October 20, 2017

China launches data relay satellite for future space station crews

A Long March 3C/G2 rocket lifted off with the fourth Tianlian 1 data relay satellite Tuesday. Credit: Xinhua
A Long March 3C/G2 rocket lifted off with the fourth Tianlian 1 data relay satellite Tuesday. Credit: Xinhua

China added a fourth craft Tuesday to a network of geostationary data relay satellites tasked with keeping mission control in steady contact with Shenzhou crew capsules and a planned space station.

The new satellite is the fourth in China’s Tianlian 1 series, joining data relay stations launched in 2008, 2011 and 2012.

A Long March 3C/G2 rocket blasted off with the Tianlian 1-04 satellite at 1524 GMT (10:24 a.m. EST) Tuesday, heading east from the Xichang launch center in Sichuan province in southwest China, according to China’s state-run Xinhua news agency.

The launch occurred at 11:24 p.m. Beijing time.

The 18-story rocket dropped its two strap-on boosters, each powered by a hydrazine-fueled engine, just after the two-minute point in the flight, and the Long March 3C’s first stage shut down and jettisoned moments later.

A hydrazine-fueled second stage and hydrogen-fueled third stage propelled the Tianlian 1-04 satellite into a “supersynchronous” transfer orbit with a peak altitude of nearly 26,000 miles (42,000 kilometers), a low point around 120 miles (about 200 kilometers) above Earth, and an inclination of 17.4 degrees, according to publicly-available U.S. military tracking data.

The spacecraft will conduct maneuvers in the coming days and weeks to circularize its orbit nearly 22,300 miles (nearly 35,800 kilometers) over the equator, where its velocity will match the rate of Earth’s rotation. That allows the satellite to stay over the same part of Earth at all times.

Developed by the China Academy of Space Technology, the fourth Tianlian 1 satellite will join its counterparts to “achieve global network operation,” Xinhua reported.

“The network is expected to provide data relay, measurement and control services for China’s manned spacecraft, space labs and space stations, according to the (Xichang) center,” Xinhua said. “The network will also offer data relay services for the country’s medium- and low-Earth orbiting resources satellites, as well as measurement and control support for spacecraft launches.”

The Tianlian satellites are similar in function to NASA’s Tracking and Data Relay Satellites.

Tuesday’s launch came less than five days after two astronauts wrapped up a month-long mission aboard China’s Tiangong 2 space lab, returning to Earth inside the Shenzhou 11 spacecraft to a parachute-assisted landing on the remote plains of the country’s Inner Mongolia territory.

Chinese engineers are testing the country’s first robotic supply ship, named Tianzhou 1, for a launch in April 2017 to dock with the Tiangong 2 module in orbit. The unpiloted Tianzhou 1 spacecraft will attempt to demonstrate refueling procedures in space, a capability needed for China’s future space station.

The core module of the next-generation space station could launch as soon as 2018, with at least two science research modules to be added by 2022 to support crew stays lasting up to six months.

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