пишут, что испытывали новое топливо, более энергетическое
http://www.iflscience.com/space/breaking-virgin-galactic-s-spaceshiptwo-crashes-over-mohave-desert Earlier this year, Virgin Galactic reformulated the fuel in an effort to give the space plane more power. The motor has been through four powered flight tests before. This was a first test for the fuel mixture in a powered air test, though it had been tested many times on the ground with no problems.
первое испытание в воздухе из четырех запланированных, наземные испытания прошли без проблем
