LARGE ORBITAL MIRRORS
NASA is currently working on an amazing solar sail propulsion system that would use huge reflective mirrors to harness the sun's radiation. These mirrors would be placed a couple hundred thousand km from Mars and use the mirrors to reflect the sun's radiation to heat the Martian surface. A proposal has been made which questions the idea of building mirrors that would have a diameter of 250 km, weight 200 000 tons, and would cover an area larger than Lake Michigan. Because these mirrors would be so large and heavy, they would have to be launched from space. An interesting fact to note is the possibility that the mirrors may and could be constructed from material, which is already found in space. If a mirror of this size were to be directed at the Martian surface, it is possible that it could raise the surface temperature of a small area by a few degrees. This concept could prove to be very useful if the mirror were positioned to concentrate their reflective energy on the polar ice caps. The ice caps would theologically melt and release carbon dioxide, which is trapped inside the ice. Over many years, the rise in temperature would release greenhouse gases.