More Commercial Imaging Constellation Satellites! [Long March 2D Y99]

Four additional PIESAT-02 satellites were delivered to orbit from Taiyuan.

The Long March 2D Y99 vehicle lifting off from Launch Complex 9 at the Taiyuan Satellite Launch Center.

A Long March 2D lifted off from Launch Complex 9 at the Taiyuan Satellite Launch Center at 02:50 am China Standard Time (December 17th), or 18:50 pm Universal Coordinated Time (December 16th), heading to sun-synchronous orbit with a small group of satellites onboard.

Atop of the rocket for this mission was a group of four PIESAT-02 satellites, owned and operated by Zhuzhou Space Interstellar Satellite Technology Co Ltd (株洲太空星际卫星科技有限公司). For this launch, the satellites were designed and manufactured by GalaxySpace (银河航天网络技术有限公司). The four new PIESAT-02 spacecraft, numbered 9 through 12, will provide high-precision synthetic aperture radar imaging.

Four PIESAT-2 satellites in a cleanroom prior to integration on the launch vehicle at Taiyuan.

Back in October, Zhuzhou Space announced it would launch twelve satellites to expand its “Zhuzhou Constellation”, the first four satellites were launched back in March 2023 ahead of the announcement. Last month saw the first of three launches to expand the constellation take place, with four satellites placed into orbit by a Long March 2C. The third and final launch for the expansion of the constellation is currently set for no later than the end of March 2025.

Once the twelve additional satellites have been launched the company will have a small constellation of sixteen spacecraft for commercial synthetic aperture radar imaging. According to the company’s technical director, Tang Daquan (汤大权), this small constellation will be able to repeatedly image anywhere on Earth within two and a half hours.

Like the two recent launches from Jiuquan, temperatures at Taiyuan were much colder than in other months of the year. To mitigate any potential issues extra thermal insulation material was attached to the fairing, interstage, and engine section of the Long March 2D to keep propellants and consumables from freezing. This thermal insulation falls away harmlessly during liftoff. Speaking about the launch conditions, the Shanghai Academy of Spaceflight Technology said:

“In December, the temperature of Taiyuan Satellite Launch Center plummeted, and the historical temperature of the launch window was close to the lowest launch conditions. Based on the previous low-temperature safeguard measures, and with the full support and close cooperation of the Taiyuan Satellite Launch Center, the test team re-examined and detailed optimization measures and strived for excellence to ensure the smooth implementation of the launch mission.”

If there are any problems with this translation please reach out and correct me.

For the first time, a new 3.8-meter diameter composite fairing was used on the Long March 2D, according to the Shanghai Academy. This fairing is claimed to offer a larger internal volume and expand the Long March 2D’s offerings for commercial customers.

The Long March 2D Y99 launch mission patch.

Today’s launch was the 94th mission for the Long March 2D, the 227th Long March vehicle launch from the Shanghai Academy of Spaceflight Technology, and the 553rd launch of the Long March launch vehicle series. This was also the 65th launch from China in 2024.

Liftoff video via 中国航天科技集团 on Weibo.

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Check out the previous Long March 2D launch

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What is the Long March 2D?

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

The Long March 2D is also one of the oldest launch vehicles from China performing missions regularly to low earth and sun-synchronous orbits by the Shanghai Academy of Spaceflight Technology, as a two-stage version of the Long March 4 vehicles. The two stages of the launch vehicle both burn Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine.

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

• 3,500 kilograms to low Earth orbit

• 1,300 kilograms to a sun-synchronous orbit

The Long March 2D Y99 vehicle at Launch Complex 9 prior to launch.

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.

On the launch pad, the Long March 2D is 41.05 meters tall and weighs 232,250 kilograms when fully fuelled. The first and second stages have a diameter of 3.35 meters, with the fairing having a diameter of either 3.35, 3.8, or approximately 4 meters.

So far the Long March 2D 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 first-stage and fairing of the Long March 2D Y99 vehicle heading to the launch pad and during integration.

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