Replacement Mapping Satellite Delivered From Winter Taiyuan [Long March 4B Y61]

The latest Ziyuan-3 spacecraft for China’s Ministry of Land and Resources has entered orbit to begin its remote sensing tasks.

The Long March 4B Y61 vehicle lifting off from Launch Complex 9 at the Taiyuan Satellite Launch Center on December 16th 2025.

Off of Launch Complex 9 at the Taiyuan Satellite Launch Center, a Long March 4B lifted off at 11:17 am China Standard Time (03:17 am Universal Coordinated Time) on December 16th, carrying a single satellite into polar orbit.

Atop of the launch vehicle was the Ziyuan-3-04 (资源三号04星) remote sensing satellite dedicated to creating three-dimensional maps and collecting high-resolution images of Earth below. China’s Ministry of Land and Resources (中华人民共和国国土资源部) will operate the satellite, having it produced by the China Academy of Space Technology.

A render of Ziyuan-3-04 observing and collecting data of Earth below.

In order to perform its task, Ziyuan-3-04 is equipped with: three panchromatic cameras for stereoscopic imaging; a multispectral camera to analyse the characteristics of a material; and a laser altimeter for measuring an object’s length and height relative to the satellite. With those instruments, it is expected that the satellite will contribute to agricultural and forestry industries, help prevent and reduce natural disasters, support ecological protection, and assist in the planning of transportation networks and new urban developments.

Ziyuan-3-04 is the first addition to the Ziyuan-3 series since July 2020 and was approved in May 2023. Now in orbit, the satellite will work with Ziyuan-3-02 and Ziyuan-3-03, as well as Gaofen-7, while serving as a replacement to the retired Ziyuan-3-01.

The Shanghai Academy of Spaceflight Technology’s patch for the Long March 4B Y61 launch mission on December 16th 2025.

Following the successful conclusion of today’s launch mission, the Shanghai Academy of Spaceflight Technology shared that the Long March 4B’s teams implemented previously proven winter launch adaptations, as temperatures at Taiyuan remained at minus twenty-five degrees Celsius. Those adaptations included installing insulative materials to the rockets engines section, fairing, and first-to-second stage interstage that fall away harmlessly after liftoff.

Today’s launch was the 55th mission for the Long March 4B, the 115th launch for the Long March 4 series, the 254th Long March vehicle launch from the Shanghai Academy of Spaceflight Technology, and the 617th launch of the Long March launch vehicle series. This was also the 87th launch from China in 2025.

Liftoff video via 航天五线谱 on Weibo and 我们的太空 on WeChat.

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Check out the previous Long March 4B launch

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What is the Long March 4B?

This section is for those less familiar with China’s Long March series of launch vehicles.

The Long March 4B is an older generation low Earth and sun-synchronous orbit workhorse of the Shanghai Academy of Spaceflight Technology. All three stages of the rocket burn Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine, with no engine restart capability.

The payload capacity of the launch vehicle is currently as follows:

• 4,200 kilograms to low Earth orbit

• 2,800 kilograms to a sun-synchronous orbit

• 1,500 kilograms to a geostationary transfer orbit

The Long March 4B Y61 vehicle at Launch Complex 9 before its launch mission.

The first-stage is powered by four YF-21C engines, which generate 302 tons of thrust burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine. The second-stage is powered by a single YF-22C engine and four YF-23C verniers that generate 80 tons of thrust while also burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine. The third-stage is propelled by two YF-40 engines that provide 10 tons of thrust by once again burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine.

On the launch pad, the Long March 4B is 44.1 meters tall and weighs 249,200 kilograms when fully fuelled. The first and second-stage have a diameter of 3.35 meters, while the third-stage has a diameter of 2.9 meters, and a fairing diameter of either 3.8 or 4.2 meters.

So far, the Long March 4B has flown from all three inland launch sites, the Jiuquan Satellite Launch Center, the Taiyuan Satellite Launch Center, and the Xichang Satellite Launch Center.

The Long March 4B’s fairing being lifted onto the launch vehicle with Ziyuan-3-04 inside.

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