▁ 2 0 0 6 , ▁the ▁Russian ▁Express - AM 1 1 ▁communic ations ▁satellite ▁was ▁struck ▁by ▁an ▁unknown ▁object ▁and ▁rendered ▁in oper able ; ▁its ▁engine ers ▁had ▁enough ▁contact ▁time ▁with ▁the ▁satellite ▁to ▁send ▁it ▁into ▁a ▁gra vey ard ▁orbit . ▁ ▁S ources ▁ ▁Dead ▁space craft ▁▁ ▁In ▁ 1 9 5 8 , ▁the ▁United ▁States ▁launched ▁V angu ard ▁I ▁into ▁a ▁medium ▁Earth ▁orbit ▁( ME O ). ▁, ▁it , ▁and ▁the ▁upper ▁stage ▁of ▁its ▁launch ▁ro cket , ▁are ▁the ▁oldest ▁surv iving ▁human - made ▁space ▁objects ▁still ▁in ▁orbit . ▁In ▁a ▁catalog ▁of ▁known ▁launch es ▁until ▁July ▁ 2 0 0 9 , ▁the ▁Union ▁of ▁Conc ern ed ▁Scient ists ▁listed ▁ 9 0 2 ▁oper ational ▁sat ell ites ▁from ▁a ▁known ▁population ▁of ▁ 1 9 , 0 0 0 ▁large ▁objects ▁and ▁about ▁ 3 0 , 0 0 0 ▁objects ▁launched . ▁ ▁An ▁example ▁of ▁additional ▁der el ict ▁satellite ▁de br is ▁is ▁the ▁remains ▁of ▁the ▁ 1 9 7 0 s / 8 0 s ▁Soviet ▁R ORS AT ▁naval ▁surve ill ance ▁satellite ▁program . ▁The ▁satellite ' s ▁B ES - 5 ▁nuclear ▁re actor ▁were ▁co o led ▁with ▁a ▁cool ant ▁loop ▁of ▁sod ium - pot ass ium ▁al loy , ▁creating ▁a ▁potential ▁problem ▁when ▁the ▁satellite ▁reached ▁end ▁of ▁life . ▁While ▁many ▁sat ell ites ▁were ▁nomin