Wednesday, April 11, 2012

North Korea Is Lying About Its Rocket Launch, Sat-Watchers Show

A North Korean soldier stands in front of the country's Unha-3 rocket, slated for liftoff between Apr. 12 to 16. Photo: AP/David Guttenfelder


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  • North Korea claims that its impending satellite launch, scheduled for this week, is merely a mission to study the country’s “distribution of forests” and weather patterns. But after analyzing the satellite’s potential flight paths, a network of amateur and professional spaceflight specialists have concluded that Pyongyang’s claim is all but impossible. In order for the North Koreans to get a weather or observation satellite into the proper orbit, these experts say, Pyongyang would have to risk the early stages of its rockets dropping on its neighbors’ and allies’ heads.

    “I believe that the most reasonable interpretation is that they are lying about this being a satellite launch, which has been betrayed by the incompetence of their propagandists in over-reaching in their cover story,” longtime satellite watcher Ted Molczan noted on the SeeSat listserv.
    The Pyongyang regime has a long history of malarkey, of course. After its last satellite, the Kwangmyongsong-2 (Bright Star 2), plopped into the Pacific Ocean minutes after liftoff, North Korea swore that the thing was in orbit and transmitting “immortal revolutionary paeans” back to Earth. But this time, the debunking appears to be underway even before the rocket takes off from the Sohae Satellite Launching Station.
    Shortly after announcing its latest launch, North Korea published the intended flight path of the rocket that would attempt to take the 1,000-kilogram Bright Star 3 satellite into space. As part of a standard warning to the region’s shipping and airline companies — known as a “notice to airmen” or “NOTAM” — Pyonyang said the booster rocket would fly due south, ejecting its first stage just west of South Korea and its second just east of the Philippines. “A safe flight orbit has been chosen so that carrier rocket debris to be generated during the flight would not have any impact on neighboring countries,” the state-run KCNA news service promised on Mar. 16. Airlines are now re-routing their flights based on that North Korean warning.

    North Korea's stated flight path for its rocket launch, as plotted by the Union of Concerned Scientists.
    Pyongyang swore that the flight path would enable the satellite to assume what’s known as a “sun-synchronous” orbit — one that provides a constant angle between the sun, satellite, and the ground below, giving the Bright Star-3 an almost consistent view of North Korea with every overflight. That’s the kind of orbit used by the overwhelming majority of low-earth-orbit imagery and weather satellites. And it would be consistent with North Korea’s promise that the Bright Star 3 was designed to examine its own crops and climate.
    One small problem: The flight path published in North Korea’s “NOTAM” and its promised sun-synchronous orbit don’t match up, as Molczan, a veteran observer of spacecraft, discovered when he crunched the numbers. (This illustration best explains his analysis.)
    “I do not see how North Korea could reach a sun-synchronous orbit from the new launch site without risk to populated areas,” he wrote on the SeeSat list. “Launching directly toward the required 192.3 [degree] azimuth would result in a trajectory that skirts China’s east coast near Shanghai. The rocket’s second stage would overfly Taiwan, before impacting in a zone bordering within perhaps 50 km of the west coast of the northern Philippines.”
    In other words, North Korea might be telling the truth about the direction of its launch, or the contents of it. But not both.