October 4, 2001
By ALLISON GATLIN
MOJAVE - The first baby steps toward civilian access to space were taken Wednesday when XCOR Aerospace's EZ-Rocket successfully completed its first up-and-away test flight in the skies above the Mojave Airport.
With aviation pioneer Dick Rutan at the controls, the EZ-Rocket climbed to 6,200 feet in 96 seconds of rocket-powered flight, then glided to a runway landing.
"It's quite a ride," said Rutan as he piloted the EZ-Rocket through its climb. The aircraft reached 160 knots - 184 mph - before the engines were shut down.
The rocket plane - the world's first privately built rocket-powered aircraft - made its first successful test flight on July 21 in a runway test here, flying a few hundred feet. Wednesday's flight was the first time the aircraft flew a complete flight pattern over the airport and the first flight with both engines.
"It ran just as advertised," Rutan said following the 5-minute, 20-second flight. "The ride was very smooth."
The EZ-Rocket is a modified Long-EZ airplane, a kit plane developed by Rutan's brother, Burt. The Long-EZ is powered by a propeller engine in the rear of the plane. The EZ-Rocket replaces that with twin 400-pound-thrust rocket engines.
Mojave-based XCOR Aerospace is developing safe, reusable, routinely operable rocket engines with the intent of opening up private, commercial access to space.
"(The flight) is the first baby step for civilian access to space," Rutan said.
Other attempts at new rocket propulsion systems have aimed for high performance first, then looked at reliability and ease of operation. XCOR takes the opposite approach.
"Our focus is on routine operations, rather than performance," said Rich Pournelle, director of business development.
The goal is to first create a safe, reliable rocket engine with the capability to offer a quick turnaround between operations, then increase the performance of the engine.
"Our goal is routine access to space," said Dave DeLong, chief engineer. "We think the way to get there is to do the routine part first."
Unlike some more aggressive programs that have failed, XCOR is taking small steps, Pournelle said, gradually increasing the engines' performance.
XCOR's research and development harkens back to the old school of flight test, with more actual in-flight research and less reliance on wind tunnel models.
One cornerstone of XCOR's engine designs is the use of nontoxic fuels. This is not only safer, but it greatly reduces cost by eliminating the expense of safely using and disposing of hazardous materials.
The EZ-Rocket engines use liquid oxygen and isopropyl alcohol, the same kind found in most medicine cabinets, only more concentrated.
The alcohol makes a good fuel for test flight, as it is clean-burning and easy to work with, Pournelle said. Often used as a solvent for cleaning, the alcohol is easier to use than kerosene or other fuels.
Unlike most rockets, XCOR's engines are designed to be re-lit after shutdown, in the air if necessary. This allows the pilot to abort a glider landing and try again.
The engines are also uniquely designed to avoid the problem of a hard start. This occurs when too much propellant pools in the combustion chamber before ignition. When it is then lit, it burns suddenly, creating pressure that can go beyond what the chamber was meant to handle.
Most rocket engine explosions are due to hard starts, DeLong said. In the company's more than 2,000 firings of four generations of engines, there have been no explosions.
"We think we've designed engines that are inherently safe," DeLong said.
The next step for the EZ-Rocket is continued flight test, including touch-and-goes, something never before accomplished with rocket-powered aircraft.
The 2-year-old company is raising funds for the next phase of its rocket development: a higher-performing vehicle.
"The performance of this vehicle is severely limited by the airframe," said Jeff Greason, XCOR president. The Long-EZ cannot withstand the speeds that the rocket engines are capable of producing.
Despite its limitations, the EZ-Rocket has provided experience in designing and packaging a propulsion system in a vehicle.
"We've learned an awful lot about things we didn't know needed to be learned," Greason said.
In addition to the EZ-Rocket, XCOR also has a government contract with the National Reconnaissance Office, creating satellite rockets that use nontoxic fuels.
Wednesday's flight was the first time since the 105th flight of the X-1 program that a rocket plane completed a flight after taking off from the ground on its own power. Other rocket-powered aircraft such as the X-15 were carried aloft by a larger airplane then launched in the air.
It was also the first flight of a rocket-powered aircraft since the final flight of the X-24B - the last of NASA's lifting body program - in 1975.
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