The write stuff: Astronaut's pen catches internet's attention

China's Shenzhou XIV spaceship launched into space on Sunday, with the three astronauts aboard tasked with completing construction on the country's first space station.

As people across the country watched the launch closely, an ink pen drifting in the crew cabin caught the attention of many.

In video footage sent back from the spaceship, astronaut Cai Xuzhe was seen letting go of the pen to watch it twirl and float in the cabin.

The pen was produced by Shaoguan Shengyi Stationery Co Ltd in Guangdong province, which is a pioneer in making pens used in outer space.

"The space pen's core, ink and structure are all different from a common pen," said company representative Guo Yi.

The structure of a common pen can neither withstand the impact and vibration experienced by the spacecraft cabin during rocket launch nor write properly in a zero-gravity environment, Guo said.

The pen has a core made using special alloys and a built-in self-pressurizing device to enable writing in low gravity.

The ink within the pen is also composed of liquid with high viscosity, making writing stick to surfaces tightly instead of flying off as hazardous droplets.

In addition, the head of the pen is less sharp than a normal pen's to avoid puncturing astronauts' spacesuits or other valuable equipment.

A space pen developed by the company was sent into space aboard the Shenzhen X spacecraft in 2013, making China the second country in the world, after the United States, able to independently produce a pen usable in space.