December 18, 2017

Chinese broadcasting satellite ends up in wrong orbit after rocket failure

File photo of a previous Long March 3B launch. Credit: Xinhua

Ground controllers could try to salvage a Chinese television broadcasting satellite deployed in a lower-than-planned orbit Sunday by a Long March 3B rocket.

A brief statement from the China Aerospace Science and Technology Corp., a state-run contractor for China’s space program, confirmed an anomaly in the Long March 3B rocket’s third stage left the Chinasat 9A communications satellite in the wrong orbit following a liftoff from the Xichang space center.

An investigation into the cause of the launch failure is underway, CASC said.

The contractor said the Chinasat 9A satellite separated from the Long March 3B’s third stage after the anomaly and deployed its electricity-generating solar panels and antennas. The spacecraft is apparently healthy and in contact with engineers on the ground, who are taking “relevant efforts” to control the satellite, according to CASC.

Officials did not elaborate on what went wrong on the Long March 3B’s third stage, which is powered by a dual-nozzle YF-75 engine that burns a mixture of liquid hydrogen and liquid oxygen propellants.

Sunday’s launch mishap was the first time one of China’s Long March 3-series rockets has failed to deliver a payload into its intended orbit since August 2009. Variants of the Long March 3 rocket, which include configurations with and without strap-on boosters, logged 49 straight successful launches in the last seven-and-a-half years.

China’s other Long March rockets, which use the same engine technology as the Long March 3-series, have suffered failures in recent years. A Chinese Earth observation satellite was destroyed during the botched launch of a Long March 4C booster Sept. 1, and a Long March 2D placed a pair of commercial Earth-imaging spacecraft into a lower-than-intended orbit in December, but those satellites recovered from the rocket mishap.

A diagram of China’s Long March 3 family of rockets. The Long March 3B, center, features four strap-on boosters. Credit: China Great Wall Industry Corp.

U.S. military tracking data indicated Chinasat 9A is orbiting around Earth at altitudes ranging between 120 miles (193 kilometers) and approximately 10,165 miles (16,360 kilometers), significantly lower than intended.

The rocket’s upper stage aimed to release Chinasat 9A in an egg-shaped elliptical orbit with an apogee, or high point, around 35,800 kilometers (22,300 miles) above Earth.

Chinasat 9A carried its own fuel to circularize its orbit more than 22,000 miles over the equator following its deployment from the Long March 3B. If the satellite is able to overcome the altitude deficit after Sunday’s launch, it will have to consume more of its on-board propellant supply than expected, likely shortening its useful life.

In addition to the orbit-raising maneuvers needed to reach its final operating position, Chinasat 9A must also reshape its orbit, which is currently tilted 25.7 degrees to the equator, into one that always hovers over the equator.

The 184-foot-tall (56-meter) Long March 3B rocket lifted off with Chinasat 9A at 1611 GMT (12:11 p.m. EDT) Sunday from the Xichang launch base in southwestern China’s Sichuan province.

The liquid-fueled launcher, comprised of a three-stage core and four strap-on boosters, turned east from Xichang after blasting off at 12:11 a.m. Monday, Beijing time.

Chinese media did not release any photos of the launch, but an amateur video from Xichang shared on Twitter shows the rocket taking off just after midnight.

The early portion of the mission went according to plan, and the Long March shed its four boosters and first stage a few minutes after liftoff. A second stage firing also apparently performed well, and the third stage took over nearly six minutes into the flight for the first of two burns needed to place Chinasat 9A into a geostationary transfer orbit.

The third stage’s first engine firing was expected to cut off around 10 minutes after liftoff to propel Chinasat 9A into a preliminary low-altitude orbit, and a second burn a few minutes later was supposed to send the spacecraft toward its high-altitude target.

Chinasat 9A, with a launch mass estimated in excess of 11,000 pounds (5 metric tons), was scheduled to separate from the Long March 3B’s third stage less than a half-hour after liftoff.

Based on the DFH-4 satellite design built by the China Academy of Space Technology, Chinasat 9A is China’s first domestically-made communications satellite for direct-to-home television broadcasting, according to China Satcom, the craft’s owner and operator.

Chinasat 9A was supposed to enter service later this year in geostationary orbit over the equator at 101.4 degree east longitude, where its orbital velocity would match the speed of Earth’s rotation, making the satellite remain fixed over the same geographic coverage area.

The satellite’s 24 Ku-band transponders are designed to provide television broadcasts and other media services to China Satcom customers in China, Hong Kong, Macau and Taiwan, the company said.

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