Long March 3B/E launches Zhongxing-9A satellite, fate uncertain
An archive photo of a Long March 3B/E launching LaoSat-1 on Nov. 20, 2015. Using the same type of rocket, China’s Zhongxing-9A satellite was launched toward space on June 18, 2017. Photo Credit: Qin Haishi / Xinhua
A Chinese Long March 3B/E rocket lifted off at 12:12 EDT (16:12 GMT), June 18, 2017, from the Xichang Satellite Launch Center in southern China to deliver the Zhongxing-9A indigenous television satellite to geosynchronous transfer orbit (GTO). Since the launch, however, there has been no official word the mission was successful.
China is usually tight-lipped about its rocket launches, but confirmation of a successful Zhongxing-9A deployment was expected within an hour, according to the GBTimes. This has led some to speculate the mission might not have been a success.
UPDATE: According to an official announcement reported on GBTimes: “China has confirmed that the Long March 3B/E rocket which launched the Zhongxing-9A communications satellite on Sunday suffered an issue with its third stage, leaving the satellite in a lower than intended orbit.”
The report also states: “The China Aerospace Science and Technology Corporation (CASC), the main contractor for the space programme, announced the issue on its website, stating that the specific cause is under investigation.
“The statement added that the satellite’s solar panels and systems are operating normally, and effective measures being taken. Its current orbit was not stated.”
The last time one of the country’s rockets had a failure was in September 2016. During the flight of a Long March 4C rocket, the third stage underperformed, preventing the Gaofen-10 satellite from reaching orbit.
The Zhongxing-9A mission utilized China’s workhorse carrier rocket outfitted in its “enhanced” configuration. It was the country’s seventh launch of 2017.
Liftoff
When the countdown reached zero, the rocket’s four YF-25 booster engines and the core stage’s lone YF-21C engine ignited in a cloud of nitrogen tetroxide and unsymmetrical dimethylhydrazine byproducts. The 185-foot (56.3-meter) tall Long March 3B/E heavy-lift rocket leapt off the pad at Xichang’s Launch Complex 3 and climbed spaceward.
The five engines produced a combined 1.3 million pounds-force (5,923.2 kilonewtons) of sea-level thrust, easily enough to lift the rocket and payload off the pad.
Having consumed their hypergolic propellants, the four strap-on boosters separated from the core stage 2 minutes, 20 seconds after liftoff and later impacted the ground several hundred miles from the launch site. Twenty seconds later, with its job complete, the first stage separated as the second stage’s YF-24E propulsion cluster, consisting of a single YF-22E engine and four YF-23C vernier thrusters, ignited.
If all went according to plan, the rocket’s second stage (or third, depending on how the boosters are classified) fired its YF-22E engine while still attached to the core stage in an operation known as “hot staging”. This negates the need for stage separation motors, reducing both the weight of the vehicle and the complexity of the staging process.
Consuming the same propellants as the first stage, the second stage was expected to have burned through its 108,900 pounds (49,400 kilograms) of fuel in just over three minutes.
Orbital insertion
If the mission had been successful, some six minutes after leaving Xichang, the third stage’s liquid hydrogen and liquid oxygen consuming YF-75 engine would have ignited.
On a nominal flight path, the third stage would have entered into an initial low-Earth orbit before later re-igniting to deliver the satellite into GTO. There, the spacecraft would have detached from the rocket to begin its mission.
Zhongxing-9A is expected to use its onboard propulsion system to raise its orbit to settle in its geostationary slot some 22,300 miles (35,800 kilometers) above the equator at 92.2 degrees East longitude. Once there, the satellite will provide direct-to-home television services to Chinese customers.
If the satellite ended up in a lower than planned orbit, however, more of its onboard propellant would be required to raise it up into a geostationary orbit. This could potentially shorten its expected 15-year lifespan.
Video courtesy of Rocket Watch
This article was updated (shown in italics) at 09:24 EDT, June 19, 2017.
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.
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