Mankind is very likely to establish permanent colonies elsewhere in the solar system at some point – and Mars is probably the best long-term option.
Mankind is very likely to establish permanent colonies elsewhere in the solar system at some point – and Mars is probably the best long-term option.
Human pioneers could become ‘planetary engineers’, eventually transforming Mars into a habitable world.
Mars has about the same area of dry land as Earth despite being half our planet’s size.
It has water frozen at the poles and in space terms is a near neighbour – so it’s considered the most likely planet to colonise.
But there are huge technological and economic challenges to overcome. So far only NASA's robot probes have landed on the red planet.
They include the car-sized remote-controlled probe Curiosity, which landed in August 2012 on a mission to study the planet's climate and suitability for supporting life.
Getting humans there is far more complex. While a manned trip to the moon takes two or three days – short enough to endure in a tiny, uncomfortable craft – reaching Mars will take months.
The spacecraft would have to be much larger, more comfortable and carry many more supplies.
It would probably have to be built in Earth’s orbit to avoid having to launch it into space.
The first manned missions will be round-trips to gather scientific information.
But to make the long voyage worthwhile, astronauts will probably stay much longer than a day or two.
Once they arrive, they will need the basics of survival: shelter, food and water.
All these could be provided by a large, self-contained dome or other building.
On Mars, shelter means more than just keeping the weather out.
The atmosphere is almost all carbon dioxide. Only a tiny fraction is oxygen.
It is also extremely thin – the atmospheric pressure is only one-hundredth of that on Earth.
A dome, a habitable bubble of Earth-like atmosphere, would protect its inhabitants from the solar wind – a stream of high-energy charged particles from the sun.
Earth is protected from these by an invisible shield called the magnetosphere, which Mars does not have.
The dome would be a closed ecosystem with the astronauts venturing out and returning only via an airlock.
Plants growing inside would produce oxygen and food for them to breathe and eat.
They would breathe out carbon dioxide, which the plants would absorb.
Liquid and solid human waste would be recycled into drinking water and fertiliser.
Experiments along these lines have already been done in a closed system called Biosphere 2 in Arizona in the 1990s, and in several NASA experiments looking at the requirements for deep space travel.
A dome could even be up and running before people set foot on the planet – using robot builders.
Intelligent robots could even replicate, making more robots from materials on the planet.
Several studies have shown this is the best and quickest way to carry out major building work or mining on other planets.
The ultimate goal for Mars colonists would be to move out of the dome and live on the planet’s surface.
Changing a planet to make it habitable is called ‘planetary engineering’ or, more commonly, ‘terraforming’.
To make an atmosphere similar to Earth’s, chemicals would have to be brought in from other planets or asteroids and released.
Carefully selected microbes and plants could provide the correct balance of gases.
Terraforming Mars would be a huge undertaking lasting hundreds of years.
But eventually Mars could change from a cold, desolate, red planet to an inhabited, blue one like Earth.
