"The treaties that govern space allow private individuals and corporations to travel the stars, but only with the licensure and legal backing of an earthbound government. It’s similar that way to the laws of the sea. And today, on Earth’s oceans, more than 11 percent of all the tons of freight shipped is carried on boats that fly the Liberian flag (In contrast, U.S.-registered ships carry just 0.7 percent of the freight tonnage).
In exchange for lower taxes and looser regulations, both the shipping companies of the present and the Martian explorers of tomorrow could pay to register their vessel with a small country they have no other connection to (Liberia earns more than $20 million a year this way) and carry its flag (and laws) with them, wherever they go."
Maggie Koerth-Baker at 538 (via The Browser)