NASA’s Chris McKay and Mars visionary Robert Zubrin have suggested that
there are three possible ways to terraform Mars.
The first is to construct giant mirrors, with diameters in excess of two
hundred miles, to focus the sun’s energy on Mars, to cook out frozen carbon
dioxide at the Martian poles and in the Martian surface to thicken the Martian
atmosphere. The second is to artificially produce a greenhouse effect by
building plants on Mars that would produce chlorofluorocarbons or CFCs and
release them into the atmosphere. The third and most drastic method is to smash
ammonia rich asteroids onto Mars, releasing a great deal of energy, melting
trillions of tons of water and raising the temperature of Mars to a livable
level in a matter of decades.
Because using mirrors alone might be insufficient to trigger a Martian
greenhouse effect and using ammonia rich asteroids would be the equivalent of
bombing Mars with 70,000 megaton explosions, McKay and Zubrin conclude that
using greenhouse gas producing plants on Mars, perhaps along with mirrors, is
the better solution for terraforming.
Bringing Mars to Life
The first stage for terraforming Mars would be to create nuclear powered
greenhouse plants that would extract greenhouse gasses from the Martian soil
and release it into the atmosphere. McKay and Zubrin believe that this would
require a large industrial infrastructure on Mars supported by several thousand
people and with a budget of several hundred billion dollars.
As the temperature of Mars rises, the atmosphere thickens, the radiation
level on the Martian surface decreases, and water begins to flow, genetically
engineered plants can be introduced to begin creating an oxygen rich
atmosphere. McKay and Zubrin estimate, given current technology, that this method
would produce a Mars upon which people can go outdoors unprotected in about
nine hundred years. Long before that time, people could go outside on Mars
wearing nothing more complicated than breathing gear.
Greater power sources—say fusion derived—for the greenhouse plants and
better engineered plants could compress that time from centuries to decades.
Developing such technology in the 21st Century would not be inconceivable,
given the history of technological advances just in the past century.