TOKYO — Asnaro-1, the first of Japan’s planned fleet of small Earth observation (EO) satellites, is now scheduled for launch in December 2012 — a year later than planned —  aboard a Russian Dnepr rocket rather than a domestic launcher as originally planned.

Despite the delay, the Japanese government is close to finalizing a deal that will see Japan help Vietnam buy two Asnaro series satellites.

With a development cost of 6 billion yen ($74.7 million) Asnaro-1 is the first in a series of standardized optical- and radar-imaging satellites being built by Tokyo-based NEC Corp. for the Ministry of Economy, Trade and Industry (METI) in partnership with the Ministry’s space arm, the Institute for Unmanned Space Experiment Free Flyer.

Short for Advanced Satellite with New system Architecture for Observation, Ansaro got its start in 2008.

The project hit a snag last year when it was denied funding needed  to complete development of the first satellite, an optical-imaging spacecraft small enough to fit, fully deployed, inside a delivery truck.

The budget shortfall prompted METI to delay the mission a year and look abroad for a cheaper launch, Nobutaka Takeo, deputy director of METI’s Space Industry Office, said in a June 17 interview.

Asnaro-1 should have been launched on Japan’s new Epsilon solid rocket this year, according to METI’s original development schedule. However, both the Epsilon and Asnaro projects were hit by budget shortfalls in 2010, delaying both projects, and making the Epsilon unavailable for a 2012 launch, Takeo said.

The delay also means that a second Asnaro satellite, which is to carry an X-band radar, will now be delayed until about 2014. Takeo said the delay should permit Ansaro-2 to  be launched by the Epsilon, which is a three-stage solid rocket being developed by the Japan Aerospace Exploration Agency (JAXA).

Asnaro  is being pursued as a series of 500-kilogram class satellites that will carry optical sensors capable of resolving images smaller than a half meter across, and radars with  better than 1-meter resolution from a 500-kilometer orbit. The satellites are designed to be low cost and provide very fast and flexible data services, according to developers.

Officials at METI,  NEC and Pasco Corp., a Tokyo-based geospatial information provider  responsible for controlling the satellites and processing and selling their data, said they are confident that the satellite system’s advanced features will be useful for a wide range of customers.

NEC and METI envision Asnaro as a flexible platform based on the use of a modular bus, or satellite frame, that can readily accommodate different types of sensors and other subsystems, Yasuo Horiuchi, senior manager of NEC Corp’s Satellite Business Development Office, said June 17. Asnaro’s bus, for example, is  going to be used by the Japan Aerospace Exploration Agency  for a future series of Sprint science satellites. The first of these, Sprint-A,  is scheduled to launch aboard the first flight of the Epsilon rocket in 2013 on a mission to observe the atmospheres of Venus, Jupiter and Mars from Earth orbit in extreme ultraviolet spectrum.

Beyond that, the Asnaro spacecraft, which will be built by NEC at its Keihin factory, near Yokohama, will be marketed commercially as Nextar-branded satellites sometime between 2015 and 2020, Horiuchi said.

Other Ansaro features include standardized component interfaces, Shoichiro Mihara, the Asnaro group manager at METI’s Institute for Unmanned Space Experiment Free Flyer, said June 17.

The optical sensors will use a 70centimeter diameter silicon carbide mirror designed by NEC that, at under 100 kilograms, is significantly lighter, less prone to distortion, and requires fewer mechanical control systems than conventional glass-based mirrors, according to Toshiaki Ogawa, NEC’s Asnaro project manager.

For its part, Pasco is designing a data processing and communication system that will enable it to provide images to customers within 30-60 minutes of the request depending on the order, said Tetsuo Fukunaga, deputy director of the company’s satellite business division.

“Our system will maximize the performance capabilities of the satellite’s usability, in terms of communications coverage, in direct tasking, downlink, data transmission, data processing and data delivery … all will be done within a one hour timeframe,” Fukunaga said June 17.

Pasco has already completed two ground stations — one on the northern Japanese island of Hokkaido and one on Okinawa in the south — and is developing a mobile, truck-based ground station, among other infrastructure, Fukunaga said.

Meanwhile, in a deal expected to be finalized this summer, Japan is set to offer two Asnaro radar satellites to Vietnam for disaster monitoring and  resource and environmental management  missions, with the first scheduled for launch in 2017 and the second for 2020 in a 48 billion yen Overseas Development Assistance package paid for by Japan, Takeo said.

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...