Mars Astrobiology: Recent Status and Progress - Planetary Exploration and Science: Recent Results and Advances - page 220

by introducing dark extremophile microbial life forms such as lichens, algae, and
bacteria. The ground would then absorb more sunlight, warming the atmosphere.
If algae or other green life were established, it would also contribute a small
amount of oxygen to the atmosphere, though not enough to allow humans to
breathe. The conversion process to produce oxygen is highly reliant upon water. The
CO 2 is mostly converted to carbohydrates. On 26 April 2012, scientists reported
that lichen survived and showed remarkable results on the adaptation capacity
of photosynthetic activity within the simulation time of 34 days under Martian
conditions in the Mars Simulation Laboratory (MSL) maintained by the German
Aerospace Center (DLR).

Asteroid Impact

Another way to increase the temperature would be to direct small asteroids onto
the Martian surface. This could be achieved through the use of space-borne lasers
to alter trajectories or other methods proposed for asteroid impact avoidance. The
impact energy would be released as heat. This heat could sublimate CO 2 or, if there
is liquid water present at this stage of the terraforming process, could vaporize it
to steam, which is also a greenhouse gas. Asteroids could also be chosen for their
composition, such as ammonia, which would then disperse into the atmosphere on
impact, adding greenhouse gases to the atmosphere. Lightning may have built up
nitrate beds in Mars' soil. Impacting asteroids on these nitrate beds would release
additional nitrogen and oxygen into the atmosphere.

Thermodynamics of Terraforming

The overall energy required to sublimate the CO 2 from the south polar ice cap is
modeled by raising the temperature of the poles by four Kelvin which would be
necessary in order to trigger a runaway greenhouse effect. If using orbital mirrors,
an estimated 120 MWe-years would be required in order to produce mirrors large
enough to vaporize the ice caps. This is considered the most effective method,
though the least practical.
If using powerful halocarbon greenhouse gases, an order of 1,000 MWe-years
would be required to accomplish this heating. Although ineffectual in comparison,
it is considered the most practical method. Impacting an asteroid, which is often
considered a synergistic effect, would require approximately four 10-billion-ton
ammonia-rich asteroids to trigger the runaway greenhouse effect, totaling an 8 ı
increase in temperature.

8.8.2.3 New Proposals for Mars Terraforming

I make two proposals (suggestions) for Mars terraforming, and they are outlined
in the form of research steps - firstly, aboard Earth's International Space Station