By Larry Shaughnessy
If North Korea launches a missile in the next couple of weeks, as it has promised, it will be the result of international cooperation stretching from Moscow to Tehran and, perhaps, Beijing.
Experts who track North Korea's space program expect the communist regime will roll out a somewhat improved version of the Taepodong-2 (or the Unha-2 as North Korea refers to it) missile it last tested in April 2009.
The Taepodong-2 has never had a completely successful launch but, according to David Wright of the Union of Concerned Scientists, "We can go back and model that (2009) trajectory pretty well. The trajectory certainly appears to be the kind of trajectory they would have used for a satellite launch."
Experts expect the missile that the North Koreans are preparing to test is not drastically different from the vehicle used three years ago.
"I don't expect any major new things utterly visible on the launch vehicle. I expect it to be the same basic configuration as we saw in 2009," said Charles Vick, senior fellow in space policy for GlobalSecurity.Org.
After years of watching North Korea's activities and past launches, experts like Vick and Wright have been able to learn a lot, but not everything, about the Taepodong-2.
Most large modern rockets are built in several parts, or stages. In this case, the first, or lower, stage provides the bulk of the power to lift the missile off the launch pad and into its initial flight trajectory. When the first stage runs out of fuel, it falls off and the second, or middle, stage kicks the missile to a higher altitude and gets it going faster. The third, or upper, stage carries the payload and provides that last kick of power to lift the payload (in this case a small satellite) into orbit at a speed that will keep it there.
Wright believes the upper stage of the Taepodong-2 comes from a missile first built by the Soviets in their heyday 50 years ago. In 1962, the Soviets started developing a new submarine-launched ballistic missile, the SSN-6. It was made up of a large engine that provided lift and some small steering engines on top that kept it on course.
About the upper stage Wright said that what many observers think, "having looked at both what we've seen of the structure of it and also how it operated in the 2009 launch, is that it uses small engines from a Russian submarine-launched missile that Russia built ... called the SSN-6."
The small engines are liquid-fueled and originally were meant to steer the sub-launched missile.
But this is where the experts Security Clearance spoke to disagree. Vick said the upper stage of the Taepodong-2 has a very different ancestry.
"The third stage is of Chinese origin," he said. "The third stage is actually a Chinese solid motor surrounded by shrouds."
Whatever the origin, that upper stage has never worked. Referring to the 2009 launch, Wright said, "As far as we can tell, the third stage simply didn't fire and fell into the ocean with the second stage."
The two experts agree that the second stage of the Taepodong-2 missile comes from the SSN-6.
"The second stage, from the size and the way it operated, was essentially one of these SSN-6 Soviet missiles," Wright said. "We have some good photos of this launch vehicle that the North Koreans provided; it has the right size and shape. If you do some of the computer modeling that we've done, it has some of the performance you would expect of the Soviet missile."
The bottom or first stage represents about 80% of the Taepodong-2's initial weight. While it appears North Korea had the most to do with its design and construction, it also may have started in the old Soviet Union.
The stage is made up of a cluster of North Korea Nodong engines, which were developed from old Soviet Scud missiles.
Vick is convinced that Pyongyang is working together with Tehran on the missile development. "Iran and North Korea have cooperated totally together on this launch vehicle. Iran did a lot of propulsion work," he said.
Wright agrees there is some link, but exactly how it works is unclear to him.
"It's sometimes hard to tell which direction the flow of knowledge and technology is going," he said. "Iran developed a missile called the Shahab 3, which appears to be very similar to the Nodong missile. So there is always the question of whether North Korea gave them parts (or) it gave them help."
The biggest concern for U.S. officials is what this launch means for American security. So far the situation has been that the Taepodong-2 has never had a fully successful launch and there has been no indication that North Korea has the ability to make a nuclear weapon small enough to be a payload on a Taepodong-2.
But on Tuesday, South Korean media reported that the North may be building a bigger, more powerful missile that could carry a bigger payload even farther than the Taepodong-2.