Definition of Life

Preliminary Steps
  Geological Survey
  Sample Collection

Present Life
  Spectroscopic Analysis
  Organic Analysis
  Biology Experiments

Past Life
  Thin Section
  Isotope Analysis


Experimental Design

Introduction: Table of Assumptions





Life on Earth requires water

  • Water is located near the Martian poles
  • Water is located beneath the Martian surface

-Life will only exist on Mars near water

-Look underground or near poles

Drill below the surface and test for water.

-Mars probably has an oxidizing surface due to the presence of superoxides

-Mars has very little atmospheric pressure

-The atmosphere is mostly CO2

-The surface is unshielded from UV radiation

Martian life, if it exists, will not exist on the surface; rather, it will exist deep underground or below the surface of large rocks

-Examine the surfaces of rocks for evidence of life just below the rock surface


-Life on Earth is carbon-based

-Carbon has by far the most diverse chemistry of any element

Martian life will also be carbon based

Test for the presence of complex organic molecules

Earth life is based on four particular organic compounds: nucleic acids, proteins, carbohydrates, and lipids

Martian life will also use these classes of compounds

Test for the presence of these compounds

Life on Earth is associated with energetic simple molecules

Martian life will also use these energy sources

Look for energetic simple molecules, such as CH4, H2, CO, H2S, and FeS, as well as evidence of past carbon and nitrogen cycles

Life on Earth is attracted to sources of thermal and light energy

The surface is inhospitable, so Martian life will be attracted to geothermal heat sources.

Look for geothermal heat sources [will be done by satellite not part of mission]

-Earth life metabolizes organic molecules

-Earth life produces gaseous products of such metabolism

Mars life will also metabolize organic molecules to gaseous products

Look for evidence of metabolic gas products, and confirm that they are not caused by abiotic chemical reactions (labeled-release)

Some forms of Earth life are photosynthetic and chemosynthetic, and able to convert CO and CO2 to complex molecules

There will also be photosynthetic or chemosynthetic Mars life

Look for evidence of CO2 uptake and retention (pyrolytic release)

No Mars missions have examined the subsurface structure of Mars

It would be helpful to have such information in order to drill

Conduct a geological survey

Earth life is occasionally preserved in rocks as visible organic structures

Mars life would be similarly preserved

Examine rocks for visible fossil evidence

Metabolism in Earth life discriminates between different isotopes

Mars life will discriminate similarly

Look for differences in isotope ratios between organic carbon and inorganic carbon

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Comments and questions to mission2004-students@mit.edu Last updated: 10 December, 2000