, ▁ 1 9 6 1 ▁President ▁John ▁F . ▁Kennedy ▁announced ▁the ▁Moon ▁landing ▁goal ▁before ▁ 1 9 7 0 , ▁which ▁completely ▁by pass ed ▁NASA ' s ▁Earth ▁orb ital ▁Olymp us ▁Station ▁plans . ▁ ▁Development ▁history ▁When ▁NASA ▁awarded ▁the ▁initial ▁Apol lo ▁contract ▁to ▁North ▁American ▁A viation ▁on ▁November ▁ 2 8 , ▁ 1 9 6 1 , ▁it ▁was ▁still ▁assumed ▁the ▁lun ar ▁landing ▁would ▁be ▁achieved ▁by ▁direct ▁as cent ▁rather ▁than ▁by ▁lun ar ▁orbit ▁rende z vous . ▁Therefore , ▁design ▁proceeded ▁without ▁a ▁means ▁of ▁dock ing ▁the ▁command ▁module ▁to ▁a ▁lun ar ▁exc urs ion ▁module ▁( LE M ). ▁But ▁the ▁change ▁to ▁lun ar ▁orbit ▁rende z vous , ▁plus ▁several ▁technical ▁obst acles ▁encountered ▁in ▁some ▁sub system s ▁( such ▁as ▁environmental ▁control ), ▁soon ▁made ▁it ▁clear ▁that ▁substantial ▁red es ign ▁would ▁be ▁required . ▁In ▁ 1 9 6 3 , ▁NASA ▁decided ▁the ▁most ▁efficient ▁way ▁to ▁keep ▁the ▁program ▁on ▁track ▁was ▁to ▁proceed ▁with ▁the ▁development ▁in ▁two ▁versions : ▁ ▁Block ▁I ▁would ▁continue ▁the ▁pre lim inary ▁design , ▁to ▁be ▁used ▁for ▁early ▁low ▁Earth ▁orbit ▁test ▁fl ights ▁only . ▁ ▁Block ▁II ▁would ▁be ▁the ▁lun ar - cap able ▁version , ▁including ▁a ▁dock ing ▁h atch ▁and ▁incorpor ating ▁weight ▁reduction ▁and ▁less ons ▁learned ▁in ▁Block ▁I . ▁D etailed ▁design ▁of ▁the ▁dock ing ▁cap ability ▁dep