China conducts surprise launch of second Shijian-16 satellite
Without any prior notice, China carried out a secretive liftoff of its Long March 4B booster carrying the Shijian-16 No.2 satellite. The rocket blasted off at exactly 11:21 a.m. local time (03:21 GMT) on Wednesday, June 29, from Launch Site 43 at the Jiuquan Satellite Launch Center, located in China’s northwest Gansu Province.
Very little is known about this mission and the only indication of a potential launch came in the form of navigational warnings. According to these pre-launch alerts, the rocket was to fly on an unusual trajectory, toward the southeast, aiming for a low-Earth orbit (LEO) inclined at 75 degrees.
NORAD reports issued after the launch confirmed the satellite reached LEO with a perigee of 370 miles (595 kilometers) and an apogee of 383 miles (616 kilometers).
China insisted the Shijian-16 satellite will be used for conducting spatial environment detection and technological experiments. However, due to its secretive nature and unusual orbit, it is believed the spacecraft could also be employed for military purposes.
The first Shijian-16 satellite was put into space in October 2013. The program dates back to 1971 when the first Shijian spacecraft was launched.
Over the years, Shijian satellites were delivered into a variety of orbits to fulfill various assignments, including testing electric propulsion, checking thermal control or monitoring, and tracking space debris.
The three-stage Long March 4B carrier rocket employed for Wednesday’s launch was designed to deliver satellites into LEO and Sun-synchronous orbits (SSO). The 150-foot (46-meter) tall launch vehicle has been in service for more than 16 years and has conducted 28 missions. Only one of them ended unsuccessfully.
With a liftoff mass of 249 metric tons, the Long March 4B booster is capable of delivering up to 4.2 metric tons to LEO, 2.8 metric tons to SSO, or 1.5 metric tons to a geostationary transfer orbit (GTO).
The rocket’s first stage is 91.5 feet (28 meters) long and 11 feet (3.35 meters) in diameter. It is powered by four YF-20B engines. The second stage, 35 feet (11 meters) long and 11 feet (3.35 meters) in diameter, is equipped with one YF-22C main engine and four YF-23C vernier engines.
The 49-foot (15-meter) long third stage measures 9.5 feet (2.9 meters) in diameter and is powered by two YF-40 engines.
Wednesday’s liftoff was the 231st mission for the Long March family of launch vehicles. This mission was also the second flight of a Long March 4B this year and the third liftoff overall from the Jiuquan Satellite Launch Center in 2016. It was China’s third orbital flight this month and so far the country has launched nine missions this year—all of them successful.
The next Chinese mission is currently scheduled for July when a Long March 2D booster is slated to send the QUantum Experiments at Space Scale (QUESS) technology demonstrator into orbit, also from Jiuquan. However, the exact date of the launch has yet to be announced.
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