Latest Research
Researchers have found that there are two ways to terraform Mars: Melting the ice caps, causing heavier atmosphere; or absorbing sunrays with black, carbon objects on the surface. Melting the icecaps would involve a massive reflector panel, thinner than a sheet of aluminum foil, that heats up the surface temperature of Mars thus melting the polar ice caps, resulting in the release in carbon dioxide into the atmosphere. Absorbing the sunlight on the surface also causes the temperature to rise. The main focus is to raise the temperature of the surface in order to melt the ice caps and supply the planet with flowing water and heavier atmosphere resulting in a "Greenhouse Effect".

NASA has also been working on a project known as "solar sail". Basically using mirrors to harness the sun's radiation to propel a spacecraft through space. They estimate the mirrors would have a diameter of 250km, cover an area larger than Lake Michigan and weigh roughly about 200,000 tons. Because of their massive size they would be unable to launch them from the Earth.