Virgin Galactic : During the 16-second engine burn , the spaceship broke the sound barrier , according to a statement from Virgin Galactic . The first stage of the rocket is a solid fuel booster that will be used to propel the spacecraft into orbit. Test was not a space flight , but company says it anticipates space flight by year 's end . The aircraft broke the sound barrier during propulsion , Virgin Galactic says .
Virgin Galactic : The first stage of the rocket is a solid fuel booster that will be used to propel the spacecraft into orbit. Test was not a space flight , but company says it anticipates space flight by year 's end . The aircraft broke the sound barrier during propulsion , Virgin Galactic says .