A multi-planet humanity is a hedge against an Earth catastrophe eradicating our species, sure, but there are financial considerations as well to interstellar development. From Tim Fernholz’s new Atlantic article about Elon Musk’s SpaceX:

“With 33 commercial launches on its manifest in the next four years, a plan to launch manned missions by 2017, and subsidies from Texas to build its own spaceport there after several years of leasing government facilities, SpaceX is now a serious competitor in the launch industry. That’s a validation for NASA’s public-private partnership, which was focused on developing a business, not a product.

But the question for Musk and his investors now is whether he can be more than just a better rocket builder. They want to unlock something far more challenging: A space economy where humans can vastly increase their productivity in the vacuum around our tiny world and beyond, even if nobody is quite sure how yet. Nolan of Founders Fund compares this hopeful uncertainty to the founding of the internet. ‘It wasn’t clear exactly what kind of business can come out of exchanging information really rapidly,’ he says.

For example, if it weren’t so pricey, investors could imagine putting up hundreds of new satellites in lower orbits than existing ones, making their communications and imaging far more powerful. Because of the high launch costs, current satellites aren’t upgraded frequently and are stationed relatively far from earth so that they can last longer—the closer a satellite flies to earth, the faster its orbit decays, leading to its eventual demise. As a result, the electronics in them are relatively old technology.

Cheap enough launches could also enable terrestrial flights that hop up over the atmosphere, turning a day-long flight around the world into a matter of hours. Space tourism is often cited as a possible source of revenue, as is commercial research, even asteroid mining, but making any of those sustainable will mean—you guessed it—far lower costs, as NASA has found in its failure to drum up much commercial research at the ISS.

Can the $6 million launch—or even cheaper—replace the $60 million launch?”