Readers have emailed in queries about the location of the Vortex Generators (VG) so for clarity, the VG’s are lined up right in front of the seam-line, and are “thicker” than the tufts. Look at the”i” in “Virgin”…there’s 3 in the stem, as well as one between the stem and the dot (this one, on the white background, shows the difference between the VGs and the tufts). There are 3 more right below the “i”, four more right above the bottom rudder counterweight and two below it
UPDATE: Virgin Galactic president Will Whitehorn has told Hyperbola that WK2 reached 18,000ft on the 5 February