China launched the Haiyang-2E (HY-2E) oceanographic satellite on July 2, 2026, aboard a Long March 4B rocket from the Jiuquan Satellite Launch Center (JSLC) in northwest China. The satellite, whose name means “Ocean” in Chinese, is designed to replace the HY-2B spacecraft that has been in orbit since October 2018, more than doubling its planned three-year service life. The mission was China’s 47th space launch of 2026 and the 654th flight of the Long March rocket family since its debut in 1970.
The Haiyang Satellite Series
The Haiyang series (Chinese for “Ocean”) is China’s fleet of marine remote sensing satellites, operated by the National Satellite Ocean Application Service (NSOAS) under the Ministry of Natural Resources. The satellites are developed by the China Academy of Space Technology (CAST), a subsidiary of the state-owned China Aerospace Science and Technology Corporation (CASC).
China operates four distinct sub-series of Haiyang satellites, each designed for a specific type of ocean observation:
| Sub-series | Primary Function | Current Status |
|---|---|---|
| HY-1 | Ocean color monitoring (chlorophyll, algal blooms, sediment) | HY-1C (2018), HY-1D (2020) |
| HY-2 | Ocean dynamic environment (winds, waves, temperature, sea level) | HY-2B/C/D/E |
| HY-3 | Ocean surveillance (X-band SAR for all-weather high-resolution imaging) | HY-3A (2023) |
| HY-4 | Ocean salinity measurement | HY-4-01 (2024) |
The HY-2 series, to which HY-2E belongs, was China’s first satellite system dedicated to marine dynamic environment monitoring. The first satellite in this series, HY-2A, was launched in August 2011 and operated for over a decade before its retirement. Since then, HY-2 satellites have provided continuous data for marine disaster prevention and mitigation, offshore resource development, maritime security, and oceanographic research.
These satellites have captured precise typhoon data during storms affecting China, contributed to tsunami early warning systems, and supplied data to global numerical weather prediction models. The wind, wave and current data they generate also helps analyse major fishing grounds, allowing fishing vessels to locate fish schools more efficiently and reduce offshore operating costs.
HY-2E: Payloads and Capabilities
The HY-2E satellite carries four microwave remote sensing payloads along with supporting instruments, enabling it to acquire high-precision, high-resolution data on key ocean parameters. The satellite operates in a sun-synchronous orbit (SSO) at approximately 963 km altitude with a 99.3 degree inclination and a 14-day ground-track repeat cycle.
| Payload | Type | Key Measurements |
|---|---|---|
| Radar Altimeter (ALT) | Active microwave | Sea surface height, significant wave height |
| Microwave Scatterometer (SCAT) | Active Ku-band radar | Sea surface wind speed and direction |
| Microwave Radiometer Imager (MWRI) | Passive microwave | Sea surface temperature, wind speed, water vapour, sea ice |
| Calibration Microwave Radiometer (CMR) | Passive microwave | Atmospheric water vapour correction for altimeter |
The scatterometer is the satellite’s most prominent instrument. It transmits Ku-band pulses at approximately 13.5 GHz toward the ocean surface and measures the backscattered signal from centimetre-scale surface ripples called Bragg waves, which are generated directly by near-surface wind stress. By collecting returns from multiple angles, the instrument derives both wind speed and wind direction. The scatterometer has a swath width of 1,300 km, meaning a single pass covers a vast strip of the ocean.
The radar altimeter fires nanosecond-pulse radar signals vertically downward and measures the round-trip travel time to determine sea surface height with centimetre-level accuracy. It simultaneously measures significant wave height from the shape of the return pulse and wind speed from the pulse’s backscatter strength.
The MWRI is a passive instrument that detects naturally emitted microwave radiation from the ocean surface across multiple frequency channels. It has an even wider swath of 1,600 km and provides measurements of sea surface temperature, water vapour column density, wind speed (but not direction), and sea ice concentration.
A Calibration Microwave Radiometer corrects for signal delay caused by water vapour in the atmosphere, a critical correction without which the altimeter’s sea surface height measurements would be corrupted by errors of several centimetres.
French Collaboration: The DORIS System
HY-2E also carries a receiver for France’s DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) system, a collaboration between the French space agency CNES and China that has been part of every HY-2 satellite since HY-2A in 2011. DORIS works in the opposite direction from GPS. A receiver aboard the satellite listens for Doppler-shifted signals broadcast upward from roughly 60 ground beacons distributed worldwide. By measuring how the signal’s frequency shifts as the satellite passes over each beacon, the system derives the satellite’s range rate with a precision of about 0.3 mm per second. Combined with GPS data and a Laser Retroreflector Array (LRA) on the satellite, DORIS enables precise orbit determination that places the satellite’s position within a few centimetres. This precision is essential because a 3 cm error in the satellite’s altitude translates directly into a 3 cm error in reported ocean height, which is the same scale as the sea level anomalies used in ocean circulation models and El Nino forecasting.
Vessel Tracking
Since the HY-2B satellite, the series has also carried an Automatic Identification System (AIS) receiver that continuously acquires vessel position, speed and call sign data, improving navigation security and maritime domain awareness.
A Structured Fleet Modernization
HY-2E is the first of three replacement satellites that China plans to deploy by 2027 under a structured upgrade of its ocean dynamic environment constellation. The three new satellites HY-2E, HY-2F and HY-2G will each replace one member of the aging HY-2B/C/D trio.
| Satellite | Launched | Design Life | Status |
|---|---|---|---|
| HY-2B | October 2018 | 3 years | To be replaced by HY-2E |
| HY-2C | September 2020 | 3 years | To be replaced by HY-2F |
| HY-2D | December 2021 | 3 years | To be replaced by HY-2G |
HY-2B has remained operational for nearly eight years, far exceeding its designed three-year lifespan. Its instruments have experienced calibration drift over time, a common issue with aging satellite sensors. Replacing it with HY-2E, which carries updated instruments, restores measurement accuracy and anchors China’s ocean data products to newer, better-characterised sensor baselines. This matters particularly for climate research time series, where consistent calibration is essential for detecting long-term trends.
Zhang Qingjun, an expert from CAST, stated that HY-2E will initially work alongside the currently operational HY-2C and HY-2D satellites to ensure continuity of monitoring services. Once all three replacement satellites are in orbit and commissioned, China will operate a fully refreshed constellation capable of monitoring approximately 80 percent of the world’s ocean surface winds within six hours, a significant capability for global weather forecasting.
Long March 4B: A Proven Workhorse
The Long March 4B (CZ-4B) rocket that carried HY-2E to orbit is one of China’s oldest active launch vehicles. Developed by the Shanghai Academy of Spaceflight Technology (SAST) under CASC, it made its first flight in May 1999. Thursday’s mission was its 57th flight.
| Parameter | Specification |
|---|---|
| Stages | 3 |
| Length | 44.1 m |
| Diameter | 3.35 m |
| Launch Mass | 249 tonnes |
| LEO Capacity | 4,200 kg |
| SSO Capacity | 2,800 kg |
| Propellant | N2O4 / UDMH (hypergolic) |
All three stages of the Long March 4B burn dinitrogen tetroxide and unsymmetrical dimethylhydrazine, a hypergolic propellant combination that ignites on contact and can be stored indefinitely in tanks. However, this older propellant is acutely toxic and environmentally persistent, unlike the cleaner liquid oxygen and kerosene or liquid hydrogen used in China’s newer Long March 6, 7 and 8 series rockets. The Long March 4B also has no engine-restart capability in its third stage, meaning the stage must complete its burn in a single continuous arc to deliver the satellite to the correct orbit.
The launch took place from Launch Site 94 at JSLC, the same pad used for the HY-2C and HY-2D launches. The 654th flight of the Long March series spans a history that began on April 24, 1970, when a Long March 1 rocket launched China’s first satellite, Dong Fang Hong 1, making China the fifth nation after the Soviet Union, the United States, France and Japan to independently achieve orbital launch capability.
China’s Accelerating Space Cadence
China’s 47th orbital launch of 2026 reflects the country’s rapidly accelerating space programme. China conducted 92 orbital launches in 2025, a 35 percent increase over the 68 launches in 2024. The country is targeting approximately 140 orbital launches in 2026, which would represent a 52 percent year-on-year increase.
This surge is driven by multiple factors. State-owned enterprises under CASC continue to deploy navigation, communication and Earth observation satellites. Commercial space startups, including companies like CAS Space and Galactic Energy, are adding to the launch manifest with small satellite missions. The buildout of China’s satellite internet constellation, sometimes compared to Starlink, also requires frequent launches.
The Haiyang programme itself is part of this broader expansion. With nine Haiyang satellites now in orbit across all four sub-series, China has built a layered ocean observation system that serves scientific research, economic activity and strategic maritime interests simultaneously. The upcoming HY-2F and HY-2G launches later in 2026 and 2027 will continue this modernisation cycle.
Key Takeaways
- China launched the Haiyang-2E (HY-2E) oceanographic satellite on July 2, 2026, using a Long March 4B rocket from the Jiuquan Satellite Launch Center.
- The HY-2 series is China’s first satellite system dedicated to marine dynamic environment monitoring, operated by the National Satellite Ocean Application Service (NSOAS) under the Ministry of Natural Resources.
- HY-2E replaces the HY-2B satellite launched in October 2018 and is the first of three planned replacement satellites (HY-2E, HY-2F, HY-2G) to be deployed by 2027.
- The satellite carries four microwave remote sensing payloads including a radar altimeter, scatterometer, microwave radiometer imager, and calibration radiometer along with a DORIS receiver from the French space agency CNES for centimetre-level orbit determination.
- The launch was the 654th flight of the Long March rocket series, which began with China’s first satellite Dong Fang Hong 1 in April 1970.
- The mission was China’s 47th orbital launch of 2026, with the country targeting approximately 140 launches for the year, up from 92 in 2025.
