Sometime during the first week in April, North Korea is expected to launch a three-stage, long-range rocket for only the third time in its history.
The North Koreans say the rocket is purely civilian in nature, designed to put a satellite in orbit. But suspicions have grown that this launch may actually be a test of a long-range ballistic missile.
American satellites are watching the launch site carefully to determine North Korea's true intentions.
Preparations have been under way for weeks at Musudan-ni in North Korea for the launch of a rocket, known as the Taepodong-2. The activity at the site provoked concern in the U.S. that the North Koreans were preparing to test a long-range missile that might have the capability one day to deliver a warhead on U.S. territory.
But recently, the North Korean government has taken steps that point to an attempt to put a satellite into orbit, says Mitchell Reiss, vice provost at the College of William and Mary and former head of policy planning at the State Department.
"There's a context in which this launch is going to take place. And so far, the North Koreans are trying very hard to manipulate and shape the context to persuade everybody that this is a civilian-based space launch vehicle," he says.
Earlier this month, North Korea notified international organizations that it intends to launch the rocket between April 4 and 8, on a trajectory east from North Korea. It has warned ships and aircraft to avoid that flight path during those days.
The North Korean actions have been persuasive, says Jack Pritchard, president of the Korea Economic Institute.
"I do think that they are going to attempt to launch a satellite of some form," he says.
Recently, the U.S. director of national intelligence, Adm. Dennis Blair, told the Senate Armed Services Committee that he had reached the same conclusion.
"I tend to believe that the North Koreans announced that they are going to do a space launch, and I believe that that's what they intend. I could be wrong, but that would be my estimate," he said.
Still, uncertainties persist. The North Koreans are assembling the rocket inside a long covered building, out of sight. They will disassemble it, bring the parts out to the launch pad, and reassemble it there. Erecting the rocket on the launch pad will take three days, and it will take another two days to fill it with liquid fuel.
Satellite photos of the rocket on the launch pad will not be available until then.
The rocket will be highly vulnerable to attack once it's been reassembled, hardly a sign that this is a military test launch. But many analysts say civilian and military launches are quite similar, according to Evans Revere, president of the Korea Society.
"Whether it's a satellite launch or something else, what they are essentially doing here is developing the launch vehicle, the same launch vehicle that could be used to launch a warhead of some sort at one of its neighbors or even the United States at some point down the line," he says.
Experts in rocketry say there are significant differences between a space launch vehicle and a long-range missile. Their trajectories are quite different, and that makes for different stresses on the rocket.
With its assortment of sensors in space and radars in Japan, Alaska and at sea, the United States will know within the first minute whether the North Koreans really are trying to put a satellite in orbit.
There has been much talk of using American missile defense interceptors to destroy the North Korean rocket, but such an attempt would be considered only if it was on a flight path to reach U.S. territory. North Korea has said that would constitute an act of war.
Pritchard, of the Korea Economic Institute, believes the North Korean rocket is highly unlikely to pose a threat to the U.S.
"There's no public, nor do I understand, any classified information that suggests that there is any type of warhead, conventional or otherwise. So the potential for this being a risk to U.S. security is not there, as far as we know," he says.
There also is great concern in Japan about this rocket because it will overfly Japanese territory.
Reiss, of the College of William and Mary, believes that everybody ought to take a deep breath and use diplomacy to get North Korea back to the bargaining table over its nuclear weapons and its missile development.
"What we need to do is to think very clearly about what level of threat this space launch vehicle really presents to us, make sure that our allies don't overreact, then try to think through exactly what it is that we want from the North Koreans in the future," he advises.
This will be only the third time North Korea has launched a Taepodong-2. In 1998, Pyongyang claimed it put a satellite in orbit, but there has been no proof of that. In 2006, there was a missile test, but it exploded 45 seconds after launch.