"Dawn's" mission profile called for it to study Ceres from a series of circular polar orbits at successively lower altitudes. It entered its first observational orbit ("RC3") around Ceres at an altitude of 13,500 km on 23 April 2015, staying for only approximately one orbit (fifteen days). The spacecraft subsequently reduced its orbital distance to 4,400 km for its second observational orbit ("survey") for three weeks, then down to 1,470 km ("HAMO;" high altitude mapping orbit) for two months and then down to its final orbit at 375 km ("LAMO;" low altitude mapping orbit) for at least three months.