A series of North Korean Earth observation satellites, of which two have been successfully launched and placed into Earth orbit to date. After three failed launch attempts between September 1998 and April 2012, the 100-kg Kwangmyŏngsŏng-3 lifted off from the Sohae Satellite Launching Station aboard an Unha-3 rocket on 12 December 2012 and achieved polar orbit at an altitude between 505.6 km and 588.8 km. A second successful launch occurred on 7 February 2016, which placed Kwangmyŏngsŏng-4 into polar orbit between 465 km and 502 km.