Sunday's failure of an improved version of the North Korean
Taepo-Dong-2 has deprived U.S. intelligence agencies from assessing performance
of the vehicle's third stage. This is deemed critical to determining the
precise threat the vehicle poses as an ICBM that could attack Alaska, Hawaii or
deeply into the continental U.S.
Almost immaterial in the post-flight analysis is the failure
of the vehicle to place a small communications satellite in low earth
orbit, North Korea's stated intention.
Unlike on the previous launches of earlier versions of the long-range
vehicle, the North Koreans announced the planned impact zones for the first
and second stages of the vehicle to warn ships and commercial aircraft out of
the area.
North Korea says the satellite launch mission succeeded, but
the U.S. says the vehicle failed about half way through an about 13-minute
ascent. This plunged the second and third stages, along with the satellite into
the mid-Pacific Ocean.
The vehicle was heavily redesigned after its 1998 initial
launch failure that succeeded in sending the second stage over Japan.
A redesigned version was launched in July 2006
and this time failed early in first stage flight.
The design was then changed again
to the version launched Sunday, with liquid propellant first and second stages
and a long narrow solid propellant upper stage with a short bulbous satellite
shroud.
A factor lost on virtually all news media commentators in
describing the vehicle following its launch is that the North Korean rocket
flown is a three-stage, not a two-stage vehicle.
The U.S. was able to monitor key phases of the countdown
using land, sea and air-based electronic intelligence assets. In the minutes
prior to launch, the North Korean activation of its tracking radars was a tip
off that the launch was imminent.
Following liftoff at 0230 GMT (10:30 p.m. EDT Saturday) the
vehicle flew on essentially a 90.5-degree azimuth. The launch occurred at 11:30
a.m. local time at the North Korean Musudan-ri launch on the northeast coast of
the Korean peninsula.
Radars in Japan and on U.S. and Japanese destroyers in the
Sea of Japan and the western Pacific detected the launch immediately as it
occurred as did two or three Defense Support Program (DSP) missile early
warning spacecraft monitoring the Pacific region. The DSPs likely also detected
the fiery reentry and breakup of the vehicle over the west-central Pacific
several minutes later.
The first stage burned as planned and fell into the Sea of
Japan 280 kilometers (173 miles) west of northern Japan.
Japanese navy ships were pre positioned in the area and
raced to the splashdown area with the hope of recovering debris for analysis.
The second stage may have ignited, but analysts are still
assessing for how long it burned. If it did ignite, the second stage did not
complete its firing. As a result the vehicle impacted 1,070 kilometers (664
miles) in the Pacific off the east coast of Japan. This was several hundred
miles west and short of the area that North Korea announced where the second
stage and payload shroud debris would fall.
U.S. intelligence agencies are closely assessing whether the
first and second stages used an up-rated rocket engine compared with the
previous two launches.
The third stage has not yet been tested in flight, a key
objective for both North Korean success and U.S. analysis of the rocket's
capabilities.
"Once they are successful with a third stage they would
have a missile that could reach the western U.S.," according to Rep. Jane
Harmon (D-Calif.), chairwoman of the House Homeland Security Subcommittee On
Intelligence and Risk Assessment. "This is very serious and so it is critical
that this administration play keen attention to this test activity," she
said in a recent NBC interview.
The solid propellant upper stage resembles that used on the
U.S. Thor-Able rocket design flown in the early 1960s.
The North Korean stage would have accelerated the payload to
17,500 mph velocity for the orbital mission or a targeted slower velocity
cutoff for ICBM missions to North America.
Light-weight variations of the TD-2 with an advanced third
stage could fly as far as 15,000 kilometers (9,315 miles) placing much of the
U.S. at risk from a nuclear or biological attack if the North Koreans are able
to master the miniaturization of such weapons.
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