Virgin Galactic performs the second test of VSS Unity, reaching Mach 1.9
https://phys.org/news/2018-05-virgin-galactic-vss-unity-mach.html
This was the second time that the VSS Unity flew since 2014, when the VSS Enterprise suffered a terrible crash while attempting to land, killing one pilot and injuring the other. The first propulsive test took place two months ago after several additional tests were performed on the craft. And with that last success, Virgin Galactic moved ahead with its second powered test earlier this week.
The focus of the latest test flight was to learn more about how the spaceship handles at supersonic speeds. It was also intended to test the control system's performance when the vehicle was closer to its ultimate commercial configuration. As the company stated, "This involved shifting the vehicle's center of gravity rearward via the addition of passenger seats and related equipment."