. ▁restart ed ▁their ▁AS AT ▁programs ▁in ▁the ▁ 1 9 8 0 s ▁with ▁the ▁V ought ▁AS M - 1 3 5 ▁AS AT . ▁A ▁ 1 9 8 5 ▁test ▁destroyed ▁a ▁ ▁satellite ▁orbit ing ▁at ▁, ▁creating ▁thousands ▁of ▁de br is ▁larger ▁than ▁. ▁Due ▁to ▁the ▁alt itude , ▁atmos pher ic ▁drag ▁decay ed ▁the ▁orbit ▁of ▁most ▁de br is ▁within ▁a ▁de cade . ▁A ▁de ▁fact o ▁mor ator ium ▁followed ▁the ▁test . ▁ ▁China ' s ▁government ▁was ▁condem ned ▁for ▁the ▁military ▁imp lications ▁and ▁the ▁amount ▁of ▁de br is ▁from ▁the ▁ 2 0 0 7 ▁anti - s at ellite ▁miss ile ▁test , ▁the ▁largest ▁single ▁space ▁de br is ▁incident ▁in ▁history ▁( cre ating ▁over ▁ 2 , 3 0 0 ▁pieces ▁golf - ball ▁size ▁or ▁larger , ▁over ▁ 3 5 , 0 0 0 ▁ ▁or ▁larger , ▁and ▁one ▁million ▁pieces ▁ ▁or ▁larger ). ▁The ▁target ▁satellite ▁orb ited ▁between ▁ ▁and ▁, ▁the ▁portion ▁of ▁near - E arth ▁space ▁most ▁dens ely ▁populated ▁with ▁sat ell ites . ▁Since ▁atmos pher ic ▁drag ▁is ▁low ▁at ▁that ▁alt itude ▁the ▁de br is ▁is ▁slow ▁to ▁return ▁to ▁Earth , ▁and ▁in ▁June ▁ 2 0 0 7 ▁NASA ' s ▁Terra ▁environmental ▁space craft ▁man eu ver ed ▁to ▁avoid ▁impact ▁from ▁the ▁de br is . ▁ ▁On ▁ 2 0 ▁February