I have discussed the problems here. The foremost problems are density, atmosphere & average temperature on Mars. We are pretty sure that we'll be able to generate power on Mars using solar energy.
Space Suits. This is very necessary before keeping our first steps on Mars. Otherwise, we will be boiling inside & freezing outside. The problem would be, if we are planning to civilise the planet, we can't be wearing space suits forever. The only option we can see now is living within an artificial dome, like the movie The Martian, which can reflect off heavy radiation as well. Another proposed solution is terraforming the planet.
What will terraforming be like?
We need to heat up the planet.
We will first need a magnetosphere. This will protect us against the deadly particle blasts from the sun & solar winds. Mars doesn't have one. NASA says we can launch a satellite with a very strong magnet and put it between the planet & Sun.
We will have to trap CO2 and other gases within the atmosphere itself. There is some CO2 trapped in the ground & polar ice caps of Mars. The idea proposed by Elon Musk was that we should bombard the ice caps with nuclear missiles, which would result in melting of ice to give us water as well as release the trapped CO2. Another way to heat up Mars would be to set up and slowly expand industries that would release artificial greenhouse gases. This method was proposed by Robert Zurbin.
After this, we will have to release bacteria in the atmosphere. This bacteria can absorb some of the nutrients on Mars & release oxygen back into the atmosphere. This is how oxygen got into Earth's atmosphere, billions of years ago. We will have to wait for a few hundred - few thousand years for this.
Terraforming is a slow process. There is some still bad news. We don't know if there is enough stuff on Mars. We need enough CO2, enough nutrients & enough nitrogen. So, in reality, we are several generations away from actually trying terraforming Mars.
This video is part of Mars & Space Exploration series. Please check them out here:
1. Mars