Monday, October 31, 2016

China to Debut Its Powerful Next-Generation Long March 5 Launcher on Thursday

Long March 5 rocket being rolled out to the launch pad at the Wenchang Satellite Launch Center on Oct. 28, 2016. Photo Credit: 9ifly.cn

China plans to introduce on Thursday, Nov. 3, its new next-generation heavy lift Long March 5 booster expected to become a workhorse of the country’s space program. The launcher’s maiden flight will be carried out from the Launch Complex 1 (LC-1) at the Wenchang Satellite Launch Center on Hainan Island.

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.

The original plan envisioned six different variants of the Long March 5 rocket (from A to E) produced by China Academy of Launch Vehicle Technology (CALT). However, there are currently only two versions of this launcher under development - “B” and “E”. The rocket in its most powerful “basic” configuration (known as “E”) is designed for geostationary transfer orbit (GTO) missions, while the “B” variant will be used to send payload into a low-Earth orbit (LEO).

The basic version has 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. 

This variant has two stages that will use various propellants. The core stage which is 108 feet (33 meters) long and 16.4 feet (5 meters) in diameter, will use two liquid oxygen (LOX) and liquid hydrogen (LH2) powered YF-77 engines, whereas four strap-on boosters - 88.5 feet (27 meters) tall and 11 feet (3.35 meters) wide - will 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.

Additionally, the Long March 5 in its basic configuration can fly with an optional upper stage called Yuan Zheng-2 (YZ-2 for short). This stage is 17 feet (5.2 meters) in diameter and is designed to deliver spacecraft directly into targeted orbit, at different altitudes and on different orbital planes, without the need to use their own propulsion.

The smaller Long March 5B variant is 176 feet (53.6 meters) tall and weighs some 923 tons (837 metric tons). It also uses a quarter 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.

Other four variants of the Long March 5 rocket that were apparently cancelled as the Chinese media are not offering any updates on their development, were much lighter versions. For example, the smallest configuration - CZ-5-200 - without any strap-on boosters, would weigh only 90 tons (82 metric tons) and would carry a maximum of 1.65 tons (1.5 metric tons) of payload into LEO.

Thursday’s first flight of Long March 5 will feature the rocket in its basic variant. The launcher will carry the Shijian-17 (meaning “practice” in Chinese) satellite - a technology demonstrator that will test electric propulsion. China has not disclosed so far any details about this experimental satellite but it is believed that it will be inserted into GTO to complete a demonstration of ion propulsion for station keeping.

While no detailed information about the flight profile and timeline is currently available, the rocket’s parameters indicate that the maiden flight of Long March 5 will probably see the launch vehicle flying for slightly more than 20 minutes to deliver its payload into GTO. The four boosters will power the rocket for about three minutes after liftoff, before separating from the core stage that will burn until about nine minutes into the flight. Next, the second stage will assume control over the mission, burning its two YF-75D engines for approximately 11 minutes.

The debut flight of Long March 5 was initially scheduled for late 2014, but it was delayed for two years. Next launch date was set for September 2016, however, it was postponed one more time - to Nov. 3.

The initial tests of the Long March 5 booster commenced last year in September and lasted more than four months. These tests, carried out at the Wenchang Satellite Launch Center, were necessary to check the compatibility of the rocket with ground facilities at the center. Final field tests concluded in February 2016. On Oct. 28, the rocket was rolled out to the launch pad.

The Long March 5 rocket is planned to be employed for orbital launches on a regular basis starting in 2017. Among many missions planned to be lifted off atop this booster are the Tianhe-1 core module of China’s future space station, the Chang’e-4 and Chang’e-5 lunar spacecraft.

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

Thursday’s launch will mark 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 as 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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