The rocket launched earlier this month by North Korea had the capability to travel more than 6,000 miles, meaning this type of rocket could strike the United States, South Korean defense officials said.
In remarks to reporters Friday, which were embargoed until Sunday, three officials with South Korea's defense ministry offered their observations about the Dec. 12 launch based on a recovered oxidizer tank that had been part of one of the rocket's boosters. According to NASA, an oxidizer tank contains oxygen compounds that allow rocket fuel to burn in the atmosphere and outside of it, in space.
North Korean officials cheered what they hailed as a successful launch of a long-range rocket, which they said put a satellite in orbit. But the mission drew international condemnation, with many viewing it as cover for testing of ballistic missile technology, which the United Nations has forbidden Pyongyang from using.
The South Korean military officials said the evidence they found helps show their nuclear-equipped rival's intent and progress in developing intercontinental ballistic missiles.
Based on a simulation, the officials estimated the rocket can travel more than 10,000 kilometers (6,200 miles), meaning it could reach the U.S. mainland from North Korea. It can carry a payload of about 500 to 600 kilograms (225 to 275 pounds).
The oxidizer tank used red fuming nitric acid, based on technology the officials said originated in the former Soviet Union and can now be found in Iran. They said an Internet analysis suggests a technological connection between North Korea and Iran, though there is no firm evidence that any of the parts discovered thus far were imported from another country.
The South Korean officials said the oxidizer tank appeared to be produced using rudimentary technology, suggesting it may have been made by hand.
The rocket launch's success, after years of failed attempts, triggered worries among world leaders about nuclear weapons, Iran and the balance of power in the Pacific. U.S. Defense Secretary Leon Panetta called it a "clear provocation."
Experts do not believe North Korea has a nuclear warhead small enough to fly on the kind of missile that Pyongyang has now proved it can send long-distance. But the launch did allow the regime to flex its military and technological muscle on the world stage.
North Korean leader Kim Jong Un has "stressed the need to continue to launch satellites in the future," the state-run Korean Central News Agency said in a report this month, raising the prospect of more controversial moves to come.
Panetta told CNN earlier this month that he is "very confident" that, if North Korea were to launch a missile at the United States, the U.S. military could guard against it.