Spaceflight Insider

Japanese Epsilon rocket sends ASNARO-2 radar satellite to orbit

Japan Aerospace Exploration Agency JAXA Epsilon rocket image credit JAXA

Image Credit: JAXA

A Japanese Epsilon rocket successfully delivered the ASNARO-2 radar Earth observation satellite to orbit this afternoon. The Epsilon rocket launched from Uchinoura Space Center at 6:06 Japan Standard Time, or (21:06 UTC on Wednesday).

The Advanced New Satellite with New System Architecture for Observation (ASNARO) series of satellites are spacecraft created for the Japanese Ministry of Economy, Trade, and Industry (METI) by the Japan Space Systems company.

ASNARO 2 photo credit NVS Live

The ASNARO 2 satellite. Photo Credit: NVS Live

The launch of ASNARO-2 aboard its Epsilon rocket was origionally scheduled for Nov. 12, 2017. However, it was delayed by an electrical problem. Additionally, bad weather prompted a delay from Jan. 16, 2018.

The first ASNARO satellite was launched on a Dnepr rocket in 2014 and carried an optical observation system with a resolution better than 6.5 feet (two meters) per pixel. ASNARO-2 carries an X-band Synthetic Aperture Radar (SAR) for terrain mapping.

A third satellite in the series is planned to carry a hyperspectral observation payload for imaging in optical and other bandwidths.

The ASNARO satellites are designed to be small, lightweight spacecraft with masses around 900-1,300 pounds (400-600 kilograms) with a common spacecraft bus largely built from commercial-off-the-shelf parts and interchangeable payload sections. This commonality is designed to reduce cost and simplify mission planning and preparation.

ASNARO-2 carries an X-band SAR weighing about 485 pounds (220 kilograms). The SAR has a resolution of better than 1.3 feet (one meter) per pixel, and has three observation modes: spotlight, stripmap, and ScanSAR. The narrowest, spotlight, has an image width of more than 6.2 miles (10 kilometers).

The common ASNARO bus weighs about 672 pounds (305 kilograms) without fuel and carries two gallium-arsenide solar array wings that together generate up to 1,300 watts of power. The bus also carries 100 pounds (45 kilograms) of hydrazine fuel for maneuvering, in addition to reaction wheels and magnetic torque rods for attitude control.

The Epsilon rocket has three solid-fueled stages and an optional Compact Liquid Propulsion Stage (CLPS) upper stage, which was used in the launch of ASNARO-2. In fact, of the three total Epsilon flights, this was the second to utilize a CLPS.

The Epsilon launch vehicle delivered the ASNARO-2 spacecraft to a polar, Sun-synchronous orbit with an inclination of 97.4 degrees and an altitude of about 313 miles (504 km). The three solid fueled stages completed their burns after about nine minutes, and the CLPS stage separated from the spacecraft after about four and a half minutes after third stage separation.

The next launch of an Epsilon rocket is expected later this year (2018) with a quartet of small satellites, including OrigamiSat-1, which will demonstrate the deployment and behavior of membrane structures in space, and AOBA-VELOX 4, a joint Japanese-Singaporan 2U cubesat to study Lunar Horizon Glow, the anomalous light possibly caused by dust around the edge of the Moon.

The launch was noted on NASASpaceFlight and Gunter’s Space Page.




Christopher Paul has had a lifelong interest in spaceflight. He began writing about his interest in the Florida Tech Crimson. His primary areas of interest are in historical space systems and present and past planetary exploration missions. He lives in Kissimmee, Florida, and also enjoys cooking and photography. Paul saw his first Space Shuttle launch in 2005 when he moved to central Florida to attend classes at the Florida Institute of Technology, studying space science, and has closely followed the space program since. Paul is especially interested in the renewed effort to land crewed missions on the Moon and to establish a permanent human presence there. He has covered several launches from NASA's Kennedy Space Center and Cape Canaveral for space blogs before joining SpaceFlight Insider in mid-2017.

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