UPDATED Jan. 30, 1:35 p.m. EDT

TOKYO — Japan’s launch on Jan. 27 of a pair of reconnaissance satellites marked the beginning of a multiyear effort to rebuild a spy satellite network that has been hobbled by a spate of on-orbit failures and a botched 2003 launch that destroyed two satellites.

Liftoff of Japan’s newest Information Gathering Satellites (IGS) aboard a Mitsubishi Heavy Industries H-2A rocket from Tanegashima Space Center in southwest Japan occurred at 1:40 p.m. local time. The Japan Aerospace Exploration Agency, JAXA, said the satellites successfully separated from their launcher 20 minutes after liftoff.

One of the satellites, IGS-Radar 4, carries a synthetic aperture radar that enables the satellite to peer through clouds and observe targets at night. The other satellite carries an experimental optical payload, according to JAXA and the Cabinet Satellite Intelligence Center, which runs the IGS program.

After completing several months of on-orbit checkout, IGS-Radar 4 satellite will provide what one Cabinet Satellite Intelligence Center official described as a much-needed enhancement to the system.

The IGS program, was initiated to give Japan an independent capability for monitoring North Korea following an August 1998 missile test that overflew Japan. The system  originally was conceived as a four-satellite constellation of two optical and two radar satellites. However, the program has been plagued with problems, with two satellites lost to an H-2A launch failure in November 2003 and several other satellites suffering mission-ending component failures within their first five years of service. The IGS-4B radar satellite became the latest such casualty when it stopped working in summer 2010, just three and a half years into its mission. That left the IGS constellation with three working optical satellites and only one functioning radar satellite, IGS-7A, which launched in 2008.

All IGS satellites to date have been built by Mitsubishi Electric Corp. at the company’s Kamakura Works southwest of Tokyo.

The Cabinet Satellite Intelligence Center official, who spoke on the condition of anonymity, said the launch of IGS-Radar 4 will restore the constellation’s radar reconnaissance capability.

Of the three optical IGS satellites Japan had in service prior to the Jan. 27 launch, the oldest, IGS-3, was launched in September 2006 and has exceeded its five-year design life. The satellite “is functioning beyond its lifespan, but we will continue to keep on using it as long as we can,” the Cabinet Satellite Intelligence Center official said.

The other two optical satellites, IGS-5A and IGS-6A, launched in November 2009 and September 2011, respectively.

To replenish the constellation, the Cabinet Satellite Intelligence Center plans to launch an optical satellite and a radar satellite in  2014, another optical satellite and radar satellite in 2016 and a  radar satellite in 2017, the Cabinet Satellite Intelligence Center official said.

Meanwhile, the Jan. 27 launch marked the H-2A rocket’s 16th consecutive launch since the November 2003 failure that destroyed two early version IGS satellites. Since becoming Japan’s mainstay launcher in 2001, the H-2A has amassed a record of 21 successful launches out of 22 tries.

“It’s good news,” the Cabinet Satellite Intelligence Center official said. “With its track record, the H-2A rocket can be considered by us to be basically reliable.”



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A graduate of the Columbia Graduate School of Journalism, where he won the Horgan Prize for Excellence in Science Writing, Paul Kallender-Umezu is co-author of “In Defense of Japan: From the Market to the Military in Space Policy” (Stanford University...