The May 13th flight of the privately-financed SpaceShipOne has verified that the craft and its operators are close to attempting suborbital flight. Their goal: Two consecutive missions, two weeks apart, aimed at winning the Ansari X Prize purse.

Another test hop is on the books, before trying to win the $10 million Ansari X Prize competition, according to sources close to the project.

Back-to-back flights

The quest by Scaled Composites to demonstrate non-government piloted space flight operations is led by aerospace innovator, Burt Rutan, who heads the company. Financial backer of the space plane project is Paul Allen, Microsoft co-founder and chief executive officer of Vulcan Inc.

The Ansari X Prize money is to be awarded to the first company or organization to launch a vehicle capable of carrying three people to a height of 62.5 miles (100 kilometers or some 330,000 feet), then return safely to Earth, and repeat the flight with the same vehicle within two weeks.

Teams from various nations have signed up for the Ansari X Prize competition, many of which are actively testing hardware in the hopes of beating Rutan in the suborbital race.

The purse is being offered by the X Prize Foundation of St. Louis, Missouri. The cash reward offer expires as of January 1, 2005.

Most demanding flight

Flight data from the May 13 test of the rocket plane – the most demanding on craft and pilot -- has been officially released by Scaled Composites.

After deployment from the White Knight carrier plane at 46,000 feet, SpaceShipOne fell for 10 seconds prior to motor light off.

SpaceShipOne’s hybrid rocket motor then blazed away for 55 seconds -- the longest burn-time yet for the propulsion system. An engine run time of over one-minute is expected to reach X Prize altitude.

The rocket plane’s first powered flight took place on December 17, 2003, with the motor firing for 15 seconds. A second powered trek occurred on April 8th of this year, with the engine burning for 40 seconds.

On the May 13 flight, the vehicle boosted itself smoothly to 150,000 feet and reached Mach 2.5 – or two-and-a-half times the speed of sound. After motor shutoff, momentum carried the craft to 211,400 feet altitude.

Smooth sailing

During a portion of SpaceShipOne’s boost, the flight director display did not function properly. Pilot Mike Melvill, however, continued the planned trajectory referencing the external horizon through cockpit windows.

Melvill used the ship’s reaction control system to reorient SpaceShipOne to entry attitude. The vehicle’s tail section was flipped up – called feather position -- converting SpaceShipOne to a high-drag configuration, permitting stable atmospheric entry.

The ship was “de-feathered” starting at 55,000 feet. As SpaceShipOne glided toward its runway touchdown, onboard avionics was rebooted. The craft made a smooth and uneventful landing at the Mojave Airport, according to Scaled Composites log data.

Suborbital history

The most recent test of SpaceShipOne is part of Scaled Composites’ “Tier One” program.

In unveiling the SpaceShipOne on April 18, 2003 at Mojave, California ceremonies, Rutan noted the history behind taming the suborbital heights.

Suborbital manned space flights have been done before using the Redstone rocket/Mercury space capsule combination in 1961 and by the B-52 carried X-15 rocket plane in 1963.

“Even though the experience, as described by Alan Shepard, Gus Grissom and Joe Walker was awe-inspiring, suborbital space flights were ignored for the next 40 years. The view from the apex of a suborbital flight is similar to being in orbit, but the cost and risk is far less,” Rutan explained.

“Our goal is to demonstrate that non-government manned space flight operations are not only feasible, but can be done at very low costs. Safety, of course is paramount, but minimum cost is critical,” Rutan said. “We look to the future, hopefully within ten years, when ordinary people, for the cost of a luxury cruise, can experience a rocket flight into the black sky above the Earth's atmosphere, enjoy a few minutes of weightless excitement, then feel the thunderous deceleration of the aerodynamic drag on entry.”