MEMO: N. H. Horowitz to J. Lederberg Feb. 6, 1960

Back-contamination and the goals of exobiological research.

Against the slight risk of pandemic disease and the perhaps greater one of
economic nuisance, one must weigh the votential benefits to mankind of un-
hampered traffié with the planets. The present situation may be likened to
that which obtained in Europe in the decade before Columbus set forth on his

voyage of discovery. If men had known then that Columbus would bring back with

him a disease--syphilis--that was to plague Burope for centuries, they might
well have prevented him from ever leaving Spain. Suppose, however, that they

had known also of the tremendous benefits that were to flow from the discovery

of the New World. Can there be any doubt what their decision would have been
then?

In view of the small risk involved in the premature return of planetary probes,
it would be inadvisable to adopt a position--~e.g., an embargo on returning space=

craft--which might prejudice the devehopment of the necessary technology for
return flights. Also to be considered is the probably deleterious effect on

the fact that definitive information on the biological composition=--and the
chemical composition, as well--of the lunar and planetary surfaces will come

public opinion of an excessively cautious policy. Rather, we should recognize

only from studies in a terrestrial laboratory of soil samples from these bodies.

The procurement of such samples should therefore be the primary goal of exo-
biological researche It should be understood that the biolggical exploration
of the planets by instrumented robot payloads is not a substitute for this
primary objective, but is only a step toward ite This and all other aspects
of the exobiological research program should be subordinate to the &tainment
of the primary goal.

¥ By tha > pasane Mat The fou Wlbe may oe piplieah © 8 ot
puter iu ppoee wpletionn