Japan’s QZSS constellation to receive replacement satellite

The successor to the first quasi-zenith satellite, dubbed Michibiki, is expected to launch this year.

Michibiki was launched by the Japan Aerospace Exploration Agency (JAXA) in September 2010 and was transferred to the Cabinet Office in 2017. The replacement satellite is now undergoing prototype testing at the satellite manufacturer’s facility  (Mitsubishi Electric Co. Ltd. Kamakura Seisakusho) in Kanagawa. 

The tests will confirm performance of the replacement satellite before it is put into service. It is undergoing acousitic, vibration and thermal vacuum tests to ensure it will remain functional after launch and in space. 

After testing, the satellite will be transported to the Tanegashima Space Center for launch, which is expected to take place later this year.

Though built to succeed the first QZSS satellite, the replacement is based on the second and fourth satellites

Main specifications of the successor to the first machine and other machines

item	First machine	Units 2 and 4	Unit 3	Successor to the first machine
Orbit	Quasi-zenith	Quasi-zenith	Rest	Quasi-zenith
Positioning signal	L1-C / A, L1C, L1S, L2C, L5, L6	L1-C / A, L1C, L1S, L2C, L5, L5S, L6	L1-C / A, L1C, L1S, L1Sb, L2C, L5, L5S, L6	L1-C / A (L1-C / B (* 1)), L1C, L1S, L2C, L5, L5S, L6
L band antenna	Helical method (* 2)	Helical method (* 2)	Patch method (* 3)	Patch method (* 3)
Generated power	5.3kW	6.3kW	6.3kW	6.3kW
mass	About 4t	About 4t	About 4.7t	About 4t
Design life	10 years or more	Over 15 years	Over 15 years	Over 15 years
Launch year	2010	2017	2017	2021 (planned)
Launch rocket	H2A202	H2A202	H2A204	H2A202

(* 1) Signal transmitted by BOC (Binary Offset Carrier) modulation of L1-C / A code

(* 2) Antenna with spiral antenna elements arranged

(* 3) Antenna with planar antenna elements arranged

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