▁up ▁to ▁ 2 0 0 , 0 0 0   ft ▁( ~ 6 0   km ) ▁where ▁separation ▁occurs . ▁The ▁first ▁stage ▁flight ▁profile ▁is ▁almost ▁entirely ▁vertical , ▁with ▁only ▁slight ▁side ways ▁motion ▁to ▁keep ▁above ▁the ▁launch / land ing ▁area . ▁The ▁first ▁stage ▁then ▁dro ps ▁back ▁to ▁the ▁launch ▁site , ▁experien cing ▁' re entry ▁he ating ' ▁roughly ▁compar able ▁to ▁the ▁SR - 7 1 , ▁re le asing ▁a ▁dro gue ▁ch ute ▁at ▁ 1 2 0 , 0 0 0   ft , ▁and ▁dec eler ating ▁and ▁landing ▁with ▁ 3 0 ▁seconds ▁reserve ▁fuel ▁on ▁the ▁jet ▁engines . ▁ ▁Second ▁stage ▁The ▁second ▁stage ▁is ▁cone ▁sh aped , ▁, ▁, ▁and ▁cone ▁angle ▁of ▁ 1 1 . 5 ▁degrees . ▁It ▁has ▁an ▁empty ▁weight ▁of ▁, ▁car ries ▁ ▁of ▁hydro gen ▁and ▁o xygen , ▁and ▁a ▁gross ▁weight ▁of ▁ ▁at ▁separation . ▁It ▁is ▁fitted ▁with ▁two ▁R L - 6 0 ▁and ▁a ▁small ▁R CS ▁system . ▁At ▁ ▁st aging ▁height ▁the ▁air ▁is ▁so ▁thin ▁the ▁engines ▁can ▁be ▁optim ised ▁for ▁vac u um ▁without ▁performance ▁penalty . ▁The ▁inter - t ank ▁section ▁doubles ▁as ▁the ▁flight ▁and ▁cargo ▁cabin . ▁Power ▁is ▁provided ▁by ▁batter ies ▁and ▁a ▁strip ▁of ▁solar ▁pan els ▁that ▁run ▁around ▁the ▁top ▁of ▁the ▁cabin . ▁Re entry ▁is ▁base ▁first ▁and ▁is ▁protected ▁by