U.S. officials say the satellite put into orbit by North Korea's rocket launch this week is wobbling, but that doesn't necessarily mean the launch itself was unsuccessful.
U.S. analysts say the North Koreans' main goal was not to put a satellite into orbit, but just to see all three stages of their rocket work, to show that the rocket could carry its payload a long distance. That it did. In the last test, in April, the first rocket stages worked as designed, but the third stage failed. Charles Vick, a missile expert at GlobalSecurity.org, credits the North Koreans with learning from their past mistakes.
"They have demonstrated not merely an ability to identify problems, but to resolve those problems and get the total system to work together, all three stages working as a single launch vehicle," he said.
So, the North Koreans are making progress.
Next question: What, if anything, did this launch mean for Iran?
We know North Korea and Iran have worked together in missile design. Vick says the evidence can be seen by comparing the North Korean Nodong missile with Iran's Shahab missile.
"In every detail, right down to the re-entry vehicles, Nodong-A is the Shahab-3," he says. "The technology is being transferred in both directions, and I think that's what's going on in the nuclear technology, too."
This cooperation may well have contributed to the success of this week's rocket launch.
Theodore Postol, a missile expert at MIT, says the third stage of the North Korean rocket launched this week looks like a comparable stage in a rocket designed by the Iranians.
"They were able to collaborate with equipment given to them or sent to them from North Korea, and at the same time do a lot of the research and engineering development needed to build this upper stage," Postol says.
What this means, Postol thinks, is that this week's North Korean rocket was actually a joint production between North Korean and Iranian engineers.
"While the North Koreans were working on the first stage, these guys were working on the third stage," he says. "So there's no doubt, looking at the technology, you don't need access to the intelligence information to see that these programs are very, very strongly collaborating."
Who's Helping Whom?
Missile analysts think the rocket technology now used by Iran came originally from North Korea. But Jeffrey Lewis, a proliferation expert at the Monterey Institute of International Studies, thinks nowadays it's the Iranians assisting the North Koreans with missile development.
"The Iranians were doing innovation and change, taking things apart and putting them back together, and it now, to me, looks like the Iranians are better at this than the North Koreans," Lewis says. "And so the North Koreans have gone from being a technology supplier to possibly the recipient of technologies and services back from the Iranians."
This reversal — from North Korea helping Iran to Iran helping North Korea — is important. Remember, a big question is whether this week's rocket launch helped Iran as well as North Korea. Some U.S. officials have worried about that, but Lewis is not convinced.
"I look at this test as a contribution to North Korea's program, but I think it's probably a pretty marginal contribution to the Iranian program," he says.
Of course, Lewis says, every test is a learning experience. Iran may want to develop its own long-range, intercontinental ballistic missile; North Korea's demonstration of such a capability this week should provide data that Iranian engineers can put to good use.
A final point: Successfully testing a long-range missile is one thing; putting a nuclear warhead on the missile is quite another. Experts say both North Korea and Iran are still a long way from being able to do that.