▁claim ▁that ▁its ▁Av ang ard ▁H GV ▁travel s ▁at ▁Mach ▁ 2 7 ▁and ▁" const antly ▁changes ▁its ▁course ▁and ▁alt itude ▁while ▁it ▁f lies ▁through ▁the ▁atmosphere , ▁cha ot ically ▁z ig z ag ging ▁on ▁its ▁path ▁to ▁its ▁target , ▁making ▁it ▁impossible ▁to ▁predict ▁the ▁weapon ' s ▁location ", ▁thus ▁making ▁it ▁supposed ly ▁" inv ul ner able ▁to ▁inter ception ". ▁ ▁Re entry ▁vehicle ▁use ▁The ▁technique ▁was ▁used ▁by ▁the ▁Soviet ▁Z ond ▁series ▁of ▁circum l un ar ▁space craft , ▁which ▁used ▁one ▁skip ▁before ▁landing . ▁In ▁this ▁case ▁a ▁true ▁skip ▁was ▁required ▁in ▁order ▁to ▁allow ▁the ▁space craft ▁to ▁reach ▁the ▁higher - lat itude ▁landing ▁areas . ▁Z ond ▁ 6 , ▁Z ond ▁ 7 ▁and ▁Z ond ▁ 8 ▁made ▁successful ▁skip ▁entries , ▁although ▁Z ond ▁ 5 ▁did ▁not . ▁The ▁Ch ang ' e ▁ 5 - T 1 , ▁which ▁fle w ▁mission ▁profiles ▁similar ▁to ▁Z ond , ▁also ▁used ▁this ▁technique . ▁ ▁The ▁Apol lo ▁Command ▁Module ▁used ▁a ▁skip - like ▁concept ▁to ▁lower ▁the ▁he ating ▁loads ▁on ▁the ▁vehicle ▁by ▁extending ▁the ▁re - entry ▁time , ▁but ▁the ▁space craft ▁did ▁not ▁leave ▁the ▁atmosphere ▁again ▁and ▁there ▁has ▁been ▁considerable ▁debate ▁whether ▁this ▁makes ▁it ▁a ▁true ▁skip ▁profile . ▁NASA ▁referred ▁to ▁it ▁simply ▁as ▁" l ifting ▁entry ". ▁A ▁true ▁multi - skip ▁profile ▁was