WASHINGTON — Although a crucial third stage of a North Korean rocket apparently failed in a launch Sunday, U.S. military and intelligence officials and weapons experts said the test raises new concerns about advances in Pyongyang's mastery of missile technology.
North Korea said the purpose of the launch was to place a civilian satellite into orbit. U.S. and Western officials said it was not clear whether there was a satellite on the rocket, but that if there was, it never made it into orbit.
The launch was the latest North Korean rocket test to fall short of objectives, but still shows disturbing progress in that country's pursuit of the ability to deliver a nuclear warhead, according to U.S. officials and weapons experts. They said the mission could boost the regime's ambitions and its standing among countries with similar goals.
Unlike North Korea's 2006 test in which a Taepodong 2 rocket failed 40 seconds after launch, the rocket this time successfully went through the first two stages.
A senior Defense official said the military was now "clearly more worried" about the North's missile technology. The senior official spoke on the condition of anonymity because the Pentagon did not authorize anyone to speak publicly about the launch.
U.S. officials said the rocket launched Sunday was a multistage Taepodong 2 and there was broad agreement that the North Korean explanation about launching a satellite was merely cover for a long-range ballistic missile test.
"The U.S. knows enough to conclude this was not a peaceful satellite launch," said Michael J. Green, a senior advisor at the Center for Strategic and International Studies.
Weapons experts said that while the launch cleared Japan, it is unclear whether the rocket ever reached its third stage, or failed after its second engine fired, sending its remaining booster as well as its payload into the Pacific Ocean.
"There was no successful satellite launch," said a U.S. official familiar with intelligence reports on the rocket and discussing it on condition of anonymity. "If indeed there was a satellite involved, that didn't come to pass."
Even so, North Korea demonstrated an ability to launch a multistage rocket that is likely to bolster its reputation among other states seeking that capability, several top experts said.
"North Korea will still be looked upon as a supplier of reasonably good missiles, and the pariah state leader in technology on missiles," said David Albright, head of the Institute for Science and International Security.
