In early February, $175 million in public funds will be handed over to a small handful of spaceship developers, with the goal of making demonstration flights to the international space station and back. NASA has now narrowed the field of competitors: from an original batch of submissions in 2006, four companies are finalists.
NASA's Commercial Orbital Transportation Services (COTS) exists to encourage privately-operated companies to create "space transportation systems" for transporting cargo and astronauts.
