Long March 3B to launch Zhongxing-9A television satellite

Image Credit: People’s Republic of China

China is preparing to launch the Zhongxing-9A direct-to-home (DTH) television service satellite aboard the country’s Long March 3B/E carrier rocket. Although news from the country’s tight-lipped space agency is difficult to come by, information from the GBTimes indicates the launch may occur as soon as June 18, 2017, from the Xichang Satellite Launch Center.

The satellite

Tipping the scales at more than 11,200 pounds (5,100 kilograms) is the Zhongxing-9A satellite, also known as ChinaSat 9A. It will ride to space atop the 185-foot (56.3-meter) tall Long March 3B/E.

File photo of a Long March 3B being prepared for launch at the Xichang Satellite Launch Center. Photo credit: Chinanews.com

Built on the indigenous DFH-4 bus, the spacecraft is China’s first domestically-produced DTH satellite. It will provide services to mainland China, the autonomous regions of Macau and Hong Kong, and the island of Taiwan via 24 Ku-band transponders.

ChinaSat 9A has a design lifetime of 15 years and will be positioned at 101.4 degrees East in geostationary orbit.

The rocket

One of China’s workhorse rockets, the Long March 3B will deliver the spacecraft into a geosynchronous transfer orbit (GTO). The booster has launched 39 times – notching 37 successes, one partial failure, and one total failure – across both its standard (3B) and enhanced (3B/E) configurations.

Although it hasn’t been confirmed, it’s assumed the rocket will be configured in its enhanced arrangement to support delivering the heavy payload to GTO.

The Long March 3B/E is a three-stage rocket, with four supplemental liquid-fueled strap-on boosters. When outfitted in the enhanced configuration, the vehicle is capable of lifting 12,100 pounds (5,500 kilograms) into GTO, compared to the 11,200 pounds (5,100 kilograms) in the standard configuration.

At liftoff, the first stage’s YF-21C engine and the supplemental power supplied by a single YF-25 on each of the four boosters provide 1.33 million pounds-force (5,923.2 kilonewtons) of sea-level thrust. The boosters operate for 140 seconds before falling away, while the first stage burns for an addition 20 seconds.

The vehicle’s second stage is powered by a YF-24E propulsion unit comprising a lone YF-22E engine and a quartet of YF-23C vernier thrusters. In total, the second stage provides 209,162 pounds-force (930.4 kilonewtons) of thrust and operates for slightly more than three minutes.

Like its first stage and booster siblings, the second stage’s YF-24E burns a relatively inefficient mixture of nitrogen tetroxide and unsymmetrical dimethylhydrazine. Although this toxic mixture is significantly less efficient than either a kerosene / liquid oxygen or liquid hydrogen / liquid oxygen combination, it has the benefit of being able to be stored at room temperature.

The third stage is outfitted with a single YF-75 engine, producing 37,581 pounds-force (167.17 kilonewtons) of vacuum thrust and burning a mixture of liquid hydrogen and liquid oxygen. This stage can operate for nearly eight minutes across two ignitions.

This will mark China’s seventh launch in 2017.

Article updated at 17:11 EDT, June 18, 2017, to correct rocket statistics.

Tagged: China Lead Stories Long March 3B/E Xichang Satellite Launch Center Zhongxing-9A

Curt Godwin

Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting - and safer - career field. He's worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.