CHESTER BEATTY RESEARCH INSTITUTE
INSTITUTE OF CANCER RESEARCH: ROYAL CANCER HOSPITAL,

TELEGRAMS: GANCER, SOUTH KENS, LONDON. FULHAM ROAD,
TELEPHONE: FLAXMAN 1484-5-6,
LONDON, S.W. 3.

15th May, 1958.

Dr. Joshua Lederberg,
Department of Genetics,

The University of Wisconsin,
Madison, Wisconsin,

U.S.A.

Dear Dr. Lederberg,

We have just finished a two day meeting of the
committee on contamination by extra-terrestrial exploration
(CETEK).

At this meeting Professor Florkin showed us your very
interesting paper which you prepared for presentation in Washington.
As rapporteur for the committee, I am now preparing its report
and have been instructed to send you the first draft of our
recommendations dealing with biological contamination.

I should be very grateful if you would study our
conclusions and let me have your comments on them as soon as
possiblef~not later than the 9th June. By the middle of June I
hope to have received comments from a large number of experts
who we have approached with specific questions on a number of
topics. With these comments to hand, I shall then draft for the
committee's approval our final report.

I should be very pleased if you could supply me with a
copy of the same paper that you sent to Professor Florkin, and
any other relevant documents that you may have come into possession
of at the Washington meeting.

CETEX is very concious of the difficulty of forming an

authoritative report on a topic which covers so many specialised
aspects and we should be grateful for any information we can get.

Yours ee

P, Alexander.
Cosmic dust

The possibility that valuable information concerning cosmic
(i.e., inter-stellar and interplanetary) dust may be lost by disturbing
the moon's surface has been considered but was not thought to be serious.
This interesting material is known to consist largely of low atomic
number elements such as hydrogen, carbon, nitrogen and oxygen and many
of the corresponding molecules will be volatilised by solar radiation.
Hence only residues of high atomic number elements will remain on the
moon and this material is no more informative than similar deposits

of interplanetary material which can be found at the bottom of the oceans.

Panspermia hypothesis

The suggestion that moon dust might help in evaluating the
hypothesis that dissemination of life in the cosmos occurred by
transport of forgs of life in the cosmic dust mist be rejected for the
same reason as that given above. Namely that solar radiation (in
high vacuo) would decompose "biospores" just as it decomposes cosmic
dust. Contamination by organic or living matter would therefore not
be harmful in this connection although it must be avoided for another

reason (see below).

Contamination of th 2 iyi

There is no possibilit: that the introduction of cells such
as spores or bacteria might give rise to life on the moon of the same
type (i.e., containing DNA) as on earth which might confuse later
investigators. There are no cells on earth which grow or multiply
in the absence of water and at the high vacuum of the moon no water

can exist.

tL 9 of com 9

The basic problem concerning the origin of life is how complex
molecules (on the earth they are based on carbon) came to be built up
and become replicated. It is conceivable that the interior of the moon

dust may provide some valuable clues in this direction. It is not
beyond the bounds of possibility that some "pre-life" processes

may be occurring on the moon and these may be similar or different

from those which had taken place on earth. If there are such
processes then the introduction of "foreign" macromolecules from

the earth may cflase a serious upset in the lunar processes, ‘The

earth macromolecujes may under lunar conditions act as templates and
provide new foci for "pre-life" growth. If such events were started
indiscriminately all over the moon the pattern might be distorted.

It is important to emphasise that living cells are not envisaged for
this process and that in this conneetion a dead bacterium from an
aseptic rocket would be as harmful as a live one. Admittedly the
occurrence of any such growth reactions is remote but the problem is so
important that we recommend that a simple precaution against endangering
future studies is to limit the areas of landing on the moon and

thereby to localise the effects - if any - of terrestrial templates.

Q ination : V

The problens of reaching the planets are of the same kind as
those involved in lunar exploration and objects will no doubt be sent
there relatively quickly after the moon has been reached (initially by
circumnavigation, if our findings (above) are heeded). The danger of
contamination of these planets is mainly biologicalbince there is a
reasonable probability that the conditions on Mars are such that some
terrestrial organisms might grow. Water, nitrogen, carbon oxides and
light for photosynthesis are all available.

It is therefore of the greatest importance that space vehicles
should not land either accidentally or deliberately on Mars (and possibly
also Venus) unless all precautions have been taken to exclude living
organisms from them. Otherwise the most challenging of all planetary
studies, that of extra-terrestrial life, may be put in jeopardy. The
same consideration concerning possible pre~life processes discussed
under 'the development of complex molecules! above , abe of//) ,

In view of the greater distances no nuclear explosion would

be detectable on the planets and the problem of radioactive contamination
is therefore not likely to arise.