September 21, 2016 - China Launches Environmental Monitoring Satellite

The launch you're thinking of actually took place on November 11, 2016, not September 21. China's Yunhai 1-01 satellite lifted off from Jiuquan Satellite Launch Center aboard a Long March 2D rocket, settling into a sun-synchronous orbit roughly 760 kilometers above Earth. It's designed to monitor the atmosphere, oceans, and near-space environment while supporting disaster response and scientific research. There's quite a bit more to this mission than its launch date suggests.

Key Takeaways

• China launched the Yunhai 1-01 satellite on November 11, 2016, not September 21, as sometimes referenced in search queries.
• Yunhai 1-01 is an environmental monitoring satellite built by Shanghai Academy of Spaceflight Technology using the CAST2000 bus.
• The satellite was launched aboard a Long March-2D rocket from Jiuquan Satellite Launch Center into a 760 km sun-synchronous orbit.
• Yunhai 1-01 monitors atmospheric chemistry, ocean surface conditions, space weather, and supports disaster prevention and prediction systems.
• The satellite is part of the Yunhai-1 series; "Yunhai" (云海) means "sea of clouds," reflecting its atmosphere and ocean monitoring mission.

What the Yunhai 1-01 Satellite Was Built to Do

The Yunhai 1-01 satellite was built to tackle five core missions: monitoring the atmosphere and oceans, detecting space weather, supporting disaster prevention, and conducting scientific experiments. You can think of it as a versatile environmental watchdog operating across multiple domains simultaneously.

It's equipped to analyze atmospheric chemistry, track ocean surface conditions, and observe marine-atmospheric interactions. It also monitors space plasma, radiation, and ionospheric disturbances while gathering data that supports earthquake and storm prediction systems.

One of its standout capabilities involves spaceborne lidar technology, which enables precise detection of atmospheric and environmental parameters. Beyond observation, it serves as a research platform for testing new technologies and conducting atmospheric physics experiments. In short, it's designed to deliver critical environmental data across Earth's atmosphere, oceans, and near-space environment. The satellite was designed and manufactured by Shanghai Academy of Spaceflight Technology, the organization responsible for building the entire Yunhai-1 satellite series.

Satellites in the Yunhai-1 series are launched using the Long March-2D rocket, a reliable carrier vehicle operated under China's state space program managed by CASC. This kind of space-based environmental monitoring builds on a legacy dating back to TIROS-1's launch in 1960, which first demonstrated that satellites could deliver large-scale atmospheric data to support weather forecasting and disaster preparedness.

The Long March 2D Rocket That Carried Yunhai 1-01

Lifting Yunhai 1-01 into orbit was the Long March 2D, a two-stage rocket manufactured by the Shanghai Academy of Spaceflight Technology (SAST) that measures 41 meters long and weighs 250 metric tons at liftoff. Unlike other Long March 2 variants, it's derived from the Long March 4 design, optimizing its orbital mechanics for LEO and SSO missions.

Its first stage runs four YF-21C engines generating 2,961.6 kilonewtons of thrust, while the second stage uses YF-24C engines producing 789.1 kilonewtons. Both stages burn UDMH, a propellant requiring careful propellant handling due to its toxic and corrosive nature.

With a 3,500-kilogram LEO capacity and a 99.5% success rate across 101 missions, the Long March 2D remains China's reliable workhorse for Earth observation satellites. The rocket launched from LC-9 at Taiyuan, a launch site that has been operational since 1968 and sits at an elevation of approximately 1,500 meters above sea level.

The Long March 2D entered service in 1992 and has since been employed primarily for deploying satellites into low Earth orbit and sun-synchronous orbit, making it one of China's most consistently utilized launch vehicles for such missions. Much like the IP-licensing model pioneered by ARM Ltd, which enabled widespread adoption of its processor technology without directly manufacturing chips, China's approach to standardizing the Long March 2D for repeated LEO and SSO missions reflects a strategy of leveraging a proven platform to maximize reliability and output.

How Yunhai 1-01 Reached Its 760 Km Polar Orbit

On November 11, 2016, a Long March 2D (2) rocket lifted off from Jiuquan Satellite Launch Center's LC-43/94, carrying Yunhai 1-01 toward its 760 km polar orbit. The launch timeline began with a vertical ascent, followed by a pitch-over maneuver after strap-on burnout, reducing drag through the dense lower atmosphere.

You'd recognize the orbital mechanics at work as the rocket gradually adjusted its trajectory, using thrust vector control to reach a 98.5-degree inclination. The upper stage then inserted Yunhai 1-01 into a parking orbit before circularizing it between 760 km and 787 km. After separation, the satellite deployed its solar arrays and fired onboard propulsion burns, achieving its operational sun-synchronous orbit optimized for atmospheric and marine environmental monitoring. Its successor, Yunhai 1-02, launched in September 2019, would later become notable for surviving a confirmed orbital collision with debris from a 1996 Zenit-2 rocket in March 2021.

The Long March rocket family itself traces its lineage to the Soviet R-2 missile, which China received through a 1956 Soviet technology transfer agreement negotiated by Tsien Hsue-Shen, forming the foundation from which the DF missile series and eventually the Long March launch vehicles were developed. Much like Canada's Aerial Experiment Association, which pooled expertise from figures such as Alexander Graham Bell and Glenn Curtiss to advance early aviation technology, the development of the Long March program relied on collaborative engineering knowledge and institutional support to achieve its foundational milestones.

The Team That Built Yunhai 1-01: SAST and CASC

Putting Yunhai 1-01 into a 760 km polar orbit required engineering precision—but that precision started long before launch day, in the workshops and offices of the Shanghai Academy of Spaceflight Technology (SAST).

Founded in 1961 and headquartered in Shanghai, SAST carries a deep legacy—the SAST legacy—of building China's most advanced aerospace and air defense systems.

As CASC's Fourth Academy, SAST built Yunhai 1-01 on the proven CAST2000 bus, targeting atmospheric, marine, and space environment observation.

That CASC collaboration gave SAST the institutional muscle to develop the entire Yunhai-1 series—01 through 04—launching each from Jiuquan on CZ-2D rockets.

You're looking at an organization that doesn't just build satellites; it builds programs, production lines, and long-term capability for China's earth observation mission. CASC's Fourth Academy has also proposed the Trans-Cloud project, a low orbit satellite constellation system consisting of hundreds of satellites designed to enable seamless IoT information access worldwide. Alongside SAST, the China Academy of Space Technology stands as one of the historical dominant builders of Chinese satellites, together accounting for the vast majority of the country's orbital hardware across decades of production.

What "Yunhai" Means and Why the Name Fits

The name Yunhai (云海) translates directly as "sea of clouds"—two characters, 云 (yún) for "cloud" and 海 (hǎi) for "sea," fused into a poetic construction that's been part of the Chinese lexicon since at least the Tang dynasty.

You'll find this cloud poetry tradition rooted in Buddhist and classical Chinese thought, where oceanic imagery signals vastness, abundance, and boundless possibility. In Buddhist usage, the term appears in canonical texts such as the Commentary on the Mahavairocana Sutra, where it serves as a metaphor for great abundance.

The cultural symbolism runs deeper than aesthetics. In Taiwan's central mountains, afternoon clouds literally settle below peaks, creating the mist that defines high-mountain tea cultivation.

That atmospheric phenomenon mirrors exactly what Yunhai 1-01 does from orbit—monitoring Earth's atmosphere and oceans across vast territories. Much like how the designated hitter rule transformed baseball by shifting focus toward specialized offensive roles, Yunhai 1-01 represents a similarly specialized tool designed to maximize a single, focused purpose.

The name doesn't just sound fitting; it functionally describes the satellite's mission through centuries of layered meaning. The name is considered predominantly unisex in usage, though it has historically been given more commonly to males across Chinese-speaking cultures.

The Gap Yunhai 1-01 Filled in China's Earth Observation Network

Beyond the poetry embedded in its name, Yunhai 1-01 addressed something far more practical: a set of real gaps in China's Earth observation infrastructure.

Before its launch, you'd find China's satellite network leaning heavily on weather forecasting through the Fengyun series, with separate ocean-focused assets like Haiyang handling color and altimetry data. Nothing unified these streams.

Disaster response teams worked with fragmented data pulled from disconnected meteorological and imaging missions. There was no single platform delivering real-time integration of atmospheric, oceanic, and space environment readings simultaneously.

Yunhai 1-01 changed that. Operating from a 760–787 km sun-synchronous orbit, it introduced multi-layered monitoring that connected previously isolated data domains.

China's disaster prevention network finally had a cohesive tool capable of tracking typhoons, floods, and marine hazards through one coordinated system. This kind of unified national coverage from a single orbital platform echoed what Canada demonstrated in 1974, when Anik A1's shaped beam connected Arctic communities to the national communications grid for the first time. The satellite was developed and built by the Shanghai Academy of Spaceflight Technology, the same organization responsible for the Long March 2D rocket that carried it to orbit.

How Yunhai 1-01 Differed From Fengyun, Haiyang, and Gaofen

Comparing Yunhai 1-01 against China's other Earth observation satellites makes its unique design philosophy stand out immediately. Each program served distinct roles:

1. Fengyun focused purely on civilian meteorology under CMA oversight
2. Haiyang specialized in ocean color, wind fields, and sea temperatures
3. Gaofen prioritized high-resolution optical Earth imaging for surveys
4. Yunhai 1-01 combined atmospheric, marine, and space environment detection under SAST's military assessment mandate

You'll notice Yunhai's multi-environment sensing capability set it apart from Fengyun's weather-only instruments and Haiyang's microwave ocean dynamics.

While Fengyun data flowed freely through WMO channels, Yunhai operated under military-civil fusion principles. Its three-axis stabilization and broader sensor suite reflected a satellite built to complement, not duplicate, what China's civilian constellation already delivered. The FY-1 series, which included four satellites total, began as experimental missions before transitioning to fully operational satellites with expanded 10-channel imaging capability. The Yunhai 2 constellation later expanded on this foundation, employing GNSS radio occultation to gather atmospheric, ionospheric, climate, and gravity data.

How Yunhai 1-02 and 1-03 Expanded the Series After 2016

China followed up on Yunhai 1-01's 2016 debut by rolling out two additional satellites that deepened the constellation's coverage without reinventing its core mission. Yunhai 1-02 launched in September 2019, joining 1-01 in a roughly 790 km sun-synchronous orbit. It survived a March 2021 orbital collision with Zenit-2 debris, demonstrating constellation resilience by retaining orbit-adjustment capability post-impact. That collision marked the first confirmed major in-orbit collision since 2009.

Yunhai 1-03 followed in September 2022, settling into a ~765 km orbit at 98.5° inclination. Each satellite continued the series' focus on atmospheric, marine, and space environment monitoring, disaster prevention, and scientific experiments. All three launched from Jiuquan on Long March 2D rockets, keeping the constellation's architecture consistent throughout its expansion. The growth of low-Earth orbit infrastructure has also attracted commercial space station development, with private companies like Axiom Space partnering with NASA to build modular platforms in similar orbital regimes. Yunhai 1-03 lifted off from Jiuquan Satellite Launch Center on September 21, 2022, at 7:15 a.m. local time atop a Long March 2D rocket. The satellites were developed and manufactured by Shanghai Academy of Spaceflight Technology, a subsidiary of the China Aerospace Science and Technology Corporation responsible for the spacecraft's design and construction.

Why Yunhai 1-01's Data Still Supports Climate Research Today

Outlasting its initial design life, Yunhai 1-01 continues feeding climate researchers a multi-year dataset that newer satellites can't yet replicate. Its sun-synchronous orbit ensures consistent lighting conditions, making long term trends far easier to isolate and validate across years of observations.

You can leverage this archive through four key research applications:

1. Atmospheric trend analysis spanning nearly a decade of baseline data
2. Cross calibration methods aligning Yunhai 1-01 readings with newer sensors
3. Ocean-atmosphere interaction studies using sustained marine monitoring records
4. Ionosphere-climate connection research drawn from continuous space environment metrics

Chinese space agency archives keep this data accessible, letting you integrate it with global datasets. That historical continuity makes Yunhai 1-01 genuinely irreplaceable for understanding environmental change since 2016. The broader Yunhai program has since expanded significantly, with Yunhai-2's second cluster of six additional satellites launching in March 2024 to further extend this constellation's meteorological and climate monitoring capabilities.

Sun-synchronous environmental satellites like Yunhai 1-01 typically maintain near-circular orbital profiles, with altitudes and inclinations carefully tuned to preserve consistent solar lighting, a design reflected across modern Earth observation missions operating between roughly 600 and 900 kilometers at inclinations near 97 to 99 degrees. This commitment to sustained environmental monitoring parallels planetary science missions like NASA's Mars rovers, which similarly outlasted original design lifetimes to deliver long-term datasets, with Spirit's solar array output remaining functional through 2,208 sols before the mission concluded.