At some point in the next decade or two one of us is going to plant a space-suited foot on the surface of Mars and make that first footprint.
However, that first trip to Mars will not involve a couple of days in a spacecraft, a few hours on the surface grabbing rocks and taking pictures, before heading home.
Using current space technology, getting from Earth to Mars takes a few months.Then, when we get there, we cannot fill some bags with samples, take some pictures and head home, because we will have to wait until Earth and Mars are in the right relative positions for the return trip. This means we will have to have a Mars base suitable for living in comfortably for a few months, in other words, not far short of a permanently manned base, or even a good practice run for the first colony.
Long ago, Mars was a warm, wet world with a thick atmosphere, just like our Earth. However, because Mars is a smaller world than Earth, its core solidified much faster and the planet’s magnetic field decayed. This let the solar wind hit the top of the atmosphere to start scouring it away. Mars’ gravity is less than Earth’s allowing the atmosphere to spread further upwards, enhancing the rate at which it is still being lost to space.
The result is that today the Red Planet is a cold, almost airless desert. The air pressure is about 0.3% of the air pressure on the Earth’s surface, so that even if it were pure oxygen, each breath would bring in nowhere near enough oxygen for us to survive. However, there is very little oxygen in Mars’ atmosphere. In addition, even through a warm, summer’s day on the Martian equator might reach 20 degrees Celsius, at night the temperature will drop far below zero, and over most of Mars, it is well below zero all the time.
The result is that for us to survive on Mars, we will have to live in sealed habitats, under bubbles, as depicted in science fiction stories, or, more likely, in underground habitats, where the soil acts as insulation against the temperature variations and protection against radiation. If we want to work outside we will need spacesuits, or ride in sealed, insulated vehicles.
Living like this will be highly inconvenient for those living and working on the planet over years, or lifetimes. We know that Mars was once very much like the Earth. Could we make it like that again? Could we terraform Mars?
Various methods are talked about, genetically-modified plants that like the local environment and spit out oxygen, or numerous industrial scale machine complexes that do the same thing, or maybe a mixture of both.
For example, pump a lot of carbon dioxide into the atmosphere to increase the greenhouse effect and the temperature, which will then melt the ice, liberating water, and provide a starting point for getting vegetation
going. This would take in the carbon dioxide and release oxygen. We would hope that the dense atmosphere would still have enough greenhouse effect to keep things warm.
However, the processes that turned Mars from warm and watery to cold and dry will still be active, and that atmosphere we would be working hard to produce would continue to flowing off into space. Our terraforming process would therefore be an ongoing fight with Mother Nature.
There is another very important issue:- If we find there is still some form of life on Mars, even bacteria, making the planet right for us would make it hostile to them. Have we the moral right to do that? When we find life
out there,” we should respect its right to exist, as we expect would be the case when alien visitors arrive at our world and start complaining about the surface conditions.
Jupiter is conspicuous in the south overnight, with Saturn to its left. Mars rises around 11pm and Venus, shining even brighter than Jupiter, appears in the early hours. The Moon will reach Last Quarter on the 11th, and be New on the 18th.
Ken Tapping is an astronomer with the National Research Council’s Dominion Radio Astrophysical Observatory in Penticton. To contact the writer, email: firstname.lastname@example.org