Left Flank

I was just too young to experience the excitement of July 20, 1969, when Neil Armstrong landed on the moon. Still, Star Trek reruns and the original Star Wars (before it became Part IV) were enough to plant the bug of space exploration into my adolescent brain. Along with grad school discussions of near-earth orbiting weapons platforms and two trips to Cape Canaveral, this constitutes my space indoctrination.

So, it's absolutely thrilling to read The Economist crow about SpaceShipTwo.

But Virgin Galactic has passed an important milestone. At an event held at the American Museum of Natural History in New York, on January 23rd, the company unveiled the design of its new generation of vehicles, and said that the first examples had almost been finished at Mr Rutan's factory. White Knight Two is due to begin test flights towards the middle of 2008, but may roll out of the hangar in the next few weeks. Test flights of SpaceShipTwo itself could start towards the end of the year.

The combination of a carrier aircraft and a spaceship to get into space is akin to building a two-stage rocket. Air-launched rockets have a long history. SpaceShipOne and White Knight were, in essence, vastly improved and much cheaper versions of the X-15 rocket plane that set speed and altitude records in the early 1960s and the B-52 bomber that carried the rocket plane under its wing. But pure rockets, such as the ones that lift the space shuttle, won out because the Space Race between America and Russia emphasised speed over cost, and rockets were proven technology, having already been developed as intercontinental ballistic missiles. However, they consume a huge amount of power as they claw their way up through the Earth's thick atmosphere. By contrast a rocket lifted by a plane with wings before being launched can be made much smaller and lighter. The plane itself is light because its engines breathe air. It thus needs to carry less fuel than a rocket, and no chemical oxidant to burn that fuel, as a rocket would. Each craft—plane and rocket—can therefore be optimised for its own job, which is easier than designing a single vehicle that has to make lots of compromises to do both.

Virgin Galactic's second generation of craft are based on SpaceShipOne and White Knight, but with plenty of differences. White Knight Two has been redesigned wholesale to lift a much larger spaceship with eight people on board instead of three. It has a wingspan equivalent to that of a Boeing 757, is three times larger than its predecessor and is the largest aircraft made entirely from composite materials like carbon fibre. It is powered by four Pratt & Whitney engines. With its twin boom and long wing, it looks more like the Global Flyer than its predecessor. It has also been engineered to be able to treat any passengers it carries to zero-gravity swoops on the way down after they have watched the spaceship being released for its trip into space.

SpaceShipTwo itself will accommodate two pilots at the front and also six passengers, who will have room enough to bounce around in zero gravity. It has more of a dolphin-like nose than its prototype and more windows. It will also go a little higher than its predecessor, so that its passengers will experience five minutes or so of weightlessness before flying back to receive their astronauts' wings. But, crucially, it has the same flip-up wings. These are used when the craft reconfigures itself for re-entry into the Earth's atmosphere. The wings rotate through 90° to give it extremely high drag, which allows it to begin its slow deceleration through the atmosphere earlier and at higher altitudes than previous spaceflight re-entries.

The spaceship will be fuelled by a «hybrid rocket»—so-called because it contains both liquid and solid propellants. These rockets can be cheaper to develop and operate, and the fuel is safer to store than in purely liquid-fuelled ones. SpaceShipOne used rubber and laughing gas. Scaled Composites is studying alternatives to rubber that may offer better performance.

Another change in the design of the spaceship is the insertion of a flexible glass-fibre section into its composite structure. This will allow the rocket's oxidiser tank to expand when it is full. All these changes mean that when SpaceShipTwo does begin flight tests, the programme will last at least a year before paying customers can take to the skies.

Work will also begin soon on fitting out another factory to start making more of these craft. Virgin Galactic has ordered five spaceships and two carrier aircraft. The spaceships will take longer to refuel for their next flight than the carrier aircraft do, so—thinking just as an airline would—the firm has concluded it needs more spaceships than carriers. Each spaceship should eventually be capable of making two trips into space every day, and the launch aircraft three or four flights. Mr Rutan says they could operate from a number of airports and spaceports around the world.

Virgin Galactic believes the fleet it has ordered should be large enough to furnish its space-tourism business in the early years. Trips are expected to cost some $200,000 each to start with. Hundreds of people have put down a total of $30m in deposits. However, as the firm also made clear at the announcement in New York, the new craft may one day do a lot more than ferry day-trippers to the edge of space and back. Stephen Attenborough, Virgin Galactic's commercial director, says the spaceship is revolutionary because it is able to take not just people into space, but other payloads too.

In a companion editorial, The Economist continues its giddiness with total abandon. Another possibility SpaceShipTwo conjures is cheap terrestrial transport.

Such applications will never be cheap; they are unlikely, for example, to usher in an era when Londoners ponder at their breakfast tables the merits of dinner (or rather, given the time-shift, a second breakfast) in Sydney. But another development of the technology may indeed become ubiquitous. That would be to use it to launch small satellites.

Satellites are just packages of electronics, and the price of electronics is falling without foreseeable end. It is the launch cost ($20m a time) that restricts their use. A successor to the SpaceShip/White Knight combination could deal with that. First, the whole caboodle is more economical than using throw-away rockets. Second, rather than having to wait ages on the ground for the right launch window, an air-launcher can fly to a better location. Such changes could bring satellite ownership to cities, universities and companies. Ultimately, it may bring it within the purse of individuals. Who could resist having their own, private window on the world?

It is famously difficult to predict the market for disruptive technologies, whether they be computers, muskets, jet engines or digital cameras. But cheap access to space, and to the other side of the Earth, is likely to be revolutionary. For many years the question has been why taxpayers should pay to put people into space. The point of private-sector space travel is that the world will rapidly and accurately come to a conclusion about what space is for. The invisible hand may, indeed, point upwards. Then again, it may not.

If it does, however, it may also point to a revolution of a different kind. Many people date the emergence of the environmental movement to the publication of a photograph taken from Apollo 8 of the Earth rising over the lunar horizon. When space becomes a democracy—or, at least, a plutocracy—the rich risk-takers who have seen the fragile Earth from above might form an influential cohort of environmental activists. Those cynics who look at SpaceShipTwo and think only of the greenhouse gases it is emitting may yet be in for a surprise.

Compared to this, and another article about how easy space travel just might be for most healthy 80-year old rich guys, NASA's Constellation program looks like retread Apollo schlock.