Space Invaders? Microbes' Travel Raises Concern

STEVE INSKEEP, host:

Suppose you're one of those people who wonders if life on Earth came from outer space. This isn't just the stuff of science fiction. Scientists really wonder about this - wonder if microbes traveled here on a meteorite. One question, though, is whether a microbe could survive the trip through space.

Later this year, if all goes well, a scientific mission will test that idea. NPR's Nell Greenfieldboyce has more.

NELL GREENFIELDBOYCE: Sometimes rocks get blasted off planets and travel through space. The idea that life might hitch a ride isn't new. But Bruce Betts says no one has ever done a key experiment: sending microbes out for a long trip through the harsh conditions of deep space and then bringing them back to see how they've fared.

Mr. BRUCE BETTS (The Planetary Society): It's an untested piece of the puzzle of whether life can travel between planets inside rocks.

GREENFIELDBOYCE: So, the group he works for, The Planetary Society, is planning to do this test. It will send various sorts of life on a nearly three year trip. The living things will travel in a simulated space rock. It won't look like a rock.

Mr. BETTS: You can hold it in your hand. Looks kind of like a small metal hockey puck. The outside is titanium.

GREENFIELDBOYCE: And inside?

Mr. BETTS: There are 30 small tubes that will contain three sets of ten different organisms.

GREENFIELDBOYCE: These tiny life forms will represent the diversity of life on earth. There will be things like yeast and bacterial spores. And they'll be hearty - tough enough to survive, even if there's no water and lots of radiation. The capsule will also carry a bit of soil and whatever life it contains from a harsh earth environment - the Russian tundra.

It will be the Russian tundra because the capsule will be traveling on a Russian spacecraft. Betts says that the Planetary Society was looking around for a space mission that might provide a long roundtrip ride, and they learned that Russia was planning a robotic mission that would go to a Martian moon, collect a sample of dirt and rocks and return it to earth for analysis.

Mr. BETTS: So, we contacted them and we are essentially piggybacking with them. So our - what we call the life bio module sits inside next to their sample return capsule and comes back to Earth, which is the requirement we have.

GREENFIELDBOYCE: It will come back, assuming all goes well. But some critics worry that the mission could go awry. What if this capsule full of earth life lands not on the dead Martian moon but on Mars itself, a planet that scientists think could possibly support life?

In a worst-case scenario, the capsule would break open, spewing out hardy little earthlings. They could contaminate the Red Planet or make it impossible for us to know if Mars ever had its own life. The Planetary Society takes all of this very seriously, but Betts says the chances of anything bad happening are incredibly small.

Mr. BETTS: It's not actually easy to hit another planet, even if you're going in the general vicinity.

GREENFIELDBOYCE: And he says even if the spacecraft did hit Mars, the capsule is designed to withstand a hard impact. Now, there are actually international agreements about not contaminating alien worlds with non-native life. In fact, depending on the destination, sometimes a spacecraft has to get a thorough cleaning before launch.

Cassie Connolly(ph) works for NASA. Her title is planetary protection officer. She says the Planetary Society's experiment does comply with international guidelines, but that doesn't mean she thinks everything about the space capsule is wise.

Ms. CASSIE CONNOLLY (Planetary Protection Officer, NASA): My discomfort is high at the idea of sending Russian tundra.

GREENFIELDBOYCE: She says whatever is living in that soil sample might find Mars to be downright homey.

Ms. CONNOLLY: Because of all the places on earth, Russian tundra or any other tundra really is one of the places that has the potential for having organisms that might be most able to survive on the Martian surface.

GREENFIELDBOYCE: And she says a bit of soil can contain all kinds of unknown things.

Ms. CONNOLLY: If you send an uncharacterized soil sample, then it just increases the risk that you're going to have an accident and have the potential for having something happen that you weren't aware of simply because you didn't have all the information before you started.

GREENFIELDBOYCE: She says she has expressed her concern, but other than that, there's nothing she can do. The mission is scheduled to blast off later this year.

Nell Greenfieldboyce, NPR News. Transcript provided by NPR, Copyright NPR.