Wole VISHWIAC

Ca pa,
Application fer a Grant te the National Science Foundati

anstituticn: Yale University, New Haven, Connecticut

Fiscal Officer: Mr, Spencer Miller

Associate Treasurer 2f Yale University
1 “a

452. Tollege Street
New Haver. 11, Connecticut

Principal Investigater: By. Walf Vishnia-
Tenactment of Microbielogy
Tete University
310 Cedar Street
New Haven 11, Connecticut

Title: Detection of Nicroorganisms on Other. Planets: Develorment of
Suitable Instruments

Aporoved by:

 

Vernor W. Lippard, M.D., Dean, School of Medicine

 

Herry P. Treffers, Ph.D., Chairman, Devartment of
, Microbiology

 

Wolf Vishniac, Ph.D., Principal Investigator
PLEASE PETUSN TO THE
NATIONAL SocHCE FOURDATION

ENVIROMENTAL BIOLOGY

 
Introduction. On Decewrer 39 ans 20, (458, + mecting was held at the
“assachusette Institute of Technelopy, chaired by Prefessor Brunc Rossi, under the
auspices pf the N.A.S.-NR.C, Space Sedance Board, Sor tre rurpese of discussing
ways and means of detecting extraterrestrial Life. In the course of this meeting
Dr. Thomab'Gold of the Harvard University astronomy Departnent inquired as to the
feasibiliky of constructing a device, weighing less than 30 reunds, which when.
claced on.a solid surface would detect and sigmal the presence of microorganisms.
I volunteered to design and supervise the construction of such an apparatus, and I
am applying for $4,485.00 to make this construction possible.

Purpose. It is proposed to develop a device which will automatically sample,
detect, and signal the presence of bacteria, and which can serve as the prototype
of a device which could be included among the instruments tc be landed on Mara or
Venus. This device, for the purposes of this proposal to be called a Bug Detector,
will illustrate the feasibility of letting bacteria signai their own presence by
making use of the changes which bacteria bring about in the envirorment in which
they grow. The present device is exnected to work on Earth only, but is meant to
indicate in what fashion life on other planets may be studied.

Principlep and Methods. In principle the anparatus ahall consist of a hollow
evacuated cylihder from which a fragile probe extends in the direction of the
expected impact. Upon impact the tip of the probe will shatter, and the internel
vacuum will draw dust from the surface into the intericr of the cylinder. In the
cylinder there will be exnosed media in which bacteria might grow, er at least in
which some of the hacteria present might grow. After the cylinder interior has
reached atmosynheric pressure, the cpening will be closed by a spring-loaded valve
to prevent evaporation of culture media and contamination of the planetary surface
by terrestrial organic matter. Bacterial growth will havé at least two likely
results: the turbidity of ths medium will increase and the acidity of tha medium
change. Both these changes can te easily detected, the change in turbidity by a

photoelectric cell and the change in acidity by a vair of pH eleatrodes, Either
or both of these changes may trip a relay which in turn may activate
some signaling device. This principle of the Bug Detector is
susceptible to a variety of modifications. At first it is planned
to build the simplest possible device, which will provide only one
medium for bacterial growth, and which will give only a yes- or -no

answer. After the successful construction of such a model it is planned

to elaborate it, all within the sunvested weight Jimit or 20 soos, in the rollew-
ing directions: First, soverdl media may be. provided wht ok may be made to select
for different types of microorganisrs, includic: photosy.thetic bacteria; secondly,
the response of the signaling device could be modified from a simple yes-o1r-—no
answer to a more complex response. ‘The change in turtiiity of the medium as a result
of bacterial growth, which would result in e change in light intensity registered
by the photoelectric cell, could be ccupled. te a chanye in frequency in the sig-
naling device. In this case the variation of the signal would be a measure of. the
growth of the bacteria, from which it should be possible tc plot a growth curve.
Similarly,-a change in acidity might be signaled in terms cf a rate of change
rather than as a simvle yes-or-ne signal, |

Interpretation of Results. If wa assume that sa working model has been built
and mcedifind for. inclusion ina space vehicle, how can we interpret the signals
which the Bug Detectcr weuld emit? Let us assume that- the device is successfully
larded in Mars and that irrciiately upon impact the signals indicate a marked

,

change [save and a masked charge in pH. 3uech a result weuld have ne meaning,
except that it might be interpreted in-the sense that cemoonerts of the atmosphere
or of the scil were strongly acidic or basic sc that they immediately changed the
pH of the medium, and that the’dust was sc dense that it immediately obscured the
vision of the chotoelectric cell, However, if after impact none cr only a few of
the signals indicete any changes ard if more changes are sigraled in the course
of several hours or days, then we may reasonably conclude that some gradual changes

have taken nlace which may well be the result of the bacterial activity, Should a

device be built which will signal a gradual change in turbidity of the medium, then
it will be pessible to obtain a curve by plotting tuitity against time which might
nave the characteristic sigmcii shace of a prowth curve, uch a result would be
the most meaningful, and woul? be the most convincing evidence for the existence of
microorganisma on cther nlanets.

Materials and Construction. The Bug Detectcr will be built in such a fashion
that portions of it can be evacuated and sterilized without effecting the electric
cemponents of the device, It is anticipated that plastic materials will be- used,
in particular the vessels for the medium may be made of volypropylene since it is
almost transparent and yet chemically resistant and shatterproof. The electric
components. wiil contain no tubes or other fragile materials and will be housed. in
a metal shell. It is anticipated that one or several working models will be
built within one year.

Cther Suprort. No other apnlication for funds to supoort this project has
been made. The main work carried out in this laboratory, dealing with photosyn-
thesis, chemosynthesis, and related problems in bacterial intermediate metabolism,

is supported by N.S.F, (G7124) and N.I.H. (£128).
BUDGET

The following budget is expected to cover the construction of one or
more working models of the Bud Detector within one year.

Services of the machine shop (tocl engineerinz,

BLO

1 r) *1,200.0°
4 zZ ad wg
Services of e.ectronics shop (consultation, degsien, lator) 2060, OF
Mater ials | "760,00
wh total
Sut total , 33,900, 00
‘niversity overhead at 15% 585,00
q
Grand total

$4,485.00