Chinese TV broadcasting satellite launched on 300th Long March rocket

A Chinese television broadcasting satellite lifted off Saturday aboard a Long March 3B booster, the 300th orbital launch by the country’s Long March rocket family since 1970.

The Long March 3B rocket climbed away from the Xichang space center at 1628 GMT (11:28 a.m. EST) Saturday, and headed east from the inland spaceport located in a hilly region of southwestern China’s Sichuan province. Liftoff occurred at 12:28 a.m. Beijing time Sunday.

The rocket jettisoned four hydrazine-fueled boosters and its core stage less around two-and-a-half minutes into the mission, followed by engine firings by the Long March 3B’s second stage and a cryogenic hydrogen-fueled third stage. Around a half-hour after liftoff, the Long March 3B deployed the Chinasat 6C, or Zhongxing 6C, communications satellite in an elliptical geostationary transfer orbit.

Chinese officials declared the launch a success, and publicly-available tracking data provided by the U.S. military indicated the Chinasat 6C spacecraft was released in an orbit ranging in altitude between 120 miles (200 kilometers) and roughly 25,500 miles (41,000 kilometers), with an inclination of 24.6 degrees to the equator.

The Chinasat 6C satellite, based on the DFH-4 spacecraft design built by the China Academy of Space Technology, will use its own propulsion system to maneuver into a circular geostationary orbit more than 22,000 miles (nearly 36,000 kilometers) over the equator, entering service at a position at 130 degrees east longitude to provide television broadcast services for China Satcom.

The launch of Chinasat 6C marked the 300th orbital flight by a member of the Long March rocket family, which debuted April 24, 1970, when a Long March 1 rocket carried China’s first satellite into space. China has upgraded the Long March series, originally based on long-range missile technology, with new engines, strap-on boosters, and upper stages over the last five decades.

The Long March 3B rocket lifted off at 12:28 a.m. Beijing time Sunday with the Chinasat 6C satellite. Credit: Xinhua

The Long March 3 rocket first flew in 1984, and the Long March 3B model launched for the first time in 1996.

But the Long March 3B’s inaugural launch from Xichang ended in disaster when the rocket flew off course moments after liftoff and crashed into a nearby village. China’s state-run Xinhua news agency reported the accident killed six people, but some estimates put the death toll much higher.

China has launched several new Long March rocket designs, including the kerosene-fueled Long March 5, Long March 6 and Long March 7 launchers, and the solid-fueled Long March 11. The newest Long March rocket variants no longer consume toxic hydrazine and nitrogen tetroxide propellants, and the Long March 5 and 7 are based at a new spaceport on Hainan Island, allowing the launchers to fly over water, instead of land.

The Long March 5 is the heaviest rocket in China’s inventory, capable of hauling up to 25 metric tons (55,000 pounds) to low Earth orbit. China has launched two Long March 5 rockets to date, but the second flight in 2017 faltered before reaching orbit, following a successful inaugural launch in 2016.

China plans to launch the third Long March 5 rocket as soon as July, paving the way for the launch of the Chang’e 5 lunar sample return mission before the end of the year on the fourth Long March 5 mission.

Since the Long March 5’s failure in 2017, China’s Long March family has logged 50 consecutive successful launches, delivering navigation, communications and scientific missions to space. Long March rockets have launched 460 spacecraft since 1970, including more than 50 satellites from foreign owners, according to the China Academy of Launch Vehicle Technology, or CALT, China’s primary rocket-builder.

China’s launch rate has quickened in recent years. It took 37 years to accomplish the first 100 Long March launches, eight years for the second 100 flights, and four years for the third 100 missions.

The Chinasat 6C satellite. Credit: CAST

The Chinasat 6C satellite launched Saturday is designed for a 15-year mission, with 25 C-band transponders covering China, Southeast Asia, Australia and islands in the South Pacific, according to information released by CAST, the spacecraft’s manufacturer.

Chinasat 6C will broadcast television programming, and features “enhanced” anti-interference technology, such as beam and frequency switching, and the suppression of unauthorized uplinks to the satellite, CAST officials said.

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