Burt Rutan has revealed that he intends to achieve the first privately financed manned spaceflight within 12 months with his company Scaled Composites making good progress flight testing its two-stage sub-orbital vehicle (Flight International, 29 April-4 May).

Rutan said at the show that captive testing of the 7,700kg (17,000lb) White Knight/SpaceShipOne combination began late last month, and that testing of the second stage's specially developed hybrid rocket motor is progressing well.

"We had one test firing of 45s a couple of weeks ago, a 55s test scheduled soon, and the goal is a burn of 65s, so we're almost there," he says. All the hardware used during ground and flight tests is qualified for spaceflight, says Rutan.

California-based Scaled launched the project under the designation Tier One in 1996, and evaluated several concepts before settling on the current two-stage design, which Rutan says is the most efficient solution for a sub-orbital flight. "A high-altitude launch allows the SpaceShipOne to be just one-third the weight required for a ground launch," he says.

The high ballistic coefficient of the second stage produces an early deceleration during re-entry. "We never go above 150kt EAS [equivalent airspeed] on re-entry", says Rutan, "and the jack-knifed configuration is so stable that no pilot control inputs are required."

The fuselage temperature will reach 590°C (1,100°F) during re-entry, however, and the composite structure is protected by a paste that can be applied in a few hours. He says he will not consider entering the X-Prize private rocket competition until a successful first flight has been completed.

Source: Flight International