But some people dream of terraforming Mars, which means making it a truly Earth-like planet, albeit rather cool, Mars being twice as far from the Sun as the Earth, and thus receiving only one quarter as much solar radiation as the Earth per unit of ground area. Terraforming means giving Mars an Earth-like atmosphere. Earth's atmosphere weights 16 pounds per square inch of ground area, or ten tons per square meter. Mars has a surface are of 144 million square kilometers, so to give Mars an Earth-like atmosphere would require the addition of ten million tons of air per square kilometer, or 144 trillion tons for the whole planet.
On Earth, compressed air costs about 100 USD per ton. At that price, enough air for an Earth-like atmosphere on Mars would cost about one point five trillion USD, or just over one percent of global yearly GDP. So, yeah, we could afford to provide Mars with an atmosphere -- that's if we knew where to get the air. Taking that much air from the Earth would probably cause folks to complain, riot even. And then there's the cost of shipping. Currently, that would meam paying SpaceX ten million dollars a ton for delivery, or about ten thousand times the cost of the freight to be delivered.
But if your dream is to climb the Martian peak, Olympus Mons, the highest mountain in the solar system, there may be no need to await the terraforming of the planet. You could do it now so long as you don't mind sweating inside a bulky space suit. As for reaching the mountain, for somewhere between ten and 100 million dollars Elon Musk will likely be happy to provide you with Earth-Mars return transportion.
