HARVARD COLLEGE OBSERVATORY
CAMBRIDGE 38, MASSACHUSETTS

October 14, 1956

Professor Joshua Lederberg
Genetics Building
University of Wisconsin
Madison 6, Wisconsin

Dear Dr. Lederberg:

Thank you for your reprint about biological space research.
I was very interested to read it, and I quite agree that there is the
possibility of the transference of organic materials amongst the planets
or even further afield. In fact I recall giving a lecture on this subject
in Cambridge, England, in about 1949,

Iam in complete agreement with you that Mars and Venus should
not be contaminated by terrestrial life until there has been a chance to
examine what is there, One could, in that case, visualize the possibility,
remote though it is, that physical and chemical circumstances ; suit-
able for the reproduction of some terrestrial micro-organisms whose pre-
sence might mislead us later and who might even displace some local form
of life. This argument does not apply to the case of the Moon, of course,
and there it would seem to me that contamination should only be kept so
low that the chance of finding some contaminant in any sample that is later
collected is extremely small. Iam not really sure that I would even be
worried about the contamination, gross though it is, of a dead dog plunging
into the Moon, but I agree that that point is possibly debatable. Certainly
sterilizing rockets before letting them go seems to me over-cautious by
quite a large margin.

I should be very glad to be put on your mailing list for any other
space-biological articles that you may write, especially as I am on the
committee that is concerned with making recommendations in this field,
amongst others,

Yours sincerely,

—_—

T. Gold
Professor of Astronomy

TG:mad