Two minutes after launching from the Baikonur Cosmodrome in Kazakhstan tonight, a Russian heavy-lifting Proton rocket suffered a malfunction of its second stage, leading to apparent destruction of a Japanese satellite payload riding aboard the booster.

The 18-story Proton M rocket soared away from pad 39 at 6:43 p.m. EDT (2243 GMT), marking an on-time start for a planned seven-hour ascent to geosynchronous transfer orbit for the four-stage launcher.

The six hydrazine-fueled first stage engines propelled the Proton into a clear, predawn sky over the desert steppes of Central Asia. Riding its fiery tail of super-heated exhaust, the vehicle arced downrange with normalcy.

As the first stage was nearing the time its engines would deplete their fuel reserves and snuff out, the four engines on the second stage were supposed to ignite, revving to full throttle at the same time as the spent lower stage would drop away.

The staging event, when visible by ground tracking cameras, always provides a dramatic spectacle in the sky with streaks of smoke as the first stage is blasted away.

But tonight something didn't seem quite right.

"I just got word from the launch site in Baikonur that we experienced a problem with the second stage engines. Apparently they did not ignite," said Greg Gilmore, senior director of marketing and sales for International Launch Services.

"Therefore we are now faced with an anomaly that we must go and find out more about. Unfortunately for our customers and everybody involved, we appear as though we've had a problem with the second stage engines, which didn't ignite."

Without a successful ignition of the second stage, the rocket was dealt a helpless scenario of plummeting back to Earth. An impact area for the vehicle was not immediately reported.

ILS is the U.S.-based firm that markets Proton rockets to commercial customers. Tonight was the 42nd Proton flight for ILS dating back to 1996 and the fourth to end in failure. The earlier mishaps in 1997, 2002 and 2006 were caused by problems with the upper stage motors.

Proton's lower stages had enjoyed a faultless track record for nearly eight years, until tonight. The most recent trouble -- also affecting the second stage -- downed a pair of Russian government launches in July and October 1999. Those failures were traced to poor workmanship and debris in the engines.

Destroyed in tonight's launch accident was the JCSAT 11 communications spacecraft, the first commercial Japanese satellite to ever fly on Proton.

Russia's workhorse Proton was making its 327th flight. Developed more than four decades ago, the heavy-duty rocket has lofted scores of satellites, interplanetary spacecraft and pieces of orbiting space stations, including the International Space Station's initial control and living quarters modules -- Zarya and Zvezda.

The JCSAT 11 spacecraft, built by Lockheed Martin, was headed for geostationary orbit 22,300 miles (36,000 kilometers) above the equator. JSAT Corp. of Tokyo would have operated the satellite to provide telecommunications services to Japan, the Asia-Pacific region and Hawaii.

The 8,800-pound (4,000-kilogram) craft was fitted with 30 Ku-band and a dozen C-band transponders. It had an anticipated service life of 15 years.

JSAT planned to use the satellite as an in-space backup to the company's fleet of eight older spacecraft.

ILS promises a full investigation into the failure.

We'll update this story as more information becomes available.

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