, and possibly coated with toxic soil. But no one is willing to say life there is impossible, which raises the question, is NASA up to the challenge of keeping an extraterrestrial sample isolated? A chapter in the agency's past raises troubling concerns.
KENNEDY: I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the Moon and returning him safely to the Earth.
GROSSMAN: The year was 1961, the height of the cold war.
[Kennedy's announcement continues]
GROSSMAN: President Kennedy, eager to prove American superiority, unveiled the Apollo Project. The goal was ambitious, but NASA accomplished the feat in July, 1969.
ARMSTRONG: Tranquillity Base here. The Eagle has landed.
GROSSMAN: To the public, the mission appeared flawless. But the agency stumbled when it came to isolating the lunar samples from the Earth's biosphere.
NEALSON: We heard an array of stories that would have boggled your mind.
GROSSMAN: Biologist Ken Nealson chaired a National Academy of Sciences panel that was briefed by Apollo scientists about the moon mission.
KLEIN: A huge amount of safeguards and other things were mostly just a facade.
GROSSMAN: Among the old-timers who spoke to the panel was Harold Klein. He was part of a group overseeing NASA's plans to avoid contaminating Earth in the unlikely event microorganisms were ferried home from the Moon.
KLEIN: We had recommended that the Apollo capsule land near an aircraft carrier, that the aircraft carrier would have a crane, which would then lift the entire spacecraft out of the water onto the deck.
GROSSMAN: The group told NASA to keep the astronauts and their cargo isolated until tests proved there was no hazard. But that's not what happened.
SHIP: Don't want to affect your splashdown area, over.
ASTRONAUT: I'll turn around, I'll splashdown here...
KLEIN: When the spacecraft landed in the water, the hatch was opened, it went right out to the open, and then we know, you know, that the inside of the Apollo spacecraft had a lot of lunar dust kicking around in it. And that's what we were trying to avoid, any of that dust getting out into the atmosphere. That was a clear breach.
GROSSMAN: There were other breaches, as well. When the capsule entered the Earth's atmosphere, a vent was opened to cool the interior. That released lunar dust. And at the Houston lab where moon rocks were studied and astronauts quarantined, rubber seals broke. The rocks turned out to be sterile, but that wasn't proven until months of exhaustive studies were completed. Harold Klein resigned from the committee in disgust. In a scathing postmortem of the lunar program in 1975, the group's co-chair, John Bagby, denounced what he called NASA's outright resistance to his committee's quarantining recommendations. "Many top managers considered the precautions unnecessary, and worried they would cause unacceptable delays," he wrote. NASA officials have pledged to do a better job when they bring a sample from Mars back to Earth. And they're already sketching out how the extraterrestrial payload will be tested.
WAINWRIGHT: This is a horseshoe crab. It's a primitive marine invertebrate, and the part of the organism we're very interested in is its immune system, its defense mechanisms.
GROSSMAN: At the Marine Biological Laboratory in Woods Hole, Massachusetts, Norman Wainwright pulls a fist-sized horseshoe crab from a shallow tank. For about 200,000,000 years, this creature has remained almost unchanged, a fact Dr. Wainwright says is due in part to the animal's striking ability to detect and contain microbial intruders. Dr. Wainwright is harnessing the animal's talents to make one of the most sensitive tests known for the presence of microbes.
WAINWRIGHT: Would you like to see what the actual test looks like? It's very simple.
GROSSMAN: Norman Wainwright strides to a black laboratory bench, where a rack of test tubes contain varying mixtures of horseshoe crab blood and fungal cells. Each tube is hooked to a detector. Even a tiny portion of a fungal cell is enough to cause the blood to clot and turn cloudy, a change the researcher monitors on a computer. Dr. Wainwright is exploring how sensitive the test is, and how many kinds of microbes he can detect.
WAINWRIGHT: This screen will show the information being collected from one tube, and will graph how turbid a sample is becoming over time. As you see, the graph just updated itself to show an increase. So this would, in fact, be a point which this sample has shown to be positive.
GROSSMAN: A test like this could sound the first warning that a sample brought back from Mars bears interplanetary stowaways. Last year, a National Academy of Science's panel issued a report recommending how NASA should protect Earth from Martian microbes.
NEALSON: In essence, we were doing what I would call an interplanetary environmental assessment.
GROSSMAN: Ken Nealson says the panel, which he headed, concluded that the risk posed by a Mars sample is exceedingly small.
NEALSON: We tried and tried to dream up a worst-case scenario, and really couldn't come up with much.
GROSSMAN: Couldn't come up with much, because they said anything that tolerates the harsh conditions of Mars would most likely find Earth unsuitable. Too warm, too wet, and so on, but just in case, they did recommend that any payload should be carried back in a sealed container and examined on Earth in a secure laboratory, the kind the Centers for Disease Control uses to contain Earth's most deadly microbes. Ken Nealson says, if these precautions are taken, there should be no threat.
NEALSON: We bring Ebola virus into this country to study, and we know that's dangerous. You know, so there shouldn't be any big qualm about bringing a Martian rock, which we suspect is not dangerous.
GROSSMAN: And since the Apollo project, laws have been passed, like the requirement for environmental impact statements. They make it more likely that when NASA brings Mars rocks home, the precautions will be handled better.
NEALSON: One should expect they'll be done better this time, because if you don't ensure that they're going to be done better, I don't think the mission will fly. I think there'll be a lawsuit filed, and one well-placed lawsuit will delay this entire enterprise for two years at a time.
GROSSMAN: And if there's one thing NASA fears more than alien microbes, it's a lawsuit. For Living on Earth, I'm Daniel Grossman.
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