min i - sh utt le ' ▁designs ▁that ▁use ▁transport ▁aircraft ▁as ▁first ▁stages ▁also ▁face ▁similar ▁problems ▁with ▁ice / fo am ▁as ▁the ▁Space ▁Sh utt le ▁due ▁to ▁the ▁requirement ▁they ▁also ▁carry ▁a ▁large ▁external ▁tank ▁for ▁their ▁fuel . ▁▁ ▁Space X ▁is ▁the ▁only ▁launch ▁provider ▁which ▁achieved ▁first - stage ▁reuse ▁of ▁an ▁orb ital ▁vehicle ▁with ▁the ▁two - stage ▁Fal con ▁ 9 ▁and ▁ 2 . 5 - stage ▁Fal con ▁He avy . ▁ ▁Hel ic opter - like ▁first ▁stage ▁T aking ▁the ▁view ▁that ▁air plane ▁like ▁operations ▁do ▁not ▁translate ▁to ▁air plane - like ▁appearance , ▁some ▁re usable ▁T ST O ▁concepts ▁have ▁first ▁stages ▁that ▁operate ▁as ▁V TO L ▁or ▁V TO HL ▁aircraft . ▁The ▁DC - X ▁has ▁proven ▁the ▁V TO L ▁option ▁design ▁work able . ▁Other ▁designs ▁like ▁the ▁D H - 1 ▁concept ▁take ▁it ▁a ▁step ▁further ▁and ▁use ▁a ▁' pop - up / pop - down ' ▁approach , ▁which ▁del ivers ▁the ▁orbit ing ▁stage ▁to ▁a ▁point ▁about ▁ 6 0   km ▁above ▁the ▁earth ' s ▁surface , ▁before ▁dro pping ▁down ▁to ▁the ▁launch ▁pad ▁again . ▁In ▁the ▁case ▁of ▁the ▁D H - 1 , ▁the ▁upper ▁stage ▁is ▁effectively ▁an ▁' al most ▁S ST O ' ▁with ▁a ▁more ▁real istic ▁mass ▁fraction ▁and ▁which ▁was ▁optim ised ▁for ▁reli ability . ▁ ▁Air plane -