Sunday, June 26, 2016

China Conducts Maiden Launch of Its Next-generation Long March 7 Rocket

The first Long March 7 rocket launches from the Wenchang Satellite Launch Center on June 25. Photo Credit: 9ifly.cn

China successfully carried out on Saturday the first launch of its next-generation Long March 7 rocket. The country’s currently most powerful launcher took to the skies from the Site LC-2 at the Wenchang Satellite Launch Center on the island of Hainan, carrying a prototype of a re-entry capsule and several small satellites. Liftoff occurred at 8:00 a.m. EDT (12:00 GMT).

After launch, the Long March 7 rocket started a short vertical ascent before turning south-east over the South China Sea. During the initial phase of the flight, the launch vehicle was powered by its four strap-on boosters for slightly more than three minutes until their separation. Then, the rocket was accelerated by its first stage alone for about 15 seconds, and shortly after, this stage was also released. Afterwards, the mission was relying on the second stage and its four engines.

The launch vehicle continued its flight towards orbit until it detached from the optional Yuanzheng-1 (YZ-1) upper stage. The mission entered its final phase that included a series of four tests burns of YZ-1 and orbital injection of the capsule and satellites. However, due to very little information was released by the Chinese media about the mission profile, the exact time of the payload separation is uncertain. According to various speculations by Western analysts, the flight lasted slightly more than 10 minutes, counting from liftoff to orbital insertion.

The re-entry capsule is expected to land in a remote area in Inner Mongolia on June 26, between 3:00 a.m. and 4:00 a.m. EDT (7:00 and 8:00 GMT ). This scaled-down model of a re-entry capsule will test the descent capabilities for future crewed flights.

The rocket was delivered to the Wenchang Satellite Launch Center in May 2016, where it was assembled. Next, the booster underwent a set of initial checkouts to fully prepare it for its rollout to the launch pad that took place on June 22.

The Long March 7 rocket is a 174.2-foot (53.1-meter) tall two-stage launch vehicle. It was developed by the China Academy of Launch Vehicle Technology (CALT) and is based on the Long March 2F rocket. The nearly 600-metric-ton launch vehicle is 11 feet (3.35 meters) in diameter and is capable of lifting up to 13.5 metric tons to a low-Earth orbit (LEO) and about 5.5 metric tons to a Sun-synchronous orbit (SSO). 



The rocket is fitted with four strap-on boosters powered by YF-100 engines. The boosters are attached to the first stage of the launch vehicle which is 11 feet (3.35 meters) in diameter and is equipped with two YF-100 engines. The second stage has the same diameter as the first stage; however, it is powered by different propulsion units – a set of four YF-115 engines. The YZ-1 upper stage is optional and is capable of delivering payload into variety of orbits.

The rocket would be used to transport cargo for China’s planned space station and is expected to become the main launcher for future space missions. China also hopes that its new Long March 7 rocket will be more environment-friendly than previous launchers in the series. The new booster relies on liquid oxygen and kerosene as fuel, cheaper and less dangerous than the propellants used by some of the earlier launch vehicles.

Long March 7 is designed to be more weather-resistant than its predecessors. The booster is waterproof and can be launched on rainy days. Moreover, the rocket is equipped with wind-resistance devices allowing it to withstand gales during its flight into space.

The capsule that launched on Saturday’s mission, features a Global Navigation Satellite System (GNSS) antenna, parachutes, and an antenna specially designed to prevent radio silence during hypersonic re-entry. The spacecraft is being designed with the aim to serve as a future transportation system for cargo and crews to LEO and beyond, including possible missions to the Moon.

According to various media reports, the mission also carries a CubeSat, a block of ballast and two other small satellites named ADRV and BPV.

The launch marks the first liftoff from the Wenchang Satellite Launch Center constructed in November 2014. The center was selected for its low latitude, which will allow for a substantial increase in payload, necessary for the future manned programs. Due to its proximity to the equator, it can save fuel consumption during space launches. 

The launch site, thanks to its location on an island, enables easy transportation of the large rocket components by ship and ensures that rocket debris descending from the sky falls into the ocean instead of over populated inland areas.

However, according to Liu Xiaohua, a senior engineer at the Wenchang center, this location records more than 100 days of thunderstorms annually. Because of this, four 105-meter steel lightning conductors were installed to protect the site from this threat. They surround each launch pad and are effective against nearly all thunderstorms. Moreover, a special anti-corrosion cover is used on metal surfaces at the center, to protect against moist and salty environment.

The launch was open for the public. Up to 25,000 spectators were able to view it in person for the first time in the history of Chinese orbital launches. For this occasion, the government designated eight viewing areas.

The maiden flight of Long March 7 was the eighth orbital mission for China this year. It was also the 230th launch of the Long March rocket series. The country’s next mission is currently scheduled for July 2016 when a Long March 2D booster is slated to send the QUantum Experiments at Space Scale (QUESS) technology demonstrator into orbit from the Jiuquan Satellite Launch Center in Gansu Province. However, the exact date of the launch is yet to be announced.

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