▁use ▁of ▁modern ▁miss iles ▁in ▁war fare , ▁the ▁German ▁V - 1 ▁and ▁V - 2 ▁program ▁of ▁World ▁War ▁II . ▁ ▁British ▁f igh ters ▁destroyed ▁some ▁V - 1 ▁" bu zz ▁bomb s " ▁in ▁flight , ▁although ▁concentr ated ▁bar rages ▁of ▁heavy ▁anti - air craft ▁art illery ▁had ▁greater ▁success . ▁Under ▁the ▁l end - lease ▁program , ▁ 2 0 0 ▁US ▁ 9 0 ▁mm ▁AA ▁guns ▁with ▁S CR - 5 8 4 ▁rad ars ▁and ▁Western ▁Electric / B ell ▁L abs ▁computers ▁were ▁sent ▁to ▁the ▁UK . ▁These ▁demonstrated ▁a ▁ 9 5 % ▁success ▁rate ▁against ▁V - 1 s ▁that ▁fle w ▁into ▁their ▁range . ▁ ▁The ▁V - 2 , ▁the ▁first ▁true ▁ball istic ▁miss ile , ▁was ▁impossible ▁to ▁destroy ▁in ▁the ▁air . ▁S CR - 5 8 4 ' s ▁could ▁be ▁used ▁to ▁plot ▁the ▁traject ories ▁of ▁the ▁miss iles ▁and ▁provide ▁some ▁warning , ▁but ▁were ▁more ▁useful ▁in ▁back track ing ▁their ▁ball istic ▁traject ory ▁and ▁determ ining ▁the ▁rough ▁launch ▁locations . ▁The ▁Al lies ▁launched ▁Operation ▁Cross bow ▁to ▁find ▁and ▁destroy ▁V - 2 s ▁before ▁launch , ▁but ▁these ▁operations ▁were ▁largely ▁in effect ive . ▁In ▁one ▁instance ▁a ▁Sp it fire ▁happened ▁upon ▁a ▁V - 2 ▁rising ▁through ▁the ▁trees , ▁and ▁fired ▁on ▁it ▁with ▁no ▁effect . ▁This ▁led ▁to ▁al lied ▁efforts ▁to ▁capture