China launches latest Land Surveying Satellite into space
A Long March 2D rocket took to the skies March 17, 2018, sending China’s fourth Land Surveying Satellite into orbit. The booster roared skyward at 3:10 a.m. EDT (07:10 GMT) from the Jiuquan Satellite Launch Center in China’s Gansu Province.
Given that the task of the mission was to deliver the satellite into a low-Earth orbit (LEO), the flight most likely lasted for about 10 minutes. The exact timeline of the mission remains undisclosed as China usually does not reveal any details about its orbital launches, including pre-launch preparations.
Sticking to the nominal flight profile, the Long March 2D’s first stage should have powered the mission for about three minutes. During this phase, the rocket started heading South over mainland China and toward the South China Sea. When the first stage’s fuel was depleted, it separated and fell away from the second stage, which took control over the mission when its YF-24C cluster engine ignited.
The second stage, tasked with deploying the spacecraft into the designated orbit, should have finished its job some 10 minutes after liftoff before deploying the satellite in LEO. However, details regarding its orbital parameters remain unknown to the public.
Land Surveying Satellite-4 (also known as LKW-4, Ludikancha Weixing-4 or Yaogan Weixing-34) was built by the China Academy of Space Technology (CAST). It is believed to be an electro-optical observation satellite based on the military Jianbing-6 series. The spacecraft most likely utilizes uses the CAST-2000 bus, which has a dry mass of about one metric ton.
The first Yaogan satellite was launched in 2006, whereas the second generation of the series was inaugurated in 2008. LKW-4’s predecessors, designated LKW-1, LKW-2 and LKW-3, were orbited by China on Dec. 3, 2017, Dec. 23, 2017, and Jan. 13, 2018, respectively. All four LKW spacecraft will probably operate from an altitude of about 310 miles (500 kilometers).
As was the case with previous three LKW satellites, China claims that LKW-4 will be used for civilian purposes. The state-run Xinhua press agency insists that it is a land-exploration satellite and therefore will be mainly used for remote sensing exploration of land resources.
The two-stage Long March 2D rocket was developed by the Shanghai Academy of Spaceflight Technology. It is used to launch a variety of satellites into LEO. The 135-foot (41.15-meter) tall booster can launch payloads of up to 3.5 metric tons to LEO and up to 1.3 metric tons into a Sun-synchronous orbit.
The Long March 2D was launched for the first time on Aug. 9, 1992, from the Jiuquan Satellite Launch Center. It orbited the Fanhui Shei Weixing FSW-2-1 recoverable satellite. The March 17, 2018, launch was the 268th flight of the Long March rocket series.
China’s next orbital mission is currently scheduled to take place on March 26 when a Long March 3B booster will send two BeiDou-3 satellites into space. However, some other mission could be launched sooner as many of the country’s orbital flights are unannounced.
The launch of LKW-2 on Dec. 23, 2017. Video courtesy of CCTV+
Tomasz Nowakowski is the owner of Astro Watch, one of the premier astronomy and science-related blogs on the internet. Nowakowski reached out to SpaceFlight Insider in an effort to have the two space-related websites collaborate. Nowakowski's generous offer was gratefully received with the two organizations now working to better relay important developments as they pertain to space exploration.