A rocket booster from a Chinese Long March launch of a commercial communications satellite landed near houses in Guizhou Province, southwest China, last week.

A Long March 3B carrier rocket lifted off from Xichang Satellite Launch Centre in Sichuan Province at 00:06 local time on May 4 (16:06 UTC May 3), successfully placing the Apstar-6C satellite into a geostationary transfer orbit.

However, footage from the morning following the launch shows the mangled wreckage of a liquid propellant rocket booster in a field near houses in Heba Town in Shiqian County.

The boosters separate from the rocket core after use, falling to Earth while the rocket continues its attempt to reach orbital speeds.

As well as the threat of falling debris, the highly toxic hypergolic propellant - unsymmetrical dimethylhydrazine fuel and dinitrogen tetroxide oxidiser - would be hazardous to those nearby.

Spent rocket components falling to land are common in China, which has three inland launch sites at Jiuquan, Taiyuan and Xichang, with only one coastal site - Wenchang - which opened in 2016 and has hosted just four missions.

To prevent injuries and deaths, China releases notices and in some instances evacuates areas within the carefully calculated drop zones ahead of launch. However, footage of falling and recently landed rocket stages taken by locals suggests that some ignore the orders or the rocket debris falls outside of expected zones.

In February this year a spent booster landed atop a building in Guangxi, while a flaming booster was found in Tiandeng county of the same region in January. In 2015, a rocket engine found its way into a man's kitchen.

Security concerns, rocket reusability

China's first three launch sites were established during the times of deep security concern during the Cold War, with tensions with the Soviet Union spilling over into border skirmishes and the United States considering preemptive strikes against China on sites linked to nuclear weapon launch capabilities.

This sees launches drop spent rocket stages and payload fairings over land downrange from the launch sites, in both remote regions and near populated areas.

This year, China is aiming to carry out around 40 launches, including 17 from Xichang, many of which will see Long March 3B boosters drop in Guangxi and Guizhou.

Such incidents do not take place in the United States or Europe, which launch from the coast or from French Guiana, seeing rockets mostly fly over the Atlantic.

China recently stated that it is developing reusable rockets, with first stages and boosters being landed, recovered and reused following powered descent or parachute landing. Despite the apparent success of SpaceX in landing and reusing Falcon 9 rocket first stages, some level of scepticism remains in China as to the cost reduction of the vertical takeoff, vertical landing and relaunching approach.

China will also attempt its first sea launch this year, as well as other methods to control landings and mitigate its rocket debris problem.

Quelle: gbtimes