How to make life possible on Mars
There is ample evidence to show that about 3.5 billion years ago, Mars had liquid surface water, a mild climate and was capable of supporting life.
It lost most of its atmosphere because, unlike Earth, it doesn’t have a magnetic field to deflect very high-speed charged particles mainly from deep space but also from the Sun. These energetic particles depleted the Martian atmosphere by colliding with and breaking up its molecules. Today Mars has an atmosphere 100 times thinner than Earth’s.
The average global temperature on Mars is minus 60 degrees Celsius compared to 15C on Earth. The Martian atmosphere is 96 per cent carbon dioxide and has trace quantities only of oxygen, hence it is completely unbreathable.
Given these facts, the idea of modifying the planet to make it habitable seems ludicrous. Not so, say Zubrin and Mckay. Their strategy for terraforming Mars has three objectives: to increase the temperature, to build up its atmosphere and to provide a magnetic field.
Increasing the temperature focuses on exploiting the greenhouse effect. Mars has significant quantities of carbon dioxide bound up in its soil and substantial amounts of frozen carbon dioxide at its poles, which also contain huge quantities of water ice. There is enough water at the poles to cover the entire planet in a shallow sea.
The idea is to heat Mars using orbiting mirrors to direct sunlight on to its south pole, slowly melting it and liberating copious amounts of carbon dioxide and water. Carbon dioxide is a greenhouse gas and gradually as its gas blanket increases, Mars will become warmer. Calculations show that the solar mirrors would have to be gigantic, about 200 kilometres across.
Ammonia has greenhouse-gas properties and would help load the Martian atmosphere with more gas to increase the pressure on the planet. There are many asteroids rich in ammonia and small asteroids would be selected and pushed on a collision course with Mars, using nuclear-powered thrusters.
The power requirements to achieve this could be reduced with the appropriate use of major planet gravity assist. By weight, ammonia is mainly nitrogen – 78 per cent of the Earth’s atmosphere is nitrogen and is the main ‘‘buffer gas’’, an inert gas that adds pressure and controls the rate and extent of oxygen combustion in the atmosphere.
The third requirement to terraform Mars is a magnetic field. The idea is to encircle the planet with superconducting refrigerated metallic rings and their associated magnetic fields. This is achievable using today’s technology.
The efforts won’t stop there. In the short term, oxygen will have to be made in chemical plants installed on Mars and colonists of the planet will require breathing apparatus to work outside. One proposal is to oxygenate the atmosphere by growing phytoplankton on a massive scale on Mars. These are tiny aquatic organisms that discharge oxygen as a waste product.
Calculations show it will take many thousands of years before Mars can be terraformed to sustain life but it is reasonable to assume that in the next few hundred years significant technological improvements will make the task more feasible and quicker. Terraforming Mars be our only survival option.