HARVARD COLLEGE OBSERVATORY
CAMBRIDGE 38, MASSACHUSETTS

September 23, 1958

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

Dear Professor Lederberg:
I have only just come back from abroad, and am replying to your

letter of June 23rd, concerning the question of lunar dust. I wrote an
article on this subject in the Monthly Notices of the Royal Astronomical

' Society, of which I am enclosing a copy.

I think I read something in a journal recently about the question
of a biological investigation of the lunar surface and the risk of the con-
tamination of the Moon by terrestrial material brought up in rockets. A
rapid calculation will show, however, that all the biological material that
might accidently be carried up in even quite a large number of rockets
that maylp explode and scatter themselves near the Moon would still not
produce a biological contamination that would result in a remote chance
of showing up on an arbitrary sample of the lunar surface taken at a later
time. I cannot believe that any kind of precautions are necessary, and
hope that no such greatly over-cautious policies will be allowed to inter-
fere with lunar experimentation. If you have any other views on this, I
should be glad to hear them.

Yours sincerely,

7G fl
T. Gold

Professor of Astronomy

TG:mad
Enclosure