SpaceShipOne Burns Rubber, Laughing Gas—More Fun Facts

Brian Handwerk
for National Geographic News
October 12, 2004
SpaceShipOne, the first privately built manned spacecraft, has traveled to space twice in a week to claim the ten-million-dollar (U.S.) Ansari X Prize. The feat may launch a new era of private space travel. Below, facts behind the unprecedented effort:

• A turbojet aircraft named White Knight ferried SpaceShipOne to some 45,000 feet (13,700 meters). There, the spacecraft disengaged and fired its rockets—soon reaching top speeds of 2,500 miles an hour (4,000 kilometers an hour).

White Knight and SpaceShipOne launched and landed at California's Mojave Airport, which is now technically a spaceport.

• After reaching an altitude of 367,442 feet (69.6 miles/112 kilometers), well within the zone of suborbital space, SpaceShipOne returned to the ground in about 90 minutes.

SpaceShipOne's hybrid engine burns a mixture of rubber and laughing gas, or nitrous oxide.

• The spacecraft's test pilots do not wear spacesuits. The craft's space-worthy cockpit is housed within a larger, similarly protective shell. The redundancy protects against an individual failure destroying the ship and maintains shirt-sleeve-temperature comfort for pilots.

• G-forces in the cockpit of SpaceShipOne peak during reentry to the Earth's atmosphere. Pilots experience a peak of over 5 g's (five times the force of Earth's gravity) for less than ten seconds—a level equivalent to some amusement park rides.

• Though controlling the craft requires skill and attentiveness, test pilots Mike Melvill and Brian Binnie still found time to eat candy, float a miniature SpaceShipOne in the weightless cockpit, and snap pictures of Earth from space.

• To claim the Ansari X Prize, SpaceShipOne had to travel with one pilot plus two passengers or something equally the weight of two passengers. Rather than passengers, the ship hauled personal effects of team members—including the ashes of SpaceShipOne designer Burt Rutan's late mother Irene.

SpaceShipOne's distinctive smattering of windows was designed to give the pilot a view of the horizon throughout the entire course of the flight. The portholes were kept small to save weight. They are round because of that shape's greater structural strength. Each window is double-paned to ensure cabin security in the event of a crack or break.

• British tycoon and adventurer Richard Branson announced plans to license SpaceShipOne technology. His new enterprise, Virgin Galactic, aims to offer commercial flights to space tourists as early as 2007. Ticket price: U.S. $200,000.

• Carrier aircraft White Knight features a cockpit and systems identical to those of SpaceShipOne, allowing for in-flight pilot training of procedures like boost, approach, and landing. The turbojet can also carry payloads of up to 8,000 pounds (3,600 kilograms) and climb to 53,000 feet (16,000 meters).

• Had SpaceShipOne designers employed a more dangerous ground launch system, the required extra fuel would have doubled the weight of the spacecraft.

• In space the ship's wings are folded up into a "shuttlecock" position, which creates drag to reduce stress during reentry. The shape also automatically orients SpaceShipOne into a belly-down position. The pilot uses a pneumatic system to reconfigure the wings into glider mode, which enables the ship to cruise up to 60 miles (100 kilometers) before landing.

• The spacecraft's engine has features of both solid and liquid rocket motors. While hybrid engines are nothing new, SpaceShipOne's system is unique. The engine fires when the fuel—hydroxy-terminated polybutadiene (HTPB or rubber)—is subjected to a heat source and mixed with an oxidizer. SpaceShipOne uses nitrous oxide (laughing gas) as an oxidizer. Hybrid configurations are unlikely to start accidentally.

• There is no single rocket throttle in SpaceShipOne. The pilot "lights the candle" with two switches—one to arm the rocket and another to fire it.

• Designer Burt Rutan developed the concept for SpaceShipOne in 1996. Full development did not begin until May 2001. Just over three years later, and after only three powered flights, the craft became the first private manned aircraft to reach space in June 2004.

• Rutan also developed Voyager, the first plane to fly nonstop around the world without refueling, a feat completed in 1986.

• Rutan's company, Scaled Composites, teamed with billionaire Microsoft co-founder Paul Allen to form Mojave Aerospace Ventures to develop SpaceShipOne.

• Total costs of the project have yet to be disclosed. But reported estimates hover in the range of 25 million dollars (U.S.). Such a budget could be considered shoestring compared to the expenditures of government space programs.

• Brian Binnie piloted SpaceShipOne's third, X Prize-winning flight. Binnie is a U.S. Navy-trained test pilot with 21 years of experience and over 4,600 hours of flight time in 59 different aircraft. He was also at the controls when SpaceShipOne broke the sound barrier in December 2003. That flight ended in the brush edging the Mojave Airport's landing strip, where a hard touchdown damaged the spaceship's landing gear. Designer Burt Rutan was quick to point out that the fault was in craft design rather than pilot error.

• Michael Melvill enjoyed a wild ride on SpaceShipOne's first qualifying X Prize flight. The craft went into a series of 29 unplanned rolls at the peak of its flight path.

Melvill became the first private pilot to earn his astronaut wings when he flew SpaceShipOne's maiden space voyage on June 21, 2004. He has 19 years of experience test piloting everything from bush planes and crop dusters to fighter jets—logging some 6,950 hours.

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