Thursday, November 3, 2016

China Conducts Maiden Launch of Powerful Long March 5 Booster

China launches Long March 5 carrier rocket. Photo Credit: Xinhua / Li Gang

Thundering off from Launch Complex 1 (LC-1) at the Wenchang Satellite Launch Center on Hainan Island, China’s powerful Long March 5 rocket started its first test flight. The launch vehicle, carrying an experimental satellite, lifted off at 8:43 a.m. EDT (12:43 GMT) on Thursday, Nov. 3.

Originally planned for late 2014, the debut of Long March 5 was delayed for two years. The next launch date was set for September 2016; however, it was postponed once again to Nov. 3. Tests of this booster began last year in September and lasted for more than four months. They were carried out at the Wenchang Satellite Launch Center and were necessary to check the compatibility of the rocket with ground facilities at the center. The final field tests were concluded in February 2016. On Oct. 28, the rocket was rolled out to the launch pad.

Igniting its core stage, powered by two YF-77 engines, and its four strap-on boosters fitted with one YF-100 engine each, the Long March 5 launch vehicle in its basic “E” configuration commenced a short vertical ascent. Then the rocket turned east and started heading toward over the South China Sea.

The quadruplet of boosters, which provides additional thrust during the initial phase of the flight, was jettisoned about three minutes after liftoff. The rocket continued its mission while being powered by the core stage alone. The duo of YF-77 engines burned until approximately eight and a half minutes into the flight, after which the core stage separated from the launch vehicle. Meanwhile, at about T+5 minutes, the payload fairing was separated.

Afterward, the two YF-75D engines of the second stage were ignited. This stage assumed control over the flight for the next 21 minutes, aiming for the release of the Yuanzheng-2 (YZ-2 for short) upper stage carrying the experimental satellite called Shijian-17 (meaning “practice” in Chinese). The second stage conducted two burns, lasting nearly six minutes each one. The YZ-2 upper stage separated some 30 minutes after launch.

Shijian-17 was released into space by YZ-2 at about 30 and a half minutes after liftoff, beginning its cruise toward the designated geostationary transfer orbit (GTO). The spacecraft is a technology demonstrator that will test electric propulsion. Although China has not disclosed, so far, any details about this experimental satellite, it is believed that it will complete a demonstration of ion propulsion for station keeping.



The “E” variant that was launched today is the basic version of the Long March 5 rocket, designed to send payloads into GTO and deep space destinations. It has a launch mass of 956 tons (867 metric tons) and is 187 feet (57 meters) tall. It is capable of delivering up to 28 tons (25 metric tons) of payload into LEO and up to 15 tons (14 metric tons) into GTO.

The Long March 5E has two stages that use various propellants. The core stage, which is 108 feet (33 meters) long and 16.4 feet (5 meters) in diameter, uses two liquid oxygen (LOX) and liquid hydrogen (LH2) powered YF-77 engines, whereas the four strap-on boosters – 88.5 feet (27 meters) tall and 11 feet (3.35 meters) wide – utilize two LOX and kerosene powered YF-100 engines each. With a length of 37.7 feet (11.5 meters) and a diameter of 16.4 feet (5 meters), the second stage is fitted with two LOX and LH2 powered YF-75D engines.

The “E” variant can fly into space with the optional Yuanzheng-2 upper stage. This stage is 17 feet (5.2 meters) in diameter and is designed to deliver spacecraft directly into a targeted orbit, at different altitudes and on different orbital planes, without the need for them to use their own propulsion.

Besides the Long March 5E, China is currently developing a smaller version of this booster – the “B” variant, which is 176 feet (53.6 meters) tall and weighs some 923 tons (837 metric tons). It also uses a quadruplet of strap-on boosters, but only one core stage. This version is designed to send up to 25.3 tons (23 metric tons) of payload into LEO.

Initial plan envisioned six different variants of the Long March 5 rocket (from A to E) produced by the China Academy of Launch Vehicle Technology (CALT). However, the other four proposed variants of the Long March 5 rocket, apparently, have been canceled; the Chinese media are not offering any updates on their development, but the rockets were much lighter versions. For example, the smallest configuration – CZ-5-200 – without any strap-on boosters would have weighed only 90 tons (82 metric tons) and would have carried a maximum of 1.65 tons (1.5 metric tons) of payload into LEO.

The Long March 5 is China’s most powerful launch vehicle with comparable capabilities to Arianespace’s Ariane 5 and United Launch Alliance’s (ULA) Delta IV Heavy boosters. The rocket will be used for a wide spectrum of space missions, including launching commercial satellites, space station modules, as well as deep space probes. Starting in 2017, the rocket is planned to enter regular service. The Tianhe-1 core module of China’s future space station, as well as the Chang’e-4 and Chang’e-5 lunar spacecraft, is among the many missions scheduled for launch atop this booster.

According to China’s State Administration of Science, Technology and Industry for National Defence (SASTIND), the Long March 5 integrates top space technologies, including non-toxic environmentally-friendly fuel and a highly stable controlling system, representing a landmark in the country’s carrier rockets.

“It adopted lots of new technologies, which presents a big coordination problem. It’s hard to make 21 men march without any missteps, not to mention 21 complex systems. But we have our own solutions, with the help of this command system and the detailed rulebook,” launch commander Hu Xudong told CCTV.

The Long March 5, along with Long March 6 and 7, is expected to replace the country’s aging family of overexploited Long March 2 (CZ-2), CZ-3, and CZ-4 launchers. The Long March 6 debuted in September 2015, while the Long March 7 was launched into space for the first time in June 2016.

Thursday’s launch marks the 238th flight of the Long March rocket and the 16th orbital mission conducted by China this year. The country plans one more mission in November when it will send its Hard X-ray Modulation Telescope (HXMT) into space atop a Long March 2D booster from the Jiuquan Satellite Launch Center. However, the exact date of this launch has yet to be announced.

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