??????According to the announcement of China Manned Space Agency(CMSA),at 6:20 am, Apr.2,2018, Tiangong-1 stayed at an average altitude of about132.75 km (perigee:130.9 km; apogee: 134.6 km; inclination:42.70°). The estimated reentry time is at 8:42 am (the earliest time is at 8:24 am and the latest time is at 9:01 am ), 2 April, Beijing time. The reentry center is located at 40.4°W and 27.4°S.??????