Exob.
8

COMMENT ON LONG RANGE PLANS
NASA Space Flight Programs

In eartier representations the Exobiology Committee of the Space Sclence
Board has formulated its suggestions for the work of the next five years. In
brief, this would be mainly to lay the groundwork, by laboratory investigation,
for the first planetary landfalls anticipated circa 1965. This work would consist,
on the one hand, of continued observations of the planets from earthbased balloon
and satellite telescopes, the chemical analysis of meteorites, and most urgently,
the development of necessary strategy and instrumentation for the detection and
characterization of planetary life. The Committee has concluded that the strategic
effort be concentrated on the examination of micro-organisms. {t is extremely
difficult to see beyond the first stages of such investigation since, obviously,
each experiment will depend in large measure on the results of the earlier studies.
This is true to a much larger degree here than In the physical sciences since we
lack the framework, perhaps even the possibility, of a rigorous theory for
prediction. If organisms are detected on the early missions we should, at the
same time, learn enough about them to be able to better plan the later tests.

For example, a preliminary survey of a large variety of culture media may allow
a decision as to which one is the best to use for the large scale cultivation of
a typical organism. From such cultures more significant tests could be made of
the biochemical composition and metabolic activity of the indigenous organisms,
At this stage also one might contemplate the closer examination of the possible
invasiveness of the planetary organisms for terrestrial life (for example, cells
in tissue culture), anda general consideration of their chemistry may allow
some decision as to the possible hazards of permitting their return to the earth.

For the decade of the 1970's we may anticipate the possibility of a con-
siderable scaling up of the payloads and the question has been asked what would
be the most significant experiments in space science once such very large
payloads were feasible. For Biology the answer is obvious -- namely, the return
‘of planetary specimens for examination in great detail in the terrestrial
laboratory. However, we plainly cannot afford to do this until we have made the
most exhaustive possible study of their existence and behavior in situ. It is
to the latter purpose that the most effort must be spent in the p preceding years.

Meanwhile, we can expect a concomitant development of procedures and
information on planetary chemistry and from these to have a better understanding
of the capabilities for terrestrial life to exist and propagate on the planetary
surface. tn some cases this may lead to a relaxation of present cautions
against the contamination of the targets by terrestrial micro-organisms carried
by our space craft. In others, we may have even better founded cause for deep
concern. We should have to know enough about the chemistry of each planet to be
able to make reasonable predictions as to the consequences of implanting various
types of micro-organisms from the earth to the planetary surface. Until our
assurances and concerns can thus be fortified by more knowledge, we must meanwhile
make an unremitting effort to avoid an unprecedented catastrophe by inattention
to the problem of space craft decontamination. As previous memoranda have
noted, the presence of living man on such craft would so greatly complicate this
and other problems that it is doubtful whether he can play a useful scientific
function during the early stages of exploration of the solar system.

J. Lederberg
Stanford University
9/4/60
2.
Biological experiments on space probes

At the present time, Mars is the only planetary target for which the
available physical data would encourage biological exploration. Before biological
missions are planned for the moon or for Venus, chemical and physical studies
should take precedence. In the long run, the planet Jupiter may be the most
interesting planet from a biochemical standpoint in view of its size and
abundance. in lighter elements. The means of approaching its surface for detailed
chemical study are a worthy challenge to the high performance vehicles of the
future,

The interplanetary medium has the same interest for biology as for the other
sciences: measurements of radiation and particles can improve our insight into the
evolution of the solar system, and indirectly the conditions of initiation and
maintenance of life within it. The one point that might be overlooked by other
students concerns the chemistry of the cosmic dust, especially carbonaceous
particles which are too fragile to be readily detected in the meteoritic infall
to the earth. Feasible methods for capturing and analyzing such dust have yet to
be devised; however, while impacting particles might not be collected intact,
their fragments might be analysed as pulses of gas. Earth satellites should play
an important role in these studies as well as in furnishing platforms for the
telescopic study of the planets.

Comment on lunar landing mission

The Exobiology Committee has studiously reviewed the possibilities of
biological experimentation in lunar landing missions. We feel that no significant
biological experiment can be designed on the basis of present information of the
moon's surface, and that in fact the biological interest in the moon would depend
primarily on some improbable, though still possible, contradictions of our present
conception of its characteristics. We have suggested that the safest policy is
to avoid the possibility of irretrievable harm to later biological experiments by
careless missions in the event that there should be some new finding that would
then encourage a biological survey. This would depend, for example, on the
detection of potentially volatile compounds beneath the exposed surface of the
moon. in sum, we have therefore recommended that extensive physical and chemical
experimentation should take full precedence over any biological studies. We
hope, however, that such experiments will take account of the biological interest
in the prevalence of carbon-containing molecules, in the temperature profile of
the moon's surface, and of the possible retention of volatile materials in certain
areas on the moon that is perhaps suggested by Kozyrev's claimed observations. The
unique use of the moon as a storehouse of meteoritic infall, from which more
insight could be obtained into the molecular chemistry of interplanetary space,
has also been noted. The mass spectrometer and gas chromatograph are evidently
most useful for this type of investigation. However, further developments may be
needed to adapt jt to the ready analysis of products adsorbed to the solid
substratum.

In due course, experiments should be programmed for the search for minute
residues of spores or other stigmata of extra-lunar origin to test the hypothesis
of panspermia. However, it seems inadvisable to plan this experiment until after
3.

the first studies have better defined the environment in which this search must be
made. it might be contemplated at such time as we could visualize landing a
detector that could screen, say, a square meter of funar surface, to a depth of
ten centimeters. Perhaps this time is not so very far off but it would be
premature to go into the details of such an. experiment until we Had the first
results on at least the texture of lunar surface. It can also be argued that

this fine an analysis might more appropriately be made on samples brought. back

to the earth.

For early experiments, some attention should be given to general surveys,
for example, the examination of surface material by a Vidicon camera at microscopic
as well as other magnifications. The present development of opaque i} lumination
for microscopy should make this enterprise a relatively easy one and it might
have the additional virtue of being a preliminary test of the instrumentation
intended for planetary exobiological study. This experiment is not intended to
find specific biological structures in the microscopic field but mainly to give
a better idea of the texture of the lunar surface down to micron size particles.