H - 1 ▁vehicles ▁themselves , ▁rather ▁than ▁payload ▁space ▁on ▁a ▁company ▁launch ▁vehicle , ▁as ▁is ▁currently ▁the ▁norm . ▁ ▁First ▁stage ▁The ▁first ▁stage ▁is ▁cyl ind rical ▁in ▁shape , ▁ ▁and ▁. ▁It ▁has ▁an ▁empty ▁weight ▁of ▁, ▁car ries ▁ ▁of ▁m eth ane ▁and ▁o xygen , ▁and ▁a ▁gross ▁lift - off ▁weight ▁( G LOW ) ▁of ▁, ▁including ▁the ▁second ▁stage . ▁It ▁is ▁fitted ▁with ▁five ▁R L - 6 0 ▁and ▁ 4 ▁R L - 1 0 ▁sust ainer ▁engines , ▁and ▁ 4 ▁small ▁jet ▁landing ▁engines , ▁all ▁modified ▁to ▁burn ▁m eth ane . ▁At ▁launch ▁it ▁is ▁mounted ▁on ▁four ▁internal ▁launch - rails ▁fitted ▁with ▁p neum atic ▁shock ▁absor bers , ▁rather ▁than ▁locked ▁to ▁the ▁launch ▁frame ▁with ▁explos ive ▁bol ts . ▁Allow ing ▁the ▁D H - 1 ▁to ▁rise ▁as ▁soon ▁as ▁thrust ▁exceed s ▁weight ▁avoid s ▁sudden ▁shock ▁loads ▁and ▁allows ▁it ▁to ▁sett le ▁back ▁onto ▁the ▁launch ▁frame ▁in ▁the ▁event ▁of ▁critical ▁engine ▁failure ▁in ▁the ▁first ▁few ▁meters ▁of ▁flight . ▁ ▁Fl ight ▁is ▁function ally ▁similar ▁to ▁the ▁DC - X . ▁At ▁launch ▁all ▁ 9 ▁rock ets ▁are ▁fired ▁until ▁the ▁D H - 1 ▁reaches ▁ 1 0 0 , 0 0 0 ▁feet . ▁At ▁that ▁point ▁the ▁R L - 6 0 s ▁are ▁shut ▁down ▁and ▁the ▁sust ainer ▁engines ▁push ▁the ▁ro cket