QZS-6

QZS-6

Artist's rendering of QZS-6 in orbit
Mission type	Navigation
Operator	CAO
COSPAR ID	2025-023A
SATCAT no.	62876
Website	https://qzss.go.jp/
Spacecraft properties
Spacecraft type	QZS Block III-G [1]
Bus	DS2000
Manufacturer	Mitsubishi Electric
Launch mass	4.8t
Dry mass	2.0t
Payload mass	647kg [2]
Dimensions	5 × 2.3 × 2.36 m (20 × 8 × 8 ft)
Power	6.7kW
Start of mission
Launch date	2 February 2025, 08:30:00 (2025-02-02UTC08:30Z) UTC
Rocket	H3-22S
Launch site	Tanegashima, LA-Y2
Contractor	JAXA
Orbital parameters
Reference system	Geocentric
Regime	Geostationary orbit
QZSS ←  QZS-1R QZS-5  →

QZS-6 (Michibiki No.6) is a Japanese navigation satellite consisting part of the Quasi-Zenith Satellite System (QZSS). QZS-6 was deployed to a geostationary orbit (GEO). With the launch of QZS-5, QZS-6, and QZS-7, the QZSS will expand from a GNSS augmentation service to an independent regional navigation satellite system (RNSS) covering the Asia-Pacific region.

Satellite

QZS-6 is the first of three Michibiki satellites to be launched to expand QZSS to a seven-satellite constellation. In 2017, Michibiki's four-satellite constellation established, and with it there are at a minimum two Michibiki satellites (one in QZO and one in GEO) constantly visible from Japan. Satellite navigation requires at least four satellites to be visible, so users need to receive signals from QZSS and other global navigation satellite system (GNSS) at the same time. ^[3] In its seven-satellite constellation, four Michibiki satellites (one in QZO, two in GEO, and one in quasi-geostationary orbit (QGEO)) will be constantly visible from Japan, thus eliminating the system's dependancy on other GNSS. QZS-6 joined QZS-3 in geostationary orbit.

QZS-6 was manufactured by Mitsubishi Electric (MELCO), and its positioning mission payload was manufactured by NEC. ^[4] QZS-6 has a design life of 15 years. ^[2] The satellite has a Precise Ranging Payload (PRP) consisting of Inter-satellite ranging (ISR) and satellite/ground bi-directional ranging. PRP enables the satellite to achieve a precise positioning measurment compared to previous Michibiki satellites. The Japan Aerospace Exploration Agency's Advanced Satellite Navigation System (ASNAV) project is responsible for Michibiki's PRP. ^[5] For ISR, QZS-6 will receive signals sent from QZS-5 and will measure the distance between them. ^[6]

Secondary payload

United States Space Command delegation visiting Mitsubishi Electric's Kamakura Works

Following a Memorandum of Understanding between the governments of Japan and the United States made in 15 December 2020 regarding hosted payloads, ^[7] QZS-6 hosts a secondary payload from the United States Space Force as part of the Quasi-Zenith Satellite System Hosted Payload (QZSS-HP) framework, called QZS6-HP1. ^[8] The US Space Force Mission Delta 2's Situational Awareness Camera Hosted Instrument (SĀCHI, meaning 'search' in Japanese), developed by MIT Lincoln Laboratory, is a space domain awareness (SDA) payload that will monitor objects in geosynchronous orbit and send the data in near real time to the SDA database at Schriever Space Force Base. ^{[9] [10]} QZS-6 is the third foreign-owned satellite to carry a US Space Force payload, following Space Norway's ASBM 1 and 2.

Launch

QZS-6 was launched on 2 February 2025. By May 2025, the US Space Force's QZS6-HP1 achieved first light. ^[8]

Comparison of QZS-5, 6, and 7

Comparison of QZS-5, 6, and 7 ^{[2] [1]}

Schematics of satellite	QZS-5	QZS-6	QZS-7
Design life (after launch)	15 years
Launch date	22 December 2025	2 February 2025	February 2026
Orbit	QZO	GEO	QGEO
Rocket	H3-22S
Mass (dry/launch)	1.8t/4.8t	1.9t/4.9t	2.0t/5.0t
Block type	III-Q	III-G	III-G
Payload electricity consumption	2.4kW	2.7kW	3.0kW
Position, Navigation, and Timing (PNT)	L1-C/A (L1-C/B), L1C, L5
Precise Point Positioning (PPP)	L6
Position Technology Verification Service (PTV)	—	L1Sb, L5S
L-band antenna type	Patch antenna
Precise Ranging Payload (PRP)	Inter-satellite ranging (ISR), satellite/ground bi-directional ranging
Message Communication Payload (MCP)	—		S-band (MCP developed by MELCO)
Secondary Payload	—	SĀCHI

References

1. "Constellation Information". Cabinet Office . Retrieved 2025-12-09.
2. "Establishing A Seven Satellite Constellation for Quasi-Zenith Satellite System in order to Realize High Precision Positioning Society" (PDF) (in Japanese). Mitsubishi Electric. 2021. Retrieved 2025-12-09.
3. Hayashi, Kimiyo (December 6, 2024). "準天頂衛星「みちびき」7機体制へ—「マイハザードマップ」を作る中学生の期待". DSPACE (in Japanese). Retrieved 2025-12-09.
4. "「みちびき」7機体制で、GPSの日本単独運用を目指す 高精度な測位サービスを支えるNECの技術と人" (in Japanese). NEC . Retrieved 2025-12-09.
5. "高精度測位システム（ASNAV）". JAXA . Retrieved 2025-12-09.
6. Watanabe, Hibiki (December 9, 2024). "準天頂衛星システムみちびき6号機機体公開". Space Authors Club (in Japanese). Retrieved 2025-12-09.
7. "Agreement Between the UNITED STATES OF AMERICA and JAPAN Effected by exchange of notes at Tokyo December 15, 2020 Entered into force December 15, 2020" (PDF). GovInfo. 15 December 2020. Retrieved 2025-12-15.
8. McGovern, Anne (June 5, 2020). "New optical sensing system will improve space domain awareness". MIT News . Retrieved 2025-12-15.
9. "U.S. Space Force's Space Systems Command and Japan launch First Bilateral Space Effort" (Press release). Space Systems Command. February 4, 2025. Retrieved December 15, 2025.
10. Ryan, Dorothy (December 3, 2020). "Lincoln Laboratory is designing a payload to integrate on Japanese satellites". MIT News . Retrieved 2025-12-15.

External links

• Special website of launch (in Japanese)
• Michibiki seven-satellite constellation special website (in Japanese)