SpaceShipTwo is scheduled to test a new plastic-based rocket fuel for the first time, in its first powered flight in nine months. Engineers were switching out the previous engine, which burned rubber-based fuel. Scaled Composites is reported to have previously experienced problems with the rocket on the ground. The new motor is intended to push SpaceShip Two five times higher than it had ever flown before—to the edge of space 62 miles above the Earth. Maximum speed iss expected to reach about 2,500 miles an hour during its ascent.