Spaceflight Insider

Japan gearing up to launch Michibiki-3 navigation satellite

The Michibiki-3 satellite, part of Japan’s QZSS navigation system, sits on display ahead of launch. Photo Credit: Japan’s Cabinet Office, National Space Policy Secretariat

The Japanese Aerospace Exploration Agency (JAXA) is in final preparations to launch the third of the country’s Quasi-Zenith Satellite System (QZSS) series atop an H-IIA rocket. The satellite, also called Michibiki-3, will augment Global Positioning System (GPS) navigation services in the island nation.

H_IIA_No._F23_with_GPM_on_its_way_to_the_launchpad Photo Credit: Bill Ingalls / NASA

Archive photo of H-IIA. Photo Credit: Bill Ingalls / NASA

The mission is scheduled to launch at 1 a.m. EDT (2 p.m. Japan Standard Time / 05:00 GMT) on Aug. 12, 2017, from Pad 1 at the Tanegashima Space Center. The Japanese space agency will have a 9-hour window to get the mission off the ground, should weather or technical difficulties spring up.

Augmenting GPS in the archipelago

Although GPS provides reasonably accurate positioning to civilian receivers worldwide, its signal can be blocked or attenuated when penetrating dense urban canyons and mountainous terrain, something in no short supply in the Japanese archipelago.

To combat this shortcoming, Japan has developed its own line of satellites designed to provide a more effective service for its citizens and emergency response personnel.

Michibiki-3 will join its two on-orbit siblings, providing more accurate positioning information to surface-based receivers, though from a vastly different vantage point. While the first two spacecraft are operating in a highly inclined and slightly elliptical orbit that draws a figure-eight ground trace, Michibiki-3 will be positioned in a geostationary orbit high above the equator at 127 degrees East.

Once complete – Japan plans to field a constellation consisting of at least four satellites – this combination of spacecraft in Tundra and stationary orbits will provide a tailored navigation service that will augment the U.S.-developed GPS system.

The spacecraft and its ride to orbit

Like the other satellites in the series, Michibiki-3 was constructed on the Mitsubishi Electric DS-2000 spacecraft platform. Tipping the scales at approximately 10,361 pounds (4,700 kilograms), Michibiki-3 will be outfitted with twin solar panels and a propulsion system utilizing the R-4D rocket engine.

Primary payload on the satellite is an array of navigation transponders, along with S-, Ku-, and L-band antennas, supporting messaging communications for the QZSS Safety Confirmation Service (Q-ANPI). Rounding out the vehicle’s capabilities is an SBAS-signal antenna that will provide error correcting positioning information to aircraft.

The satellite has an expected life span of approximately 15 years and will be delivered to orbit atop an H-IIA launch vehicle. The H-IIA, manufactured by Mitsubishi Heavy Industries and outfitted in its 204 configuration (four solid rocket boosters attached to the core), can deliver up to 13,227 pounds (6,000 kilograms) to geostationary transfer orbit.

This will be the fourth H-IIA launch of 2017, and the second in the 204 configuration. The 204 has seen a 100 percent success rate, though it has a short flight history of only three launches. Michibiki-3 will mark only the fourth mission of variant.

This also will mark the final flight of 2017 for the Japan Aerospace Exploration Agency.

Video of the launch of Michibiki-2



Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.

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