North Korea's first orbital space launch attempt occurred on August 31, 1998 and was unsuccessful. This launch attempt was performed by a Paektusan rocket. The particular vehicle used in the first attempt was named the Taepo Dong 1. It used a solid motor third stage, a Scud-missile-based second stage, and a Rodong-1 based first stage. Rodong-1 was a North Korean-developed stage thought to be a scale-up of the old Soviet Scud missile. TaepoDong 1 stood 22.5 metres tall, was 1.8 metres in diameter, and weighed about 21 tonnes.
The next launch vehicle, the Unha-2, is believed to be a three-stage rocket derived from North Korea's Taepodong-2ballistic missile - a missile that first flew, unsuccessfully, in 2006. The rocket failed after 40 seconds. TaepoDong 2's new first stage is thought to be powered by four engines, one of which powered the country's earlier Taepo Dong 1 first stage. The four engines may produce 112 tonnes-force (1,100 kN) of liftoff thrust, sufficient to rapidly lift the 78 tonne carrier rocket. According to Japanese reports, the second stage splashed down in the Pacific Ocean approximately 3,200 kilometers from the launch site.
The January 3, 2013 internet edition of the Rodong Sinmun, the Workers' Party official newspaper, quoted a scientist saying there would be six more satellite launch vehicles. Reports say the Unha 4 and 5 are intended to launch earth observation satellites, Unha 6, 7 and 8 would presumably place into orbit communications satellites and Unha 9 would carry a lunar orbiter. 
Model of a Unha-9 rocket on display at a floral exhibition in Pyongyang.
The Unha's first stage consists of four clustered Nodong motors, which themselves are enlarged Scud motors. Some analysts believe the second stage is based on SS-N-6 technology North Korea is believed to have acquired, although others believe it is based on Scud technology. The third and last stage might be identical to the Iranian Safir's second stage which is propelled by two small gimballed motors.
On 24 February 2009, North Korea announced that a Unha rocket would be used to launch the Kwangmyŏngsŏng-2 satellite. According to the South Korean government, the launch took place on 5 April from the Tonghae Satellite Launching Ground in Hwadae county. Several countries, including South Korea, the U.S.A., and Japan, have voiced concern that the launch might violate United NationsSecurity CouncilResolution 1718 which prohibits North Korea from testing ballistic missiles. Russia also announced they urged North Korea to refrain from its planned rocket launch. It was also reported that the launch may be a cover for a suborbital test of the Taepodong-2 missile. The large first stage of the Unha-2 launcher is new and has not been successfully flight-tested. The only previous flight test was in July 2006. The first stage had failed approximately 40 seconds into the launch causing the launcher to crash a few kilometres from the launch site.
On April 5, 2009 the Unha-2 rocket was launched at around 02:30 hours UTC (11:30 hours KST). The U.S Northern Command said that the first stage of the rocket fell into the Sea of Japan (East Sea of Korea), while the other rocket stages as well as the payload fell into the Pacific Ocean, and no object entered orbit. Later analysis indicated the rocket impacted 2,390 miles (3,850 km) from the launch site, and that the second stage operated normally but the rocket's third stage failed to separate properly. North Korea maintains that the rocket successfully put its payload in orbit.
On December 12, 2012, the Unha-3 rocket was launched at 00:49 UTC (7:49 EST). The U.S Northern Command said that the first stage of the rocket fell into the Yellow Sea, while the debris of the second stage was assessed to have fallen into the Philippine Sea and confirmed that an object had entered orbit.