Exhibition of the QZS-3

The third Quasi-Zenith Satellite (QZS-3), a geostationary orbit (GEO) satellite in the Quasi-Zenith Satellite System (QZSS), was exhibited to members of the press on June 15 at Mitsubishi Electric Corporation’s Kamakura Works (Kamakura City, Kanagawa).
QZS-3 was exhibited in the Satellite Plant of the Kamakura Works. It has a height of roughly 5.4 meters, width of roughly 3.2 meters, and length of roughly 4.1 meters. When deployed, the solar array wings are approximately 19 meters tip to tip.

Mr. Moriyama of the Cabinet Office

Before the exhibition, Mr. Hiromichi Moriyama, executive director, QZSS Strategy Office, National Space Policy Secretariat, Cabinet Office explained the functions of the QZSS. He described the features of this system, including better positioning accuracy with the increased number of satellites, improved centimeter level precision utilizing GNSS-based control stations, transmission of individual safety confirmation information and evacuation shelter status to disaster-prevention institutions in times of disaster, and transmission of Satellite-based Augmentation System (SBAS) signals.

He also introduced international collaboration strategies with other countries including Europe and Singapore, usage examples in the road traffic and agriculture fields, examples of applications including i-construction, and a distribution demonstration project using unmanned aerial vehicles.

Next, Mr. Yasunori Futagi (project manager, director, QZSS Division, Space System Department, Kamakura Works) of Mitsubishi Electric Corporation gave an overview of QZS-2, QZS-3, and QZS-4.
QZS-3 will be put on a GEO (east longitude of 127 degrees over the equator). The payload (including mission equipment) has a mass of 475 kilograms and the bus (main satellite functions) has a mass of 1,210 kilograms, with a total launch mass of 4,700 kilograms including the propellant for orbit transfer and control. QZS-2 and QZS-4, which will be put on a quasi-zenith satellite orbit (QZO) , have a launch mass of 4,000 kilograms including the payload (370 kilograms) and bus (1,180 kilograms).

A major feature of QZS-3 is its two antennas for message communication used in the QZSS Safety Confirmation Service (Q-ANPI): one expandable S-band antenna with a diameter of 3.2 meters and one fixed Ku-band antenna with a diameter of one meter. QZS-1, QZS-2, and QZS-4 have L-band antennas that are helical array antennas, but QZS-3 uses flat patch antenna. QZS-3 is also equipped with an SBAS-signal L1Sb antenna to provide positioning satellite error correction and defect information, including to aircraft.

The H2A204 launch vehicle, with four solid rocket boosters (SRB-A), will be used for QZS-3. The launch is scheduled for around 2:00 to 11:00 p.m. (Japan Standard Time) on August 11 at the Tanegashima Space Center’s Yoshinobu Launch Complex.

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