Exobiology: Quarantine for Space Travelers?

Space is notoriously dangerous for astronauts, but the first astronauts who return from the moon or Mars may be a danger to all life on earth. The exotic microorganisms that they bring with them may become man's deadliest ene mies, warns a panel of eminent scientists headed by Biologist Allan H.

Brown of the University of Pennsylva nia. The panel's report, "Potential Haz ards of Back Contamination from the Planets," was made public last week after nearly a year of hush-hush treatment by the National Aeronautics and Space Administration. It added a chill ing new factor to the future of space exploration.

Raging Pestilences. Life is likely to exist on Mars, says the panel, which was brought together by the National Academy of Sciences. And no one can be sure that life does not lurk below the surface of the moon. If its chemistry is similar to life on earth, given any opportunity it might attack earthly plants and animals. The panel recalls many instances when earthly microorganisms swept through populations that had no natural resistance. Many New World peoples were reduced to remnants by plagues of measles and smallpox brought by explorers from Europe.

Even if extraterrestrial organisms have a different chemistry, they may do incalculable damage on earth by multi plying wildly in competition with native plants. A more subtle danger is that they may upset the delicate chemical . balance on which earthly life depends.

An exotic organism living humbly in the soil might starve native plants by turning some vital nutrient, such as nitrogen, into a form they cannot use. If the earth's plants die of starvation, its animals, including man, will die too.

Since the nature of extraterrestrial life is not known, the most farsighted scientists cannot imagine at present all the ways that it might affect earthly life.

In the case of the lunar landing that NASA is still planning for 1969, the scientists on the panel believe that the exterior of the returning spacecraft will probably be free of lunar microorganisms. A more likely carrier of moon contamination will be the lunar soil and rock that the astronauts are planning to bring back with them. More than 40 universities and other scientific institutions have already asked for samples of this fascinating material, but the panel thinks their pleas should be rejected. It insists that the potentially dangerous moonstuff must be carried in germtight containers and must be stored when it reaches the earth in germproof rooms where it can be handled by remote control.

Infected Astronauts. The returning astronauts themselves will be much more difficult to deal with than moon soil. Slow-growing germs or viruses may be lurking in their intestines and respiratory passages. The very least precaution that must be taken against them, says the panel, is to quarantine them rigidly for at least three weeks. But Deputy Surgeon General Dr. David E. Price, a member of the panel, believes that even this inhospitable welcome will not be enough. Says Dr. Price: "Quarantine is a crude approach to a problem of this sort. I would not feel safe in placing a large part of my faith in it as a security method."