A Chinese Long March 4B rocket took a Haiyang oceanography satellite to orbit early Wednesday morning. Liftoff from the Jiuquan Satellite Launch Center occurred approximately 12:03 PM local time (04:03 UTC) on 19 May.
The Haiyang-2D satellite, the fourth in the Haiyang-2 series and eighth Haiyang satellite overall, was deployed into sun synchronous orbit to conduct oceanographic research.
The mission launched from the SLS-2 launch pad, part of Launch Area 4 at the Jiuquan Satellite Launch Center in Inner Mongolia. The launch of Haiyang-2D was the seventh launch from Jiuquan this year.
The Long March 4B rocket, also known as the Chang Zheng 4B, is a three stage launch vehicle operated by the China Aerospace Science and Technology Corporation (CASC), the primary Chinese state-owned aerospace company which operates all of the Long March rocket families. Haiyang-2D was the second Long March 4B launch of the year.
The rocket’s first stage was powered by four YF-21C engines, fueled by hypergolic unsymmetrical dimethylhydrazine (UDMH) fuel and dinitrogen tetroxide (N2O4) oxidizer. The engine produced 2,961.6 kN of thrust with a specific impulse of 259.9 seconds.
After stage separation, the first stage fell back to the surface while still over land. Depending on a mission’s flight path, this can cause safety problems downrange. Past launches have dropped spent stages, including toxic residual UDMH fumes, near populated areas.
While these concerns have largely gone unaddressed by China’s space program, some previous launches have begun to include grid fins to steer descending stages towards unpopulated drop zones. The previous Haiyang launch, Haiyang-2C in September 2020, included a set of four grid fins on Long March 4B’s first stage.
Long March 4B’s second stage was powered by a YF-22C engine, also fueled by UDMH and N2O4, in addition to four YF-23C vernier engines. The YF-22C produced 742 kN of thrust with a specific impulse of 299.9 seconds.
The third UDMH and N204 fueled stage used two YF-40 engines to produce 101 kN of thrust and a specific impulse of 303 seconds.
The Long March 4B rocket has now completed 41 successful launches since its debut in 1999. Only one launch failure has been suffered, the CBERS-3 mission in December 2013, due to foreign debris in one of the YF-40 engines on the third stage.
In sun synchronous orbit, the Haiyang-2D satellite will be operated by the National Satellite Ocean Application Service (NSOAS), the satellite operating agency within China’s State Oceanic Administration responsible for state-run oceanographic research.
The Haiyang satellites’ capabilities are used for disaster relief, marine forecasting, and scientific research. Pollution monitoring is also a large part of the Haiyang program.
The constellation consists of four Haiyang-1 satellites and four Haiyang-2s. A future series of Haiyang-3 satellites are planned to begin deployment later this year.
The Haiyang-1 series of satellites included ocean color scanners and CCD cameras and were used to monitor chlorophyll concentration, surface temperature, and pollution, among others.
The Haiyang-1A and 1B satellites massed approximately 360 kilograms, and the 1C and 1D successors grew to approximately 442 kilograms. These satellites operated between 760 and 800 kilometers in altitude.
The Haiyang-2A and 2B satellites were deployed into higher orbits, between 880 and 950 kilometers altitude. On board are new microwave imagers used to measure surface winds, sea surface height, and temperatures.
The Haiyang-2C and 2D satellites mass approximately 1,575 kilograms and are the only two Haiyang spacecraft to launch from Jiuquan, with the rest of the constellation lifting off from the Taiyuan Satellite Launch Center.
The Haiyang-2 satellites were developed by Dongfanghong Satellite Corporation, a state-owned company underneath CASC.
The Haiyang-3 series will include synthetic aperture radar (SAR) imaging capability, enabling all weather and all day long observations.
Haiyang-2D is the 14th Chinese orbital launch attempt this year. In addition to numerous satellite launches in support of civilian and military missions, China has launched the first module of a new space station, Tianhe, on a Long March 5B in April 2021.
The first visiting vehicle to Tianhe is also slated to launch on 19 May (UTC) from the Wenchang Spacecraft Launch Site, when a Long March 7 lofts the Tianzhou-2 cargo spacecraft. With the module successfully supplied, the first crew will launch to the station on a Long March 2F rocket, from Jiuquan, on the Shenzhou-12 mission.
An additional cargo and crew mission are each planned to launch to the station later in 2021, with new modules, cargo, and crew missions continuing in 2022.
In addition to China’s return to human spaceflight using a new space station, the China National Space Administration (CNSA) successfully landed the robotic Tianwen-1 mission on Mars.
The Chinese space program’s launch cadence is second internationally only to the United States. The United States, Russia, and China are the only countries with domestic crew launch capability, although Shenzhou-12 will be the first human spaceflight launch from China since Shenzhou-11 in 2016.
(Lead photo of Long March 4B launching Haiyang-2D)