▁the ▁return ▁to ▁Earth . ▁This ▁method ▁was ▁brought ▁to ▁the ▁attention ▁of ▁NASA ▁Associ ate ▁Administr ator ▁Robert ▁Se am ans ▁by ▁Lang ley ▁Research ▁Center ▁engineer ▁John ▁C . ▁Hou bol t , ▁who ▁led ▁a ▁team ▁to ▁develop ▁it . ▁ ▁Besides ▁requiring ▁less ▁payload , ▁the ▁ability ▁to ▁use ▁a ▁lun ar ▁land er ▁designed ▁just ▁for ▁that ▁purpose ▁was ▁another ▁advantage ▁of ▁the ▁L OR ▁approach . ▁The ▁LE M ' s ▁design ▁gave ▁the ▁astr onaut s ▁a ▁clear ▁view ▁of ▁their ▁landing ▁site ▁through ▁observation ▁windows ▁approximately ▁ ▁above ▁the ▁surface , ▁as ▁opposed ▁to ▁being ▁on ▁their ▁back s ▁in ▁a ▁Command ▁Module ▁land er , ▁at ▁least ▁ ▁above ▁the ▁surface , ▁able ▁to ▁see ▁it ▁only ▁through ▁a ▁television ▁screen . ▁ ▁Develop ing ▁the ▁LE M ▁as ▁a ▁second ▁cre wed ▁vehicle ▁provided ▁the ▁further ▁advantage ▁of ▁redundant ▁critical ▁systems ▁( elect rical ▁power , ▁life ▁support , ▁and ▁prop ulsion ), ▁which ▁enabled ▁it ▁to ▁be ▁used ▁as ▁a ▁" l if eb o at " ▁to ▁keep ▁the ▁astr onaut s ▁alive ▁and ▁get ▁them ▁home ▁safely ▁in ▁the ▁event ▁of ▁a ▁critical ▁C SM ▁system ▁failure . ▁This ▁was ▁en vision ed ▁as ▁a ▁cont ing ency , ▁but ▁not ▁made ▁a ▁part ▁of ▁the ▁LE M ▁specific ations . ▁As ▁it ▁turned ▁out , ▁this ▁cap ability ▁proved ▁in valu able ▁in ▁ 1 9 7 0 , ▁saving ▁the ▁lives ▁of ▁the ▁Apol lo ▁ 1 3