Virgin Galactic’s SpaceShipTwo rocket plane took another step toward lighting up its engine in flight today, by simulating the shift in its weight with water instead of rocket fuel.
Today’s test flight involved sending up the plane, christened VSS Unity, from California’s Mojave Air and Space Port attached to its twin-fuselage White Knight carrier airplane.
Once the paired aircraft reached the proper altitude, White Knight Two released VSS Unity for an unpowered, gliding descent back to base. That’s been done four times before since last December, but this time, there was an added twist: Before takeoff, about 1,000 pounds of water were loaded into a ballast tank in the back of Unity’s fuselage.
The water, a stand-in for the fuel that will be consumed in Unity’s hybrid rocket engine, was dumped during the glide.