▁orb ital ▁alt itude ▁depend ▁on ▁the ▁energy - abs or bing ▁effects ▁of ▁the ▁upper ▁atmosphere ▁to ▁reli ably ▁de or bit ▁a ▁space craft ▁within ▁weeks ▁or ▁months . ▁ ▁In cre asing ly , ▁spent ▁upper ▁stages ▁in ▁higher ▁or bits — orb its ▁for ▁which ▁low - delta - v ▁de or bit ▁is ▁not ▁possible , ▁or ▁not ▁planned ▁for — and ▁architect ures ▁that ▁support ▁satellite ▁pass iv ation , ▁at ▁end ▁of ▁life ▁are ▁pass iv ated ▁at ▁end ▁of ▁life . ▁This ▁removes ▁any ▁internal ▁energy ▁contained ▁in ▁the ▁vehicle ▁at ▁the ▁end ▁of ▁its ▁mission ▁or ▁useful ▁life . ▁While ▁this ▁does ▁not ▁remove ▁the ▁de br is ▁of ▁the ▁now ▁der el ict ▁ro cket ▁stage ▁or ▁satellite ▁itself , ▁it ▁does ▁substantial ly ▁reduce ▁the ▁lik elihood ▁of ▁the ▁space craft ▁destruct ing ▁and ▁creating ▁many ▁smaller ▁pieces ▁of ▁space ▁de br is , ▁a ▁phenomen on ▁that ▁was ▁common ▁in ▁many ▁of ▁the ▁early ▁gener ations ▁of ▁US ▁and ▁Soviet ▁space craft . ▁ ▁Upper ▁stage ▁pass iv ation ▁( e . g . ▁of ▁D elta ▁boost ers ) ▁by ▁re le asing ▁resid ual ▁prop ell ants ▁reduces ▁de br is ▁from ▁orb ital ▁explos ions ; ▁however ▁even ▁as ▁late ▁as ▁ 2 0 1 1 , ▁not ▁all ▁upper ▁stages ▁implement ▁this ▁practice . ▁Space X ▁used ▁the ▁term ▁" prop uls ive ▁pass iv ation " ▁for ▁the ▁final ▁man eu ver ▁of ▁their ▁six -