Fifth Gaofen 11 remote-sensing satellite reaches orbit [Long March 4B Y58]

A Long March 4B lifted off from Taiyuan carrying the fifth Gaofen 11 satellite to sun-synchronus orbit.

The Long March 4B Y58 vehicle lifting off from the Taiyuan Satellite Launch Center with Gaofen 11-05.

At 11:03 am China Standard Time, or 03:03 am Universal Coordinated Time, on July 19th, a Long March 4B lifted off from Launch Complex 9 at the Taiyuan Satellite Launch Center and headed for sun-synchronus orbit. Onboard the Long March 4B was the Gaofen 11-05 spacecraft.

Gaofen 11-05 is expected to provide services for land mapping, urban and road construction planning, agricultural yield forecasting, and disaster prevention and mitigation. Alongside these services, the China Aerospace Science and Technology Corporation expects that the spacecraft will provide information to support the Belt and Road Initiative, along with the modernization of China’s national defense capabilities. It did not specify how the spacecraft would assist with modernization.

Gaofen 11-05 is also the fifth of the Gaofen 11 group of satellites, all of which were launched into a sun-synchronus orbit by a Long March 4B. The Shanghai Academy of Spaceflight Technology mentioned in their post-launch WeChat blog post that the Long March 4B and Gaofen 11 teams have worked together for over six years. The blog post also said the following:

“The six-year and five-star cooperation has witnessed the deep friendship between the Long March 4 team and the Gaofen-11 satellite team, and the subsequent teams will further cooperate to write a beautiful chapter of China's space industry.”

(Please excuse and correct any mistranslation on my part)

Previous Gaofen 11 satellites were launched in July 2018, September 2020, November 2021, and December 2022 respectively. All four of the previous satellites currently are residing in orbits near 500 kilometers in altitude.

The Long March 4B Y58 vehicle just after clearing the launch tower carrying Gaofen 11-05.

For the Long March 4B this was the 49th launch overall, and the 48th success. This was also the 105th launch of a Long March 4 series launch vehicle, the 213th from the Shanghai Academy of Spaceflight Technology, and the 528th launch of a Long March rocket.

The Long March 4B Y58 launch mission patch.

China is still believed to be aiming to complete 100 launch missions this year, today’s launch brought the total performed up to 33. To achieve the goal of 100, a launch currently has to occur every 2.5 days.

Part of the Long March 4B Y58 team at the Taiyuan Satellite Launch Center.

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 a three-stage rocket that burns Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine in all three of its stages. It is manufactured by the Shanghai Academy of Spaceflight Technology.

The Long March 4B is believed to be able to carry up to 4,200 kilograms to low Earth orbit, 2,800 kilograms to a sun-synchronous orbit, or 1,500 kilograms to a geosynchronous transfer orbit.

The Long March 4B Y58 vehicle on its launchpad at the Taiyuan Satellite Launch Center.

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-24C engine that generates 80 tonnes of thrust by burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine. The third stage is propelled by two YF-40 engines that provide 10 tonnes of thrust by burning Dinitrogen Tetroxide and Unsymmetrical Dimethylhydrazine.

On the launchpad, the Long March 4B is believed to be over 44 meters tall, with a first and second-stage diameter of 3.35 meters along with a third-stage diameter of 2.9 meters. Fully fuelled the launch vehicle weighs a believed 249,200 kilograms.

The fairing of the Long March 4B Y58 being lifted onto the launch vehicle with Gaofen 11-05 inside (Top), the third-stage of the Long March 4B Y58 vehicle ahead of being integrated onto the launch vehicle (Middle), the first-stage of the Long March 4B Y58 being transported to its launchpad (Bottom).