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Re-start of QZS test operation

Sep.07,2018
National Space Policy Secretariat, Cabinet Office 

On June 2, 2018, an anomaly occurred on the third Quasi-Zenith Satellite (QZS-3, a geostationary satellite) in orbit. The switching device which selects the signal amplifier for the satellite's signal transmission was unexpectedly flipped, and the switch ceased functioning. (Announced on June 5, 2018)

Accordingly, test signal transmission was temporarily halted for QZS-2/QZS-3/QZS-4, which are equipped with the same switches.
An investigation was conducted to determine the cause of this anomaly based on the views of experts. The future operation method was been considered. Finally, our investigation has been completed, and the test signal transmission for QZS-2/QZS-3/QZS-4 will be re-started.

We reach a conclusion that the switch drive unit malfunctioned due to an electric discharge phenomenon on the satellite. This malfunction made QZS-3's L5S signal (for the Positioning Technology Verification Service) switch and L1 signal (satellite positioning signal) switch partially cease functioning.

It has been decided to re-start transmission for all signals, including L1 and L5S, because safety measures have been taken so the satellites can be operated in a stable manner, even if the switch drive unit malfunctions.

QZS-3's L1 signal will be operated at a lower transmission output than originally planned. However, it has been confirmed that this signal can be used, even at the lower output, in regular environments.

The Cabinet Office will make every effort to continue preparing for the start of QZSS services in November.

END