China science, technology news summary -- Nov. 20

BEIJING, Nov. 20 (Xinhua) -- The following is a summary of published science and technology news of China.

DEORBITING SAIL

Hundreds of millions of items of human-made debris are continually circling Earth. Keen to tackle the space-junk problem, Chinese scientists have managed to use a large "sail" to de-orbit spacecraft at the end of their life.

The de-orbiter is a sail-like device made of a thin f