SpaceShipOne used nitrous oxide as an oxidizer to enable the combustion of a synthetic rubber rocket fuel. The nitrous oxide feeding the rocket engine remained liquid through most of the ship's flight, but turned gaseous toward the end of the rocket burn to reach space. SpaceShipTwo will use similar hybrid rocket technology, so-called because of the combination of solid fuel and liquid oxidizer.
While Scaled begins to pick up the pieces in an effort that's likely to take months, other private spaceship companies press onward. The European Aeronautic Defense and Space Company, prime contractor for the European Space Agency and owner of Airbus, announced in June that its EADS Astrium division would build its own tourist spaceship. The planned ship, a spaceplane the size of a business jet, features twin jet engines and a rocket engine powered by methane with liquid oxygen, or lox, as oxidizer.
EADS Astrium hopes to start construction in 2008 for first flights beginning in 2012 with financing from as-yet-unannounced business partners. The design borrows heavily from that of American company Rocketplane Kistler, which hopes to launch a jet-and-rocket hybrid built around a Learjet fuselage by 2009.
Amazon.com CEO Jeff Bezos has been quietly testing subscale versions of his planned New Shepard vertical-takeoff and -landing spaceship away from public view at a specially built launch facility in West Texas. Bezos won't talk to the press, but the website for his space startup, Blue Origin, says he wants to "lower the cost of spaceflight so that ... we humans can better continue exploring the solar system."
PayPal cofounder and head of Space Exploration Technologies, or SpaceX, is heading straight to orbit with his kerosene/lox Falcon rockets. A Falcon 1 test flight reached 200 miles in altitude last March, and SpaceX plans to launch a satellite into orbit later this year.
Musk's ultimate mission is to send people to Mars. Long before then, though, the first commercial space stations will likely open for use by researchers and thrill-seekers by 2012 if the plans of Las Vegas Real Estate developer Robert Bigelow come to fruition. Bigelow's company Bigelow Aerospace launched its second small-scale test satellite July 12 aboard a converted Russian ICBM. Large-scale tests will soon follow.