After several glide flights over the preceding months, in July 2017, Richard Branson suggested that the craft was to begin powered tests at three-week intervals. In September 2017, CEO George Whitesides suggested that engine testing was complete, and that only a "small number of glide flights" remained before VSS "Unity" would begin powered tests flights. In October 2017, Branson suggested that SpaceShipTwo could reach space within three months, and that he could travel to space aboard a SpaceShipTwo within six months. A seventh high speed glide test was completed in January 2018. On 13 December 2018, SpaceShipTwo VSS "Unity" reached its highest altitude of 82.72 km (51.4 miles). This surpassed the US Government definition of space at 80 km (50 miles) but not the standard used elsewhere at 100 km (62.1 miles). Despite the debate on where outer space begins, Mark Stucky would receive his astronaut wings, while Frederick W. Sturckow would not as he has already flown on the Space Shuttle four times.