▁observations ▁of ▁all ▁objects ▁in ▁Earth ▁orbit . ▁ ▁The ▁observations ▁are ▁used ▁in ▁new ▁orbit ▁determ ination ▁calculations ▁that ▁maintain ▁the ▁overall ▁accuracy ▁of ▁the ▁satellite ▁catalog . ▁ ▁Coll ision ▁avoid ance ▁calculations ▁may ▁use ▁this ▁data ▁to ▁calculate ▁the ▁probability ▁that ▁one ▁orbit ing ▁object ▁will ▁col lide ▁with ▁another . ▁ ▁A ▁satellite ' s ▁operator ▁may ▁decide ▁to ▁adjust ▁the ▁orbit , ▁if ▁the ▁risk ▁of ▁collision ▁in ▁the ▁present ▁orbit ▁is ▁un accept able . ▁ ▁( It ▁is ▁not ▁possible ▁to ▁adjust ▁the ▁orbit ▁for ▁events ▁of ▁very ▁low ▁probability ; ▁it ▁would ▁soon ▁use ▁up ▁the ▁prop ell ant ▁the ▁satellite ▁car ries ▁for ▁orb ital ▁station - keep ing .) ▁▁▁ ▁Other ▁countries , ▁including ▁Russia ▁and ▁China , ▁have ▁similar ▁tracking ▁assets . ▁ ▁History ▁ ▁Or bit ▁determ ination ▁has ▁a ▁long ▁history , ▁beginning ▁with ▁the ▁pre histor ic ▁discovery ▁of ▁the ▁plan ets ▁and ▁subsequent ▁attempts ▁to ▁predict ▁their ▁mot ions . ▁Johannes ▁Ke pler ▁used ▁Ty cho ▁Bra he ' s ▁careful ▁observations ▁of ▁Mars ▁to ▁dedu ce ▁the ▁elli pt ical ▁shape ▁of ▁its ▁orbit ▁and ▁its ▁orientation ▁in ▁space , ▁der iving ▁his ▁three ▁laws ▁of ▁planet ary ▁motion ▁in ▁the ▁process . ▁ ▁The ▁mathematical ▁methods ▁for ▁orbit ▁determ ination ▁origin ated ▁with ▁the ▁publication ▁in ▁ 1 6 8 7 ▁of ▁the ▁first ▁edition ▁of ▁Newton ' s ▁Princi p ia , ▁which ▁gave ▁a ▁method ▁for ▁finding ▁the ▁orbit ▁of ▁a ▁body ▁following ▁a