Terraforming of a planet or moon

Terraforming of a planet or moon is the hypothetical process of deliberately modifying its atmosphere, temperature, surface topography or ecology to be similar to the environment of Earth to make it habitable by Earth-like life.

Habitability requirements

In its astrobiology roadmap, NASA has defined the principal habitability criteria as “extended regions of liquid water, conditions favorable for the assembly of complex organic molecules, and energy sources to sustain metabolism.”

Preliminary stages

Once conditions become more suitable for life of the introduced species, the importation of microbial life could begin. As conditions approach that of Earth, plant life could also be brought in. This would accelerate the production of oxygen, which theoretically would make the planet eventually able to support animal life.

Biological Terraforming

Many proposals for planetary engineering involve the use of genetically engineered bacteria.

As synthetic biology matures over the coming decades it may become possible to build designer organisms from scratch that directly manufacture desired products efficiently.

The synthetic biology, scientists could genetically engineer humans, plants and bacteria to create Earth-like conditions on another planet.

Paraterraforming

Also known as the “worldhouse” concept, paraterraforming involves the construction of a habitable enclosure on a planet which encompasses most of the planet’s usable area. The enclosure would consist of a transparent roof held one or more kilometers above the surface, pressurized with a breathable atmosphere, and anchored with tension towers and cables at regular intervals. The worldhouse concept is similar to the concept of a domed habitat, but one which covers all (or most) of the planet.

Adapting humans

It has also been suggested that instead of or in addition to terraforming a hostile environment humans might adapt to these places by the use of genetic engineering, biotechnology and cybernetic enhancements.

This is a conception view of the Western hemisphere of Mars with oceans and clouds. Olympus Mons is visible on the horizon beyond the Tharsis Montes volcanoes and the Valles Marineris canyons near the center. Credit: Kevin Gill