It could take a year to figure out what caused the Virgin Galactic SpaceShipTwo to disintegrate in the sky, killing one co-pilot and raising questions about the future of commercial space flight.

But two new clues have emerged about what went wrong before the Friday disaster. And both involve the spacecraft's "feathering," a process used to stabilize and slow the spacecraft down toward Earth.

During feathering, two pieces on the back of the vehicle - the "feathers" - lift up perpendicular to the spaceship, making the vehicle look like it's arching its back as it descends.

But on Friday, "the feather lock-unlock lever was moved by the co-pilot from the locked position to the unlocked position" prematurely, the National Transportation Safety Board said Sunday night.

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