The pilot of a passenger-carrying spaceship being readied for suborbital flight reported some handling problems in an otherwise successful shakeout test.

To date, the trio of practice flights have had pilot Mike Melvill at the controls.

SpaceShipOne is the brainchild of aviation maverick Burt Rutan, who faces stiff competition for the X Prize, which will be awarded to the first privately-funded group that sends people to space and back safely twice in a two-week period.

The recent glide flight of SpaceShipOne checked out center of gravity conditions of the free-falling vehicle. During the test, the craft's overall stability was appraised.

The White Knight mother ship hauled SpaceShipOne to a drop altitude of 46,800 feet. During the climb, a heating system was able to keep the space plane's nitrous oxidizer conditioned. That hardware is tied to the SpaceShipOne's hybrid rocket motor that has yet to be revved up while airborne.

Load factors on SpaceShipOne after its high-altitude release, as well as maneuver and spin control conditions, were assessed. Also evaluated were space-worthy gear doors and an upgraded landing gear extension mechanism, according to Scaled Composites.

Once in free-fall, SpaceShipOne's pilot did encounter unexpected flight-handling issues. The nose of the vehicle rose on its own accord before reaching a wing stall angle of attack. This in-flight characteristic was worse than predicted and will demand follow-up attention by Scaled Composites engineers.

Last month, the White Knight also made a number of test hops. Winging its way over California desert, the jet-powered plane's Global Positioning System (GPS) equipment was wrung out, and various flight profiles were judged.

Future flights of SpaceShipOne are being planned.