JET PROPULSION LABORATORY INTFEROFFICE MEMO
TO _M. Eimer ‘FROM G. L. Hobby DATE 11/11/60 __
SUBJECT Lederberg Life Detection System for Mars Soft Lander (2966)

 

 

The proposed overell system can be divided into three subsystems, each
eapable of independent as well as integrated operation. The essential
funetion of each of the cystems will be phase eontrest microseopy,
microabsorptionspectrophotometry, and growth detection.

System I. Basic System - Phase Contrast Microscopy
A. Punetions
i. Collect a sample of dust or soil from the Martien atmosphere
or surfece.
2. Trensport the sample to a device which will prepare it for
density fractionation.
3. Fraetionate the sample according to particle density.
. Transport the low density fraction to the stage of a phase
econtrest microseope.
5. Video observation of sample
B. Speeifieations
1. Sample Collection
‘@. The method of sempile eollection mst not be from
arers subjected to retro-reeket blaste during the landing.
b. Partiele size should be limited to that whieh is
compatible with optimum sample manipulation and micro-
scepie observation.
e. Size of sample must be sufficient to ensure « high
Probability of obteining a viable particle.
«2

2. Prepsretion cf same
Sample should be treated to encourage deedsorption of
microorganisms fron mineral. particles to provide density
separation operation.
3- Mass Density Seperation |
a. Partieles having miss densities greater than 1.2
must be seperated fran particles having densities less
than 1.2.
b. Particles in the class of greeter density will be
Qtecardied; perticles cf lower density will be retained for
observation.
4. Transport System
| The refined sample musi be transported to the stage of the
phase contrast microscope for observation under conditions
optimal for phese-contrast niecroscopy.
3° Video, phase contrast micrascope system.
a. The stage of the miczoseope will require an autefocusing
aystem and horizontal alignment capability.
bd. Optieal system: 2 Lindel hy |
1) Resolution: 0.5 miarens ( eae) Kay SUNS UL
ji 2) Magnification: Approx. 1000 dteneters ( 4oy |
8)\ WyeeAyneran opts
6. Diserimination System
a. Will permit observation of particles having internal.
structural detail, but not opaque particles or those having
homogeneous optical trezamission.
bd. Will compress data from selected particles to a specified
minimum level in order to reduce bandwidth requirements.
System Il. Microahsorptionspectrophotometry

The purpose of this experiment will be to obtain absorption spectra
of selected particulate material in order to attempt bicehemical. analysis
of the chemical eomposition.

The experiment will utilize the sample colleetion, processing,
fractionation, transport and vidicon microseope of the basic systen.
Absorption speetrophotometry will be done on individual perticles. ‘This
will require that the stage of the microseope be designed to aligt the
selected partiele in the optical center of the microscope in preperation
for the spectrometric observation.

The monochromator should provide a spectral. coverage between 2400 to
6000,A, with a resolution of 10 A. A compromise system would cover 2:00
to 4400 with 50 A resolution.

The detection system should be eapable of observing eight intensity
levels.
abe
Systen ITI Growth Experinent
the purpose of this aystem is to attempt to cultivate and grov
mieroorgenisms eollected from the soil or atmosphere of Mars.
A. Funstions
1. Colleet a seme of soil or dust.
&. Sift the gross sample and selest particles of a size consistent
with optimal functioning of system.
3+ Deposit these particles in suitable growth eapsules or chambers.
4. Ruriodieally trensport the grovth chambers to the stage of
the mieroseope for video inspection.
3+ Or alternatively, periodically transport the grovth capsules
to & photomstric deviee for optical density meagurements and to
PH meter for pH measurements.
B. Speeifieations
2. Semple Collection
&. The necessity for sollesting vieble microurganians
makes it necessary to consider the possible effeet of
retrerceket blests 1f these methods are used on the soft
lander.
b. If the semile is obtained from the atmosphere of Mars,
direst deposition of the solid phase into the grovth eapsules
may be possible. However, if soil samples, containing
meterial in the form or felatively large grains are obtained
sifting of the sample may be necessary to obtain particles
whieh may easily be deposited inte the capsules.
GLH: aef

<-5-
2. Growth Capsules
a. Growth capsules mist be transported periodically to the
mieroseope stage.
b. Severe] hundred eapsules containing different types of
growth media will be necessary.
ce. The faces of the capsules mst be ecupetible with good
optical inspection of the biological samples under the
mieroseope.
a. The capsule material will require a yrange of optical
trensmission from 2400 to 8000 2.
e. Capsules must be designed to prevent exeessive evaporation
of water from media.