12

Table

1:

Greenhousing

Mars

with

CFCs

Induced

Heating

CFC

Pressure

CFC

Production

Power

Required

(degrees

K)

(

micro-bar)

(tonnes/hour)

(MW

e)

5 0.012 263 1315

10 0.04 878 4490

20 0.11 2414 12070

30 0.22 4829 24145

40 0.80 17569 87845

In a matter of several decades, using such an

approach Mars could be transformed from its current

dry and frozen state into a warm and slightly moist

planet capable of supporting life. Humans could not

breath the air of the thus transformed Mars, but they

would no longer require space suits and instead

could travel freely in the open wearing ordinary

clothes and a simple SCUBA type breathing gear.

However because the outside atmospheric pressure

will have been raised to human tolerable levels, it will

be possible to have large habitable areas for humans

under huge domelike inflatable tents containing

breathable air. On the other hand, simple hardy

plants could thrive in the CO

2

rich outside

environment, and spread rapidly across the planets

surface. In the course of centuries, these plants

would introduce oxygen into Mars's atmosphere in

increasingly breathable quantities, opening up the

surface to advanced plants and increasing numbers

of animal types. As this occurred, the CO

2

content of

the atmosphere would be reduced, which would

cause the planet to cool unless artificial greenhouse

gases were introduced capable of blocking off those

sections of the infrared spectrum previously

protected by CO

2

. The halocarbon gases employed

would also have to be varieties lacking in chlorine, if

an ultraviolet shielding ozone layer is to be built up.

Providing these matters are attended to, however,

the day would eventually come when the domed

tents would no longer be necessary.

Activating the Hydrosphere

The first steps required in the terraforming of Mars,

warming the planet and thickening its atmosphere,

can be accomplished with surprisingly modest

means using in-situ production of halocarbon gases.

However the oxygen and nitrogen levels in the

atmosphere would be too low for many plants, and if

left in this condition the planet would remain

relatively dry, as the warmer temperatures took

centuries to melt Mars' ice and deeply buried

permafrost. It is in this, the second phase of

terraforming Mars, during which the hydrosphere is

activated, the atmosphere made breathable for

advanced plants and primitive animals, and the

temperature increased further, that either space

based manufacturing of large solar concentrators or

human activity in the outer solar system is likely to

assume an important role.

Activating the Martian hydrosphere in a timely

fashion will require doing some violence to the

planet, and , as discussed above, one way this can

be done is with targeted asteroidal impacts. Each

such impact releases the energy equivalent of 10

TW-yrs. If Plowshare methods of shock treatment for

Mars are desired, then the use of such projectiles is

certainly to be preferred to the alternative option

3

of

detonation of hundreds of thousands of

thermonuclear explosives. After all, even if so much

explosive could be manufactured, its use would

leave the planet unacceptably radioactive.

The use of orbiting mirrors provides an alternative

method for hydrosphere activation. For example, if

the 125 km radius reflector discussed earlier for use

in vaporizing the pole were to concentrate its power

on a smaller region, 27 TW would be available to melt

lakes or volatilize nitrate beds. This is triple the power

available from the impact of 1 10 billion tonne

asteroid per year, and in all probability would be far

more controllable. A single such mirror could drive

vast amounts of water out of the permafrost and into

the nascent Martian ecosystem very quickly. Thus

while the engineering of such mirrors may be

somewhat grandiose, the benefits to terraforming of

being able to wield tens of TW of power in a

controllable way can hardly be overstated.

Oxygenating the Planet

The most technologically challenging aspect of

terraforming Mars will be the creation of sufficient

oxygen in the planet's atmosphere to support animal