TOKYO — Vietnam will buy a pair of Japanese-designed Earth observing radar satellites under a just-finalized deal representing Japan’s first export of a remote sensing satellite system, government officials here said.

The sale, financed through a Japanese foreign aid package, was sealed in an agreement signed here Oct. 31 by Japan’s ambassador to Vietnam, Yasuaki Tanizaki, and Vietnam’s minister of planning and investment, Bui Quang Vinh.

The satellites will be based on Japan’s new ASNARO — Advanced Satellite with New System Architecture for Observation — remote sensing platform, whose development was spurred by a shift in government space policy that places more emphasis on practical and commercial applications. The first ASNARO satellite, an optical observation craft, is slated for launch around the end of 2012 on a Russian Dnepr rocket.

Japan will finance the satellite project through overseas development assistance loans it is providing to Vietnam as part of a broader 92.6 billion yen ($1.2 billion) package that includes the building of a major shipping port, a highway project and efforts to bolster flood-prone Vietnam’s ability to respond to natural disasters.

About half of the total aid package, or 46.4 billion yen, is earmarked for the satellite project, a decade-long undertaking that will see Japan build a ground station and train Vietnamese engineers and ground controllers.

Japan will provide an initial 7.2 billion yen over the next two years to begin work on the X-band satellites, the first of which will be built in Japan and launched in 2017, according to Nobutaka Takeo, deputy director of the Space Industry Office at the Ministry of Economy Trade and Industry (METI), which proposed the project. The second satellite, slated to launch in 2020, will be assembled in Vietnam, he said.

In addition to funding a joint effort between Vietnam and Japan to establish payload specifications for the satellites, some of the initial money will be used to begin setting up an assembly, integration and test center in Vietnam and to start training Vietnamese technicians, Takeo said.

While Japan makes extensive loans under its Overseas Development Assistance program to emerging Asian economies, the deal with Vietnam marks the first time Japan has used the program to fund satellites, Takeo said. The deal also marks Japan’s first export sale of an Earth observation satellite.

“It’s a major success and good news for Japan. This shows that we have developed mature space technologies that can be used by other countries,” Takeo said in a Nov. 2 interview.

The satellite loan will be coordinated via the Japan International Coordination Agency (JICA), a quasi-governmental body responsible for implementing Japan’s overseas aid programs. JICA will provide the loan for the two satellites and related facilities, and help Vietnam develop the capacity to operate and maintain the facilities and equipment, said Yoshio Wada, deputy director general of JICA’s Southeast Asia Department.

“It is the first attempt for JICA to provide assistance for Earth observation satellites,” Wada said Nov. 2. “Vietnam has a relatively higher risk of the incidence of natural disasters. Particularly, typhoons and floods are serious problems.

“Given such circumstances, it is recognized that establishment of a continuous Earth observation satellite system is essential to conduct monitoring, forecasting and impact evaluation of climate change.”

Takeo said the satellites will be based on the ASNARO series of satellites being built by NEC Corp. of Tokyo. The ASNARO program will consist of multiple 500-kilogram-class satellites, some of which will be equipped with optical sensors capable of resolving images smaller than half a meter across, while others will carry radar imagers offering slightly lower resolution.

Nobuyuki Matsumoto, the official in charge of satellite planning at METI’s Space Industry Office, said NEC is scheduled to build three ASNARO satellites for Japan’s use. The first is an optical satellite due to launch in December 2012 aboard a Russian Dnepr rocket. An X-band radar satellite similar to those being offered to Vietnam is planned for launch in 2014. An ASNARO satellite carrying a hyperspectral sensor is planned for launch in 2016 or later, Matsumoto said. Of these, the optical and hyperspectral satellites are being funded entirely by the government. The radar satellite is being partially funded by the private sector, Matsumoto said.

Takeo said METI is in talks with a number of other developing countries around the Asian region about providing ASNARO-based satellites, but he declined to provide further details.

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...