Is the Earth Safe From Lunar Contamination?

Fortunately, the possibility that living organisms exist on the moon is remote. But if they do exist, and in turn infect the astronauts, the Apollo 11 flight may indeed be an historic event.

With that ironic understatement, a doctor at the Manned Spacecraft Center in Houston last week summarized an increasing concern among some scientists that returning astronauts may contaminate the earth with strange and perhaps dangerous bugs. His statement added fuel to a controversy that broke into the open last month when it was revealed that NASA had relaxed its elaborate quarantine plans for the Apollo 11 crew (TIME, May 16).

Most scientists agree that there is little chance of any life existing on the moon. But they differ widely on the possible consequences to earth if there are lunar organisriis and any of them hitch a ride with the returning astronauts. University of Chicago Chemist Edward Anders and several of his colleagues are so unconcerned about the danger of contamination that they have volunteered to expose themselves "in every medically reasonable way" to any rocks that the Apollo 11 mission manages to bring back from the moon. They would be willing, they say, to swallow small samples to prove their point.

Escaped Fragments. The apparent boldness displayed by Anders and others stems from their strong doubts that lunar life exists and their conviction that quantities of lunar debris have been falling on the earth's surface for billions of years. Thus, they reason, even if there are lunar organisms, terrestrial life has long been exposed to them without any catastrophic results. According to their theory, meteors often strike the moon with enough momentum to knock lunar fragments loose at escape velocities. Most such fragments captured by the earth's gravitational pull would be incinerated as they plunge through the atmosphere. But those in a certain size range, the scientists say, would drift down and arrive on earth relatively unscathed, safely delivering any organisms they might contain.

Others are more concerned. Although he agrees that organisms might survive a moon fragment's entry into the earth's atmosphere, Cornell Exobiologist Carl Sagan is less confident that they could live through the heat generated by a meteor impact on the moon. For that reason he has doubts that lunar organisms have ever reached the earth and that terrestrial life has already proved its immunity. Sagan, like most other scientists, believes that the odds are high against life existing on the moon. But he cautions that there is "an exceedingly small risk of possibly great harm" in not maintaining strict quarantine procedures for the returning Apollo 11 astronauts. "Maybe it's sure to 99% that Apollo 11 will not bring back lunar organisms," he says, "but even that one percent of uncertainty is too large to be complacent about."

Inadequate Quarantine. University of Rochester Biochemist Wolf Vishniac is not particularly concerned about the Apollo 11 mission, which will bring back only surface samples. But Vishniac is convinced that more elaborate quarantine precautions should be taken thereafter. On later missions, he points out, astronauts will dig for samples from below the surface, where radiation and temperature variations are less severe and the prospects of life more likely.

Whatever the prospects for lunar life, Cornell Microbiologist Martin Alexander feels that NASA's present Apollo quarantine plans are on shaky scientific grounds and hopelessly inadequate. In discussing the plans with those in the Apollo program, he says, he has heard such statements as, "Of course, it's a sham, but what else could we do?" and, "The public needs to be comforted, and the quarantine serves that function." Shocked by this seeming indifference to what could be a real threat, Alexander calls on NASA to reveal its quarantine plans fully and "to solicit frank opinions and criticism" from the scientific community.

In response to criticism from the Committee on Back Contamination, a group of scientists representing a variety of federal agencies, NASA has improved the complex quarantine procedures in Houston's $15.8 million Lunar Receiving Laboratory (TIME, Dec. 29, 1967), where the returned astronauts and their lunar samples will spend most of their three-week isolation period. The space agency has also taken makeshift measures to plug a major gap in the quarantine defenses: the post-splashdown exposure of the Apollo cabin atmosphere and the astronauts themselves in the earth's environment.

Antiseptic Solution. To minimize contamination of the command module interior, the two astronauts who walk on the lunar surface will leave their boots and gloves behind on the moon. Before they emerge from the spacecraft in the Pacific, the crew will have vacuumed the interior, collecting the swept-up material in canisters containing a chemical absorbent. Instead of climbing through the command module's open hatch and into a raft before donning their biological isolation garments, the astronauts will remain inside the spacecraft until a frogman opens the hatch, tosses the garments inside, and then closes it again. They will change into their bug-containing outfits and step into a raft filled with disinfectant. Then the frogman will spray more disinfectant on the astronauts and around the spacecraft hatch.

Despite these elaborate decontamination procedures, however, organisms-might well survive in the bodies of the astronauts and in the spacecraft atmosphere. Thus, when the craft is vented upon splashdown and when the hatch is opened twice--no matter how briefly--dangerous organisms could escape into the air and the ocean, perhaps to thrive and pose a threat to life on earth.

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