Julian A. Hiscox
Department Of Microbiology,
Bbrb 17, Room 361,
University Of Alabama At Birmingham
Birmingham, Al 35294-2170, Usa.
E-mail: Julian_hiscox@micro.microbio.uab.edu
I. Introduction
From The Perspective Of Biology, Planetary Engineering Is The Ability To Alter The Environment Of A Planet So That Terrestrial Organisms Can Survive And Grow (mckay, 1982). The Feasibility Of Altering Planetary Environments Is Clearly Demonstrated By Mankind's Activities On The Earth (levine, 1991; Fogg, 1995a) And It Is Increasingly Apparent That In The Near Term Future Mankind Will Gain The Technological Capability To Engineer The Climate Of Mars. Current Thought Experiments/proposals For The Planetary Engineering Of Mars Differ In Their Methodology, Technical Requirements, Practicality, Goals And Environmental Impact (reviewed And Discussed By Fogg, 1995b).
The Planetary Engineering Of Mars May Be Divided Into Two Distinct Mechanistic Steps, Ecopoiesis Followed By Terraforming. Ecopoiesis, A Term Derived By Haynes (1990) Which, When Applied To Mars, Can Be Viewed As The Creation Of A Self-regulating Anaerobic Biosphere. On The Other Hand, Terraforming Refers To The Creation Of A Human Habitable Climate (discussed In Fogg 1995b). Whether The Creation Of Such Biospheres Are Possible Is Not Known (fogg, 1989; Pollack And Sagan, 1993; Fogg, 1995b). However, The Majority Of These Planetary Engineering Models Invoke The Use Of Biological Organisms, Both During Alteration Of The Planetary Environment And In The Regulation Of The Resulting Biosphere. This Article Will Briefly Review The Implications Of The Current Martian Environment And Assets For Biology And Then Discuss The Relationship Between Biology And Planetary Engineering.
Ii. Current Martian Environment And Implications For Biology
At Present The Martian Surface Environment Is Effectively Sterilizing For All Forms Of Terrestrial Organisms (rothschild, 1990; Mancinelli And Banin, 1995; Dose Et Al. 1995), Although Some Protected Niches May Exist Above And Below The Surface Of Mars (friedmann, 1986; Thomas And Schimel, 1991; Boston Et Al. 1992; Rothschild, 1990, 1995). The Properties Of The Martian Environment That Would Preclude The Survival And Growth Of Terrestrial Organisms Are As Follows (but See Also Mckay (1982); Rothschild (1990); Banin And Mancinelli, (1995); Mancinelli And Banin (1995)):
1. Low Pressure. The Atmospheric Pressure On Mars (table 1), Mostly Due To Carbon Dioxide, Varies From Approximately 7.4 To 10 Millibar (mbar) (hess Et Al. 1980). Extremely Low Pressure Damages Organisms And Can Affect Efficient Dna Repair (ito, 1991; Koike Et Al. 1991).
Low Temperature. The Average Diurnal Temperature Ranges From Approximately 170 K To 268 K. During The Martian Summer The Temperature Perhaps Rises Above The Freezing Point Of Water At Some Equatorial Latitudes. From Temperature Requirements Alone, Organisms Would Not Be Able To Survive On Present Day Mars For A Number Of Reasons: First, The Temperatures Would Completely Freeze Any Organism And Depending On The Freezing Process Would Cause Cellular Damage Through The Formation Of Ice Crystals. Second, Such Low Temperatures Would Raise The Activation Energy For Enzyme Catalyzed Processes And Thus Inhibit Biochemical/metabolic Reactions. Third, Biochemical Reactions
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