▁be ▁protected ▁by ▁a ▁ball istic ▁shield . ▁ ▁Below ▁ ▁Earth - alt itude , ▁pieces ▁of ▁de br is ▁are ▁dens er ▁than ▁meteor oid s ; ▁most ▁are ▁dust ▁from ▁solid ▁ro cket ▁mot ors , ▁surface ▁er os ion ▁de br is ▁like ▁paint ▁fla kes , ▁and ▁fro zen ▁cool ant ▁from ▁R ORS AT ▁( n uc lear - power ed ▁sat ell ites ). ▁ ▁For ▁comparison , ▁the ▁International ▁Space ▁Station ▁or bits ▁in ▁the ▁ ▁range , ▁while ▁the ▁two ▁most ▁recent ▁large ▁de br is ▁events — the ▁ 2 0 0 7 ▁Chinese ▁ant isat ▁weapon ▁test ▁and ▁the ▁ 2 0 0 9 ▁satellite ▁collision — oc cur red ▁at ▁ ▁alt itude . ▁The ▁I SS ▁has ▁Wh ipp le ▁shield ing ▁to ▁resist ▁damage ▁from ▁small ▁M MO D ; ▁however , ▁known ▁de br is ▁with ▁a ▁collision ▁chance ▁over ▁ 1 / 1 0 , 0 0 0 ▁are ▁avoided ▁by ▁man eu ver ing ▁the ▁station . ▁ ▁History ▁ ▁Space ▁de br is ▁began ▁to ▁accum ulate ▁in ▁Earth ▁orbit ▁immediately ▁with ▁the ▁first ▁launch ▁of ▁an ▁artificial ▁satellite ▁into ▁orbit ▁in ▁ 1 9 5 7 . ▁After ▁the ▁launch ▁of ▁S put nik ▁ 1 ▁in ▁ 1 9 5 7 , ▁the ▁North ▁American ▁A eros pace ▁Def ense ▁Command ▁( N OR AD ) ▁began ▁compiling ▁a ▁database ▁( the ▁Space ▁Object ▁Catalog ) ▁of ▁all ▁known ▁ro cket ▁launch es