North Korea says it has the right to put a satellite into orbit under an international space treaty. The U.S. and others, suspicious the planned launch is really a test of a long-range military missile, say firing any rocket would violate a United Nations ban.

As with many legal areas, there is room for debate.

Experts say differences in the wording of the U.N. Security Council resolutions on the North's missile testing and the United Nations' Outer Space Treaty open the way to interpretation, which may be enough to allow Pyongyang to escape punishment for a launch.

The Security Council censured North Korea twice in 2006, first for carrying out a ballistic missile test that July and then for conducting a nuclear test explosion three months later.

Click to view photos | Satellite image of the launch area

Security Council Resolution 1718, adopted after the underground atomic blast, said Pyongyang "shall suspend all activities related to its ballistic missile program and in this context re-establish its pre-existing commitments to a moratorium on missile launching."

But a 1967 U.N. treaty says outer space "shall be free for exploration and use by all states without discrimination of any kind."

North Korea insists its impending rocket launch falls under the treaty's allowances, saying it wants to put a satellite in orbit.

The communist regime has been careful to follow the spirit of the treaty, keeping the world apprised of its plans, unlike its unannounced missile launches in 1998 and 2006.

Pyongyang last month said it would launch an "experimental communications satellite" for "peaceful purposes," announced an April 4-8 window for the liftoff, and provided safety information to international shipping and air organizations.

The U.S., Japan and South Korea say the North's claim of a satellite launch is a cover for testing a long-range missile capable of carrying a warhead. They say rockets that propel satellites into orbit and those that carry weapons use the same technology, and thus the launch would violate the Security Council prohibition.

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North Korea sees efforts to stop its plan as hypocritical.

"The countries which find fault with (North Korea's) satellite launch including the U.S. and Japan launched satellites before it," Pyongyang's Foreign Ministry said in a statement last week.

South Korea, Japan and the U.S. are working to gather support for U.N. punishment of the North if the launch goes off. But experts say the opponents face a tough road.

The International Crisis Group, a Brussels-based think tank, notes the two U.N. resolutions "specifically refer to missile launches and missile programs." That coupled with the space treaty's wording might provide council members China and Russia, which have been less critical of the launch plan, with ammunition to shelter North Korea from punishment.

"Such an argument would be based on a long-standing rule of interpretation applicable in both international and domestic law that a pre-existing right can only be overturned or suspended in the clearest possible language," its report said.

If the North ends up launching a satellite as it claims, then even the "very strong" U.N. resolution "may not prohibit the placing of a civil communications satellite in orbit, even if doing that might indirectly contribute to building up ballistic missile technology," said Tanja Masson-Zwaan, president of the Paris-based International Institute of Space Law.

Lee Keun-gwan, an expert on international law at Seoul National University, said that North Korea's launch cannot be viewed in isolation from its past behavior, even though there could be some room for debate over its legality.

"International society is justified in urging North Korea to respect the spirit as well as the letter of the relevant U.N. Security Council resolutions," he said.

There is also a propaganda angle to the North's plan, analysts said.

South Korea plans to launch a research satellite later this year, and Pyongyang may want to win the space race with Seoul, analysts said.

"It would be a huge propaganda coup to launch a satellite before South Korea," said Daniel Pinkston, a Seoul-based analyst for the International Crisis Group. "If North Korea can do this first, the North Korean regime will benefit in terms of nationalistic propaganda."