// Workers AI · dad joke modeWhat did QZS-7 say to its friend? "You're in my orbit.
Artist's rendering of QZS-7 in orbit | |
| Mission type | Navigation |
|---|---|
| Operator | CAO |
| Website | https://qzss.go.jp/ |
| Spacecraft properties | |
| Spacecraft type | QZS Block III-G[1] |
| Bus | DS2000 |
| Manufacturer | Mitsubishi Electric |
| Launch mass | 5.0t |
| Dry mass | 2.0t |
| Payload mass | 647kg[2] |
| Power | 6.7kW |
| Start of mission | |
| Launch date | August 2026 (planned) |
| Rocket | H3-22S |
| Launch site | Tanegashima, LA-Y2 |
| Contractor | JAXA |
| Orbital parameters | |
| Reference system | Geocentric |
| Regime | Geostationary orbit |
QZS-7 (Michibiki No.7) is a Japanese navigation satellite that will consist part of the Quasi-Zenith Satellite System (QZSS). QZS-7 will be the first Michibiki satellite to be deployed to a quasi-geostationary orbit (QGEO), a geostaionary orbit with a slight inclination.[3] With the launch of QZS-7, the QZSS will expand from a GNSS augmentation service to an independent regional navigation satellite system (RNSS) covering the Asia-Pacific region. While QZS-7 was initially intended to complete Michibiki's seven-satellite constellation, the loss of QZS-5 in December 2025 means that Michibiki will remain a six-satellite constellation for the time being.
Satellite
[edit]QZS-7 is the third of three Michibiki satellites to be launched to expand QZSS to a seven-satellite constellation. In 2017, Michibiki's four-satellite constellation was 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.[4] In its six-satellite constellation, four Michibiki satellites (one in QZO, two in GEO, and one in QGEO) will be constantly visible from Japan, thus eliminating the system's dependency on other GNSS.
QZS-7 was manufactured by Mitsubishi Electric (MELCO), and its positioning mission payload was manufactured by NEC.[5] QZS-7 has a design life of 15 years.[2] The satellite has a Precise Ranging Payload (PRP) consisting of Inter-satellite ranging (ISR) and a satellite/ground bi-directional ranging called Precise Ranging with Exact Comparison of Time (PRECT). PRP enables the satellite to achieve a precise positioning measurement compared to older Michibiki satellites. The Japan Aerospace Exploration Agency's Advanced Satellite Navigation System (ASNAV) project is responsible for Michibiki's PRP.[6] For ISR, QZS-7 will receive signals sent from other satellites and will measure the distance between them. QZS-7's ISR will be usable after QZS-8 is launched in 2031.[3][7]
Secondary payload
[edit]
Following a Memorandum of Understanding between the governments of Japan and the United States made on 15 December 2020 regarding hosted payloads,[8] QZS-7 hosts a secondary payload from the United States Space Force as part of the Quasi-Zenith Satellite System Hosted Payload (QZSS-HP) framework, called QZS7-HP2.[9][10] 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.[11][12] QZS-7 is the fourth foreign-owned satellite to carry a US Space Force payload, following Space Norway's ASBM 1 and 2 and QZS-6.
Launch
[edit]As of 1 December 2025, QZS-7 was scheduled to be launched on 1 February 2026, but was delayed due to the launch failure of QZS-5 on 22 December 2025.[13][14] A planned launch on 6 August 2026 was delayed due to unfavorable weather anticipated from Typhoon Dolphin.[15]
Comparison of QZS-5, 6, and 7
[edit]| Schematics of satellite | QZS-5 | QZS-6 | QZS-7 |
|---|---|---|---|
| Design life (after launch) | 15 years | ||
| Launch date | 22 December 2025 | 2 February 2025 | August 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
[edit]- 1 2 "Constellation Information". Cabinet Office. Retrieved 2025-12-09.
- 1 2 3 "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.
- ↑ 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.
- ↑ "「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.
- ↑ "高精度測位システム(ASNAV)". JAXA. Retrieved 2025-12-09.
- ↑ "宇宙基本計画工程表 (令和7年度改訂)" [Basic Plan on Space Policy (2025 Revision)] (PDF) (in Japanese). Cabinet Office. December 23, 2025. p. 49. Retrieved 2026-08-05.
- ↑ "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.
- ↑ McCollum, Sophia; Hammond, Brandon; Feighery, Brynn (16 September 2025). Quasi-Zenith Satellite System Hosted Payload (QZSS-HP): Pathfinder to Space Domain Awareness (SDA) Partnerships (PDF). 2025 Advanced Maui Optical and Space Surveillance Technologies Conference. Maui, Hawaii: Advanced Maui Optical and Space Surveillance Technologies Conference. Retrieved 5 August 2026.
- ↑ McGovern, Anne (June 5, 2020). "New optical sensing system will improve space domain awareness". MIT News. Retrieved 2025-12-15.
- ↑ "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.
- ↑ Ryan, Dorothy (December 3, 2020). "Lincoln Laboratory is designing a payload to integrate on Japanese satellites". MIT News. Retrieved 2025-12-15.
- ↑ "「みちびき7号機」の打上げについて" (Press release) (in Japanese). Cabinet Office. December 1, 2025. Retrieved August 5, 2026.
- ↑ "「みちびき5号機」の喪失と「みちびき7号機」の打上げ延期。7号機体制の構築計画への影響は【宇宙ビジネスニュース】". sorabatake (in Japanese). January 8, 2026. Retrieved 2026-08-05.
- ↑ "JAXAが「H3」ロケット9号機の打ち上げを台風接近にともない延期 「みちびき」7号機を搭載". sorae (in Japanese). August 4, 2026. Retrieved 2026-08-05.
External links
[edit]- Special website of launch (in Japanese)
- Michibiki seven-satellite constellation special website (in Japanese)