Flying the Spaceflight Mission

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he objective was clear: a suborbital spaceflight above 328,000 feet (100,000 meters). But this mission was far from being straightforward. SpaceShipOne was groundbreaking. And although getting off the ground wasn’t too difficult, being able to return safely to the ground with the spacecraft intact required facing some pretty tough challenges. Three test pilots, Brian Binnie, Mike Melvill, and Pete Siebold, each flew SpaceShipOne during flight testing and handled the curves, and sometimes spirals, thrown their way. “Well, it is kind of a scary little thing to fly,” said Mike Melvill of the spacecraft he piloted for the first six flights and four subsequent others.

Figure 3.1 shows SpaceShipOne and White Knight waiting for launch in the early morning sunlight.

A carefully designed vehicle flown by a highly skilled pilot could tame the perilous environment and extreme forces, but it wasn’t easy. SpaceShipOne flew a total of seventeen times during its pursuit of space and the Ansari X Prize: three captive-carry flights, eight glide flights, three powered fights within the atmosphere, and three suborbital spaceflights. The combined flight time for these was 4 hours, 11 minutes, and 4 seconds, while the total burn duration was S minutes and 47 seconds. The spaceflight profile flown by SpaceShipOne is shown in figure 3.2.

White Knight would lift off the runway at Mojave Airport with SpaceShipOne slung below. And as the pilot anxiously awaited separation, all he could do was

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Fig. 3.1. With SpaceShipOne’s oxidizer tank filled the day before a launch and a fully fueled CTN (case/throat/nozzle) installed, SpaceShipOne and White

Knight undergo preflight preparations while illuminated by the early morning Sun. Mojave Aerospace Ventures LLC, photograph by Scaled Composites

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hang on until launch altitude. Upon separation, SpaceShipOne s rocket engine fired and boosted the pilot several times faster than the speed of sound. Since the rocket engine’s fuel was rubber, it gave a whole new meaning to burning rubber. But when the rocket engine shut down, after burning 76—84 seconds, the spacecraft was still only half the distance to apogee and had to coast the remaining way through the ever-thinning atmosphere.

On the way back down, SpaceShipOne’s feather ensured a safe reentry back into Earth’s atmosphere. When the craft was no longer falling at supersonic speeds, the feather retracted. SpaceShipOne, now a glider, descended to Mojave Airport for a horizontal landing, just like an ordinary airplane. Table 3.1 shows the mission profile for each of SpaceShipOne’s suborbital spaceflights.

For a spaceflight, the duration of the entire mission was only 1.6 hours. This was the time it took White Knight to take off, release

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Table 3.1 SpaceShipOne’s Suborbital Spaceflight Mission Profile

1. Liftoff of SpaceShipOne mated to White Knight

2. Captive-carry to launch altitude

3. SpaceShipOne separation from White Knight

4. Supersonic boost to space

5. Coast to apogee

6. Freefall from apogee

7. Supersonic reentry into the atmosphere

8. Descent with feather still up

9. Gliding descent back to runway

10. Horizontal landing

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Fig. 3.2. After White Knight lifted off with SpaceShipOne mounted below, it spiraled up to a launch altitude of about 47,000 feet (14,330 meters), where SpaceShipOne then separated, ignited its rocket engine, and boosted to an apogee above 100 kilometers (62.1 miles or 328,000 feet). SpaceShipOne reentered the atmosphere with its feather deployed, then reconfigured into a glider for landing at Mojave. Mojave Aerospace Ventures LLC, provided courtesy of Scaled Composites

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SpaceShipOne, and then land. However, the spacecraft flew for about 24 minutes only, making it back from space and touching down even before White Knight did.