to ▁allow ▁tour ist ▁training ), ▁and ▁the ▁other ▁will ▁offer ▁' cut - rate ' ▁tri ps ▁to ▁the ▁str atos phere . ▁ ▁The ▁design ▁is ▁quite ▁different ▁from ▁the ▁White ▁Knight , ▁both ▁in ▁size , ▁use ▁of ▁tail , ▁engine ▁configuration ▁and ▁pla cement ▁of ▁co ck pit ( s ). ▁The ▁White ▁Knight ▁uses ▁two ▁T - t ails , ▁but ▁the ▁White ▁Knight ▁Two ▁uses ▁two ▁cru c iform ▁t ails . ▁Engine ▁configuration ▁is ▁also ▁very ▁different . ▁White ▁Knight ▁Two ▁has ▁four ▁engines ▁hung ▁under ne ath ▁the ▁wings ▁on ▁p yl ons ▁while ▁White ▁Knight ' s ▁pair ▁of ▁engines ▁are ▁on ▁either ▁side ▁of ▁its ▁single ▁fus el age . ▁ ▁Tim eline ▁of ▁introduction ▁ ▁Virgin ▁Gal actic ▁contract ed ▁a eros pace ▁designer ▁B urt ▁R ut an ▁to ▁build ▁the ▁moth ership ▁and ▁space craft . ▁ ▁On ▁January ▁ 2 3 , ▁ 2 0 0 8 ▁the ▁White ▁Knight ▁Two ▁design ▁was ▁revealed . ▁On ▁July ▁ 2 8 , ▁ 2 0 0 8 ▁the ▁completion ▁and ▁roll out ▁of ▁the ▁first ▁aircraft , ▁E ve , ▁( T ail ▁Number : ▁N 3 4 8 MS ) ▁occurred ▁at ▁Sc aled ' s ▁M oj ave ▁headquarters . ▁ ▁Br anson ▁predicted ▁that ▁the ▁ma iden ▁space ▁voyage ▁would ▁take ▁place ▁in ▁ 1 8 ▁months : ▁" It ▁represents ... ▁the ▁chance ▁for ▁our ▁ever - g row ing ▁group ▁of ▁future ▁astr onaut s