NSS Roadmap to Space Settlement Milestone 29: Terraforming and Para-Terraforming

Modification of other planets or moons to support human, animal and plant life in a manner similar to the Earth.

terraforming of MarsImage: Kevin Gill. Click image for larger version. Click resulting image for very large detailed image (and use scroll bars to scan).


Terraforming (literally, “Earth-shaping”) of a planet, moon, or other body is the hypothetical process of deliberately modifying its atmosphere, volatile components, temperature, surface topography or ecology to be similar to the environment of Earth and to make it habitable for Earth life.

Three levels or types of terraforming are:

  1. Para-terraforming – very large scale pressurized habitats and agricultural zones exist on the surface without requiring substantial external atmospheric modifications. This assumes that the cosmic radiation flux present on a surface without a dense atmosphere can be dealt with in some way.
  2. Partial terraforming – adequately blocks cosmic radiation, allows some kinds of plants to grow on the surface and humans to walk there without pressure suits and without radiation protection, but with air-breathing equipment, and at an ambient pressure of about one half Earth sea level or more.
  3. Full terraforming – extensive modification of a world’s surface to provide an Earth-type atmosphere and aquasphere, allowing survival of humans, animals and plants without special protective equipment.

Terraforming of a cold, dry planet similar to Mars would include four main phases:

  • Warming the planet so that water is not frozen.
  • Importing enough nitrogen atmospheric mass to stop galactic radiation from reaching the surface.
  • Importing enough water to provide wide areas of water surface, allowing significant humidity and rainfall.
  • Creating enough oxygen in the atmosphere from in-situ resources.

An additional long-term step may be the creation of an artificial magnetosphere around the planet, to prevent the solar wind from stripping away the new atmosphere.

Mars is the most obvious example of a terraformable planet in our solar system, but different types of planets would require different kinds of terraforming operations and sequences. A planet with an atmosphere that is too dense to breathe could, with great effort and significant time, have the excess atmosphere removed, if the air mass was not too huge. If the planet is not too hot and has water, oxygen-producing algae may be able to be introduced early on to start oxygen production.

COMPONENTS (major types of terraforming modifications)

  • Preventing cosmic radiation from reaching the surface.
  • Adjusting the average planetary temperature.
  • Adding atmospheric mass to allow water on the surface.
  • Adjusting the amount of water surface and depth.
  • Adjusting the oxygen-nitrogen amount and balance.
  • Removing toxic substances in the atmosphere.
  • Creating a biosphere on the planet’s surface.
  • Creating areas of arable land.

BARRIERS (general)

  • Opposition to terraforming by those who claim that “rocks have rights” which are considered more important than bringing life on to another world.
  • Opposition by people who think large scale human projects are morally wrong or reduce the beauty of a planet.
  • If it is decided by humankind that only totally sterile planets may be terraformed, then we will need a valid and publicly acceptable means of effectively demonstrating that a planet meets established criteria of sterility before terraforming efforts begin.
  • The need to establish a set of criteria for whether to terraform planets which are known to harbor life of some kind.

BARRIERS (items lacking)

  • Engineering and construction methods to cover large land areas with pressurized enclosures for paraterraforming efforts.
  • A means of creating perfluorocarbon (super-greenhouse) gases on some planets from carbon and fluorine, including finding large sources of fluorine in Mars minerals.
  • A means of creating (and keeping in position) giant, low mass parasols or mirrors used for thermal control at some planets.
  • A means of moving very large masses of volatiles such as frozen nitrogen, CO2 or water ice to planets where the volatiles are needed with very large space tugs.
  • A fusion space drive to power space tugs to move the huge masses of volatiles.
  • Replicator systems to build a large fleet with thousands of very large fusion powered space tugs and units for mining volatiles.
  • Smart software to safely operate this fleet and to prevent malevolent forces from taking control of them to cause mass destruction.
  • Software to simulate the climatological effects of the proposed terraforming efforts.


(A) The partial terraforming milestone (which covers several different situations) can be considered achieved when the climate and atmosphere of at least a substantial portion of one planet has been changed enough to achieve one or more of the following: (1) prevent harmful levels of radiation from reaching the surface, (2) cause water to flow on a substantial portion of the surface of a previously frozen planet, (3) enable rain to fall on the surface of a previously dry planet, (4) enable some kinds of plant life to grow on the surface or in the waters of a previously sterile planet.

(B) The full terraforming milestone will be achieved when humans, plants and animals can directly breath and use the air and work on the surface of a previously oxygen-free planet without pressure suits, oxygen supplies or radiation protection.