Unha

Unha

Unha-2
Function	Expendable carrier rocket
Manufacturer	Korean Committee of Space Technology
Country of origin	North Korea
Size
Height	32.01 metres (105.0 ft)[citation needed]
Diameter	2.41 metres (7 ft 11 in)[citation needed]
Mass	85,000 kilograms (187,000 lb)[citation needed]
Stages	3
Launch history
Status	Active
Launch sites	Sohae, Tonghae
Total launches	3
Successes	1
Failures	2
First flight	5 April 2009[1]
First stage
Engines	4 Nodong 2-1[2]
Thrust	1100 kN[2]
Specific impulse	252 sec[3]
Burn time	120 seconds[3]
Fuel	IRFNA / UDMH
Second stage
Engines	unknown[2]
Thrust	250 kN[citation needed]
Specific impulse	255 s[3]
Burn time	110 seconds[3]
Fuel	IRFNA / UDMH
Third stage
Engines	unknown[2]
Thrust	54 kN[citation needed]
Specific impulse	230 sec[3]
Burn time	40 seconds[3]
Fuel	unknown

The Unha or Eunha (Korean: 은하, 銀河, "Galaxy")^[4] is a North Korean expendable carrier rocket, which partially utilizes the same delivery system as the Taepodong-2 long-range ballistic missile.^[5]

History

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-2 ballistic 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.^[6] According to Japanese reports, the second stage splashed down in the Pacific Ocean approximately 3,200 kilometers from the launch site.^[7]

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.^[8]

Vehicle description

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. The second stage was initially thought to be based on the SS-N-6, although it is now believed to be based on Scud technology.^[2] The third and last stage might be identical to the Iranian Safir's second stage which is propelled by two small gimballed motors.^[2][9]

Recent satellite images of the Sohae Satellite Launching Station showing an enlarged launch tower under construction indicate that an enlarged version, called Unha-X, might be under development, coupled with a North Korean propaganda poster showing such a vehicle.^[10]

Launch history

On 24 February 2009, North Korea announced that a Unha rocket would be used to launch the Kwangmyŏngsŏng-2 satellite.^[11] According to the South Korean government, the launch took place on 5 April^[12] from the Tonghae Satellite Launching Ground in Hwadae county.^[13] Several countries, including South Korea, the U.S.A., and Japan, voiced concerns that the launch would violate United Nations Security Council Resolution 1718 which prohibits North Korea from testing ballistic missiles.^[14] Russia also announced they urged North Korea to refrain from its planned rocket launch.^[15]

On April 5, 2009 the Unha-2 rocket was launched at around 02:30 hours UTC (11:30 hours KST).^[16] 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.^[17][18] 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.^[19] North Korea maintains that the rocket successfully put its payload in orbit.^[20]

On December 12, 2012, the Unha-3 rocket was launched at 00:49 UTC (7:49 EST).^[21] 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.^[22]

Designation	Date	Launch Site	Payload	Remarks
Unha-2	5 April 2009	Tonghae	Kwangmyŏngsŏng-2	Failed to reach orbit[23]
Unha-3	13 April 2012	Sohae	Kwangmyŏngsŏng-3	Failed early in flight[24]
Unha-3 Unit-2	12 December 2012[25][26]	Sohae	Second version of Kwangmyŏngsŏng-3[27]	Successful launch. S.Korea military official cited 3 stage success. DPRK confirmed[28]

See also

• Comparison of orbital launchers families
• Timeline of first orbital launches by country
• Naro-1
• Simorgh (rocket)

References

External links

Wikinews has related news: North Korea launches rocket

Wikimedia Commons has media related to Unha missiles.

• "An Analysis of North Korea’s Unha-2 Launch Vehicle," David Wright, March 20, 2009.
• Robert S. Norris and Hans M. Kristensen, "Nuclear Notebook: North Korea’s nuclear program, 2005", "Bulletin of the Atomic Scientists", May/June 2005.
• "Footage Of North Korean Rocket Launch" April 5, 2009.
• "North Korea's impressive space launch vehicle "Unha-2"