1. The Viking Program
• By Matt Bogdan
• Period 2
Hyperlinks
Quick Facts
• The Viking program
consisted of a pair of
space probes sent to
Mars—Viking 1 and Viking
2.
• Viking 1 was launched on
August 20, 1975
• The second craft, Viking
2, was launched on
September 9, 1975
Specs

2. • Each vehicle was
composed of two main
parts:
• An orbiter designed to
photograph the surface of
mars from orbit.
• and a lander designed to
study the planet from the
surface
Orbiters
• The primary objectives of
the Viking orbiters were
to transport the landers
to Mars
• They performed
reconnaissance to locate
and certify landing sites,

3. act as a communications
relays for the landers
• The Orbiters perform
their own scientific
investigations, too
• The orbiters also served
as communication relays
for the landers once they
touched down.
Viking Landers
• The lander consisted of a
six-sided aluminum base,
supported on three
extended legs
• Rower was provided by
two radioisotope thermal

4. generator units
containing plutonium-238
affixed to opposite sides
of the lander base and
covered by wind
screens.
• Four 28 volts
rechargeable batteries
were also onboard to
handle peak power
loads.
Biological
Experiments
• The Viking landers
conducted biological
experiments designed to

5. detect life in the Martian
soil (if it existed) with
experiments designed by
three separate teams
• One experiment turned
positive for the detection
of current life, but based
on the results of another
test that failed to reveal
any organic molecules in
the soil
The Gas
Chromatograph
(GCMS)
• The Gas Chromatograph
— Mass Spectrometer

6. (GCMS) is a device that
separates vapor
components chemically
via a gas chromatograph
and then feeds the result
into a mass
spectrometer, which
measures the molecular
weight of each chemical.
• As a result, it can
separate, identify, and
quantify a large number
of different chemicals.
• However, the GCMS
measured no significant
amount of organic
molecules in the Martian

7. soil.
The Gas Exchange
(GEX)
• The Gas Exchange
experiment looked for
gases given off by an
incubated soil sample by
first replacing the
Martian atmosphere with
the inert gas Helium.
• The scientists
hypothesized that
metabolizing organisms
would either consume or
release at least one of

8. the gases being
measured.
• The result was negative.
The Labeled
Release (LR)
• The Labeled Release
(LR) experiment is the
one that gave the most
promise for the
exobiologists.
• In the LR experiment, a
sample of Martian soil
was inoculated with a
drop of very dilute
nutrient solution.
• The result was quite a

9. surprise following the
negative results of the
first two tests, with a
steady stream of
radioactive gases being
given off by the soil
immediately following the
first injection
• The experiment remains
inconclusive.