2 June 1961

TECHNICAL DISSERTATION

SW-1980

MICROSCOPIC SYSTEM FOR MARS

STUDY PROGRAM

Jet Propulsion Laboratory
California Institute of Technology
4800 Oak Grove Drive
Pasadena, California
Il.

SCOPE

SW-1980

This document describes the requirements of a study program for the
Microscopic System for Mars. It is the intent of this study program
to obtain basic information to establish the design parameters for
the development of an extra-terrestial life detection system. This
system will be used to explore the microbiological environment of
the planet Mars.

REQUIREMENTS

A. The Study Program

1.

The Contractor shall conduct a five-month study program and
shall recommend what optical, mechanical, and electronic
principles, methods, or techniques will show the most promise
in devising the complete system. The Contractor should also
evaluate any special research and development programs that
would advantageously advance the state-of~the-art for the
purpose of this program. The Contractor should orient his
study to the operational spacecraft and planetary surface
environment. The final result of the study should be a
detailed analysis of the methods, techniques and principles
required for the successful operation of the microscope
mission and an outline for a breadboard model. This outline
should not include detailed drawings; the analysis should
include preliminary considerations on the trade-offs between
weight, power, and volume requirements versus reliability,
and the data that can be acquired.

The Contractor shall submit a first written report one month
from the date of the awarding of the study contract, and
shall follow this first report with four successive monthly
progress reports, each due one month from the date of the
previous report. Two weeks following the completion of the
five-month study period, the Contractor shall submit to the
Jet Propulsion Laboratory a final summary report which shall
include all phases covered in the study, a recommendation
covering the kinds of optical, mechanical, electronic, or
other approaches he feels should be used in devising the
microscope system, and a proposal of a preliminary design of
the instrumentation on the basis of his study, All monthly
progress reports should be as short and concise as possible
using sketches where needed in lieu of detail drawings and
should only discuss new material not previously reported.

It will also be required that he provide cost and time
estimates for actual development of the instrument system.

The five monthly reports prepared by the Contractor should
be submitted in quadruplicate, including one reproducible
copy of text and sketches.

-l-
Sw-1980

Ten copies of the final report will be required, including
one reproducible copy of text and drawings.

B. System Description

l.

2.

Functional Description

The system will operate from a spacecraft soft-landed upon
the surface of the planet and will require either pre-
programmed automation or a system of built-in logic to control
the necessary manipulations and to process data obtained for
the spacecraft telemetry system.

The system will be designed to collect and concentrate particu-
late samples from the surface and atmosphere of the planet.
These samples will be observed by microscopy to furnish images
of particles that may resemble microorganisms in respect to
phase contrast and form.

For convenience, the microscope may be divided into three
subsystems:
(1) The sample collection, preparation, manipulation,
and delivery system which includes all instru-

mentation up to, but not including, the stage
of the microscope. ‘

(2) The optical system, This includes the optics,

the stage, the substage, and the illumination
system.

(3) The electronic system. Subsystem 3 is, however,
not part of this work statement and will be
handled separately.

General Specifications
a. Sample Collection and Preparation

The microscope system must provide the following capa-
bility:

(1) Collect samples in the form of particulate material
from a variety of surfaces comparable to frozen
clay, dusty soil, sand, gravel, scrapings from hard
rock, and atmospheric aerosols.

(2) Fractionation of Sample:

(a) Remove particles whose size would interfere
with the operation of the microscope.

-2-
(3)

(4)

SW-1980

(b) Fractionate the sample according to mass
densities greater than 1.2 and less than
1.2.

{c) Sort the sample into size groups which are
optimum for viewing under low, medium and
high magnifications.

Concentrate the refined samples on an object
support which will provide optimum conditions for
microscopic observation. The system should permit
separate observations on both high and low density
fractions as described in paragraph (2) (b) above.

The system should be capable of transporting the
object carrier to the stage of the microscope.

b. Microscope System

(1)

(2)

(3)

(4)

The microscope will provide auto~focusing. In
response to signals from the electronic logic
system, it should be capable of horizontal align-
ment of the object carrier so as to center a
particle on the optical axis to a precision of

0.2.

At high magnification, it should provide an object
field of 20 microns diameter at a resolution of
approximately 0.2 microns and project a focussed
image of 1.8 em diameter on the image plane, e.g.
vidicon target plate.» It should provide an object
field of 100 m diameter, at medium magnification
and 500 ~. diameter at low magnification. The image
should have an intensity of 0.5 to 10 foot candles.

The microscope should be capable of transmission

and color phase contrast. Corresponding filters
should be furnished to allow observation alternative-
ly in phase contrast and transmission modes.

As an option, the microscope should be capable of
incident illumination through the objective lens and
consideration should be given to the optimum optical
qualities of the object carrier, e.g. whether this
should be opaque, reflective, or transparent for
optimizing the detail that can be observed in the
sample. With a view to compact design of an incident
illumination system and economy of power, the
feasibility of incorporating a miniature light source
within the objective should be considered.

-3-
SW-1980

c. Other Requirements

(1) The system must be capable of collecting and
processing up to 100 grams of crude sample for
each observation cycle, and should be capable
of repeating at least twenty-five cycles for
the complete mission.

(2) The system must remain in stand-by condition
during the time of transit of approximately
220 days, and be capable of operation for about
thirty days after landing.

III SPACECRAFT AND PLANETARY ENVIRONMENT

It is not possible at this time to provide detailed descriptions of
the spacecraft environmental restrictions nor complete descriptions

of the Martian environment. However, it is possible to suggest work-
ing specifications which can be used as a guide for the present study.
To some degree, the design of the spacecraft will be influenced by the
requirements of the scientific experiments it is required to carry.
Therefore, the following approximate values are suggested:

A. Spacecraft Environment Requirements

1. Volume of Microscope System: less than 1200 in.3.
With sample handling using approximately 800 in.3
and the optical system 400 in.3.

2. Allowable Weight of System (Including Electronic System):
less than 12 pounds. s
Sample handling weight approximately 5 pounds and
Optical System weight approximately 3 pounds.
Electronic System (JPL-supplied) weight 4 pounds.

3. Permissable power consumption 20 watts for 5 minutes
less than 2 watts continuous per operating cycle.

4. Bandwidth available: less than 200 cps.

5. Maximum expected g-load: 100 g for 20 ms.

6. 20 g rms noise band limited 20-5KC for 10 minutes.

B. Planetary Environment

Some of the salient features of the Martian environment are:

1.

Atmospheric Pressure: 60-70 mm Hg.

74-
IV

SW-1980

2. Temperature Range: Plus 30°C to minus 80°C.
3. Average Solar Constant: 0.86 Cal/cm2/min.
4, Water Vapor Pressure: “= 0.002 x earth.
5. Gravitation: 0.37 x earth.

BACKGROUND INFORMATION

Terrestial soil is considered as a prototype of the sample that will
have to be analyzed. Such soils have an organism content varying from
some hundreds to some millions of microbes per gram and the design
efforts will have to be focused to the lower extreme of this range,

say: 10-1,000 organisms per gram. These microorganisms include a wide
variety of biological forms; the most numerous, however, are bacteria,
whose characteristic dimensions are from 1-10 microns in simple
spherical, cylindrical, and sometimes helical forms. It is the aim of
the present system (1) to achieve as far as possible a preliminary
concentration of microorganisms from a sparsely inhabited soil and (2)
to detect these microorganisms by their properties of form and
transparency under the microscope. For the first objective, flotation
in a medium of appropriate density, about 1.2, has been quite promising
in preliminary experiments and, with careful mixing of the soil, a

large proportion of the microorganisms can be extracted by flotation.
The material "Ludox,'' a coloidal dispersion of silica furnished by
Dupont, has been successfully used in these experiments and has the
particular advantage of preserving the viability of most microorganisms.
However, this fluid is not necessarily the most suitable for the present
purposes which, in any case, do not now require that the organisms be
viable at the time of examination. Other heavy fluids should, there-
fore, be examined for their suitability for this purpose. One disad-
vantage of Ludox is the possibility of its instability over long

periods of time, particularly under temperature stress. In selecting

a flotation fluid, attention should be given to the preservation of the
form of the microorganisms and the ease of dissociation of the organisms
from the particles of soil to which they may be adherent. For the
efficient separation of the microbes, it may be necessary to arrange for
the preliminary agitation of the suspension of the soil in the flotation
fluid.

In order to extract as many bacteria as possible with a given volume of
flotation fluid, it would be desirable to have a compact continuous

flow sedimentation which could process several volumes of soil with one
volume of fluid. If this is not feasible, the geometry of the sedimeter
should be such as to concentrate the light fraction containing the
organisms in the smallest usable volume, as it will be difficult to scan
very large volumes at high magnifications with the microscope.

~5-
SwW-1980

For the microscopic observation, phase contrast is presently indicated
as the most convenient means of recognizing microbes, especially since
these are usually transparent when suspended in aqueous solutions and
examined with visible wave lengths. The use of color phase contrast
should facilitate the discrimination of transparent but phase-retarding
particles like microorganisms from other components of soils. Then
with the alternation of the appropriate filters, comparison images will
indicate which particles have these properties.

Incident illumination is indicated as an approach to a possibly more
compact design for microscopy on a marginal mission, for example, the
study of the particles that may be merely collected on the window of an
objective lens cap. Incident illumination may also be particularly
advantageous for the examination of lunar as well as planetary soils
from a geophysical as well as a biophysical standpoint.

The system as a whole may be considered successful in relation to its
success in the detection of evidence of microbial life in the sparsest
of terrestial. soils, for example, desert sands which may have a density
not greater than 100 organisms per gram. Since the conditions for life
at the point of landing on Mars may be even more marginal than at any
point on the earth, it would be desirable to have a further leeway in
sensitivity of an additional two or three orders of magnitude.

The system should also include an internal means ‘of calibrating its
functions; for example, well defined and easily recognized test
objectives having considerable detail should be included at least in
the microscopic observation and perhaps even in the sample inputs.
II.

STATEMENT OF WORK - MICROSCOPIC SYSTEM FOR MARS (SW-1980)

Introduction

The Jet Propulsion Laboratory is initiating a five month program of study
to obtain basic information needed to establish the design parameters for
the development of an extra-terrestrial life-detection system which will be
used to explore the micro-biological environment of the planet Mars. The
system will operate from a spacecraft soft-landed upon the surface of the
planet and will require either pre-programmed automation or a system of
built-in logic to control the necessary manipulations and to process data
obtained for the spacecraft telemetry system.

The system will be designed to collect and concentrate particulate
samples from the surface and atmosphere of the planet. These samples will
be observed by microscopy to furnish images of particles that may resemble
microorganisms in respect to phase contrast and form.

For convenience, the microscope may be divided into three subsystems:

(1) The sample collection, preparation, manipulation, and delivery
system which includes all instrumentation up to, but not
including, the stage of the microscope.

(2) The optical system. This includes the optics, the stage,
the substage and the illumination system.

(3) The electronic system. Subsystem 3 is, however, not part of
this work statement and will be handled separately.

Scope of Study

'The contractor shall recommend what optical, mechanical, and electronic
principles, methods, or techniques will show the most promise in devising
the complete system. The contractor should also evaluate any special re-
search and development programs that would advantageously advance the state-

of-the-art for the purpose of this problem. The contractor should orient

his study to the operational spacecraft and planetary surface environment.
Iil.

-2-

The final result of the study should be a detailed analysis of the methods,

techniques and principles required for the successful operation of the micro-

scope mission and an outiine for a breadboard model. This outline should

not include detailed drawings, the analysis should include preliminary con-

siderations on the trade-offs between weight, power, and volume requirements

versus reliability, and the data that can be acquired.

Technical Requirements

A. General Specifications

1.

Sample Collection and Preparation

The microscope system must provide the following capability:

a)

b)

c)

d)

Collect samples in the form of particulate material from

a variety of surfaces comparable to frozen clay, dusty

‘soil, sand, gravel, scrapings from hard rock, and atmos-

pheric aerosols.

Fractionation of Sample:

1) Remove particles whose size would interfere with the
operation of the microscope.

2) Fractionate the sample according to mass densities
greater than 1.2 and less than 1.2.

3) Sort the sample into size groups which are optimum for
viewing under low, medium and high magnifications.
Concentrate the refined samples on an object support which
will provide optimum conditions for microscopic observation.
The system should permit separate observations on both high

and low density fractions as described in IIIAc.
The system should be capable of transporting the object

carrier to the stage of the microscope.
2. Microscope System

a)

b)

c)

da)

The microscope will provide auto-focusing. In response to
signals from the electronic logic system it should be capable
of horizontal alignment of the object carrier so as to center
a particle on the optical axis to a precision of 0.2y.

At high magnification it should provide an object field of
20 microns diameter at a resolution of approximately 0.2
microns and project a focussed image of 1.8 cm diameter on
the image plane, e.g. vidicon target plate. It should
provide an object field of 100p diameter, at medium magni-
fication and 500 diameter at low magnification. The image
should have an intensity of 0.5 to 10 foot candles.

The microscope should be capable of transmission and color
phase contrast. Corresponding filters should be furnished
to allow observation alternatively in phase contrast and
transmission modes.

As an option the microscope should be capable of incident
illumination through the objective lens and consideration
should be given to the optimum optical qualities of the
object carrier, e.g. whether this should be opaque, reflect-
ive, or transparent for optimizing the detail that can be
observed in the sample. With a view to compact design of

an incident illumination system and economy of power, the
feasibility of incorporating a miniature light source within

the objective should be considered.

3. Other Requirements

a)

The system must be capable of collecting and processing up
to 100 grams of crude sample for each observation cycle, and

should be capable of repeating at least twenty-five cycles

for the complete mission.
IV.

~he

b) The system must remain in stand-by condition during the

time of transit of approximately 220 days, and be capable

of operation for about thirty days after landing.

Spacecraft and Planetary Environment

It is not possible at this time to provide detailed descriptions of

the spacecraft environmental restrictions nor complete descriptions

of the Martian environment. However, it is possible to suggest

working specifications which can be used as a guide for the present

study. To some degree the design of the spacecraft will be influenced

by the requirements of the scientific experiments it is required to

carry. Therefore, the following approximate values are suggested:

a) Spacecraft Environment Requirements

4)

2)

3)

4)
5)
6)

Volume of Microscope System: less than 1200 in,?

With sample handling using approximately 800 in.>
and the optical system 400 in.?
Allowable Weight of System: less than 12 pounds.
Sample bandling weight approximately 7 pounds and
Optical System weight approximately 5 pounds.
Permissable power consumption 20 watts for 5 minutes
less than 2 watts continuous per operating cycle.
Bandwidth available: less than 200 cps.

Maximum expected g-load: 100 g for 20 ms.

20 g rms noise band limited 20-5KC for 10 minutes.

b) Planetary Environment

Some of the salient features of the Martian environment are:

1)
2)
3)
4)
5)

Atmospheric Pressure: 60-70 mm Hg.
Temperature Range: Plus 30°C to minus 80°C.
Average Solar Constant: 0.86 Cal/cm@/min.

Water vapor pressure: ~ 0.002 x earth.

Gravitation: 0.37 x earth.
Vv.

Reports

The contractor shall submit a first written report one month from the
date of the awarding of the study contract, and shall follow this first re-
port with four successive monthly progress reports, each due one month from
the date of the previous report. Two weeks following the completion of the
five month study period, the contractor shall submit to the Jet Propulsion
Laboratory a final summary report which shall include all phases covered in
the study, a recommendation covering the kinds of optical, mechanical,
electronic, or other approaches he feels should be used in devising the
microscope system, ania proposal of a preliminary design of the instrumentation
on the basis of his study. All monthly progress reports should be as short
and concise as possible using sketches where needed in lieu of detail draw-
ings and should only discuss new material not previously reported. It will
also be required that he provide cost and time estimates for actual develop-
ment of the instrument system.

The five monthly reports prepared by the contractor should be submitted
in quadruplicate, including one reproducible copy of text and sketches.

Ten copies of the final report will be required, including one repro-
ducible copy of text and drawings.
Proposal

Prospective study contractors who wish to participate in this program
are invited to submit proposals to the Jet Propulsion Laboratory. The
prospective contractor may submit a proposal covering either or both of the
subsystems described in paragraph I, depending upon his interest and dis-
cretion. It is expected that the proposals shall provide the following
information:
A. What will be the major objectives of this study?
B. How will the contractor organize the study program to achieve these

objectives?

Cc. What does the contractor consider will be the most important technical
VI.

problem areas?

D. How will the contractor seek solutions to these problem areas?

E. What experience has the contractor had to qualify for this study?

F. Specifically, whom of the contractors technical personnel will be
assigned to this study. How much time will each person devote to
fulfilling his duties in this contract?

G. The contractor should indicate whether or not he desires to perform
a study of both subsystems or restrict himself to one of the sub-
systems listed in I.

H. What is the contractors cost estimate for this study?

Once the contract has been awarded, JPL will provide all pertinent
information it may possess and will work closely with the study contractor
during the duration of the contract.

Although it is intended to follow the preliminary study with further
design and development contracts, it is emphasized that this preliminary
study is a separate effort and no commitment to a follow-on development
contract is or has been made.

Background Information
Terrestrial soil is considered as a prototype of the sample that will

have to be analyzed. Such soils have an organism content varying from

some hundreds to some millions of microbes per gram and the design efforts

will thave to be focussed to the lower extreme of this range, say 10-1,000

organisms per gram. These microorganisms include a wide variety of bio-

logical forms; the most numerous, however, are bacteria, whose character-
istic dimensions are from 1-10 microns in simple spherical, cylindrical and
sometimes helical forms. It is the aim of the present system (1) to achieve

as far as possible a preliminary concentration of microorgansims from a

sparsely inhabited soil and (2) to detect these microorganisms by their

properties of form and transparency under the microscope. For the first

objective, flotation in a medium of appropriate density, about 1.2, has
a
been quite promising in preliminary experiments, and with careful mixing
of the soil, a large proportion of the microorgansims can be extracted by
flotation. The material "Ludox", a coloidal dispersion of silica furnished
by Dupont, has been successfully used in these experiments and has the
particular advantage of preserving the viability of most microorganisms.
However, this fluid is not necessarily the most suitable for the present
purposes which, in any case, do not now require that the organisms be viable
at the time of examination. Other heavy fluids should, therefore, be ex-
amined for their suitability for this purpose. One disadvantage of Ludox
is the possibility of its instability over long periods of time, particular
under temperature stress. In selecting a flotation fluid, attention should
be given to the preservation of the form of the microorganisms and the ease
of dissociation of the organisms from the particles of soil to which they
may be adherent. For the efficient separation of the microbes, it may be
necessary to arrange fa the preliminary agitation of the suspension of
the soil in the flotation fluid.

In order to extract as many bacteria as possible with a given volume
of flotation fluid, it would be desirable to haye a compact continuous flow
sedimentation which could process several volumes of soil with one volume
of fluid. If this is not feasible the geometry of the sedimeter should be
such as to concentrate the light fraction containing the organisms in the
smallest usable volume, as it will be difficult to scan very large volumes
at high magnifications with the microscope.

For the microscopic observation, phase contrast is presently indicated
as the most convenient means of recognizing microbes, especially since these
are usually transparent when suspended in aqueous solutions and examined
with visible wavelengths. The use of color phase contrast should facilitate
the discrimination of transparent but phase retarding particles like micro-
organisms from other components of soils. Then with the alternation of the

appropriate filters, comparison images will indicate which particles have
-8-
these properties.

Incident illumination is indicated as an approach to a possibly more
compact design for microscopy on a marginal mission, for example, the study
of the particles that may be merely collected on the window of an objective
lens cap. Incident illumination may also be particularly advantageous for
the examination of lunar as well as planetary soils from a geophysical as
well as a biophysical standpoint.

The system as a whole may be considered successful in relation to its
success in the detection of evidence of microbial life in the sparsest of
terrestrial soils, for example, desert sands which may have a density not
greater than 100 organisms per gram. Since the conditions for life at the
point of landing on Mars may be even more marginal than at any point on the
earth, it would be desirable to have a further leeway in sensitivity of an
additional two or three orders of magnitude.

The system should also include an internal means of calibrating its
functions, for example, well defined and easily recognized test objectives
having considerable detail should be included at least in the microscopic

observation and perhaps even in the sample inpute.