Virgin Galactic managed to conduct last in 2016 flight of their VSS Unity spacecraft. It was sixth flight of this vehicle and 221st for WhiteKnightTwo.
It is second test flight after beginning of flight campaign on 3 December 2016. Since 31 October 2014 when accident of VSS Enterprise, first from two SpaceShipTwo spaceplanes, took place, Virgin Galactic has not conducted any flight of these vehicles. Company decided to return to flying, but before first engine flight of VSS Unity in 2017, number of glide flights was planned. Flight, which took place on 22 December 2016 was next from series of glide flights.
Flight was not announced earlier and all technical details are still kept in secret - we know for sure, that flight was performed probably in similar way as on 3 December.VMS Eve, motherplane took off with VSS Unity under the fuselage at 13:21 local time on 22 December from Mojave Air and Space Port. Inside VSS Unity two Virgin Galactic pilots Mark Stucky and Dave Mackay were getting ready to start their flight. After reaching correct altitude, VSS Unity was deployed at 13:59 local time. If we assume, that as on 3 December, Unity was deployed from altitude of 15000 m, probably it reached speed of around 0.6 Ma. Next, VSS Unity landed at Mojave Air and Space Port at around 14:10 local time. Its flight lasted for around ten minutes - just like during flight on 3 December. VMS Eve landed at around 14:50 local time with pilots Nicola Pecile and Rick 'CJ' Struckow. Flight engineer during this mission was again Dustin Mosher. Flight was finished with success, no problems were reported.
Virgin Galactic still not unveiled how many glide flights are planned before resuming engine flights, but probably company is targeting with first one to second half of 2017.