ally ▁boost ed ▁into ▁medium - alt itude ▁gra vey ard ▁or bits , ▁not ▁all ▁were . ▁Even ▁sat ell ites ▁which ▁had ▁been ▁properly ▁moved ▁to ▁a ▁higher ▁orbit ▁had ▁an ▁eight - percent ▁probability ▁of ▁pun ct ure ▁and ▁cool ant ▁release ▁over ▁a ▁ 5 0 - year ▁period . ▁The ▁cool ant ▁free zes ▁into ▁dro ple ts ▁of ▁solid ▁sod ium - pot ass ium ▁al loy , ▁forming ▁additional ▁de br is . ▁ ▁These ▁events ▁continue ▁to ▁occur . ▁For ▁example , ▁in ▁February ▁ 2 0 1 5 , ▁the ▁US AF ▁Def ense ▁Meteor ological ▁Sat ellite ▁Program ▁Fl ight ▁ 1 3 ▁( D MS P - F 1 3 ) ▁expl oded ▁on ▁orbit , ▁creating ▁at ▁least ▁ 1 4 9 ▁de br is ▁objects , ▁which ▁were ▁expected ▁to ▁remain ▁in ▁orbit ▁for ▁dec ades . ▁ ▁Or bit ing ▁sat ell ites ▁have ▁been ▁deliber ately ▁destroyed . ▁United ▁States ▁and ▁USS R / Russ ia ▁have ▁conducted ▁over ▁ 3 0 ▁and ▁ 2 7 ▁AS AT ▁tests , ▁respectively , ▁followed ▁by ▁ 1 0 ▁from ▁China ▁and ▁one ▁from ▁India . ▁The ▁most ▁recent ▁AS AT s ▁were ▁Chinese ▁inter ception ▁of ▁F Y - 1 C , ▁tri als ▁of ▁Russian ▁PL - 1 9 ▁N ud ol , ▁American ▁inter ception ▁of ▁USA - 1 9 3 ▁and ▁Indian ▁inter ception ▁of ▁un st ated ▁live ▁satellite . ▁ ▁Lost ▁equipment ▁▁ ▁According