Rockets Ignite

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caled Composites revealed SpaceShipOne to the public on April 18, 2003, but it had been running in secret for two years. On November 18, 2003, after about a year-long rocket-engine competition and seven glide flights, the hybrid rocket engine was qualified for flight testing in SpaceShipOne.

Flight testing is risky. Things go wrong as never-before-tested systems are evaluat­ed or new conditions are encountered. It is all part of the process of shaking the design out. It is like an artist making a sculpture of an airplane from a block of wood. At first it doesn’t look like anything, but slowly as pieces of wood are whittled away and form starts to take shape, little by little an airplane becomes more recognizable.

The process of flight testing is pretty much the same as testing other high-performance machines, whether it is a new racing sailboat or a new sports car. Nothing comes off the drawing board perfect. Flight testing is a flying laboratory. And as long as there are many more big steps moving forward than there are moving backward, good progress toward the goal is being made.

Scaled Composites attempted to become the first private company to go to space, yet the company had never even built an aircraft that broke the sound barrier. In fact, no private company had ever built an aircraft that broke the sound barrier as part of a non-governmental program.

The sound barrier, once thought impenetrable and its threshold guarded by demons, was smashed, along with the demons, by Chuck Yeager in the Bell X-l. Although this happened in 1947, the transition from subsonic to transonic to

( >1

Fig. 8.1. On December 17,

1903, Orville Wright, flying a

twin pusher-propeller biplane

with a canard, lifted off from

the sandy dunes of Kitty

Hawk, North Carolina. This

was the first flight of a

heavier-than-air, powered

aircraft capable of sustained

and controlled flight. NASA

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supersonic was still a dangerous one. Before SpaceShipOne reached past the boundary of Earth’s atmosphere, it would have to fly faster—several times faster—than the speed of sound.

“The powered flights were very different,” Mike Melvill said. “As a glider, it is completely silent, and there is no noise at all. You don’t have this overload of sensory audio. The audio side of your senses is really overloaded when the rocket motor starts. It’s very, very noisy. It vibrates a lot. It really shakes you around in the airplane. It’s a pretty exciting thing to do. The acceleration is enormous. You drop off the hooks and light the rocket motor. You get this enormous kick in your back. And right away, you turn the corner and point it straight up.”

Flying above Mach 1 was not the same as flying below Mach 1. Flying outside the atmosphere was not the same as flying within the atmosphere. And flying with a rocket engine was not the same as flying without a rocket engine.

Flight testing would now have to be taken up a few notches.