STANFORD UNIVERSITY
MEDICAL CENTER
PALO ALTO, CALIFORNIA

DEPARTMENT OF GENETICS
School of Medicine September 26, 1966

National Aeronautics and Space Administration

Dr. Homer Newell
152ceBahAStreet, N.W.
Washington, D.C.

Dear Homer:
This Is to Meeting 3 of the Planetary Sciences Subcommittee.

| think we are doing very well in the programming for the 1962 planetary
probes and this applies also to 1964 Venus Insofar as we really should not
count on a contradiction of the present estimates of a high surface tempera-
ture. If the surface Is hot, then the main Item of biological Interest
might be the possibility of a biologically Inhabited layer as an aerosol In
or beneath the reflecting clouds. However, | suspect that even for this
possibility, the best approach is Just the kind of atmospheric chemical
analysis that is on the books anyhow. 1964 Mars continues to bother me,

especially the virtues of a.drop sonde and whether this should Include a % .
biological test. What about another possibility that ! do not belleve v iP ap
was discussed at the meeting - a drop designed to culminate Ina sustained \0 di

flight at relatively low altitude, say about one kilometer. Pictures from
this helght could give another order of surface detail which should be
extremely valuable in planning the major Saturn-boosted missions later on.
For lift, ! was thinking either of a balloon-or a kite-type of design which
should require a minimum of power. The malin poser is whether the information
channe! to such a mission would be large enough to recover Some photographs,
This device could, of course, also be collecting atmospheric data, at least
as well as it could on the ground. And one supposes that the air foils

might also do multiple service for antenna radiation and for collecting solar
energy. Off-the-cuff, | would definitely prefer this to a biological
experiment that might be so indecisive that it generated more confusion than
conclusion.

Nevertheless, | think we can come up with a detector that wll! do some
sort of a job In looking for microblal life. In thinking about this,’! have
assumed that we would be constrained to a few pounds of Instruments and a
total Information capacity of a few kilobits. Since we are relying so
heavily on these premises, I think It would be extremely important to have
a carefully considered estimate of the actual capabilities of a Martiahk drop
sonde and |} hope that you can get this as the basis of further consultations

! am enclosing a sketch of the small Instrument; there are many Improves.
ments that we could and should think of If we had some more leeway In welght
and data transmission.

| will also be sending a copy of this letter and the sketch to JPL. fork
thelr advice.
Dr. Newell, cont. 3 September 6, 1960

The minutes on Meeting % made sore mention of a further meeting, presumably
in October. | was not sure wnether you intengec ta invite your consultants to
this; it happens that 1 will be in Princeton from Sunday evening, October 16

to Wednesday evening, October 19 and could route my trip via Washington at
either end ff this could be of any help for further consiceration of these

pressing questions,
Yours sincerely,

JOshua: Lederberg
Professor of Genetics

JL/Jh
Enc. |
cc; Jet Propulsion Laboratories:

Ne. barre