▁three ▁months , ▁subsequent ▁" trans fer ▁to ▁lower ▁orbit " ▁( T LO ) ▁man eu vers ▁would ▁be ▁performed ▁as ▁the ▁space craft ▁reached ▁per ia ps is , ▁eventually ▁resulting ▁in ▁an ▁approximately ▁circular , ▁ 1 1 8 - min ute ▁orbit ▁around ▁Mars . ▁ ▁The ▁primary ▁mission ▁was ▁to ▁begin ▁on ▁November ▁ 2 3 , ▁ 1 9 9 3 , ▁collect ing ▁data ▁during ▁one ▁Mart ian ▁year ▁( appro xim ately ▁ 6 8 7 ▁Earth ▁days ). ▁The ▁first ▁global ▁map ▁was ▁expected ▁to ▁be ▁completed ▁on ▁December ▁ 1 6 , ▁followed ▁by ▁solar ▁conj unction ▁beginning ▁on ▁December ▁ 2 0 , ▁and ▁last ing ▁for ▁nin ete en ▁days , ▁ending ▁on ▁January ▁ 3 , ▁ 1 9 9 4 ; ▁during ▁this ▁time , ▁mission ▁operations ▁would ▁be ▁susp ended ▁as ▁radio ▁contact ▁would ▁not ▁be ▁possible . ▁ ▁Or bit ing ▁Mars ▁at ▁an ▁approximate ▁speed ▁of ▁ 3 . 4   km / s , ▁the ▁space craft ▁would ▁travel ▁around ▁Mars ▁in ▁a ▁north ▁to ▁south , ▁polar ▁orbit . ▁As ▁the ▁space craft ▁circles ▁the ▁planet , ▁horizon ▁sens ors ▁indicate ▁the ▁orientation ▁of ▁the ▁space craft ▁while ▁the ▁reaction ▁whe els ▁would ▁maintain ▁the ▁orientation ▁of ▁the ▁instruments , ▁towards ▁Mars . ▁The ▁chosen ▁orbit ▁was ▁also ▁sun - s ynchronous , ▁allowing ▁the ▁day lit ▁side ▁of ▁Mars ▁to ▁always ▁be ▁captured ▁during ▁the ▁mid - af ternoon ▁of ▁each ▁Mart ian